(Updated 29 March 2013.  Comments to Harold Brooks)


Introduction

At NOAA's National Severe Storms Laboratory, we have begun a project to estimate the likelihood of severe weather hazards in the United States.  (Severe thunderstorms are defined in the United States as having either tornadoes, gusts at least 58 mph, or hail  at least 3/4 inch in diameter.)  The figures are of three primary kinds:
  1. The average number of days per year with the event occurring within 25 miles of any point (Total Threat).
  2. Animated loops of the probability of severe weather occurring within 25 miles of any point on a particular day with images once per week through the year (Animated Loops).
  3. Graphs showing the annual cycle of the probability of severe weather occurring within 25 miles at any point you select (Annual Cycles at Points [Clickable Maps]).
For more information on the raw data that went into the figures and how it was processed, click here.
Conference paper on climatology of strong and violent tornadoes in the US by Concannon,  Brooks, and  Doswell.
 

NEW! Severe Weather Climatology Graphics from the NWS Storm Prediction Center

Total Threat

Animated Loops

Annual Cycles at Points [Clickable Maps]

Miscellaneous Climatological Information

Data Processing