Sunday, November 17, 2013

A Tragic November Day in the Midwest

Convective outlook issued at 8:00 a.m. CST, November 17, 2013
Residents of the Midwest aren't usually thinking about tornadoes in mid-November, especially less than a week since the first measurable snow of the season. However, they woke up this morning to an outlook for a High risk of severe weather from Illinois east through Indiana and into western Ohio and southern Michigan.

At 8:00 a.m. CST radars were clear of any storms in Illinois and showers and thunderstorms were exiting southeastern Indiana.  By 9:00 a.m. storms were beginning to fire in Illinois ahead of a strong cold front, and not long after the first severe weather warnings were being issued.

Surface map at 12:00 CST Sunday, November 17

Southwest winds were already gusting to 40-50 mph in the warm sector, and wind profiles through the atmosphere were favorable for large and long-track tornadoes. Sometime around 10:00 a.m. the first tornado warnings were being issued for areas west of Peoria, Illinois. Over the next six hours there were more than 65 tornado reports in Illinois, Indiana, and western Kentucky.  Forward motion of the individual storms was as high as 65 mph.

Storm reports for November 17
NWS Storm Prediction Center

Some of the worst tornado damage occurred in central Illinois as a supercell moved northeast spawning multiple tornadoes. One of the hardest-hit communities was Washington, IL, about 10 miles east of Peoria. Damage also occurred in many other communities through central and Illinois and the western half of Indiana, including Gifford, IL only 17 miles north of my home in Champaign County. One of our CoCoRaHS observers was able to photograph this tornado as it passed to the north of her location.

Gifford, IL tornado taken from approximately 3.5 miles south of Gifford at 12:51 p.m. CST.
Photo by Jessie Starkey

Kokomo, IN, north of Indianapolis, suffered major damage and a state of emergency was established until 6:00 a.m. Monday morning. Several other Indiana communities also suffered major damage. As of this post, there have been six confirmed fatalities from the storms, all in Illinois and dozens of people injured in all the states affected.

Damage assessment teams from the National Weather Service will be out over the next two days to confirm and rate the tornadoes. It seems likely that there will be at least one EF4 tornado.

How rare is a tornado outbreak for the Midwest in November?  Like spring, fall is a transition season from the warm season to winter, and there is a secondary peak in severe weather in the fall. However, tornado outbreaks like today are rare. The last time there was a high risk for severe weather in November was in 2002 and in 2005. These high risk areas were further south than the one issued today.

Here's an interesting fact from the NWS Chicago office.

"Since 1986 there have been 194 tornado warnings issued in Illinois during the month of November. Of those 194 warnings issued, 101 of them (52%) were issued today. Credit to meteorology professor Victor Gensini (Northern Illinois University and College of Dupage) for researching this stat."

The National Weather Service Chicago has a great summary of the November 17 severe weather outbreak in the Midwest. There are also links to storm information from other NWS offices who dealt with the storms

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