Midwest Weekly Highlights - December 15-21, 2010

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Cold December Continues for Much of the Midwest

The third week of December started out cold with at least one station in every state recording a zero or below minimum temperature and -20s at several locations in the upper Midwest (Figure 1). Temperatures warmed by the end of the week but the average for the week remained below normal for much of the region (Figure 2). On the western edge of the region there were pockets averaging 1°F above normal but central and eastern parts ranged to as much as 12°F below normal. Daily temperature records were mostly record lows set on the 15th and 16th.
 

Two Snow Events Take Similar Paths

Two snow events affected the Midwest during the week. The first was on the 16th leaving a trail of fresh snow from southern Minnesota to eastern Kentucky (Figure 3). The second system followed a similar path across the region on the 21st (Figure 4). Both systems dropped several inches along their path. Precipitation totals to the southwest and northeast were much lighter (Figure 5). Away from the storm tracks, precipitation fell off to less than half of normal while southern Minnesota and northeast Iowa saw from two to five times normal precipitation (Figure 6). Daily precipitation and snowfall records occurred with each storm.
 

December Snowfall Totals

Snowfall continued to accumulate from Minnesota to eastern Kentucky during the week (Figure 7). Rochester, Minnesota (Olmsted County) has already broken records for both the snowiest December and the snowiest month with 37.9 inches. Other stations (LaCrosse NWS and Indianapolis NWS) were also ranked among their snowiest Decembers with 10 days remaining in the month. The northeastern two-thirds of the Midwest reported snow on the ground at the end of the week (Figure 8). In southeast Minnesota and west central Wisconsin snow depths exceeded two feet at some locations.
 

Driving Conditions Remained Dangerous

Traffic accidents blamed on the weather and road conditions claimed several lives for the second straight week. Fatal accidents were reported in Missouri (St. Charles County), Kentucky (Owsley, Russell, and Boyle Counties), and Illinois (Bureau and Washington Counties) while hundreds of other accidents kept police and other emergency responders busy. Snow and freezing rain made travel treacherous. Freezing rain was reported in Missouri and Kentucky with the first storm and reports stretched from Minnesota to Kentucky with the second storm.
 

-MST-