A large tornado moved through the town of El Reno, Oklahoma om May 31st and originally was classified as an EF-5 by the National Weather Service, now that rating is being downgraded.
The original EF-5 tornado rating was based on mobile radar data that found winds in excess of 295 miles per hour within 500 feet of the ground, however, tornadoes are normally rated in the amount of damage that is caused as part of the Enhanced Fujita (EF) Scale.
The original damage survey on the ground conducted by the National Weather Service in Norman, Oklahoma from winds in this tornado, rated is as an EF-3, and that was the basis for the downgrade in this rating.
The National Weather Service will now hold discussions to talk about whether the policy should be changed to allow radar data to be used in the rating of tornadoes in the future.
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