Midwest Overview - January 2010

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Precipitation and Snow

Precipitation was near (within 1/2 inch) or above normal across most of Kentucky, Missouri, and Iowa. Small parts of Minnesota, Wisconsin, Illinois, and Ohio were also more than 1/2 inch above normal. The rest of the Midwest was below normal (Figure 1). The largest positive departures were in southern Missouri and Kentucky with 3 inches more than normal and the largest negative departures were in northern Michigan with 3 to 4 inches less than normal. January snowfall ranged upward from a few inches across the region, with more than a foot in locations in southwest Missouri and eastern Kentucky, and one to three feet just downwind of the Great Lakes (Figure 2). At the end of the month, snow was on the ground in most locations except for a narrow swath from northern Missouri to southern Ohio (Figure 3). There has been little change in the drought status in the upper Midwest during January (Figure 4).

Temperatures Swing from Cold to Warm and then Back to Cold

Temperatures for the month averaged below freezing for the entire Midwest (Figure 5). Minnesota and northern Iowa were the coldest with temperatures averaging in the single digits. Compared to normal, the upper Midwest was warmer than normal with departures of up to 5°F in upper Michigan while most of the southern two-thirds of the region was below normal with departures of down to -7°F in southwest Iowa (Figure 6). The region went from much below normal in the first 10 days, to much above normal in weeks two and three, before returning to below normal for the last week of January (Figure 7).
 

Varied Weather in January

The month began with very cold temperatures settled in across the Midwest. On the 6th, a winter storm approached from the west, and over the next two days, spread snow along a swath through the central Midwest leaving parts of northwest Iowa with up to 30 inches of snow on the ground. Following that storm temperatures moderated to around freezing and several days of freezing fog settled across the region. On the 20th, Iowa was hit with the worst of an ice storm that extended all the way to Ohio. Iowa ice accumulations of around 1/2 inch were widespread. On the 23rd to 25th another storm moved into the upper Midwest bringing everything from rain, sleet, ice, and snow to northern Minnesota. As the storm moved into Canada, high winds and continued snow on the back side of the storm brought blizzard conditions to western Minnesota and Iowa. Cold temperatures returned to the Midwest following the passage of this system. The final storm of the month tracked from the panhandle of Texas to the Carolinas on the 28th to the 30th. Along the north edge of this storm, up to a foot of snow fell across the southern edge of the Midwest.
 

Flooding Centered on Illinois in January

Early in January, the cold temperatures helped create ice jams that affected northeast Missouri, eastern Iowa, northern Illinois, and southern Wisconsin. Flooding eased in week two, but heavy rains in the southern half of the Midwest, associated with the storm on the 24th, exacerbated by melting snow pushed rivers in Missouri, Iowa, Illinois and Indiana above flood stage. The Illinois River and Wabash River systems had continued flooding issues that lasted to the end of the month.
 

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