Midwest Weekly Highlights - January 8-14, 2009
Into the Deep Freeze
The mild start to January became a distant memory this week as the Arctic floodgates opened and frigid air spilled into the Midwest. By the end of the week low temperatures in the northern Midwest ranged from -20°F to less than -40°F.
The was a marked difference between temperatures across the snow-covered northern half of the Midwest and the snow-free south. Temperatures this week were below normal generally north of Interstate 80, ranging from 6°F below normal from central Iowa eastward to northern Ohio to 12°F below normal in Minnesota and western Wisconsin (Figure 1). Low temperatures across the northern half of Minnesota and northern Wisconsin were below zero every morning but one this week. Temperatures south of Interstate 80 ranged from near normal to as much as 4 °F above normal in southwestern Missouri.
Another series of low pressure systems moved through the Midwest this week, and most of the precipitation this week fell along and north of the tracks of the lows. Precipitation was four to five times normal for the week across southern Minnesota and much of Iowa, and was up to two times normal in a band eastward through northern Illinois, southern Wisconsin, and into northeastern Ohio (Figure 2). Precipitation was also above normal in most of the lake-effect areas. Most of the precipitation fell as snow (Figure 3), adding to the deep snow cover that currently exists across most of the northern half of the Midwest (Figure 4). Precipitation this week was not sufficient enough in drought-affected areas of Wisconsin and Kentucky to affect the dry conditions. Improvement shown in Kentucky on the January 13 U.S. Drought Monitor (Figure 5) mostly reflects the heavy rain that fell at the end of last week.
The March of Storms
The first of the storms this week came ashore in British Columbia on January, and by the morning of January 9 was located in eastern Nebraska (Figure 6). As the storm moved east-southeast, moderate to heavy snow spread from eastern Iowa across northern Illinois into southern Michigan and northern Ohio. To the south, freezing rain and dense fog caused travel problems in central Illinois and Indiana. The storm quickly moved off to the northeast from southwestern Indiana on January 10, but already another system was moving across the upper Midwest (Figure 7), the first of three "Alberta Clippers" to race through the region in a four-day period. This system kept snow falling across the northern Midwest on January 11, with the heaviest lake-enhanced snow over the western short of Lake Michigan. The second clipper entered the western portion of the region on January 12, bringing moderate heavy snow to first southwestern Minnesota and northern Iowa, and then to northern Illinois. As the second storm was moving through the eastern Great Lakes on January 13, the last system was dropping out of the Canadian Rockies (Figure 8). Snow rapidly developed over the Dakotas during the day, moving into western Minnesota and Iowa by mid-afternoon. By late evening snow was crossing the Mississippi River and spread southeast through Illinois and Indiana. On January 14 the storm moved through Illinois and Indiana, entering western Ohio by sunset, leaving 3 to 6 inches of snow in its wake.
During the first three days of this period 3-5 inches of snow fell across southern Minnesota and northern Iowa (Figure 9), while 5 to 8 inches fell across central Iowa into northern Illinois (Figure 10). In northeastern Illinois, southeastern Wisconsin, and southwestern Michigan, where the snow was at times lake-enhanced, 8 to 15 inches of snow accumulated (Figure 11). three to 5 inches fell across northern Ohio (Figure 12). Lake effect snow on January 14 in the wake of the low.
Colder and Colder
Each storm this week was followed by reinforcing surges of cold Arctic air. Wind chill warnings were in effect for large portions of the Midwest in the wake of the last storm on January 14 as strong northwest winds combined with the bitterly cold air to produce wind chill readings from -20°F to -50°F. High temperatures across Minnesota and Wisconsin remained in the teens and single digits the whole week (Figure 13), while overnight lows dropped to well below zero each day except one. On January 13 minimum temperatures records fell across northern Minnesota and Wisconsin, with some records dating back to the brutal winter of 1979 (Figure 14). The coldest reading on the morning of January 13 was -44°F at Embarrass, MN, followed by -42°F at Babbitt, MN, both in St. Louis County. International Falls, MN set a new record on of -40°F, breaking the old record of -36°F set in 1979. It was even colder on the morning of January 14 (Figure 15), with a record -48°F at Babbitt and -47°F at Embarrass. International Falls reached -42°F, tying a record set in 1972.
While those were the more spectacular records, record low minimum temperatures and record low maximum temperatures were recorded across much of the Midwest. A list of the records set or tied can be found at this link.