@article{holland_riordan_franklin_2006, title={A simple model for simulating tornado damage in forests}, volume={45}, ISSN={["1558-8424"]}, DOI={10.1175/JAM2413.1}, abstractNote={Abstract An analytical model is presented to describe patterns of downed trees produced by tornadic winds. The model uses a combined Rankine vortex of specified tangential and radial components to describe a simple tornado circulation. A total wind field is then computed by adding the forward motion of the vortex. The lateral and vertical forces on modeled tree stands are then computed and are compared with physical characteristics of Scots and loblolly pine. From this model, patterns of windfall are computed and are compared to reveal three basic damage patterns: cross-track symmetric, along-track asymmetric, and crisscross asymmetric. These patterns are shown to depend on forward speed, radial speed, and tree resistance. It is anticipated that this model will prove to be useful in assessing storm characteristics from damage patterns observed in forested areas.}, number={12}, journal={JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY}, author={Holland, Andrew P. and Riordan, Allen J. and Franklin, E. C.}, year={2006}, month={Dec}, pages={1597–1611} }
 @article{kaplan_charney_waight_lux_cetola_huffman_riordan_slusser_kiefer_suffern_et al._2006, title={Characterizing the severe turbulence environments associated with commercial aviation accidents. A real-time turbulence model (RTTM) designed for the operational prediction of hazardous aviation turbulence environments}, volume={94}, ISSN={["0177-7971"]}, DOI={10.1007/s00703-005-0181-4}, abstractNote={In this paper, we will focus on the real-time prediction of environments that are predisposed to producing moderate-severe (hazardous) aviation turbulence. We will describe the numerical model and its postprocessing system that is designed for said prediction of environments predisposed to severe aviation turbulence as well as presenting numerous examples of its utility. The purpose of this paper is to demonstrate that simple hydrostatic precursor circulations organize regions of preferred wave breaking and turbulence at the nonhydrostatic scales of motion. This will be demonstrated with a hydrostatic numerical modeling system, which can be run in real time on a very inexpensive university computer workstation employing simple forecast indices. The forecast system is designed to efficiently support forecasters who are directing research aircraft to measure the environment immediately surrounding turbulence. The numerical model is MASS version 5.13, which is integrated over three different grid matrices in real-time on a university workstation in support of NASA-Langley’s B-757 turbulence research flight missions. The model horizontal resolutions are 60, 30, and 15 km and the grids are centered over the region of operational NASA-Langley B-757 turbulence flight missions. The postprocessing system includes several turbulence-related products including four turbulence forecasting indices, winds, streamlines, turbulence kinetic energy, and Richardson numbers. Additionally there are convective products including precipitation, cloud height, cloud mass fluxes, lifted index, and K-index. Furthermore, soundings, sounding parameters, and Froude number plots are also provided. The horizontal cross section plot products are provided from 16,000–46,000 feet in 2,000 feet intervals. Products are available every three hours at the 60 and 30 km grid interval and every 1.5 hours at the 15 km grid interval. The model is initialized from the NWS ETA analyses and integrated two times a day.}, number={1-4}, journal={METEOROLOGY AND ATMOSPHERIC PHYSICS}, author={Kaplan, M. L. and Charney, J. J. and Waight, K. T., III and Lux, K. M. and Cetola, J. D. and Huffman, A. W. and Riordan, A. J. and Slusser, S. D. and Kiefer, M. T. and Suffern, P. S. and et al.}, year={2006}, month={Nov}, pages={235–270} }
 @article{appel_riordan_holley_2005, title={An objective climatology of Carolina coastal fronts}, volume={20}, ISSN={["1520-0434"]}, DOI={10.1175/waf869.1}, abstractNote={Abstract This study describes a simple objective method to identify cases of coastal frontogenesis offshore of the Carolinas and to characterize the sensible weather associated with frontal passage at measurement sites near the coast. The identification method, based on surface hourly data from offshore and adjacent land stations, was applied to an 11-yr dataset (1984–94). A total of 379 coastal fronts was found, 70 of which eventually made landfall along the North Carolina coast; 112 that remained offshore, and 197 were termed diurnal since they remained offshore but disappeared during daylight hours. Results show that most coastal and offshore sites experience a wind shift of about 40°–70° and a warming of about 2°–3°C during the hour of frontal passage. Exceptions include sites near colder waters where the rates are markedly reduced and frontal passage is often less discernible. Excluding diurnal fronts, just over half the cases were associated with cold-air damming (CAD) during the cold season of 16 October–15 April. Most of these winter cases linked with CAD were onshore fronts. During the warm season, most fronts were diurnal, but the association with CAD was still significant. To explore the synoptic-scale environment, composite maps for the cold season were generated for all three frontal subtypes from NCEP–NCAR reanalysis data. Results show a strong surface anticyclone centered north of the region of frontogenesis for all three composites. However, several features in the synoptic-scale regimes appear to differentiate the three frontal types. For example, cyclogenesis in the Gulf of Mexico and onshore southeasterly low-level flow along the southeast Atlantic coast accompanied by warm advection distinguish onshore fronts from the other two types. The offshore fronts are accompanied by more nearly zonal flow aloft and a surface anticyclone that stalls near the New England coastline. Finally, the diurnal type is associated with much weaker pressure and height fields and an east–west elongated surface anticyclone centered much farther south than in the other cases.}, number={4}, journal={WEATHER AND FORECASTING}, author={Appel, KW and Riordan, AJ and Holley, TA}, year={2005}, month={Aug}, pages={439–455} }
 @article{kaplan_huffman_lux_charney_riordan_lin_2005, title={Characterizing the severe turbulence environments associated with commercial aviation accidents. Part 1: A 44-case study synoptic observational analyses}, volume={88}, ISSN={["1436-5065"]}, DOI={10.1007/s00703-004-0080-0}, number={3-4}, journal={METEOROLOGY AND ATMOSPHERIC PHYSICS}, author={Kaplan, ML and Huffman, AW and Lux, KM and Charney, JJ and Riordan, AJ and Lin, YL}, year={2005}, month={Apr}, pages={129–152} }
 @article{kaplan_huffman_lux_cetola_charney_riordan_lin_waight_2005, title={Characterizing the severe turbulence environments associated with commercial aviation accidents. Part 2: Hydrostatic mesoscale numerical simulations of supergradient wind flow and streamwise ageostrophic frontogenesis}, volume={88}, DOI={10.1007/s00703-004-0079-6}, number={04-Mar}, journal={Meteorology and Atmospheric Physics}, author={Kaplan, M. L. and Huffman, A. W. and Lux, K. M. and Cetola, J. D. and Charney, J. J. and Riordan, A. J. and Lin, Y. L. and Waight, K. T.}, year={2005}, pages={153–173} }
 @article{brennan_keeter_riordan_lackmann_2005, title={Expandng horizons wth an NWS internship course}, volume={86}, ISSN={["1520-0477"]}, DOI={10.1175/BAMS-86-10-1407}, abstractNote={M eteorology students at North Carolina State University (NCSU) participated in an experimental internship course during the spring of 2004 that allowed them to gain an operational perspective on meteorology by experiencing the everyday duties of the staff at the collocated National Weather Service (NWS) Weather Forecast Offi ce (WFO) in Raleigh. Th e course was designed to meet several goals, which included allowing students to contribute to operational forecasting, gain profi ciency with routine NWS duties and soft ware tools, and sample the broad array of work performed by the NWS. Students also were exposed to operational meteorology and NWS careers and received assistance in pursuing such a career. During the semester, fi ve senior undergraduate and fi ve graduate students enrolled in the course. Th ey attended NWS training sessions, “shadowed” NWS staff , performed routine NWS duties, and assisted NWS staff during high-impact weather events. Overall, the students and NWS staff were decidedly positive about the course, which was again off ered during the spring of 2005. As the fi eld of atmospheric science continues to advance and diversify, courses of this type can play an increasingly vital role in education and professional development. In describing the new course, we hope to encourage others who may be contemplating a similar program, especially since many WFOs are located on college campuses, an arrangement that makes this type of experience feasible. Th e internship course was a natural extension of the 17 consecutive years of NOAA-funded collaboration between NCSU and the Raleigh WFO, which moved to the NCSU campus in 1994. Th e course was designed for students interested in an NWS career. Th e hands-on experience should help students decide whether an NWS career is something they might wish to pursue. Secondly, the course provided experience that will be invaluable when they apply for an entry-level NWS position. Students were selected for the course by the evaluation of a written statement of interest by NWS personnel and an interview with the NWS science operations offi cer and other NWS staff . Th e course required students to work at least 16 hours alongside NWS personnel performing routine shift duties and to maintain a journal documenting their experiences. Students initially observed NWS personnel during their shift s and gained experience with manual analysis of surface and upper-air maps, composing the state weather summary, and gathering and disseminating climate and hydrological data. With time, students became independently profi cient with these duties. In addition, the students traveled to NWS equipment sites and attended special sessions for hands-on experience with the Advanced Weather Interactive Processing System (AWIPS), seasonal familiarization with severe and winter weather forecast problems, offi ce safety, and applying for NWS jobs.}, number={10}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Brennan, MJ and Keeter, K and Riordan, AJ and Lackmann, GM}, year={2005}, month={Oct}, pages={1407–1409} }
 @article{riordan_2003, title={Forecasting for a remote island - A class exercise}, volume={84}, ISSN={["1520-0477"]}, DOI={10.1175/bams-84-6-777}, abstractNote={Students enrolled in a satellite meteorology course at North Carolina State University, Raleigh, recently had an unusual opportunity to apply their forecast skills to predict wind and weather conditions for a remote site in the Southern Hemisphere. For about 40 days starting in early February 2001, students used satellite and model guidance to develop forecasts to support a research team stationed on Bouvet Island (54°26′S, 3°24′E). Internet products together with current output from NCEP's Aviation (AVN) model supported the activity. Wind forecasts were of particular interest to the Bouvet team because violent winds often developed unexpectedly and posed a safety hazard. Results were encouraging in that 24-h wind speed forecasts showed reasonable reliability over a wide range of wind speeds. Forecasts for 48 h showed only marginal skill, however. Two critical events were well forecasted—the major February storm with wind speeds of over 120 kt and a brief calm period following several days of strong winds in early March. The latter forecast proved instrumental in recovering the research team.}, number={6}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Riordan, AJ}, year={2003}, month={Jun}, pages={777-+} }
 @article{egentowich_kaplan_lin_riordan_2000, title={Mesoscale simulations of dynamical factors discriminating between a tornado outbreak and non-event over the southeast US - Part I: 84-48 hour precursors}, volume={74}, ISSN={["0177-7971"]}, DOI={10.1007/s007030070030}, number={1-4}, journal={METEOROLOGY AND ATMOSPHERIC PHYSICS}, author={Egentowich, JM and Kaplan, ML and Lin, YL and Riordan, AJ}, year={2000}, pages={129–157} }
 @article{egentowich_kaplan_lin_riordan_2000, title={Mesoscale simulations of dynamical factors discriminating between a tornado outbreak and non-event over the southeast US - Part II: 48-6 hour precursors}, volume={74}, ISSN={["0177-7971"]}, DOI={10.1007/s007030070031}, number={1-4}, journal={METEOROLOGY AND ATMOSPHERIC PHYSICS}, author={Egentowich, JM and Kaplan, ML and Lin, YL and Riordan, AJ}, year={2000}, pages={159–187} }
 @article{egentowich_kaplan_lin_riordan_2000, title={Mesoscale simulations of dynamical factors discriminating between a tornado outbreak and non-event over the southeast US - Part III: 6 hour precursors}, volume={74}, ISSN={["0177-7971"]}, DOI={10.1007/s007030070032}, number={1-4}, journal={METEOROLOGY AND ATMOSPHERIC PHYSICS}, author={Egentowich, JM and Kaplan, ML and Lin, YL and Riordan, AJ}, year={2000}, pages={189–215} }
 @article{aneja_oommen_riordan_arya_wayland_murray_1999, title={Ozone patterns for three metropolitan statistical areas in North Carolina, USA}, volume={33}, ISSN={["1352-2310"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0032599714&partnerID=MN8TOARS}, DOI={10.1016/S1352-2310(99)00241-1}, abstractNote={As part of an effort by the state of North Carolina to develop a State Implementation Plan (SIP) for 1-h peak ozone control, a network of ozone stations was established to monitor surface ozone concentrations across the state. Between 19 and 23 ozone stations made continuous surface measurements between 1993 and 1995 surrounding three major metropolitan statistical areas (MSAs): Raleigh/Durham (RDU), Charlotte/Mecklenburg (CLT), and Greensboro/High Point/Winston-Salem (GSO). Statistical averages of the meteorological and ozone data were performed at each Metropolitan Statistical Area (MSA) to study trends and/or relationships on high ozone days (days in which one of the MSA sites measured an hourly ozone concentration⩾90.0 ppbv). County emission maps of precursor gases, wind roses, total area averages of ozone, total downwind averages of ozone deviations, upwind averages of ozone, and a modified delta ozone analysis were all obtained and analyzed. The results of this study show a reduction in the delta ozone relative to an earlier study at RDU, but no average significant change at CLT (no comparison can be made for GSO). The statistical data analyses in this study are used to quantify the importance of local contributions and regional transport, to ozone air pollution in the MSAs.}, number={30}, journal={ATMOSPHERIC ENVIRONMENT}, author={Aneja, VP and Oommen, RG and Riordan, AJ and Arya, SP and Wayland, RJ and Murray, GC}, year={1999}, month={Dec}, pages={5081–5093} }
 @article{langmaid_riordan_1998, title={Surface mesoscale processes during the 1994 Palm Sunday tornado outbreak}, volume={126}, ISSN={["0027-0644"]}, DOI={10.1175/1520-0493(1998)126<2117:SMPDTP>2.0.CO;2}, abstractNote={The tornadic storms that developed in the 27 March 1994 Palm Sunday outbreak were confined to a narrow zone extending from central and northern Alabama to western North Carolina. Analysis of surface observations and soundings is used to examine the mesoscale environment of the region starting 14 h prior to storm development. The evolution of a shallow front that formed the northern boundary of the outbreak region is tied to several diabatic processes including evaporation of precipitation and differential solar heating. The resulting front was found to both limit severe convection and focus supercell development later in the day. During the night before the outbreak, as copious widespread precipitation fell into dry air, evaporation maintained a cold air pool north of the front. By contrast, moderate southerly flow provided warm, moist conditions to the south. Precipitation-enhanced cold air damming along the eastern slopes of the Appalachians also may have provided a source of cold air for subsequent frontogenesis over areas farther west. During the daylight hours, differential solar heating across the front further enhanced frontogenesis. Intensification of convection just prior to the first tornadoes was found to be associated with areas of breaks in the overcast near and upstream of tornadogenesis. Similarly, cells that intensified were moving over a surface that had been thoroughly moistened by previous rainfall. Supercells that intersected and moved along the frontal boundary maintained their tornadic strength for many hours, whereas storms that crossed the boundary disintegrated. Blockage of inflow by upstream storm cells may also have contributed to the rapid reduction of intensity of one of the tornadic cells.}, number={8}, journal={MONTHLY WEATHER REVIEW}, author={Langmaid, AH and Riordan, AJ}, year={1998}, month={Aug}, pages={2117–2132} }
 @article{hoium_riordan_monahan_keeter_1997, title={Severe thunderstorm and tornado warnings at Raleigh, North Carolina}, volume={78}, ISSN={["0003-0007"]}, DOI={10.1175/1520-0477(1997)078<2559:STATWA>2.0.CO;2}, abstractNote={The National Weather Service issues public warnings for severe thunderstorms and tornadoes when these storms appear imminent. A study of the warning process was conducted at the National Weather Service Forecast Office at Raleigh, North Carolina, from 1994 through 1996. The purpose of the study was to examine the decision process by documenting the types of information leading to decisions to warn or not to warn and by describing the sequence and timing of events in the development of warnings. It was found that the evolution of warnings followed a logical sequence beginning with storm monitoring and proceeding with increasingly focused activity. For simplicity, information input to the process was categorized as one of three types: ground truth, radar reflectivity, or radar velocity. Reflectivity, velocity, and ground truth were all equally likely to initiate the investigation process. This investigation took an average of 7 min, after which either a decision was made not to warn or new information triggered the warning. Decisions not to issue warnings were based more on ground truth and reflectivity than radar velocity products. Warnings with investigations of more than 2 min were more likely to be triggered by radar reflectivity, than by velocity or ground truth. Warnings with a shorter investigation time, defined here as “immediate trigger warnings,” were less frequently based on velocity products and more on ground truth information. Once the decision was made to warn, it took an average of 2.1 min to prepare the warning text. In 85% of cases when warnings were issued, at least one contact was made to emergency management officials or storm spotters in the warned county. Reports of severe weather were usually received soon after the warning was transmitted—almost half of these within 30 min after issue. A total of 68% were received during the severe weather episode, but some of these storm reports later proved false according to Storm Data. Even though the WSR-88D is a sophisticated tool, ground truth information was found to be a vital part of the warning process. However, the data did not indicate that population density was statistically correlated either with the number of warnings issued or the verification rate.}, number={11}, journal={BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY}, author={Hoium, DK and Riordan, AJ and Monahan, J and Keeter, KK}, year={1997}, month={Nov}, pages={2559–2575} }