Matching Items (2)
Filtering by
- All Subjects: Severe Weather
- Creators: Krahenbuhl, Daniel
- Creators: Svoma, Bohumil
Description
The Mid-South region, which consists of west Tennessee, northeast Arkansas, north Mississippi, and the Missouri bootheel, is one of many areas in the United States that frequently faces the threats to life and property posed by tornadoes. Forecasting the occurrence of tornadoes is arguably the biggest challenge for meteorologists responsible for the region. This study analyzes synoptic scale weather conditions associated with tornadoes in the Mid-South with the hopes of identifying patterns conducive to tornadic activity and that these patterns can be used to better forecast potential tornado days. It is hypothesized that patterns associated with tornado formation can be identified and that certain patterns may be more favorable to stronger tornadoes or tornado outbreaks than others.
To find these patterns, I analyzed surface and upper air features were analyzed on days where multiple tornadoes occurred from January 1999 to March 2018. Specifically, the surface low pressure, 500hPa trough, and 850 and 300hPa jets were analyzed. Using a floating nine point grid system, I identified the location of the Mid-South in relation to the feature. In the end, eight patterns of similar grid locations were identified to be related to tornado days. For example, the Mid-South was frequently to the southeast of the surface low. However, no correlation appears to exist between the patterns and the number or intensity of tornadoes. It is recommended that in the future these patterns be tested as a forecast method and/or compared to non-tornado days to verify that they are valid tools.
To find these patterns, I analyzed surface and upper air features were analyzed on days where multiple tornadoes occurred from January 1999 to March 2018. Specifically, the surface low pressure, 500hPa trough, and 850 and 300hPa jets were analyzed. Using a floating nine point grid system, I identified the location of the Mid-South in relation to the feature. In the end, eight patterns of similar grid locations were identified to be related to tornado days. For example, the Mid-South was frequently to the southeast of the surface low. However, no correlation appears to exist between the patterns and the number or intensity of tornadoes. It is recommended that in the future these patterns be tested as a forecast method and/or compared to non-tornado days to verify that they are valid tools.
ContributorsWanless, Anna Cecilia (Author) / Cerveny, Randall (Thesis director) / Svoma, Bohumil (Committee member) / School of Geographical Sciences and Urban Planning (Contributor, Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Severe weather affects many regions of the United States, and has potential to greatly impact many facets of society. This study provides a climatological spatial analysis by county of severe weather warnings issued by the National Weather Service (NWS) between January 1st, 1986 to December 31st, 2017 for the contiguous United States. The severe weather warnings were issued for county-based flash flood, severe thunderstorm, and tornado phenomena issued through the study period and region. Post 2002 severe weather warnings issued by storm warning area were included in this study in the form of county-based warnings simultaneously issued for each affected county. Past studies have researched severe weather warnings issued by the NWS, however these studies are limited in geographic representation, study period, and focused on population bias. A spatial analysis of severe weather warning occurrences by county identify that (a) highest occurrences of flash flood warnings are located in the desert Southwest and Texas, (b) severe thunderstorm warning occurrence is more frequent in Arizona, portions of the Midwest, the South, and the Mid and South Atlantic states, (c) the tornado activity regions of Tornado Alley and Dixie Alley (i.e. Colorado, Kansas, Oklahoma, Arkansas, Texas, Louisiana, Mississippi, Alabama, Tennessee, and Illinois) contained the highest occurrences of tornado warnings, and (d) the highest instances of aggregate warning occurrences are found in the desert Southwest, the Midwest, and the Southern regions of the United States. Generally, severe weather warning “hot spots” tend to be located in those same regions, with greater coverage. This study concludes with a comparison of local maxima and general hot spot regions to expected regions for each phenomenon. Implications of this study are far reaching, including emergency management, and has potential to reduce risk of life.
ContributorsLawhorn, Brandon (Author) / Cerveny, Randall S. (Thesis advisor) / Balling, Robert C. (Committee member) / Vose, Russel S (Committee member) / Krahenbuhl, Daniel (Committee member) / Arizona State University (Publisher)
Created2019