WeatherMatrix (Jesse Ferrell)

Historic Severe Outbreak to Affect 80 Million in Metros

By Jesse Ferrell, Meteorologist/Community Director
5/25/2011, 7:06:36 AM

11 PM UPDATE: Henry and I have uploaded 3-D radar images of the large tornado NW of Oklahoma City, and the tornadoes in Dallas. More than a dozen people have been killed by the storms and nearly 50 tornado reports have been filed. Tornadoes were near OKC, in Dallas, and approaching Joplin, MO (devastated by the EF-5 tornado Sunday) all at the same time.


If you tried to draw a severe weather threat map over most of the population of the Eastern U.S., you couldn't do much better than this government forecast. One worry everyone seems to have this year (and for good reason in a Spring with record tornado deaths) is: Will my city be hit by a tornado? (It seems to be happening a lot lately).*


As you can see from the map above, which shows cities in black, nearly every major metropolitan area in the heart (and east coast) of the country is under a severe thunderstorm threat today. I tabulated the major metropolitan centers only, and came up with a number of 70 million city folks who are in the Slight Risk area, with 11.5 million in the Moderate or High Risk areas (where tornadoes are most likely to occur).



Although storms could pop up any time this afternoon, the most severe will fire in Oklahoma mid-afternoon and spread eastward. Here's one computer forecast model's estimate of what the radar will look like late in the evening:


Mike Smith says "[The 45% chance of tornado] level is reached in a forecast only once every five to ten years." The widespread distribution of this potential outbreak, combined with the large number of people affected, makes a historic outbreak likely today. And tomorrow will have 23.7 million in the Slight and 5.7 million in at least a Moderate. That's a total of over 17 million people in a tornado threat during the two days! If there were ever a time that people in the city need to prepare, it's now.

Preparation is simple, as Henry said in his video today: Know where your evacuation area is where you'll be during the day and night, and know where your family should meet if a tornado strikes your city and cuts off roads. Better safe than sorry.

*While the true cause of the unusually deadly Spring is undetermined, my opinion is that it is likely a combination of unusually strong tornadoes due to La Nina, and increasing population in these areas. These types of outbreaks have probably happened before (although it may have been more than 50 years).

Jesse Ferrell


The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or


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WeatherMatrix (Jesse Ferrell)