Thunderstorms can occur anywhere in the world and at any time of the day. All thunderstorms produce lightning and thunder. Some have the potential to produce damaging straight-line winds, large hail, heavy rain, flooding, and tornadoes.

A thunderstorm is classified as severe when it contains one or more of the following pheno mena:

• Hail 3/4" or greater
• Winds gusting in excess of 50 knots (57.5 mph)
• A tornado

The Thunderstorm Initiation Mobile Experiment (TIMEx)

MCS Electrification and Polarimetric Radar Study (MEaPRS)

Severe Storms and Tornado Research

Severe Weather Warning Applications and Technology Transfer (SWAT)

SWAT's WSR-88D Mesocyclone and Tornado Signature Case Study Page

Atmospheric Observations

Field Observing Facilities

Glidersonde Demonstrator Program

Thunderstorm FAQ

Additional Research and Educational Sites:

Camping Safety

Center for the Analysis and Predictions of Storms

NOAA Severe Storms Spotters Guide presented by the University of Illinois