Midwest Weekly Highlights - December 22-31, 2010

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Warm in the Upper Midwest, Cool to the Southeast

Temperatures for the last ten days of the year averaged as much as 10°F above normal in the upper Midwest while averaging up to 7°F below normal in southeastern Kentucky (Figure 1). The period saw a wide range of temperatures. Temperatures dropped following a storm that brought a snow on Christmas Eve and Christmas and then warmed with strong southerly winds ahead of a cold front that moved through the region on the 30th and 31st. Record lows occurred on the 26th through the 29th with record highs occurring on the 29th through the 31st.
 

Precipitation Also Varied Across the Region

Precipitation amounts ranged from less than a tenth of an inch to well over an inch for the last ten days of December (Figure 2). Most of the eastern half of the Midwest was below normal while the western half was near normal to well above normal. Northwest Indiana, southeast Michigan, and the northern edge of Ohio received less than 10% of normal while west-central Minnesota picked up five times its normal precipitation (Figure 3). Over 100 precipitation records and 200 snowfall records were set throughout the period.
 

More Snow

Minnesota picked up the most new snow with a system on the 22nd, blizzard conditions on the 31st, and snow on the 24th and 25th which was more widespread. The system on the 24th and 25th brought a white Christmas to much of the region (Figure 4). As the storm moved to the east coast of the US, it brought blizzard conditions snarling after holiday travel plans affecting thousands of flights across the country. As warm, moist air moved across the snow covered Midwest, dense fog developed in many locations. The fog affected both air and auto travel. The warm days at the end of the month melted much of the snow on the ground for the southern Midwest. However Minnesota and western Wisconsin still had more than a foot of snow on the ground as the new year began (Figure 5).
 

Tornadoes Return on 30th and 31st

A strong cold front brought unstable weather and thunderstorms to the Midwest as it moved across the region on the 30th and 31st. Severe weather, which had been absent throughout December, returned as numerous tornadoes, some as strong as EF3 rated on the Enhanced Fujita Scale, touched down in Missouri and Illinois (Figure 6). Two fatalities were associated with an EF1 tornado in Dent County, Missouri. Two additional deaths north of Rolla, Missouri (Phelps County) were due to an EF3. Across Missouri damage was severe with 280 buildings damaged and 50 destroyed. NWS offices in Springfield and St. Louis, Missouri and Lincoln, Illinois have confirmed 17 tornadoes in Missouri and three in Illinois.
 

Flooding Near Cleveland

An ice jam on the Chagrin River in northeast Ohio led to a flood advisory for Cuyahoga and Lake counties. The advisory was issued on New Year's Eve following the formation of the ice jam.
 

Rising Lakes in Minnesota

Increased precipitation in the eastern Dakotas and western Minnesota has led to multiple hydrological issues in the area. Recent years' spring flooding on the Red River and the ongoing Devils Lake situation have received a lot of government and media attention. Another issue is the rising lake levels on numerous Minnesota lakes. In Ottertail County, Minnesota, Lake Alfred is the latest of several lakes that have risen enough to affect buildings and roads. Minnesota DNR has been working to establish outlets on several lakes to prevent them from rising further.
 

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