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Posted at 02:00 PM ET, 04/20/2011

Powerful storm plows east, weakens some

Severe storm risk down from yesterday

Yesterday’s storm, visual summary. Top - snow totals over upper Midwest; bottom left - satellite image showing bright cloud tops associated with strong thunderstorms over east central U.S.; bottom right - storm reports from NOAA (blue indicates high winds, green large hail, and red tornadoes)
Another big round of severe weather smacked the east central U.S. yesterday, resulting in just shy of 900 storm reports for high winds (493), large hail (349) and tornadoes (34). The responsible storm system, which also dropped up to 10 inches of snow in portions of Minnesota, Wisconsin (including a record 9.9 inches in Green Bay) and northern Michigan, lifts northeastward today, dragging a cold front across the East. Some severe thunderstorms are possible along the front, but they should be far less numerous and less intense than yesterday.

(Video of two strong tornadoes recorded in northeast Missouri and western Illinois yesterday, courtesy (h/t Baltimore Weather Examiner))

The lower severe threat is related to a lot of the storm’s dynamics shifting toward the Northeast and southeast Canada where the air is more stable and less conducive to violent thunderstorms.

Although the air is humid and somewhat unstable here in the D.C. metro region, we are far away from strong upper level winds, vertical motions (lift) and spin needed to trigger a significant severe thunderstorm outbreak.

As such, although we can’t rule out a few strong storms here, the metro region is no longer under a “slight risk” of severe thunderstorms according to NOAA’s Storm Prediction Center. The areas of slight risk are located to our northeast where strong upper level winds may be mixed down in any developing thunderstorms.

By  |  02:00 PM ET, 04/20/2011

Categories:  Thunderstorms, U.S. Weather, Latest

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