87th AMS Annual Meeting

Wednesday, 17 January 2007: 4:45 PM
The Enhanced Fujita Scale
205 (Henry B. Gonzalez Convention Center)
Daniel McCarthy, NOAA/NWS, Norman, OK; and J. T. Schaefer and C. Maier
It has been a year since the National Weather Service announced that starting in February 2006 the Enhanced Fujita Scale (EF-Scale) would be used to evaluate tornado damage. During that time, the utility of the EF-scale was evaluated under “operational conditions” after the occurrence of tornadoes. Several slight tweaks were made to the EF-scale so ratings using the new scale would be consistent with the F-scale ratings contained in the various historic tornado records kept by the Storm Prediction Center (SPC), and the National Climatic Data Center (NCDC).

The EF-scale is an offspring of the original F-Scale developed by Dr. Theodore Fujita 35 years ago. Its development is in accordance with Fujita's vision for future refinements in tornado rating. The current EF “Damage Indicators” and their associated “Degree of Damage” descriptions will be discussed.

When completely implemented, the Enhanced Fujita Scale will provide National Weather Service partners with a tornado damage rating system. The final goal is to have an automated rating assistance package to help decrease EF-rating variations between different evaluators.

The advantages of using the EF-Scale and the lower wind estimates assigned the EF categories will be explored.

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