Partnering Research, Education, and Operations via a Cool Season Severe Weather Soundings Program

2019 ◽  
Vol 100 (2) ◽  
pp. 307-320 ◽  
Author(s):  
Keith D. Sherburn ◽  
Matthew D. Parker ◽  
Casey E. Davenport ◽  
Richard A. Sirico ◽  
Jonathan L. Blaes ◽  
...  
Keyword(s):  
North Carolina ◽  
Large Fraction ◽  
Severe Weather ◽  
High Shear ◽  
Potential Utility ◽  
Cool Season ◽  
Case Examples ◽  
Research Education ◽  
Severe Convection ◽  
Student Volunteers

AbstractRecent research has improved our knowledge and forecasting of high-shear, low-CAPE (HSLC) severe convection, which produces a large fraction of overnight and cool season tornadoes. However, limited near-storm observations have hindered progress in our understanding of HSLC environments and detection of severe potential within them. This article provides an overview of a research project in central North Carolina aimed toward increasing the number of observations in the vicinity of severe and nonsevere HSLC convection. Particularly unique aspects of this project are a) leadership by student volunteers from a university sounding club and b) real-time communication of observations to local National Weather Service Forecast Offices. In addition to an overview of sounding operations and goals, two case examples are provided that support the potential utility of supplemental sounding observations for operational, educational, and research purposes.

scholarly journals Seasonal Variations in Severe Weather Forecast Skill in an Experimental Convection-Allowing Model

2017 ◽  
Vol 32 (5) ◽  
pp. 1885-1902 ◽  
Author(s):  
Ryan A. Sobash ◽  
John S. Kain
Keyword(s):  
Warm Season ◽  
Weather Forecast ◽  
Severe Weather ◽  
Cool Season ◽  
Limited Sample ◽  
Seasonal Behavior ◽  
Severe Convection ◽  
Convective Weather ◽  
The Relationship ◽  
Do So

Abstract Eight years of daily, experimental, deterministic, convection-allowing model (CAM) forecasts, produced by the National Severe Storms Laboratory, were evaluated to assess their ability at predicting severe weather hazards over a diverse collection of seasons, regions, and environments. To do so, forecasts of severe weather hazards were produced and verified as in previous studies using CAM output, namely by thresholding the updraft helicity (UH) field, smoothing the resulting binary field to create surrogate severe probability forecasts (SSPFs), and verifying the SSPFs against observed storm reports. SSPFs were most skillful during the spring and fall, with a relative minimum in skill observed during the summer. SSPF skill during the winter months was more variable than during other seasons, partly due to the limited sample size of events, but was often less than that during the warm season. The seasonal behavior of SSPF skill was partly driven by the relationship between the UH threshold and the likelihood of obtaining severe storm reports. Varying UH thresholds by season and region produced SSPFs that were more skillful than using a fixed UH threshold to identify severe convection. Accounting for this variability was most important during the cool season, when a lower UH threshold produced larger SSPF skill compared to warm-season events, and during the summer, when large differences in skill occurred within different parts of the continental United States (CONUS), depending on the choice of UH threshold. This relationship between UH threshold and SSPF skill is discussed within the larger scope of generating skillful CAM-based guidance for hazardous convective weather and verifying CAM predictions.

scholarly journals Climatology and Ingredients of Significant Severe Convection in High-Shear, Low-CAPE Environments

2014 ◽  
Vol 29 (4) ◽  
pp. 854-877 ◽  
Author(s):  
Keith D. Sherburn ◽  
Matthew D. Parker
Keyword(s):  
Poor Performance ◽  
Severe Weather ◽  
Lapse Rate ◽  
High Shear ◽  
Unique Challenge ◽  
Weather Forecasts ◽  
Severe Convection ◽  
Composite Parameter ◽  
Tools And Techniques ◽  
Vector Magnitude

Abstract High-shear, low-CAPE (HSLC) environments, here characterized by surface-based CAPE ≤ 500 J kg−1, most unstable parcel CAPE ≤ 1000 J kg−1, and 0–6-km shear vector magnitude ≥ 18 m s−1, occur at all times of day, across all seasons, and throughout the entire United States. HSLC environments represent a unique challenge for forecasters, as they occur frequently but produce severe weather a relatively low percentage of the time. Recent studies have primarily focused on improving nowcasting and warnings for events through the identification of radar signatures commonly associated with HSLC tornadoes. Few studies have investigated the forecasting of HSLC severe weather, despite the acknowledged poor performance of traditional tools and techniques. A general climatology of HSLC significant severe weather is presented, focusing on regional, diurnal, and annual trends. Through this climatology, it becomes apparent that multiple types of HSLC environments are possible, including surface-based cases with low lifted condensation levels and high-based convection cases. A statistical analysis of HSLC events and nulls from the southeastern and mid-Atlantic states is utilized to assess the performance of conventional composite parameters in HSLC environments. Additionally, a new composite parameter is introduced that utilizes the product of the statistically most skillful parameters in HSLC environments: the 0–3-km lapse rate, the 700–500-hPa lapse rate, and multiple wind and shear metrics. The strengths and weaknesses of these ingredients-based techniques are then reviewed, with an eye toward improving future HSLC severe weather forecasts.

Examining Terrain Effects on an Upstate New York Tornado Event Utilizing a High-Resolution Model Simulation

2021 ◽  
Author(s):  
Luke J. LeBel ◽  
Brian H. Tang ◽  
Ross A. Lazear
Keyword(s):  
New York ◽  
High Resolution ◽  
Wind Shear ◽  
Model Simulation ◽  
Wrf Model ◽  
Severe Weather ◽  
Streamwise Vorticity ◽  
Low Level ◽  
Severe Convection ◽  
The Impact

AbstractThe complex terrain at the intersection of the Mohawk and Hudson valleys of New York has an impact on the development and evolution of severe convection in the region. Specifically, previous research has concluded that terrain-channeled flow in the Mohawk and Hudson valleys likely contributes to increased low-level wind shear and instability in the valleys during severe weather events such as the historic 31 May 1998 event that produced a strong (F3) tornado in Mechanicville, New York.The goal of this study is to further examine the impact of terrain channeling on severe convection by analyzing a high-resolution WRF model simulation of the 31 May 1998 event. Results from the simulation suggest that terrain-channeled flow resulted in the localized formation of an enhanced low-level moisture gradient, resembling a dryline, at the intersection of the Mohawk and Hudson valleys. East of this boundary, the environment was characterized by stronger low-level wind shear and greater low-level moisture and instability, increasing tornadogenesis potential. A simulated supercell intensified after crossing the boundary, as the larger instability and streamwise vorticity of the low-level inflow was ingested into the supercell updraft. These results suggest that terrain can have a key role in producing mesoscale inhomogeneities that impact the evolution of severe convection. Recognition of these terrain-induced boundaries may help in anticipating where the risk of severe weather may be locally enhanced.

scholarly journals Investigation of Atmospheric Rivers Impacting the Pigeon River Basin of the Southern Appalachian Mountains

2018 ◽  
Vol 33 (1) ◽  
pp. 283-299 ◽  
Author(s):  
Douglas K. Miller ◽  
David Hotz ◽  
Jessica Winton ◽  
Lukas Stewart
Keyword(s):  
North Carolina ◽  
River Basin ◽  
Large Scale ◽  
Large Fraction ◽  
Appalachian Mountains ◽  
Warm Season ◽  
Atmospheric Rivers ◽  
Southern Appalachian Mountains ◽  
Low Level ◽  
Southern Appalachian

Abstract Rainfall observations in the Pigeon River basin of the southern Appalachian Mountains over a 5-yr period (2009–14) are examined to investigate the synoptic patterns responsible for downstream flooding events as observed near Knoxville, Tennessee, and Asheville, North Carolina. The study is designed to address the hypothesis that atmospheric rivers (ARs) are primarily responsible for the highest accumulation periods observed by the gauge network and that these periods correspond to events having a societal hazard (flooding). The upper 2.5% (extreme) and middle 33% (normal) rainfall events flagged using the gauge network observations showed that half of the heaviest rainfall cases were associated with an AR. Of those extreme events having an AR influence, over 73% had a societal hazard defined as minor-to-major flooding at the USGS river gauge located in Newport, Tennessee, or flooding observations for locations near the Tennessee and North Carolina border reported in the Storm Data publication. Composites of extreme AR-influenced events revealed a synoptic pattern consisting of a highly amplified slow-moving positively tilted trough, suggestive of the anticyclonic Rossby wave breaking scenario that sometimes precedes hydrological events of high impact. Composites of extreme non-AR events indicated a large-scale weather pattern typical of a warm season scenario in which an anomalous low-level cyclone, cut off far from the primary upper-tropospheric jet, was located in the southeastern United States. AR events without a societal hazard represented a large fraction (75%–88%) of all ARs detected during the study period. Synoptic-scale weather patterns of these events were fast moving and had weak low-level atmospheric dynamics.

scholarly journals A Preliminary Statistical Study of Correlations between Inflow Feeder Clouds, Supercell or Multicell Thunderstorms, and Severe Weather

2009 ◽  
Vol 24 (4) ◽  
pp. 921-934 ◽  
Author(s):  
Rebecca J. Mazur ◽  
John F. Weaver ◽  
Thomas H. Vonder Haar
Keyword(s):  
Satellite Imagery ◽  
Statistical Study ◽  
Detection Algorithm ◽  
Severe Weather ◽  
Potential Utility ◽  
Geostationary Operational Environmental Satellite ◽  
The Relationship ◽  
Visible Imagery ◽  
Cloud Analysis

Abstract This study examines the relationship between severe weather and organized lines of cumulus towers, called feeder clouds, which form in the inflow region of supercell and multicell thunderstorms. Using Geostationary Operational Environmental Satellite (GOES) imagery, correlations between the occurrence of feeder clouds and severe weather reports are explored. Output from the Weather Surveillance Radar-1988 Doppler (WSR-88D) mesocyclone detection algorithm (MDA) is also assessed for a subset of the satellite case days. Statistics from the satellite and radar datasets are assembled to estimate not only the effectiveness of feeder cloud signatures as sole predictors of severe weather, but also the potential utility of combining feeder cloud analysis with the radar’s MDA output. Results from this study suggest that the formation of feeder clouds as seen in visible satellite imagery is often followed by the occurrence of severe weather in a storm. The study finds that feeder cloud signatures by themselves have low skill in predicting severe weather. However, if feeder clouds are observed in a storm, there is a 77% chance that severe weather will occur within 30 min of the observation. For the cases considered, the MDA turns out to be the more effective predictor of severe weather. However, results show that combined predictions (feeder clouds plus mesocyclones) outperform both feeder cloud signatures and the MDA as separate predictors by ∼10%–20%. Thus, the presence of feeder clouds as observed in visible imagery is a useful adjunct to the MDA in diagnosing a storm’s potential for producing severe weather.

The Liquid Galaxy in the library

2016 ◽  
Vol 34 (4) ◽  
pp. 657-668 ◽  
Author(s):  
Amanda Tickner
Keyword(s):  
North Carolina ◽  
Mixed Method ◽  
Google Earth ◽  
Trip Planning ◽  
Content Type ◽  
User Perceptions ◽  
Research Education ◽  
Chapel Hill ◽  
Display Technology ◽  
The University

Purpose The purpose of this paper is to investigate the usability and user perceptions of the display technology in the library to evaluate the utility of the Liquid Galaxy (LG) technology and how it was deployed in a library setting. Design/methodology/approach This paper presents the results of a mixed method (survey and interview) qualitative study of users of the LG Google Earth/Google Street View immersive display in the Research Hub of Davis Library of the University of North Carolina Chapel Hill conducted in April 2015. In total, 25 users of the LG responded to survey or interview questions about their user experience and their emotional response to the LG. Findings Users found the LG easy to use and they had many reasons for using the LG including: research, education, entertainment, trip planning and nostalgic virtual travel. Originality/value There are few studies on users’ experience of innovative non-way finding display technology in library settings and this study then adds to the literature on this subject. These results may assist organizations evaluating incorporating an immersive display such as the LG into their offerings.

Properties of Electro-Active Paper and Its Potential as a Bio-Inspired Actuator for Special Applications

Aerospace ◽  
2004 ◽  
Author(s):  
Jaehwan Kim ◽  
Woochul Jung ◽  
William J. Craft ◽  
John Shelton ◽  
Kyo Song ◽  
...  
Keyword(s):  
North Carolina ◽  
State University ◽  
University Of Maryland ◽  
Research Education ◽  
North Carolina State University ◽  
Temperature And Humidity ◽  
Cantilevered Beam ◽  
Small Force ◽  
The University ◽  
T State

On September 26, 2002, NASA announced that a consortium of six universities including: The University of Maryland, Virginia Tech, The University of Virginia, North Carolina A&T State University, North Carolina State University, and Georgina Tech had submitted the winning proposal for a National Institute of Aerospace. The Institute began formal operations in January of 2003 in Hampton, VA, and its mission included research, education, outreach, and technology transfer. One important focus of the NIA was to stimulate research among its member universities of potential benefit to NASA and to develop additional partnerships to further NIA focus areas. The work described in this paper is such an activity in bio-inspired actuator materials. This work was originally advocated and developed at Inha University, and it is being extended by teams from Inha University, North Carolina A&T State University, and NASA Langley so that the potential for these actuators as devices for special applications is better understood. This paper focuses on important performance characteristics of electro-active paper (EAPap) actuators and the potential of thes actuators to propel autonomous devices. EAPap is a paper that produces large displacement with small force under an electrical excitation. EAPap is made with chemically treated papers with electrodes on both outer surfaces. When electrical voltage is applied to the electrodes, a tip displacement is produced. One drawback in such actuators is that the actual power produced is variable, and the displacement is relatively unstable. Further, the performance tends to degrade in time and as a function of how the papers are processed. Environmental factors also impact the performance of the product including temperature and humidity. The use of such materials in ambulatory devices requires attention to these concerns and further research is needed to find what initial applications are most congruent with EAPap performance and service lift. In this paper, we have extended the knowledge base of EAPap to include additional ranges of temperature and humidity. We have also looked beyond the current tests on cantilevered beam actuators to segmented plate sections and have tested the ability of these actuators to perform as oscillatory devices both in and out of phase, and to chart their performance vs. time humidity and temperature thus emulating a rudimentary wing or walking assembly.

scholarly journals Four-Dimensional Dynamic Radar Mosaic

2007 ◽  
Vol 24 (5) ◽  
pp. 776-790 ◽  
Author(s):  
Carrie Langston ◽  
Jian Zhang ◽  
Kenneth Howard
Keyword(s):  
Radar Data ◽  
Severe Weather ◽  
Three Dimensions ◽  
Radar Observations ◽  
Weighting Schemes ◽  
Case Examples ◽  
Temporal Smoothing ◽  
Precipitation Estimates ◽  
Radar Applications ◽  
Reflectivity Data

Abstract Communities and many industries are affected by severe weather and have a need for real-time accurate Weather Surveillance Radar-1988 Doppler (WSR-88D) data spanning several regions. To fulfill this need the National Severe Storms Laboratory has developed a Four-Dimensional Dynamic Grid (4DDG) to accurately represent discontinuous radar reflectivity data over a continuous 4D domain. The objective is to create a seamless, rapidly updating radar mosaic that is well suited for use by forecasters in addition to advance radar applications such as qualitative precipitation estimates. Several challenges are associated with creating a 3D radar mosaic given the nature of radar data and the spherical coordinates of radar observations. The 4DDG uses spatial and temporal weighting schemes to overcome these challenges, with the intention of applying minimal smoothing to the radar data. Previous multiple radar mosaics functioned in two or three dimensions using a variety of established weighting schemes. The 4DDG has the advantage of temporal weighting to smooth radar observations over time. Using an exponentially decaying weighting scheme, this paper will examine different weather scenarios and show the effects of temporal smoothing using different time scales. Specifically, case examples of the 4DDG approach involving a rapidly evolving convective event and a slowly developing stratiform weather regime are considered.

scholarly journals Mesoclimatic analysis of severe weather and ENSO interactions in North Carolina

2000 ◽  
Vol 27 (15) ◽  
pp. 2269-2272 ◽  
Author(s):  
Jamie R. Rhome ◽  
Devdutta S. Niyogi ◽  
Sethu Raman
Keyword(s):  
North Carolina ◽  
Severe Weather
Sign in / Sign up

Export Citation Format

Share Document