@article{schreck iii_easterling_barsugli_coates_hoell_johnson_kunkel_labe_uehling_vose_et al._2024, title={A rapid response process for evaluating causes of extreme temperature events in the United States: The 2023 Texas/Louisiana heat wave as a prototype}, volume={3}, ISSN={["2752-5295"]}, DOI={10.1088/2752-5295/ad8028}, abstractNote={Abstract As climate attribution studies have become more common, routine processes are now being established for attribution analysis following extreme events. This study describes the prototype process being developed through a collaboration across NOAA, including monitoring tools as well as observational and model-based analysis of causal factors. The prolonged period of extreme heat in summer 2023 over Texas, Louisiana and adjacent areas provided a proving ground for this emerging capability. This event posed unique challenges to the initial process. The extreme heat lasted for most of the summer while most heat wave metrics have been designed for 3–7 day events. The eastern portion of the affected area also occurred within the so-called summer-time daytime warming hole where the warming trend in maximum temperatures has been mitigated wholly or in part by increased precipitation. The extreme temperature coincided with a strong—but not record—precipitation deficit over the region. Both observations and climate model simulations illustrate that the temperatures for a given precipitation deficit have warmed in recent decades. In other words, meteorological droughts today are hotter than their historical analogs providing a stronger attribution to anthropogenic forcing than for temperature alone. These findings were summarized in a prototype plain language report that was distributed to key stakeholders. Based on their feedback, the monitoring and assessment tools will continue to be refined, and the project is exploring other climate model large ensembles to increase the robustness of attribution for future events.
}, number={4}, journal={ENVIRONMENTAL RESEARCH-CLIMATE}, author={Schreck III, Carl J. and Easterling, David R. and Barsugli, Joseph J. and Coates, David A. and Hoell, Andrew and Johnson, Nathaniel C. and Kunkel, Kenneth E. and Labe, Zachary M. and Uehling, John and Vose, Russell S. and et al.}, year={2024}, month={Dec} }
 @article{uehling_schreck iii_2024, title={Observed Changes in Extreme Precipitation Associated with US Tropical Cyclones}, volume={37}, ISSN={["1520-0442"]}, DOI={10.1175/JCLI-D-23-0327.1}, abstractNote={Abstract Numerous recent tropical cyclones have caused extreme rainfall and flooding events in the CONUS. Climate change is contributing to heavier extreme rainfall around the world. Modeling studies have suggested that tropical cyclones may be particularly efficient engines for transferring the additional water vapor in the atmosphere into extreme rainfall. This paper develops a new indicator for climate change using the enhanced rainfall metric to evaluate how the frequency and/or intensity of extreme rainfall around tropical cyclones has changed. The enhanced rainfall metric relates the amount of rain from a storm over a given location to the 5-yr return period rainfall in that location to determine the severity of the event. The annual area exposed to tropical-cyclone-related 5-yr rainfall events is increasing, which makes it a compelling climate change indicator. Quantile regression illustrates that the distribution of tropical cyclone rainfall is also changing. For tropical storms, all quantiles are increasing. However, major hurricanes show large increases in their most extreme rainfall. This study does not attempt to make any detection claims (vs natural variability) or attribution of the observed trends to anthropogenic forcing. However, the sensitivity of the results to natural variability in tropical cyclone frequency was somewhat constrained by comparing 2 decades from the previous active era (1951–70) with two from the current era (2001–20). This comparison also shows that both the mean rainfall and the maximum rainfall associated with tropical cyclones are increasing over most areas of the eastern CONUS with the most significant increases from northern Alabama to the southern Appalachians. Significance Statement The purpose of this study is to analyze the changes in frequency and magnitude of extreme precipitation events associated with tropical cyclones with the goal of developing a new indicator for climate change. This is important because heavy rainfall and associated flooding is one of the primary causes of tropical cyclone destruction and fatalities, especially in inland locations away from where storms initially make landfall. Our results show that both the frequency and magnitude of extreme rainfall events from tropical cyclones have increased over the CONUS. The strongest storms (major hurricanes) also show more of an increase in extreme rainfall than storms of weaker intensities.}, number={14}, journal={JOURNAL OF CLIMATE}, author={Uehling, John and Schreck III, Carl J.}, year={2024}, month={Jul} }
 @article{klotzbach_jones_wood_bell_blake_bowen_caron_chavas_collins_gibney_et al._2024, title={The 2023 Atlantic Hurricane Season: An Above-Normal Season despite Strong El Nino Conditions}, volume={105}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-23-0305.1}, abstractNote={Abstract The 2023 Atlantic hurricane season was above normal, producing 20 named storms, 7 hurricanes, 3 major hurricanes, and seasonal accumulated cyclone energy that exceeded the 1991–2020 average. Hurricane Idalia was the most damaging hurricane of the year, making landfall as a Category 3 hurricane in Florida, resulting in eight direct fatalities and 3.6 billion U.S. dollars in damage. The above-normal 2023 hurricane season occurred during a strong El Niño event. El Niño events tend to be associated with increased vertical wind shear across the Caribbean and tropical Atlantic, yet vertical wind shear during the peak hurricane season months of August–October was well below normal. The primary driver of the above-normal season was likely record warm tropical Atlantic sea surface temperatures (SSTs), which effectively counteracted some of the canonical impacts of El Niño. The extremely warm tropical Atlantic and Caribbean were associated with weaker-than-normal trade winds driven by an anomalously weak subtropical ridge, resulting in a positive wind–evaporation–SST feedback. We tested atmospheric circulation sensitivity to SSTs in both the tropical and subtropical Pacific and the Atlantic using the atmospheric component of the Community Earth System Model, version 2.3. We found that the extremely warm Atlantic was the primary driver of the reduced vertical wind shear relative to other moderate/strong El Niño events. The concentrated warmth in the eastern tropical Pacific in August–October may have contributed to increased levels of vertical wind shear than if the warming had been more evenly spread across the eastern and central tropical Pacific.}, number={9}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Klotzbach, Philip J. and Jones, Jhordanne J. and Wood, Kimberly M. and Bell, Michael M. and Blake, Eric S. and Bowen, Steven G. and Caron, Louis-Philippe and Chavas, Daniel R. and Collins, Jennifer M. and Gibney, Ethan J. and et al.}, year={2024}, month={Sep}, pages={e1644–e1661} }
 @article{schreck iii_vitart_camargo_camp_darlow_elsberry_gottschalck_gregory_hansen_jackson_et al._2023, title={Advances in tropical cyclone prediction on subseasonal time scales during 2019-2022}, volume={12}, ISSN={["2225-6032"]}, DOI={10.1016/j.tcrr.2023.06.004}, abstractNote={This review describes advances in understanding and forecasting tropical cyclone (TC) subseasonal variability during the past four years. A large effort by the scientific community has been in understanding the sources of predictability at subseasonal timescales beyond the well-known modulation of TC activity by the Madden-Julian Oscillation (MJO). In particular, the strong modulation of TC activity over the western North Pacific by the Boreal Summer Intra-Seasonal Oscillation (BSISO) has been documented. Progress has also been realized in understanding the role of tropical-extratropical interactions in improving subseasonal forecasts. In addition, several recent publications have shown that extratropical wave breaking may have a role in the genesis and development of TCs. Analyses of multi-model ensemble data sets such as the Subseasonal to Seasonal (S2S) and Subseasonal Experiment (SubX) have shown that the skill of S2S models in predicting the genesis of TCs varies strongly among models and regions but is often tied to their ability to simulate the MJO and its impacts. The skill in select models has led to an increase over the past four years in the number of forecasting centers issuing subseasonal TC forecasts using various techniques (statistical, statistical-dynamical and dynamical). More extensive verification studies have been published over the last four years, but often only for the North Atlantic and eastern North Pacific.}, number={2}, journal={TROPICAL CYCLONE RESEARCH AND REVIEW}, author={Schreck III, Carl J. and Vitart, Frederic and Camargo, Suzana J. and Camp, Joanne and Darlow, James and Elsberry, Russell and Gottschalck, Jon and Gregory, Paul and Hansen, Kurt and Jackson, Justyn and et al.}, year={2023}, month={Jun}, pages={136–150} }
 @article{klotzbach_schreck iii_compo_wood_oliver_bowen_bell_2023, title={Influence of the Madden-Julian Oscillation on Continental United States Hurricane Landfalls}, volume={50}, ISSN={["1944-8007"]}, DOI={10.1029/2023GL102762}, abstractNote={Abstract The Madden‐Julian oscillation (MJO) significantly impacts North Atlantic hurricanes, with increased hurricane activity occurring when the MJO enhances convection over Africa and the tropical Indian Ocean and suppressed hurricane activity occurring when the MJO enhances convection over the tropical Pacific. Using data from 1905 to 2015, we find more tropical cyclones (TCs) make landfall in the continental United States when the MJO enhances tropical Indian Ocean convection. In addition, when the MJO enhances Western Pacific and Western Hemisphere convection, TC activity is preferentially favored in the Caribbean, leading to more Gulf Coast landfalls. As MJO‐enhanced convection moves to the Indian Ocean and Maritime Continent, more storms form in the tropical Atlantic, favoring Florida Peninsula and East Coast landfalls. The MJO's TC steering wind modulation appears to be secondary to its genesis location modulation.}, number={7}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Klotzbach, Philip J. and Schreck III, Carl J. J. and Compo, Gilbert P. and Wood, Kimberly M. and Oliver, Eric C. J. and Bowen, Steven G. and Bell, Michael M.}, year={2023}, month={Apr} }
 @article{aiyyer_schreck_2023, title={Surface Wind Speeds and Enthalpy Fluxes During Tropical Cyclone Formation From Easterly Waves: A CYGNSS View}, volume={50}, ISSN={["1944-8007"]}, url={https://doi.org/10.1029/2022GL100823}, DOI={10.1029/2022GL100823}, abstractNote={Abstract We examined the Cyclone Global Navigation Satellite System (CYGNSS) retrievals of surface wind speeds and enthalpy fluxes in African easterly waves that led to the formation of 30 Atlantic tropical cyclones during 2018–2021. Lag composites show a cyclonic proto‐vortex as early as 3 days prior to tropical cyclogenesis. The enthalpy flux distribution does not vary substantially before cyclogenesis, but subsequently, there is a marked increase in the extreme upper values. In the composites, a negative radial gradient of enthalpy fluxes becomes apparent 2–3 days before cyclogenesis. These results—based on novel data blending satellite retrievals and global reanalysis—support the findings from recent studies that the spin‐up of tropical cyclones is associated with a shift of peak convection toward the vortex core and an inward increase of enthalpy fluxes.}, number={6}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Aiyyer, Anantha and Schreck, Carl}, year={2023}, month={Mar} }
 @article{diamond_schreck_2023, title={THE TROPICS}, volume={104}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-23-0078.1}, abstractNote={© 2023 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). Corresponding author: Howard J. Diamond / howard.diamond@noaa.gov}, number={9}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Diamond, H. J. and Schreck, C. J.}, year={2023}, month={Sep}, pages={S207–S270} }
 @article{klotzbach_wood_bell_blake_bowen_caron_collins_gibney_schreck_truchelut_2022, title={A Hyperactive End to the Atlantic Hurricane Season October-November 2020}, volume={103}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-20-0312.1}, abstractNote={Abstract The active 2020 Atlantic hurricane season produced 30 named storms, 14 hurricanes, and 7 major hurricanes (category 3+ on the Saffir–Simpson hurricane wind scale). Though the season was active overall, the final two months (October–November) raised 2020 into the upper echelon of Atlantic hurricane activity for integrated metrics such as accumulated cyclone energy (ACE). This study focuses on October–November 2020, when 7 named storms, 6 hurricanes, and 5 major hurricanes formed and produced ACE of 74 × 10 4 kt 2 (1 kt ≈ 0.51 m s −1 ). Since 1950, October–November 2020 ranks tied for third for named storms, first for hurricanes and major hurricanes, and second for ACE. Six named storms also underwent rapid intensification (≥30 kt intensification in ≤24 h) in October–November 2020—the most on record. This manuscript includes a climatological analysis of October–November tropical cyclones (TCs) and their primary formation regions. In 2020, anomalously low wind shear in the western Caribbean and Gulf of Mexico, likely driven by a moderate-intensity La Niña event and anomalously high sea surface temperatures (SSTs) in the Caribbean, provided dynamic and thermodynamic conditions that were much more conducive than normal for late-season TC formation and rapid intensification. This study also highlights October–November 2020 landfalls, including Hurricanes Delta and Zeta in Louisiana and in Mexico and Hurricanes Eta and Iota in Nicaragua. The active late season in the Caribbean would have been anticipated by a statistical model using the July–September-averaged ENSO longitude index and Atlantic warm pool SSTs as predictors.}, number={1}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Klotzbach, Philip J. and Wood, Kimberly M. and Bell, Michael M. and Blake, Eric S. and Bowen, Steven G. and Caron, Louis-Philippe and Collins, Jennifer M. and Gibney, Ethan J. and Schreck, Carl J., III and Truchelut, Ryan E.}, year={2022}, month={Jan}, pages={E110–E128} }
 @article{shi_schreck iii_john_chung_lang_buehler_soden_2022, title={Assessing the consistency of satellite-derived upper tropospheric humidity measurements}, volume={15}, ISSN={["1867-8548"]}, DOI={10.5194/amt-15-6949-2022}, abstractNote={Abstract. Four upper tropospheric humidity (UTH) datasets derived from satellite sounders are evaluated to assess their consistency as part of the activities for the Global Energy and Water Exchanges (GEWEX) water vapor assessment project. The datasets include UTH computed from brightness temperature measurements of the 183.31±1 GHz channel of the Special Sensor Microwave – Humidity (SSM/T-2), Advanced Microwave Sounding Unit-B (AMSU-B), and Microwave Humidity Sounder (MHS) and from channel 12 of the High-resolution Infrared Radiation Sounder (HIRS). The four datasets are generally consistent in the interannual temporal and spatial variability of the tropics. Large positive anomalies peaked over the central equatorial Pacific region during El Niño events in the same phase with the increase of sea surface temperature (SST). Conversely, large negative anomalies were obtained during El Niño events when the tropical-domain average is taken. The weakened ascending branch of the Pacific Walker circulation in the western Pacific and the enhanced descending branches of the local Hadley circulation along the Pacific subtropics largely contributed to widespread drying areas and thus negative anomalies in the upper troposphere during El Niño events as shown in all four datasets. During a major El Niño event, UTH had higher correlations with the coincident precipitation (0.60 to 0.75) and with 200 hPa velocity potential (−0.42 to −0.64) than with SST (0.37 to 0.49). Due to differences in retrieval definitions and gridding procedures, there can be a difference of 3 %–5 % UTH between datasets on average, and larger magnitudes of anomaly values are usually observed in spatial maps of microwave UTH data. Nevertheless, the tropical-domain averaged anomalies of the datasets are close to each other with their differences being mostly less than 0.5 %, and more importantly the phases of the time series are generally consistent for variability studies.}, number={23}, journal={ATMOSPHERIC MEASUREMENT TECHNIQUES}, author={Shi, Lei and Schreck III, Carl J. J. and John, Viju O. and Chung, Eui-Seok and Lang, Theresa and Buehler, Stefan A. and Soden, Brian J.}, year={2022}, month={Dec}, pages={6949–6963} }
 @article{klotzbach_chavas_bell_bowen_gibney_schreck_2022, title={Characterizing Continental US Hurricane Risk: Which Intensity Metric Is Best?}, volume={127}, ISSN={["2169-8996"]}, DOI={10.1029/2022JD037030}, abstractNote={Abstract The damage potential of a hurricane is widely considered to depend more strongly on an integrated measure of the hurricane wind field, such as integrated kinetic energy (IKE), than a point‐based wind measure, such as maximum sustained wind speed ( V max ). Recent work has demonstrated that minimum sea level pressure (MSLP) is also an integrated measure of the wind field. This study investigates how well historical continental US hurricane damage is predicted by MSLP compared to both V max and IKE for continental United States hurricane landfalls for the period 1988–2021. We first show for the entire North Atlantic basin that MSLP is much better correlated with IKE ( r rank = 0.50) than V max ( r rank = 0.26). We then show that continental US hurricane normalized damage is better predicted by MSLP ( r rank = 0.83) than either V max ( r rank = 0.67) or IKE ( r rank = 0.65). For Georgia to Maine hurricane landfalls specifically, MSLP and IKE show similar levels of skill at predicting damage, whereas V max provides effectively no predictive power. Conclusions for IKE extend to power dissipation as well, as the two quantities are highly correlated because wind radii closely follow a Modified Rankine vortex. The physical relationship of MSLP to IKE and power dissipation is discussed. In addition to better representing damage, MSLP is also much easier to measure via aircraft or surface observations than either V max or IKE, and it is already routinely estimated operationally. We conclude that MSLP is an ideal metric for characterizing hurricane damage risk.}, number={18}, journal={JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES}, author={Klotzbach, Philip J. and Chavas, Daniel R. and Bell, Michael M. and Bowen, Steven G. and Gibney, Ethan J. and Schreck, Carl J., III}, year={2022}, month={Sep} }
 @article{durre_arguez_schreck iii_squires_vose_2022, title={Daily High-Resolution Temperature and Precipitation Fields for the Contiguous United States from 1951 to Present}, volume={39}, ISSN={["1520-0426"]}, DOI={10.1175/JTECH-D-22-0024.1}, abstractNote={Abstract In this paper, a new set of daily gridded fields and area averages of temperature and precipitation is introduced that covers the contiguous United States (CONUS) from 1951 to present. With daily updates and a grid resolution of approximately 0.0417° (nominally 5 km), the product, named nClimGrid-Daily, is designed to be used particularly in climate monitoring and other applications that rely on placing event-specific meteorological patterns into a long-term historical context. The gridded fields were generated by interpolating morning and midnight observations from the Global Historical Climatology Network–Daily dataset using thin-plate smoothing splines. Additional processing steps limit the adverse effects of spatial and temporal variations in station density, observation time, and other factors on the quality and homogeneity of the fields. The resulting gridded data provide smoothed representations of the point observations, although the accuracy of estimates for individual grid points and days can be sensitive to local spatial variability and the ability of the available observations and interpolation technique to capture that variability. The nClimGrid-Daily dataset is therefore recommended for applications that require the aggregation of estimates in space and/or time, such as climate monitoring analyses at regional to national scales. Significance Statement Many applications that use historical weather observations require data on a high-resolution grid that are updated daily. Here, a new dataset of daily temperature and precipitation for 1951–present is introduced that was created by interpolating irregularly spaced observations to a regular grid with a spacing of 0.0417° across the contiguous United States. Compared to other such datasets, this product is particularly suitable for monitoring climate and drought on a daily basis because it was processed so as to limit artificial variations in space and time that may result from changes in the types and distribution of observations used.}, number={12}, journal={JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY}, author={Durre, Imke and Arguez, Anthony and Schreck III, Carl J. and Squires, Michael F. and Vose, Russell S.}, year={2022}, month={Dec}, pages={1837–1855} }
 @article{barsugli_easterling_arndt_coates_delworth_hoerling_johnson_kapnick_kumar_kunkel_et al._2022, title={Development of a Rapid Response Capability to Evaluate Causes of Extreme Temperature and Drought Events in the United States}, volume={103}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-21-0237.1}, abstractNote={© 2022 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). CORRESPONDING AUTHOR: Joseph J. Barsugli, joseph.barsugli@colorado.edu A supplement to this article is available online (10.1175/BAMS-D-21-0237.2)}, number={3}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Barsugli, Joseph J. and Easterling, David R. and Arndt, Derek S. and Coates, David A. and Delworth, Thomas L. and Hoerling, Martin P. and Johnson, Nathaniel and Kapnick, Sarah B. and Kumar, Arun and Kunkel, Kenneth E. and et al.}, year={2022}, month={Mar}, pages={S14–S20} }
 @article{truchelut_klotzbach_staehling_wood_halperin_schreck_blake_2022, title={Earlier onset of North Atlantic hurricane season with warming oceans}, volume={13}, ISSN={["2041-1723"]}, DOI={10.1038/s41467-022-31821-3}, abstractNote={Numerous Atlantic basin tropical cyclones have recently developed prior to the official start of hurricane season, including several pre-season landfalls in the continental United States. Pre-season and early-season tropical cyclones disproportionately affect populated landmasses, often producing outsized precipitation impacts. Here we show a significant trend towards earlier onset of tropical cyclone activity in the North Atlantic basin, with threshold dates of the first three percentiles of accumulated cyclone energy shifting earlier at a rate exceeding five days decade-1 since 1979, even correcting for biases in climatology due to increased detection of short-lived storms. Initial threshold dates of continental United States named storm landfalls have trended earlier by two days decade-1 since 1900. The trend towards additional pre-season and early-season activity is linked to spring thermodynamic conditions becoming more conducive for tropical cyclone formation. Genesis potential index value increases in the western Atlantic basin are primarily driven by warming ocean temperatures.}, number={1}, journal={NATURE COMMUNICATIONS}, author={Truchelut, Ryan E. and Klotzbach, Philip J. and Staehling, Erica M. and Wood, Kimberly M. and Halperin, Daniel J. and Schreck, Carl J. and Blake, Eric S.}, year={2022}, month={Aug} }
 @article{zhu_collins_klotzbach_schreck_2022, title={Hurricane Ida (2021): Rapid Intensification Followed by Slow Inland Decay}, volume={103}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-21-0240.1}, abstractNote={Abstract Hurricane Ida recently became one of the strongest hurricanes to hit Louisiana on record, with an estimated landfalling maximum sustained wind of 130 kt (1 kt ≈ 0.51 m s −1 ). Although Hurricane Ida made landfall at a similar time of year and landfall location as Hurricane Katrina (2005), Ida’s postlandfall decay rate was much weaker than Hurricane Katrina. This manuscript includes a comparative analysis of pre- and postlandfall synoptic conditions for Hurricane Ida and other historical major landfalling hurricanes (category 3+ on the Saffir–Simpson hurricane wind scale) along the Gulf Coast since 1983, with a particular focus on Hurricane Katrina. Abundant precipitation in southeastern Louisiana prior to Ida’s landfall increased soil moisture. This increased soil moisture along with extremely weak overland steering flow likely slowed the storm’s weakening rate postlandfall. Offshore environmental factors also played an important role, particularly anomalously high nearshore sea surface temperatures and weak vertical wind shear that fueled the rapid intensification of Ida just before landfall. Strong nearshore vertical wind shear weakened Hurricane Katrina before landfall, and moderate northward steering flow caused Katrina to move inland relatively quickly, aiding in its relatively fast weakening rate following landfall. The results of this study improve our understanding of critical factors influencing the evolution of the nearshore intensity of major landfalling hurricanes in the Gulf of Mexico. This study can help facilitate forecasting and preparation for inland hazards resulting from landfalling hurricanes with nearshore intensification and weak postlandfall decay.}, number={10}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Zhu, Yi-Jie and Collins, Jennifer M. and Klotzbach, Philip J. and Schreck, Carl J.}, year={2022}, month={Oct}, pages={E2354–E2369} }
 @article{lawton_majumdar_dotterer_thorncroft_schreck iii_2022, title={The Influence of Convectively Coupled Kelvin Waves on African Easterly Waves in a Wave-Following Framework}, volume={150}, ISSN={["1520-0493"]}, DOI={10.1175/MWR-D-21-0321.1}, abstractNote={Abstract While considerable attention has been given to how convectively coupled Kelvin waves (CCKWs) influence the genesis of tropical cyclones (TCs) in the Atlantic Ocean, less attention has been given to their direct influence on African easterly waves (AEWs). This study builds a climatology of AEW and CCKW passages from 1981 to 2019 using an AEW-following framework. Vertical and horizontal composites of these passages are developed and divided into categories based on AEW position and CCKW strength. Many of the relationships that have previously been found for TC genesis also hold true for non-developing AEWs. This includes an increase in convective coverage surrounding the AEW center in phase with the convectively enhanced (“active”) CCKW crest, as well as a buildup of relative vorticity from the lower to upper troposphere following this active crest. Additionally, a new finding is that CCKWs induce specific humidity anomalies around AEWs that are qualitatively similar to those of relative vorticity. These modifications to specific humidity are more pronounced when AEWs are at lower latitudes and interacting with stronger CCKWs. While the influence of CCKWs on AEWs is mostly transient and short lived, CCKWs do modify the AEW propagation speed and westward-filtered relative vorticity, indicating that they may have some longer-term influences on the AEW life cycle. Overall, this analysis provides a more comprehensive view of the AEW–CCKW relationship than has previously been established, and supports assertions by previous studies that CCKW-associated convection, specific humidity, and vorticity may modify the favorability of AEWs to TC genesis over the Atlantic.}, number={8}, journal={MONTHLY WEATHER REVIEW}, author={Lawton, Quinton A. and Majumdar, Sharanya J. and Dotterer, Krista and Thorncroft, Christopher and Schreck III, Carl J.}, year={2022}, month={Aug}, pages={2055–2072} }
 @article{klotzbach_wood_schreck_bowen_patricola_bell_2022, title={Trends in Global Tropical Cyclone Activity: 1990-2021}, volume={49}, ISSN={["1944-8007"]}, DOI={10.1029/2021GL095774}, abstractNote={Abstract This study investigates global tropical cyclone (TC) activity trends from 1990 to 2021, a period marked by largely consistent observational platforms. Several global TC metrics have decreased during this period, with significant decreases in hurricane numbers and Accumulated Cyclone Energy (ACE). Most of this decrease has been driven by significant downward trends in the western North Pacific. Globally, short‐lived named storms, 24‐hr intensification events of ≥50 kt day −1 , and TC‐related damage have increased significantly. The increase in short‐lived named storms is likely due to technological improvements, while rapidly intensifying TC increases may be fueled by higher potential intensity. Damage increases are largely due to increased coastal assets. The significant decrease in hurricane numbers and global ACE are likely due to the trend toward a more La Niña‐like base state from 1990 to 2021, favoring North Atlantic TC activity and suppressing North and South Pacific TC activity.}, number={6}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Klotzbach, Philip J. and Wood, Kimberly M. and Schreck, Carl J., III and Bowen, Steven G. and Patricola, Christina M. and Bell, Michael M.}, year={2022}, month={Mar} }
 @article{mantripragada_schreck_aiyyer_2021, title={Energetics of Interactions between African Easterly Waves and Convectively Coupled Kelvin Waves}, volume={149}, ISSN={["1520-0493"]}, DOI={10.1175/MWR-D-21-0003.1}, abstractNote={Abstract Perturbation kinetic and available energy budgets are used to explore how convectively coupled equatorial Kelvin waves (KWs) impact African easterly wave (AEW) activity. The convective phase of the Kelvin wave increases the African easterly jet’s meridional shear, thus enhancing the barotropic energy conversions, leading to intensification of southern track AEWs perturbation kinetic energy. In contrast, the barotropic energy conversion is reduced in the suppressed phase of KW. Baroclinic energy conversion of the southern track AEWs is not significantly different between Kelvin waves’ convective and suppressed phases. AEWs in the convective phase of a Kelvin wave have stronger perturbation available potential energy generation by diabatic heating and stronger baroclinic overturning circulations than in the suppressed phase of a Kelvin wave. These differences suggest that southern track AEWs within the convective phase of Kelvin waves have more vigorous convection than in the suppressed phase of Kelvin waves. Barotropic energy conversion of the northern track AEWs is not significantly different between Kelvin waves’ convective and suppressed phases. The convective phase of the Kelvin wave increases the lower-tropospheric meridional temperature gradient north of the African easterly jet, thus enhancing the baroclinic energy conversion, leading to intensification of northern track AEWs perturbation kinetic energy. In contrast, the baroclinic energy conversion is reduced in the suppressed phase of KW. These results provide a physical basis for the modulation of AEWs by Kelvin waves arriving from upstream.}, number={11}, journal={MONTHLY WEATHER REVIEW}, author={Mantripragada, Rama Sesha Sridhar and Schreck, C. J., III and Aiyyer, Anantha}, year={2021}, month={Nov}, pages={3821–3835} }
 @article{schreck_2021, title={Global Survey of the MJO and Extreme Precipitation}, volume={48}, ISSN={["1944-8007"]}, DOI={10.1029/2021GL094691}, abstractNote={Abstract This study examines the modulation of land‐based extreme precipitation around the globe by the Madden‐Julian Oscillation (MJO). The upper‐level convergent phase of the MJO inhibits extreme events over most regions but enhancement in other phases falls in three categories. Over Brazil, Southeast Asia, and Australia, 2‐year rainfall events are most common near the core of the upper‐level divergence as expected. For most other regions in the tropics and subtropics, the extreme events occur along the periphery of the MJO's envelope. Previous regional studies suggest these extremes are driven by the MJO's low‐level circulation either advecting moisture or interacting with orography rather than directly increasing the vertical convection. Finally, extratropical extreme events are more likely associated with the MJO's impact on extratropical wave trains or tropical cyclones. Given the increasing skill of numerical models for predicting the MJO, these results could lead to subseasonal forecasts of extreme events.}, number={19}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Schreck, Carl J., III}, year={2021}, month={Oct} }
 @article{schreck_klotzbach_bell_2021, title={Optimal Climate Normals for the North Atlantic Hurricane Activity}, volume={48}, ISSN={["1944-8007"]}, DOI={10.1029/2021GL092864}, abstractNote={Abstract Most climatologies use 30‐year epochs that are updated at the start of each decade. They will shift from 1981–2010 to 1991–2020 in 2021. North Atlantic hurricane activity has large interdecadal variability that may lead to biases in a 30‐year climatology. A previous inactive hurricane period included 1981–1990, while 2011–2020 is a part of the ongoing active era. As a result, the 1991–2020 normals are more active than the 1981–2010 normals, with the median accumulated cyclone energy increasing by ∼40%. A 50‐year epoch would be more likely to capture a full cycle of multidecadal variability, and this study demonstrates that 50‐year climatologies have historically been better predictors of the subsequent decade's hurricane activity. This paper argues that the 1971–2020 climatology should, therefore, be the baseline for hurricane activity for the next decade with a possible adjustment for the non‐climatic increase in observed short‐lived tropical cyclones.}, number={9}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Schreck, Carl J., III and Klotzbach, Philip J. and Bell, Michael M.}, year={2021}, month={May} }
 @article{diamond_schreck_2021, title={THE TROPICS}, volume={102}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-21-0080.1}, number={8}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Diamond, H. J. and Schreck, C. J.}, year={2021}, month={Aug}, pages={S199–S261} }
 @article{klotzbach_schreck_compo_bowen_gibney_oliver_bell_2021, title={The Record-Breaking 1933 Atlantic Hurricane Season}, volume={102}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-19-0330.1}, abstractNote={Abstract The 1933 Atlantic hurricane season was extremely active, with 20 named storms and 11 hurricanes including 6 major (category 3+; 1-min maximum sustained winds ≥96 kt) hurricanes occurring. The 1933 hurricane season also generated the most accumulated cyclone energy (an integrated metric that accounts for frequency, intensity, and duration) of any Atlantic hurricane season on record. A total of 8 hurricanes tracked through the Caribbean in 1933—the most on record. In addition, two category 3 hurricanes made landfall in the United States just 23 h apart: the Treasure Coast hurricane in southeast Florida followed by the Cuba–Brownsville hurricane in south Texas. This manuscript examines large-scale atmospheric and oceanic conditions that likely led to such an active hurricane season. Extremely weak vertical wind shear was prevalent over both the Caribbean and the tropical Atlantic throughout the peak months of the hurricane season, likely in part due to a weak-to-moderate La Niña event. These favorable dynamic conditions, combined with above-normal tropical Atlantic sea surface temperatures, created a very conducive environment for hurricane formation and intensification. The Madden–Julian oscillation was relatively active during the summer and fall of 1933, providing subseasonal conditions that were quite favorable for tropical cyclogenesis during mid- to late August and late September to early October. The current early June and August statistical models used by Colorado State University would have predicted a very active 1933 hurricane season. A better understanding of these extremely active historical Atlantic hurricane seasons may aid in anticipation of future hyperactive seasons.}, number={3}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Klotzbach, Philip J. and Schreck, Carl J. and Compo, Gilbert P. and Bowen, Steven G. and Gibney, Ethan J. and Oliver, Eric C. J. and Bell, Michael M.}, year={2021}, month={Mar}, pages={E446–E463} }
 @article{saunders_klotzbach_lea_schreck_bell_2020, title={Quantifying the Probability and Causes of the Surprisingly Active 2018 North Atlantic Hurricane Season}, volume={7}, ISSN={["2333-5084"]}, DOI={10.1029/2019EA000852}, abstractNote={Abstract The 2018 North Atlantic hurricane season was a destructive season with hurricanes Florence and Michael causing significant damage in the southeastern United States. In keeping with most destructive hurricane seasons, basinwide tropical cyclone activity was above average in 2018—by ~25% for named storm numbers, hurricane numbers, and Accumulated Cyclone Energy (ACE). In contrast to this above‐normal activity, the August–September tropical environmental fields that explain ~50% of the variance in Atlantic basin hurricane activity between 1950 and 2017 anticipated a well below‐average 2018 hurricane season. The surprisingly large mismatch between the observed and replicated levels of hurricane activity in 2018 is an extreme example of the uncertainty inherent in seasonal hurricane outlooks and highlights the need for these outlooks to be issued in terms of probability of exceedance. Such probabilistic information would better clarify the uncertainty associated with hurricane outlooks to the benefit of users. With retrospective knowledge of the August–September 2018 key tropical environmental fields, the chance that the observed 2018 Atlantic hurricane activity would occur is about 5%. The reasons for the surprisingly high hurricane activity in 2018 are a hurricane outbreak in early September and, in particular, the occurrence of unusually high tropical cyclone activity in the subtropical North Atlantic. The hyperactive subtropical activity was not anticipated because contemporary statistical models of seasonal Atlantic hurricane activity lack skill in anticipating subtropical ACE compared to tropical ACE.}, number={3}, journal={EARTH AND SPACE SCIENCE}, author={Saunders, M. A. and Klotzbach, P. J. and Lea, A. S. R. and Schreck, C. J. and Bell, M. M.}, year={2020}, month={Mar} }
 @article{schreck_janiga_baxter_2020, title={Sources of Tropical Subseasonal Skill in the CFSv2}, volume={148}, ISSN={["1520-0493"]}, DOI={10.1175/MWR-D-19-0289.1}, abstractNote={Abstract This study applies Fourier filtering to a combination of rainfall estimates from TRMM and forecasts from the CFSv2. The combined data are filtered for low-frequency (LF, ≥120 days) variability, the MJO, and convectively coupled equatorial waves. The filtering provides insight into the sources of skill for the CFSv2. The LF filter, which encapsulates persistent anomalies generally corresponding with SSTs, has the largest contribution to forecast skill beyond week 2. Variability within the equatorial Pacific is dominated by its response to ENSO, such that both the unfiltered and the LF-filtered forecasts are skillful over the Pacific through the entire 45-day CFSv2 forecast. In fact, the LF forecasts in that region are more skillful than the unfiltered forecasts or any combination of the filters. Verifying filtered against unfiltered observations shows that subseasonal variability has very little opportunity to contribute to skill over the equatorial Pacific. Any subseasonal variability produced by the model is actually detracting from the skill there. The MJO primarily contributes to CFSv2 skill over the Indian Ocean, particularly during March–May and MJO phases 2–5. However, the model misses opportunities for the MJO to contribute to skill in other regions. Convectively coupled equatorial Rossby waves contribute to skill over the Indian Ocean during December–February and the Atlantic Ocean during September–November. Convectively coupled Kelvin waves show limited potential skill for predicting weekly averaged rainfall anomalies since they explain a relatively small percent of the observed variability.}, number={4}, journal={MONTHLY WEATHER REVIEW}, author={Schreck, Carl J., III and Janiga, Matthew A. and Baxter, Stephen}, year={2020}, month={Apr}, pages={1553–1565} }
 @article{klotzbach_bell_bowen_gibney_knapp_schreck_2020, title={Surface Pressure a More Skillful Predictor of Normalized Hurricane Damage than Maximum Sustained Wind}, volume={101}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-19-0062.1}, abstractNote={Abstract Atlantic hurricane seasons have a long history of causing significant financial impacts, with Harvey, Irma, Maria, Florence, and Michael combining to incur more than 345 billion USD in direct economic damage during 2017–2018. While Michael’s damage was primarily wind and storm surge-driven, Florence’s and Harvey’s damage was predominantly rainfall and inland flood-driven. Several revised scales have been proposed to replace the Saffir–Simpson Hurricane Wind Scale (SSHWS), which currently only categorizes the hurricane wind threat, while not explicitly handling the totality of storm impacts including storm surge and rainfall. However, most of these newly-proposed scales are not easily calculated in real-time, nor can they be reliably calculated historically. In particular, they depend on storm wind radii, which remain very uncertain. Herein, we analyze the relationship between normalized historical damage caused by continental United States (CONUS) landfalling hurricanes from 1900–2018 with both maximum sustained wind speed ( V max ) and minimum sea level pressure (MSLP). We show that MSLP is a more skillful predictor of normalized damage than V max , with a significantly higher rank correlation between normalized damage and MSLP ( r rank = 0.77) than between normalized damage and V max ( r rank = 0.66) for all CONUS landfalling hurricanes. MSLP has served as a much better predictor of hurricane damage in recent years than V max , with large hurricanes such as Ike (2008) and Sandy (2012) causing much more damage than anticipated from their SSHWS ranking. MSLP is also a more accurately-measured quantity than is V max , making it an ideal quantity for evaluating a hurricane’s potential damage.}, number={6}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Klotzbach, Philip J. and Bell, Michael M. and Bowen, Steven G. and Gibney, Ethan J. and Knapp, Kenneth R. and Schreck, Carl J., III}, year={2020}, month={Jun}, pages={E830–E846} }
 @article{mekonnen_schreck_enyew_2020, title={The Impact of Kelvin Wave Activity during Dry and Wet African Summer Rainfall Years}, volume={11}, ISSN={["2073-4433"]}, DOI={10.3390/atmos11060568}, abstractNote={This study highlights the influence of convectively coupled Kelvin wave (KW) activity on deep convection and African easterly waves (AEWs) over North Africa during dry and wet boreal summer rainfall years. Composite analysis based on 25 years of rainfall, satellite observed cold cloud temperature, and reanalysis data sets show that KWs are more frequent and stronger in dry Central African years compared with wet years. Deep convection associated with KWs is slightly more amplified in dry years compared with wet years. Further, KW activity over North Africa strengthens the lower level zonal flow and deepens the zonal moisture flux in dry years compared with wet years. Results also show that enhanced KW convection is in phase with above-average AEW variance in dry years. However, enhanced KW convection is out-of-phase with average AEW activity in wet years. In general, this study suggests that KW passage over Africa enhances convective activity and more strongly modulates the monsoon flow and moisture flux during the dry years than wet years.}, number={6}, journal={ATMOSPHERE}, author={Mekonnen, Ademe and Schreck, Carl J. and Enyew, Bantwale D.}, year={2020}, month={Jun} }
 @article{worku_mekonnen_schreck_2020, title={The Impact of MJO, Kelvin, and Equatorial Rossby Waves on the Diurnal Cycle over the Maritime Continent}, volume={11}, ISSN={["2073-4433"]}, DOI={10.3390/atmos11070711}, abstractNote={The impacts of the Madden–Julian Oscillation (MJO), Kelvin waves, and Equatorial Rossby (ER) waves on the diurnal cycle of rainfall and types of deep convection over the Maritime Continent are investigated using rainfall from the Tropical Rainfall Measurement Mission Multisatellite Precipitation Analysis and Infrared Weather States (IR–WS) data from the International Satellite Cloud Climatology Project. In an absolute sense, the MJO produced its strongest modulations of rainfall and organized deep convection over the islands, when and where convection is already strongest. The MJO actually has a greater percentage modulation over the coasts and seas, but it does not affect weaker diurnal cycle there. Isolated deep convection was also more prevalent over land during the suppressed phase, while organized deep convection dominated the enhanced phase, consistent with past work. This study uniquely examined the effects of Kelvin and ER waves on rainfall, convection, and their diurnal cycles over the Maritime Continent. The modulation of convection by Kelvin waves closely mirrored that by the MJO, although the Kelvin wave convection continued farther into the decreasing phase. The signals for ER waves were also similar but less distinct. An improved understanding of how these waves interact with convection could lead to improved subseasonal forecast skill.}, number={7}, journal={ATMOSPHERE}, author={Worku, Lakemariam Y. and Mekonnen, Ademe and Schreck, Carl J., III}, year={2020}, month={Jul} }
 @article{huang_menne_boyer_freeman_gleason_lawrimore_liu_rennie_schreck_sun_et al._2020, title={Uncertainty Estimates for Sea Surface Temperature and Land Surface Air Temperature in NOAAGlobalTemp Version 5}, volume={33}, ISSN={["1520-0442"]}, DOI={10.1175/JCLI-D-19-0395.1}, abstractNote={Abstract This analysis estimates uncertainty in the NOAA global surface temperature (GST) version 5 (NOAAGlobalTemp v5) product, which consists of sea surface temperature (SST) from the Extended Reconstructed SST version 5 (ERSSTv5) and land surface air temperature (LSAT) from the Global Historical Climatology Network monthly version 4 (GHCNm v4). Total uncertainty in SST and LSAT consists of parametric and reconstruction uncertainties. The parametric uncertainty represents the dependence of SST/LSAT reconstructions on selecting 28 (6) internal parameters of SST (LSAT), and is estimated by a 1000-member ensemble from 1854 to 2016. The reconstruction uncertainty represents the residual error of using a limited number of 140 (65) modes for SST (LSAT). Uncertainty is quantified at the global scale as well as the local grid scale. Uncertainties in SST and LSAT at the local grid scale are larger in the earlier period (1880s–1910s) and during the two world wars due to sparse observations, then decrease in the modern period (1950s–2010s) due to increased data coverage. Uncertainties in SST and LSAT at the global scale are much smaller than those at the local grid scale due to error cancellations by averaging. Uncertainties are smaller in SST than in LSAT due to smaller SST variabilities. Comparisons show that GST and its uncertainty in NOAAGlobalTemp v5 are comparable to those in other internationally recognized GST products. The differences between NOAAGlobalTemp v5 and other GST products are within their uncertainties at the 95% confidence level.}, number={4}, journal={JOURNAL OF CLIMATE}, author={Huang, Boyin and Menne, Matthew J. and Boyer, Tim and Freeman, Eric and Gleason, Byron E. and Lawrimore, Jay H. and Liu, Chunying and Rennie, J. Jared and Schreck, Carl J., III and Sun, Fengying and et al.}, year={2020}, month={Feb}, pages={1351–1379} }
 @article{worku_mekonnen_schreck_2019, title={Diurnal cycle of rainfall and convection over the Maritime Continent using TRMM and ISCCP}, volume={39}, ISSN={["1097-0088"]}, DOI={10.1002/joc.6121}, abstractNote={Abstract This study investigates the diurnal cycle of rainfall, convection, and precipitation features (PFs) over the Maritime Continent (MC). The study uses Tropical Rainfall Measuring Missions (TRMM) Multi‐satellite Precipitation Analysis (TMPA; product 3b42), TRMM PFs, and convective classifications from the International Satellite Cloud Climatology Project (ISCCP) data. Together, these satellites dataset paint a comprehensive picture of the diurnal cycle of rainfall and convection over the MC consistent with past research. Isolated convection initiates around midday over the higher terrain of the large islands (Java, Borneo, and Papua New Guinea). The convection becomes more organized through the afternoon and evening, leading to peak rainfall over the islands around 1800–2100 local standard time (LST). Over the next few hours, some of that rainfall transitions to stratiform rain over land. The convection then propagates offshore overnight with rainfall peaking along the coast around 0300–0600 LST and then over ocean around 0600–0900 LST. ISCCP data suggests that the overnight and early morning convection is more associated with isolated convective cells than the remnants of mesoscale convective systems. The coastal and oceanic diurnal ranges also seem to be larger in stratiform rainfall, in contrast to land where convective rainfall dominates. Seasonally the diurnal variation of rainfall, convection, and PFs over the region have greater amplitude during DJF (December, January, and February) than JJA (June, July, and August). Given the MC's critical role in the global climate, examining variations in these cycles with respect to the Madden–Julian Oscillation and equatorial waves may ultimately lead to improved subseasonal weather forecasts.}, number={13}, journal={INTERNATIONAL JOURNAL OF CLIMATOLOGY}, author={Worku, Lakemariam Y. and Mekonnen, Ademe and Schreck, Carl J., III}, year={2019}, month={Nov}, pages={5191–5200} }
 @article{arguez_inamdar_palecki_schreck_young_2019, title={ENSO Normals: A New US Climate Normals Product Conditioned by ENSO Phase and Intensity and Accounting for Secular Trends}, volume={58}, ISSN={["1558-8432"]}, DOI={10.1175/JAMC-D-18-0252.1}, abstractNote={Abstract Climate normals are traditionally calculated every decade as the average values over a period of time, often 30 years. Such an approach assumes a stationary climate, with several alternatives recently introduced to account for monotonic climate change. However, these methods fail to account for interannual climate variability [e.g., El Niño–Southern Oscillation (ENSO)] that systematically alters the background state of the climate similar to climate change. These effects and their uncertainties are well established, but they are not reflected in any readily available climate normals datasets. A new high-resolution set of normals is derived for the contiguous United States that accounts for ENSO and uses the optimal climate normal (OCN)—a 10-yr (15 yr) running average for temperature (precipitation)—to account for climate change. Anomalies are calculated by subtracting the running means and then compositing into 5 ENSO phase and intensity categories: Strong La Niña, Weak La Niña, Neutral, Weak El Niño, and Strong El Niño. Seasonal composites are produced for each of the five phases. The ENSO normals are the sum of these composites with the OCN for a given month. The result is five sets of normals, one for each phase, which users may consult with respect to anticipated ENSO outcomes. While well-established ENSO patterns are found in most cases, a distinct east–west temperature anomaly pattern emerges for Weak El Niño events. This new product can assist stakeholders in planning for a broad array of possible ENSO impacts in a changing climate.}, number={6}, journal={JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY}, author={Arguez, Anthony and Inamdar, Anand and Palecki, Michael A. and Schreck, Carl J. and Young, Alisa H.}, year={2019}, month={Jun}, pages={1381–1397} }
 @article{green_schreck_johnson_heath_2019, title={Education Backgrounds of TV Weathercasters}, volume={100}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-17-0047.1}, abstractNote={Abstract In the early days of television, most weathercasters lacked formal training in meteorology and instead relied on forecasts from other sources. Over the decades, degreed meteorologists became more common. A third category has recently emerged: people with certificates in broadcast meteorology from Mississippi State University (MSU). This certification and the related broadcast meteorology degrees from MSU provide weathercasters with an understanding of meteorology without advanced calculus or differential equations. This study makes no judgment on how a weathercaster’s education background might affect their on-air presentations but notes these courses are required by most guidelines for meteorological degrees, as well as the American Meteorological Society's Certified Broadcast Meteorologist (CBM) program. This study conducts a unique survey of television meteorologists using the education history listed on their station's website or LinkedIn. The backgrounds of 421 meteorologists were examined with the equivalent of a 94% response rate. Overall, 21% had a broadcast meteorology degree or certification from MSU, 64% had a traditional meteorology degree from MSU or another institution, 2% minored in meteorology or had military training, and 12% listed no or a partial education background in the field. Another way of viewing the data is that the MSU broadcast program alone has nearly as many graduates as the four largest traditional programs combined in our sample. These results were further broken down for various subsets of weathercasters, resulting in statistically significant variations by market size, region, ownership group, and gender.}, number={4}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Green, Thomas A., Jr. and Schreck, Carl J., III and Johnson, Nathan S. and Heath, Sonya Stevens}, year={2019}, month={Apr}, pages={581–588} }
 @article{stevens_schreck_saha_bell_kunkel_2019, title={Precipitation and Fatal Motor Vehicle Crashes: Continental Analysis with High-Resolution Radar Data}, volume={100}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-D-18-0001.1}, abstractNote={Precipitation, even at light intensity, contributes a significant risk of fatal motor vehicle crashes across the United States, at nearly all times of day, and in all seasons.}, number={8}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Stevens, Scott E. and Schreck, Carl J., III and Saha, Shubhayu and Bell, Jesse E. and Kunkel, Kenneth E.}, year={2019}, month={Aug}, pages={1453–1462} }
 @article{camargo_camp_elsberry_gregory_klotzbach_schreck_sobel_ventrice_vitart_wang_et al._2019, title={TROPICAL CYCLONE PREDICTION ON SUBSEASONAL TIME-SCALES}, volume={8}, ISSN={["2225-6032"]}, DOI={10.6057/2019TCRR03.04}, number={3}, journal={TROPICAL CYCLONE RESEARCH AND REVIEW}, author={Camargo, Suzana J. and Camp, Joanne and Elsberry, Russell L. and Gregory, Paul A. and Klotzbach, Philip J. and Schreck, Carl J., III and Sobel, Adam H. and Ventrice, Michael J. and Vitart, Frederic and Wang, Zhuo and et al.}, year={2019}, month={Sep}, pages={150–165} }
 @article{wood_klotzbach_collins_schreck_2019, title={The Record-Setting 2018 Eastern North Pacific Hurricane Season}, volume={46}, ISSN={["1944-8007"]}, DOI={10.1029/2019GL083657}, abstractNote={Abstract The extremely active 2018 eastern North Pacific (ENP) hurricane season set records for number of hurricane days, major hurricane days, and accumulated cyclone energy (ACE). The Western Development Region (116°W–180°) was especially active, shattering its prior record for ACE set in 2015. In addition, Hawaii was impacted by Hurricane Lane in August and Tropical Storm Olivia in September. Despite above‐normal sea surface temperatures (SSTs) and below‐normal vertical wind shear in 2018, large‐scale conditions were generally less conducive for tropical cyclone (TC) formation than in 2015. However, the strong subtropical ridge in August and September of 2018 enhanced westward steering flow, thereby keeping TCs over hurricane‐favorable conditions and preventing recurvature toward lower SSTs and higher vertical wind shear. The 2018 ENP hurricane season highlights that El Niño conditions are not necessary for extremely high ENP TC activity.}, number={16}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Wood, Kimberly M. and Klotzbach, Philip J. and Collins, Jennifer M. and Schreck, Carl J.}, year={2019}, month={Aug}, pages={10072–10081} }
 @misc{bell_brown_conlon_herring_kunkel_lawrimore_luber_schreck_smith_uejio_2018, title={Changes in extreme events and the potential impacts on human health}, volume={68}, ISSN={["2162-2906"]}, DOI={10.1080/10962247.2017.1401017}, abstractNote={Extreme weather and climate-related events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, dust storms, flooding rains, coastal flooding, storm surges, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local societal and environmental factors that affect disease burden. More information is needed about the impacts of climate change on public health and economies to effectively plan for and adapt to climate change. This paper describes some of the ways extreme events are changing and provides examples of the potential impacts on human health and infrastructure. It also identifies key research gaps to be addressed to improve the resilience of public health to extreme events in the future.}, number={4}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Bell, Jesse E. and Brown, Claudia Langford and Conlon, Kathryn and Herring, Stephanie and Kunkel, Kenneth E. and Lawrimore, Jay and Luber, George and Schreck, Carl and Smith, Adam and Uejio, Christopher}, year={2018}, pages={265–287} }
 @article{stott_christidis_herring_hoell_kossssin_schreck_2018, title={FUTURE CHALLENGES IN EVENT ATTRIBUTION METHODOLOGIES}, volume={99}, ISSN={["1520-0477"]}, DOI={10.1175/bams-d-17-0285.1}, abstractNote={© 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).}, number={1}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Stott, Peter A. and Christidis, Nikos and Herring, Stephananie C. and Hoell, Andrew and Kossssin, James P. and Schreck, Carl J., III}, year={2018}, month={Jan}, pages={S155–S157} }
 @article{herring_christidis_hoell_kossssin_schreck_stott_2018, title={INTRODUCTION TO EXPLAINING EXTREME EVENTS OF 2016 FROM A CLIMATE PERSPECTIVE}, volume={99}, ISSN={["1520-0477"]}, DOI={10.1175/bams-d-17-0284.1}, abstractNote={© 2018 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).}, number={1}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Herring, Stephanie C. and Christidis, Nikolaos and Hoell, Andrew and Kossssin, James P. and Schreck, Carl J., III and Stott, Peter A.}, year={2018}, month={Jan}, pages={S1–S6} }
 @article{semunegus_mekonnen_schreck_2017, title={Characterization of convective systems and their association with African easterly waves}, volume={37}, ISSN={["1097-0088"]}, DOI={10.1002/joc.5085}, abstractNote={ABSTRACT This study investigates the relationship between African easterly waves ( AEWs ) and different types of deep convection. It is known that AEWs impact the development of deep convection over tropical North Africa and tropical cyclone formation over the eastern Atlantic. However, the process of how AEWs interact with deep convection is not well understood. Composite analysis based on a 24‐year data set of cloud systems ( CS ) from the International Satellite Cloud Climate Project shows that the relationship changes with various types of convection over this region. This phase change relationship analysis may shed light into the dynamics of AEWs and improve the ability of forecasters to anticipate associated rainfall over the Sahel. Weak and disorganized convective systems ( WDCSs ; 50 km < radius < 100 km) are most common within the southerly phase of the AEWs over East Africa. Mesoscale convective systems ( MCSs ) with cloud radii >100 km increase in frequency within and to the west of the AEW ‐trough zone. MCSs are common features of summer in northwestern Africa. Our results indicate that the association between AEWs and deep convection is different and changes across North Africa. Weak AEWs over East Africa have a stronger relationship with WDCSs , while mature AEWs over West Africa have more MCS activity. This evolution suggests that the organization of convection from WDCS to MCS may play a critical role in AEW development. This hypothesis contrasts the traditional view that treats convection uniformly.}, number={12}, journal={INTERNATIONAL JOURNAL OF CLIMATOLOGY}, author={Semunegus, Hilawe and Mekonnen, Ademe and Schreck, Carl J., III}, year={2017}, month={Oct}, pages={4486–4492} }
 @article{schreck_2016, title={Convectively Coupled Kelvin Waves and Tropical Cyclogenesis in a Semi-Lagrangian Framework}, volume={144}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-16-0237.1}, abstractNote={Abstract This study examines how convectively coupled Kelvin waves interact with the semi-Lagrangian circulation of easterly waves to modulate tropical cyclogenesis. Recent studies have shown that fewer tropical cyclones form in the three days before passage of the Kelvin wave’s peak convection and more develop in the three days thereafter. Separately, other studies have identified the recirculation of moisture and vorticity within easterly waves using a semi-Lagrangian frame of reference. That framework is achieved by subtracting the easterly wave phase speed from the earth-relative winds. This study combines these recent findings by testing whether the equatorial westerlies from Kelvin waves can help close the semi-Lagrangian circulation. Past studies have shown that Kelvin waves tilt westward with height in the troposphere such that equatorial westerlies build upward from the surface in the days following the convective peak. This study shows that the easterly wave’s semi-Lagrangian closed circulation grows upward as it intersects the Kelvin wave’s westward tilt. The Kelvin wave’s westerly anomalies reach 500 hPa about three days after the convection has passed, which establishes the deep, vertically aligned easterly wave vortex necessary for tropical cyclogenesis. This study focuses on the eastern Pacific, but similar results are found for the North Atlantic. In other basins, the Kelvin wave accentuates the westerlies from the Madden–Julian oscillation and/or the monsoon trough. Given that Kelvin waves often last weeks and circumnavigate the globe, these results may advance long-range tropical cyclogenesis forecasting.}, number={11}, journal={MONTHLY WEATHER REVIEW}, author={Schreck, Carl J., III}, year={2016}, month={Nov}, pages={4131–4139} }
 @article{klotzbach_oliver_leeper_schreck_2016, title={The Relationship between the Madden-Julian Oscillation (MJO) and Southeastern New England Snowfall}, volume={144}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-15-0434.1}, abstractNote={Abstract The winter of 2014/15 brought record snow totals to portions of southeastern New England. Additionally, over 90% of Boston Logan Airport snowfall during the winter fell during phases 7 and 8 of the Madden–Julian oscillation (MJO) index. This motivated the authors to investigate potential connections between intense southeastern New England snowstorms and the MJO in the historical record. It was found that southeastern New England snowfall, measured since the 1930s at several stations in the region, recorded higher than average winter snowfalls when enhanced MJO convection was located over the western Pacific and the Western Hemisphere (phases 7–8). Similarly, snowfall was suppressed when enhanced MJO convection was located over the Maritime Continent (phases 4–5). The MJO also modulates the frequency of nor’easters, which contribute the majority of New England’s snowfall, as measured by reanalysis-derived cyclone tracks. These tracks were more numerous during the same MJO phases that lead to enhanced snowfall, and they were less common during phases with less snowfall.}, number={4}, journal={MONTHLY WEATHER REVIEW}, author={Klotzbach, Philip J. and Oliver, Eric C. J. and Leeper, Ronald D. and Schreck, Carl J., III}, year={2016}, month={Apr}, pages={1355–1362} }
 @article{hennon_knapp_schreck_stevens_kossin_thorne_hennon_kruk_rennie_gadea_et al._2015, title={Cyclone Center: Can Citizen Scientists Improve Tropical Cyclone Intensity Records?}, volume={96}, ISSN={["1520-0477"]}, DOI={10.1175/bams-d-13-00152.1}, abstractNote={Abstract The global tropical cyclone (TC) intensity record, even in modern times, is uncertain because the vast majority of storms are only observed remotely. Forecasters determine the maximum wind speed using a patchwork of sporadic observations and remotely sensed data. A popular tool that aids forecasters is the Dvorak technique—a procedural system that estimates the maximum wind based on cloud features in IR and/or visible satellite imagery. Inherently, the application of the Dvorak procedure is open to subjectivity. Heterogeneities are also introduced into the historical record with the evolution of operational procedures, personnel, and observing platforms. These uncertainties impede our ability to identify the relationship between tropical cyclone intensities and, for example, recent climate change. A global reanalysis of TC intensity using experts is difficult because of the large number of storms. We will show that it is possible to effectively reanalyze the global record using crowdsourcing. Through modifying the Dvorak technique into a series of simple questions that amateurs (“citizen scientists”) can answer on a website, we are working toward developing a new TC dataset that resolves intensity discrepancies in several recent TCs. Preliminary results suggest that the performance of human classifiers in some cases exceeds that of an automated Dvorak technique applied to the same data for times when the storm is transitioning into a hurricane.}, number={4}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Hennon, Christopher C. and Knapp, Kenneth R. and Schreck, Carl J., III and Stevens, Scott E. and Kossin, James P. and Thorne, Peter W. and Hennon, Paula A. and Kruk, Michael C. and Rennie, Jared and Gadea, Jean-Maurice and et al.}, year={2015}, month={Apr} }
 @article{schreck_2015, title={Kelvin Waves and Tropical Cyclogenesis: A Global Survey}, volume={143}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-15-0111.1}, abstractNote={Abstract Convectively coupled atmospheric Kelvin waves are among the most prominent sources of synoptic-scale rainfall variability in the tropics, but large uncertainties surround their role in tropical cyclogenesis. This study identifies the modulation of tropical cyclones relative to the passage of a Kelvin wave’s peak rainfall (i.e., its crest) in each basin. Tropical cyclogenesis is generally inhibited for 3 days before the crest and enhanced for 3 days afterward. Composites of storms forming in the most favorable lags illustrate the dynamical impacts of the waves. In most basins, the tropical cyclone actually forms during the convectively suppressed phase of the wave. The 850-hPa equatorial westerly anomalies provide the cyclonic vorticity for the nascent storm, and 200-hPa easterly anomalies enhance the outflow. The wind anomalies persist at both levels longer than the Kelvin wave’s period and are often related to the Madden–Julian oscillation (MJO). The onset of these wind anomalies occurs with the Kelvin wave passage, while the MJO apparently establishes their duration. Many of the composites also show evidence of an easterly wave from which the tropical cyclone develops. The composite easterly wave amplifies or even initiates within the Kelvin wave crest. These results show the importance of Kelvin waves interacting with the MJO and easterly waves during tropical cyclogenesis. Given that Kelvin waves often circumnavigate the globe, these results show promise for long-range forecasting of tropical cyclogenesis in all basins.}, number={10}, journal={MONTHLY WEATHER REVIEW}, author={Schreck, Carl J., III}, year={2015}, month={Oct}, pages={3996–4011} }
 @article{schreck_bennett_cordeira_crouch_dissen_lang_margolin_o'shay_rennie_schneider_et al._2015, title={NATURAL GAS PRICES AND THE EXTREME WINTERS OF 2011/12 AND 2013/14 Causes, Indicators, and Interactions}, volume={96}, ISSN={["1520-0477"]}, DOI={10.1175/bams-d-13-00237.1}, abstractNote={Abstract Day-to-day volatility in natural gas markets is driven largely by variability in heating demand, which is in turn dominated by cool-season temperature anomalies over the northeastern quadrant of the United States (“Midwest–East”). Energy traders rely on temperature forecasts at horizons of 2–4 weeks to anticipate those fluctuations in demand. Forecasts from dynamical models are widely available, so the markets react quickly to changes in the model predictions. Traders often work with meteorologists who leverage teleconnections from the tropics and the Arctic to improve upon the model forecasts. This study demonstrates how natural gas prices react to Midwest–East temperatures using the anomalous winters of 2011/12 and 2013/14. These examples also illustrate how energy meteorologists use teleconnections from the Arctic and the tropics to forecast heating demand. Winter 2011/12 was exceptionally warm, consistent with the positive Arctic Oscillation (AO). March 2012 was a fitting exclamation point on the winter as it featured the largest warm anomaly for the United States above the twentieth-century climatology of any month since 1895. The resulting lack of heating demand led to record surpluses of natural gas storage and spurred prices downward to an 11-yr low in April 2012. In sharp contrast, winter 2013/14 was unusually cold. An anomalous Alaskan ridge led to cold air being transported from Siberia into the United States, despite the AO generally being positive. The ensuing swell in heating demand exhausted the surplus natural gas inventory, and prices rose to their highest levels since the beginning of the global recession in 2008.}, number={11}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Schreck, Carl J., III and Bennett, Stephen and Cordeira, Jason M. and Crouch, Jake and Dissen, Jenny and Lang, Andrea L. and Margolin, David and O'Shay, Adam and Rennie, Jared and Schneider, Thomas Ian and et al.}, year={2015}, month={Nov}, pages={1879–1894} }
 @article{schreck_knapp_kossin_2014, title={The Impact of Best Track Discrepancies on Global Tropical Cyclone Climatologies using IBTrACS}, volume={142}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-14-00021.1}, abstractNote={Abstract Using the International Best Track Archive for Climate Stewardship (IBTrACS), the climatology of tropical cyclones is compared between two global best track datasets: 1) the World Meteorological Organization (WMO) subset of IBTrACS (IBTrACS-WMO) and 2) a combination of data from the National Hurricane Center and the Joint Typhoon Warning Center (NHC+JTWC). Comparing the climatologies between IBTrACS-WMO and NHC+JTWC highlights some of the heterogeneities inherent in these datasets for the period of global satellite coverage 1981–2010. The results demonstrate the sensitivity of these climatologies to the choice of best track dataset. Previous studies have examined best track heterogeneities in individual regions, usually the North Atlantic and west Pacific. This study puts those regional issues into their global context. The differences between NHC+JTWC and IBTrACS-WMO are greatest in the west Pacific, where the strongest storms are substantially weaker in IBTrACS-WMO. These disparities strongly affect the global measures of tropical cyclone activity because 30% of the world’s tropical cyclones form in the west Pacific. Because JTWC employs similar procedures throughout most of the globe, the comparisons in this study highlight differences between WMO agencies. For example, NHC+JTWC has more 96-kt (~49 m s−1) storms than IBTrACS-WMO in the west Pacific but fewer in the Australian region. This discrepancy probably points to differing operational procedures between the WMO agencies in the two regions. Without better documentation of historical analysis procedures, the only way to remedy these heterogeneities will be through systematic reanalysis.}, number={10}, journal={MONTHLY WEATHER REVIEW}, author={Schreck, Carl J., III and Knapp, Kenneth R. and Kossin, James P.}, year={2014}, month={Oct}, pages={3881–3899} }
 @article{ventrice_wheeler_hendon_schreck_thorncroft_kiladis_2013, title={A Modified Multivariate Madden-Julian Oscillation Index Using Velocity Potential}, volume={141}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-12-00327.1}, abstractNote={Abstract A new Madden–Julian oscillation (MJO) index is developed from a combined empirical orthogonal function (EOF) analysis of meridionally averaged 200-hPa velocity potential (VP200), 200-hPa zonal wind (U200), and 850-hPa zonal wind (U850). Like the Wheeler–Hendon Real-time Multivariate MJO (RMM) index, which was developed in the same way except using outgoing longwave radiation (OLR) data instead of VP200, daily data are projected onto the leading pair of EOFs to produce the two-component index. This new index is called the velocity potential MJO (VPM) indices and its properties are quantitatively compared to RMM. Compared to the RMM index, the VPM index detects larger-amplitude MJO-associated signals during boreal summer. This includes a slightly stronger and more coherent modulation of Atlantic tropical cyclones. This result is attributed to the fact that velocity potential preferentially emphasizes the planetary-scale aspects of the divergent circulation, thereby spreading the convectively driven component of the MJO’s signal across the entire globe. VP200 thus deemphasizes the convective signal of the MJO over the Indian Ocean warm pool, where the OLR variability associated with the MJO is concentrated, and enhances the signal over the relatively drier longitudes of the equatorial Pacific and Atlantic. This work provides a useful framework for systematic analysis of the strengths and weaknesses of different MJO indices.}, number={12}, journal={MONTHLY WEATHER REVIEW}, author={Ventrice, Michael J. and Wheeler, Matthew C. and Hendon, Harry H. and Schreck, Carl J., III and Thorncroft, Chris D. and Kiladis, George N.}, year={2013}, month={Dec}, pages={4197–4210} }
 @article{shi_schreck_john_2013, title={HIRS channel 12 brightness temperature dataset and its correlations with major climate indices}, volume={13}, ISSN={["1680-7316"]}, DOI={10.5194/acp-13-6907-2013}, abstractNote={Abstract. A new version of the High-Resolution Infrared Radiation Sounder (HIRS) upper tropospheric water vapor channel (channel 12) brightness temperature dataset is developed using intersatellite calibrated data. In this dataset, only those pixels affected by upper tropospheric clouds are discarded. Compared to the previous version that was based on column-clear-sky data, the new version has much better daily spatial coverage. The HIRS observation patterns are compared to microwave sounder measurements. The differences between the two types of sounders vary with respect to brightness temperature with larger differences for higher (dry) values. Correlations between the HIRS upper tropospheric water vapor channel brightness temperatures and several major climate indices show strong signals during cold seasons. The selected climate indices track climate variation signals covering regions from the tropics to the poles. Qualitatively, moist signals are correlated with troughs and ascending branches of the circulation, while dry signals occur with ridges and descent. These correlations show the potential of using the upper tropospheric water vapor channel brightness temperature dataset together with a suite of many atmospheric variables to monitor regional climate changes and locate global teleconnection patterns.}, number={14}, journal={ATMOSPHERIC CHEMISTRY AND PHYSICS}, author={Shi, L. and Schreck, C. J., III and John, V. O.}, year={2013}, pages={6907–6920} }
 @article{schreck_shi_kossin_bates_2013, title={Identifying the MJO, Equatorial Waves, and Their Impacts Using 32 Years of HIRS Upper-Tropospheric Water Vapor}, volume={26}, ISSN={["1520-0442"]}, DOI={10.1175/jcli-d-12-00034.1}, abstractNote={Abstract The Madden–Julian oscillation (MJO) and convectively coupled equatorial waves are the dominant modes of synoptic-to-subseasonal variability in the tropics. These systems have frequently been examined with proxies for convection such as outgoing longwave radiation (OLR). However, upper-tropospheric water vapor (UTWV) gives a more complete picture of tropical circulations because it is more sensitive to the drying and warming associated with subsidence. Previous studies examined tropical variability using relatively short (3–7 yr) UTWV datasets. Intersatellite calibration of data from the High Resolution Infrared Radiation Sounder (HIRS) has recently produced a homogeneous 32-yr climate data record of UTWV for 200–500 hPa. This study explores the utility of HIRS UTWV for identifying the MJO and equatorial waves. Spectral analysis shows that the MJO and equatorial waves stand out above the low-frequency background in UTWV, similar to previous findings with OLR. The fraction of variance associated with the MJO and equatorial Rossby waves is actually greater in UTWV than in OLR. Kelvin waves, on the other hand, are overshadowed in UTWV by horizontal advection from extratropical Rossby waves. For the MJO, UTWV identifies subsidence drying in the subtropics, poleward of the convection. These dry anomalies are associated with the MJO’s subtropical Rossby gyres. MJO events with dry anomalies over the central North Pacific Ocean also amplify the 200-hPa flow pattern over North America 7 days later. These events cannot be identified using equatorial OLR alone, which demonstrates that UTWV is a useful supplement for identifying the MJO, equatorial waves.}, number={4}, journal={JOURNAL OF CLIMATE}, author={Schreck, Carl J., III and Shi, Lei and Kossin, James P. and Bates, John J.}, year={2013}, month={Feb}, pages={1418–1431} }
 @article{gottschalck_roundy_schreck_vintzileos_zhang_2013, title={Large-Scale Atmospheric and Oceanic Conditions during the 2011-12 DYNAMO Field Campaign}, volume={141}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-13-00022.1}, abstractNote={Abstract An international field campaign, Dynamics of the Madden Julian Oscillation (DYNAMO), took place in the Indian Ocean during October 2011–March 2012 to collect observations for the Madden–Julian oscillation (MJO), especially its convective initiation processes. The large-scale atmospheric and oceanic conditions during the campaign are documented here. The ENSO and the Indian Ocean dipole (IOD) states, the monthly mean monsoon circulation and its associated precipitation, humidity, vertical and meridional/zonal overturning cells, and ocean surface currents are discussed. The evolution of MJO events is described using various fields and indices that have been used to subdivide the campaign into three periods. These periods were 1) 17 September–8 December 2011 (period 1), which featured two robust MJO events that circumnavigated the global tropics with a period of less than 45 days; 2) 9 December 2011–31 January 2012, which contained less coherent activity (period 2); and 3) 1 February–12 April 2012, a period that featured the strongest and most slowly propagating MJO event of the campaign (period 3). Activities of convectively coupled atmospheric Kelvin and equatorial Rossby (ER) waves and their interaction with the MJO are discussed. The overview of the atmospheric and oceanic variability during the field campaign raises several scientific issues pertaining to our understanding of the MJO, or lack thereof. Among others, roles of Kelvin and ER waves in MJO convective initiation, convection-circulation decoupling on the MJO scale, applications of MJO filtering methods and indices, and ocean–atmosphere coupling need further research attention.}, number={12}, journal={MONTHLY WEATHER REVIEW}, author={Gottschalck, Jon and Roundy, Paul E. and Schreck, Carl J., III and Vintzileos, Augustin and Zhang, Chidong}, year={2013}, month={Dec}, pages={4173–4196} }
 @article{schreck_cordeira_margolin_2013, title={Which MJO Events Affect North American Temperatures?}, volume={141}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-13-00118.1}, abstractNote={Abstract Tropical convection from the Madden–Julian oscillation (MJO) excites and amplifies extratropical Rossby waves around the globe. This forcing is reflected in teleconnection patterns like the Pacific–North American (PNA) pattern, and it can ultimately result in temperature anomalies over North America. Previous studies have not explored whether the extratropical response might vary from one MJO event to another. This study proposes a new index, the multivariate PNA (MVP), to identify variations in the extratropical waveguide over the North Pacific and North America that might affect the response to the MJO. The MVP is the first combined EOF of 20–100-day OLR, 850-hPa streamfunction, and 200-hPa streamfunction over the North Pacific and North America. The North American temperature patterns that follow each phase of the MJO change with the sign of the MVP. For example, real-time multivariate MJO (RMM) phase 5 usually leads to warm anomalies over eastern North America. This relationship was only found when the MVP was negative, and it was not associated with El Niño or La Niña. RMM phase 8, on the other hand, usually leads to cold anomalies. Those anomalies only occur if the MVP is positive, which happens somewhat more frequently during La Niña years. Composite analyses based on combinations of the MJO and the MVP show that variability in the Pacific jet and its associated wave breaking play a key role in determining whether and how the MJO affects North American temperatures.}, number={11}, journal={MONTHLY WEATHER REVIEW}, author={Schreck, Carl J., III and Cordeira, Jason M. and Margolin, David}, year={2013}, month={Nov}, pages={3840–3850} }
 @article{schreck_molinari_aiyyer_2012, title={A Global View of Equatorial Waves and Tropical Cyclogenesis}, volume={140}, ISSN={["0027-0644"]}, DOI={10.1175/mwr-d-11-00110.1}, abstractNote={Abstract This study investigates the number of tropical cyclone formations that can be attributed to the enhanced convection from equatorial waves within each basin. Tropical depression (TD)-type disturbances (i.e., easterly waves) were the primary tropical cyclone precursors over the Northern Hemisphere basins, particularly the eastern North Pacific and the Atlantic. In the Southern Hemisphere, however, the number of storms attributed to TD-type disturbances and equatorial Rossby waves were roughly equivalent. Equatorward of 20°N, tropical cyclones formed without any equatorial wave precursor most often over the eastern North Pacific and least often over the western North Pacific. The Madden–Julian oscillation (MJO) was an important tropical cyclone precursor over the north Indian, south Indian, and western North Pacific basins. The MJO also affected tropical cyclogenesis by modulating the amplitudes of higher-frequency waves. Each wave type reached the attribution threshold 1.5 times more often, and tropical cyclogenesis was 3 times more likely, within positive MJO-filtered rainfall anomalies than within negative anomalies. The greatest MJO modulation was observed for storms attributed to Kelvin waves over the north Indian Ocean. The large rainfall rates associated with tropical cyclones can alter equatorial wave–filtered anomalies. This study quantifies the contamination over each basin. Tropical cyclones contributed more than 20% of the filtered variance for each wave type over large potions of every basin except the South Pacific. The largest contamination, exceeding 60%, occurred for the TD band near the Philippines. To mitigate the contamination, the tropical cyclone–related anomalies were removed before filtering in this study.}, number={3}, journal={MONTHLY WEATHER REVIEW}, publisher={American Meteorological Society}, author={Schreck, Carl J., III and Molinari, John and Aiyyer, Anantha}, year={2012}, month={Mar}, pages={774–788} }
 @article{ventrice_thorncroft_schreck_2012, title={Impacts of Convectively Coupled Kelvin Waves on Environmental Conditions for Atlantic Tropical Cyclogenesis}, volume={140}, ISSN={["1520-0493"]}, DOI={10.1175/mwr-d-11-00305.1}, abstractNote={Abstract High-amplitude convectively coupled equatorial atmospheric Kelvin waves (CCKWs) are explored over the tropical Atlantic during the boreal summer (1989–2009). Focus is given to the atmospheric environmental conditions that are important for tropical cyclogenesis. CCKWs are characterized by deep westerly vertical wind shear to the east of its convectively active phase and easterly vertical wind shear to the west of it. This dynamical signature increases vertical wind shear over the western tropical Atlantic ahead of the convectively active phase, and reduces vertical wind shear after its passage. The opposite is true over the eastern tropical Atlantic where the climatological vertical wind shear is easterly. Positive total column water vapor (TCWV) anomalies progress eastward with the convectively active phase of the CCKW, whereas negative TCWV anomalies progress eastward with the convectively suppressed phase. During the passage of the convectively active phase of the CCKW, a zonally oriented strip of low-level cyclonic relative vorticity is generated over the tropical Atlantic. Two days later, this strip becomes more wavelike and moves back toward the west. This signature resembles a train of westward-moving easterly waves and suggests CCKWs may influence such events. Strong CCKWs over the tropical Atlantic tend to occur during the decay of the active convection associated with the Madden–Julian oscillation over the Pacific. This relationship could be used to provide better long-range forecasts of tropical convective patterns and Atlantic tropical cyclogenesis.}, number={7}, journal={MONTHLY WEATHER REVIEW}, author={Ventrice, Michael J. and Thorncroft, Christopher D. and Schreck, Carl J., III}, year={2012}, month={Jul}, pages={2198–2214} }
 @article{aiyyer_mekonnen_schreck_2012, title={Projection of Tropical Cyclones on Wavenumber-Frequency-Filtered Equatorial Waves}, volume={25}, ISSN={["0894-8755"]}, DOI={10.1175/jcli-d-11-00451.1}, abstractNote={Abstract The impact of localized convection associated with tropical cyclones (TCs) on activity ascribed to equatorial waves is estimated. An algorithm is used to remove outgoing longwave radiation (OLR) signal in the vicinity of observed tropical cyclones, and equatorial wave modes are extracted using the standard wavenumber–frequency decomposition method. The results suggest that climatological activity of convection-coupled equatorial waves is overestimated where TC tracks are densest. The greatest impact is found for equatorial Rossby (ER)- and tropical depression (TD)-type waves followed by the Madden–Julian oscillation (MJO). The basins most affected are the eastern and western North Pacific Ocean where, on average, TCs may contribute up to 10%–15% of the climatological wave amplitude variance in these modes. In contrast, Kelvin waves are least impacted by the projection of TCs. The results are likely relevant for studies on the climatology of equatorial waves in observations and global climate model simulations and for those examining individual cases of TC genesis modulated by equatorial wave activity.}, number={10}, journal={JOURNAL OF CLIMATE}, publisher={American Meteorological Society}, author={Aiyyer, Anantha and Mekonnen, Ademe and Schreck, Carl J., III}, year={2012}, month={May}, pages={3653–3658} }
 @article{schreck_molinari_mohr_2011, title={Attributing Tropical Cyclogenesis to Equatorial Waves in the Western North Pacific}, volume={68}, ISSN={["0022-4928"]}, DOI={10.1175/2010jas3396.1}, abstractNote={Abstract Tropical cyclogenesis is attributed to an equatorial wave when the filtered rainfall anomaly exceeds a threshold value at the genesis location. It is argued that 0 mm day−1 (simply requiring a positive anomaly) is too small a threshold because unrelated noise can produce a positive anomaly. A threshold of 6 mm day−1 is too large because two-thirds of storms would have no precursor disturbance. Between these extremes, consistent results are found for a range of thresholds from 2 to 4 mm day−1. Roughly twice as many tropical cyclones are attributed to tropical depression (TD)-type disturbances as to equatorial Rossby waves, mixed Rossby–gravity waves, or Kelvin waves. The influence of the Madden–Julian oscillation (MJO) is even smaller. The use of variables such as vorticity and vertical wind shear in other studies gives a larger contribution for the MJO. It is suggested that its direct influence on the rainfall in forming tropical cyclones is less than for other variables. The impacts of tropical cyclone–related precipitation anomalies are also presented. Tropical cyclones can contribute more than 20% of the warm-season rainfall and 50% of its total variance. The influence of tropical cyclones on the equatorial wave spectrum is generally small. The exception occurs in shorter-wavelength westward-propagating waves, for which tropical cyclones represent up to 27% of the variance. Tropical cyclones also significantly contaminate wave-filtered rainfall anomalies in their immediate vicinity. To mitigate this effect, the tropical cyclone–related anomalies were removed before filtering in this study.}, number={2}, journal={JOURNAL OF THE ATMOSPHERIC SCIENCES}, author={Schreck, Carl J., III and Molinari, John and Mohr, Karen I.}, year={2011}, month={Feb}, pages={195–209} }
 @article{schreck_molinari_2011, title={Tropical Cyclogenesis Associated with Kelvin Waves and the Madden-Julian Oscillation}, volume={139}, ISSN={["0027-0644"]}, DOI={10.1175/mwr-d-10-05060.1}, abstractNote={The Madden–Julian oscillation (MJO) influences tropical cyclone formation around the globe. Convectively coupled Kelvin waves are often embedded within the MJO, but their role in tropical cyclogenesis remains uncertain. This case study identifies the influences of the MJO and a series of Kelvin waves on the formation of two tropical cyclones. Typhoons Rammasun and Chataan developed in the western North Pacific on 28 June 2002. Two weeks earlier, conditions had been unfavorable for tropical cyclogenesis because of uniform trade easterlies and a lack of organized convection. The easterlies gave way to equatorial westerlies as the convective envelope of the Madden–Julian oscillation moved into the region. A series of three Kelvin waves modulated the development of the westerlies. Cyclonic potential vorticity (PV) developed in a strip between the growing equatorial westerlies and the persistent trade easterlies farther poleward. Rammasun and Chataan emerged from the apparent breakdown of this strip. The cyclonic PV developed in association with diabatic heating from both the MJO and the Kelvin waves. The tropical cyclones also developed during the largest superposition of equatorial westerlies from the MJO and the Kelvin waves. This chain of events suggests that the MJO and the Kelvin waves each played a role in the development of Rammasun and Chataan.}, number={9}, journal={MONTHLY WEATHER REVIEW}, author={Schreck, Carl J., III and Molinari, John}, year={2011}, month={Sep}, pages={2723–2734} }
 @article{schreck_semazzi_2004, title={Variability of the recent climate of eastern Africa}, volume={24}, ISSN={["1097-0088"]}, DOI={10.1002/joc.1019}, abstractNote={Abstract The primary objective of this study is to investigate the recent variability of the eastern African climate. The region of interest is also known as the Greater Horn of Africa (GHA), and comprises the countries of Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Somalia, Sudan, Uganda, and Tanzania. The analysis was based primarily on the construction of empirical orthogonal functions (EOFs) of gauge rainfall data and on CPC Merged Analysis of Precipitation (CMAP) data, derived from a combination of rain‐gauge observations and satellite estimates. The investigation is based on the period 1961–2001 for the ‘short rains’ season of eastern Africa of October through to December. The EOF analysis was supplemented by projection of National Centers for Environmental Prediction wind data onto the rainfall eigenmodes to understand the rainfall–circulation relationships. Furthermore, correlation and composite analyses have been performed with the Climatic Research Unit globally averaged surface‐temperature time series to explore the potential relationship between the climate of eastern Africa and global warming. The most dominant mode of variability (EOF1) based on CMAP data over eastern Africa corresponds to El Niño–southern oscillation (ENSO) climate variability. It is associated with above‐normal rainfall amounts during the short rains throughout the entire region, except for Sudan. The corresponding anomalous low‐level circulation is dominated by easterly inflow from the Indian Ocean, and to a lesser extent the Congo tropical rain forest, into the positive rainfall anomaly region that extends across most of eastern Africa. The easterly inflow into eastern Africa is part of diffluent outflow from the maritime continent during the warm ENSO events. The second eastern African EOF (trend mode) is associated with decadal variability. In distinct contrast from the ENSO mode pattern, the trend mode is characterized by positive rainfall anomalies over the northern sector of eastern Africa and opposite conditions over the southern sector. This rainfall trend mode eluded detection in previous studies that did not include recent decades of data, because the signal was still relatively weak. The wind projection onto this mode indicates that the primary flow that feeds the positive anomaly region over the northern part of eastern Africa emanates primarily from the rainfall‐deficient southern region of eastern Africa and Sudan. Although we do not assign attribution of the trend mode to global warming (in part because of the relatively short period of analysis), the evidence, based on our results and previous studies, strongly suggests a potential connection. Copyright © 2004 Royal Meteorological Society.}, number={6}, journal={INTERNATIONAL JOURNAL OF CLIMATOLOGY}, author={Schreck, CJ and Semazzi, FHM}, year={2004}, month={May}, pages={681–701} }