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Online 19.1: A Gallery of Tornado Photographs: Examine tornadoes at various stages of their life cycle from afar and up close.

Photos courtesy of Glen Romine, University of Illinois

Online 19.2: Simulation of Landspouts using a Numerical Model: Multiple landspouts (non-supercell tornadoes) develop in this simulation of a line of non-rotating thunderstorms. The landspouts develop along a shear zone indicated by the contrasting blue colors. The yellow columns represent the rotation of the landspouts.

Courtesy of Bruce Lee and Robert Wilhemson, University of Illinois/NCSA

Online 19.3: Simulation of Airflow in a Landspout using a Numerical Model: Airflow within landspouts (non-supercell tornadoes) can be seen in this simulation of a line of non-rotating thunderstorms. Weightless tracer particles identify the air as either rising (green) or sinking (red). Several of the landspouts merge during the animation.

Courtesy of Bruce Lee and Robert Wilhemson, University of Illinois/NCSA

Online 19.4: Frequency of Tornadoes in the United States: The sequence of images shows the likelihood of tornadoes for each calendar month in the contiguous United States. The chart below shows the number of tornadoes (according to F-scale) observed in each calendar month during a 70 year period. Note that the tornado occurrence shifts northward throughout the year with the exception of a maximum along the Gulf coast during hurricane season.
Online 19.5: Doppler Radar Reflectivity During the 3 May 1999 Tornado Outbreak: Several supercell thunderstorms are evident on the radar reflectivity animation from 3 May 1999. Note the classic hook shaped echo of each supercell and the classic precipitation pattern indicated by the color coding. The supercell that passed through Oklahoma City (OKC) and Moore produced a tornado ranked as F-5 during part of its life cycle.
Online 19.6: Doppler Radar Radial Velocity During the 3 May 1999 Tornado Outbreak: Several tornado vortex signatures are visible on the radar radial velocity animation from 3 May 1999. The signatures indicate rotation in the thunderstorm and are identified by a coupling of red (outbound) and green (inbound) colors.
Related Web Sites
Storm Prediction Center Examine severe weather outlooks and discussions to determine where and when tornadoes may develop.
WW2010 Guide to Tornadoes Learn more about tornado identification, intensity, evolution and damage.
The VORTEX Project Read about a ground breaking field study conducted in the mid-90s that intercepted and studied tornadoes.
Tornado Fact Sheet from FEMA Learn what to do before, during, and after a tornado strikes.
The Central Oklahoma Tornado Outbreak of 3 May 1999 Read a detailed case study of the largest outbreak of tornadic supercells in recent history.
WW2010 Summary of the
19 April 1996 Tornadoes
Learn more about the severe weather outbreak of April 1996.

Department of Atmospheric Sciences Severe and Hazardous Weather at Department of Atmospheric Sciences University of Illinois
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