Tornado Fujita Scale Altered

Technocrat

Tornado Fujita Scale Altered

zogger

Sat Feb 04 13:20:06 -0800 2006

Science.

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The National Weather Service has altered the Fujita scale for measuring tornadoes. The new scale won't go into effect until 2007, but is designed to more accurately reflect damage potential. Under the old scale, the F numbers registered too high as compared to all the empiirical data collected as regards actual damage. In other words, lower numbers might indicate more damage potential. The new measurements will be under an EF (Enhanced Fujita) rating, and they will not change any of the historical F ratings.

press release from NOAA, more available on their site:
"The NOAA National Weather Service today announced plans to implement the Enhanced Fujita (EF) Scale to rate tornadoes to replace the original Fujita (F) Scale. The EF Scale will continue to rate tornadoes on a scale from zero to five, but ranges in wind speed will be more accurate with the improved rating scale. The NOAA National Weather Service has approved the EF Scale and expects it to be fully implemented by February 2007.

"The EF Scale takes into account additional variables which will provide a more accurate indication of tornado strength," said retired Air Force Brig. Gen. David L. Johnson, director of the NOAA National Weather Service. "The EF Scale will provide more detailed guidelines that will allow the National Weather Service to more accurately rate tornadoes that strike in the United States."

The F Scale was developed in 1971 by T. Theodore Fujita to rate tornadoes and estimate associated wind speed based on the damage they cause. The EF Scale refines and improves the original scale. It was developed by the Texas Tech University Wind Science and Engineering Research Center, along with a forum of wind engineers, universities, private companies, government organizations, private sector meteorologists and NOAA meteorologists from across the country.

Limitations of the original F Scale may have led to inconsistent ratings, including possible overestimates of associated wind speeds. The EF Scale incorporates more damage indicators and degrees of damage than the original F Scale, allowing more detailed analysis and better correlation between damage and wind speed. The original F Scale historical data base will not change. An F5 tornado rated years ago is still an F5, but the wind speed associated with the tornado may have been somewhat less than previously estimated. A correlation between the original F Scale and the EF Scale has been developed. This makes it possible to express ratings in terms of one scale to the other, preserving the historical database.

NOAA, an agency of the U.S. Department of Commerce, is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation's coastal and marine resources.
Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners and nearly 60 countries to develop a global monitoring network that is as integrated as the planet it observes.

Relevant Web Sites
Enhanced Fujita Scale (HTML) (PDF)

NOAA Tornadoes Page

NOAA Storm Prediction Center

Tornado Fujita Scale Altered

mercedo

Sun Feb 05 09:06:54 -0800 2006
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Slightly on topic, but I must add that Mr Fujita is from same high school with me. When I was in high school, once we had had lecture from him. I think I can recall waht he had repeatedly said -when you found an object of interest, just keep on pursuing it. He had said he did it. He repeated that he did it several times in a lecture. That would probably make him known to the world.