Centennial Honors College
Western Illinois University
Undergraduate Research Day 2014
Poster Presentation
Differences in Surface and Atmospheric Conditions between Spring and Fall
Tornadoes in the State of Illinois
Alexander Leslie
Facutly Mentor: Jongnam Choi
Meteorology
Tornadoes in spring month are common in Illinois, while tornado in fall is quite rare. This
study analyzes surface and atmospheric conditions of a tornado occurred at
Washington, IL on November 17, 2013 and a tornado in the town Streator at LaSalle
County on June 5, 2010. This study examines the difference in atmospheric
environments for both tornadoes. For better understanding surface and upper-air
conditions of both tornado outbreaks, this study used variables from the surface to the
tropopause, including vertical structure, geopotential height, and thermal and moisture
advection at standard pressure levels at prior or subsequent hours of these tornadoes.
Reanalysis gridded data from the online NCEP/NCAR data archive was used to
reconstruct synoptic scale atmospheric patterns at pressure and surface levels
Unidata’s Integrated Data Viewer (IDV) was used to analyze and create composite data
and maps. The preliminary results show that both tornadoes have very similar thermal
and moisture advections to tornadoes. However, maps show difference in vorticity
advections at 500 hPa and divergence at 300 hPa for both tornadoes at both tornadoes.
Findings from this study enable meteorologists to make a better prediction on outbreaks
of tornadoes at the central Illinois which potentially induce numerous casualties by the
storms.