January 2011
Midwest Overview - January 2011
Cold and Snowy
January was a cold and generally snowy month, but was otherwise uneventful. While numerous weather systems brought snow to the region during the month, there were only two notable storms.
The mean upper level flow was characterized by a large trough over the eastern United States (Figure 1), and that favored the flow cold air into the Midwest. Temperatures during January were below normal across all but a small portion of the region. Temperatures ranged from near normal over a small portion of the upper Midwest to 5°F to 6°F below normal from western Minnesota south into western Missouri (Figure 2). The coldest weather of the month occurred on January 20-21, when temperatures plummeted to -30°F to -46°F across the northern half of Minnesota and northwestern Wisconsin, and -20°F or lower as far south as northern Iowa. In Minnesota, low temperatures plummeted to -46°F at International Falls (Koochiching County) and Babbitt (St. Louis County), and from -40°F to -43°F at six other locations. Elkader, IA (Clayton County) recorded a low of -30°F on the morning of January 21st. On the other side of the coin, temperatures across parts of southern Missouri pushed into the 70s near the end of the month as warm air was pulled northward ahead of a developing storm in the southern Plains.
Snow was a frequent occurrence during the month across most of the region. The highest totals were found in the lee of Lakes Superior and Michigan, and in northwestern Ohio (Figure 3) as northwest and west winds favored frequent lake-effect snows. Snowfall was more than twice normal this month from northwestern Minnesota south through northwestern Missouri, where snowfall was more than three times normal (Figure 4). Snowfall was also 200 percent of normal or more in the Ohio Valley. Des Moines, IA recorded snowfall on all but five days during the month. The South Bend, IN (St. Joseph County) airport measured 32.6 inches in 24 hours and 38.6 inches for a lake-effect snow event on January 7-8. The biggest large-scale snow event this month was a storm that moved across the central Midwest on January 19-20. Six to 12 inches of snow fell in a wide band across central Missouri. By January 22 snow covered the entire Midwest region (Figure 5), but by the end of the month the southern extent of the snow had retreated to a line from Kansas City, MO to Bloomington, IN (Figure 6).
Snowy, but Dry
Although snowfall was above normal in much of the Midwest, precipitation this month was below to much below normal (Figure 7). The exception was the area from northwestern Minnesota south through northwestern Missouri, where precipitation was 100 to 200 percent of normal. Most of the region received less than 75 percent of normal precipitation, with and area from southwestern Missouri into the Ohio Valley receiving less than 50 percent of normal.
The Iowa State Climate Office and Indiana State Climate Office also contributed to this report.
-SDH-