Midwest Weekly Highlights - December 1-7, 2008

Winter Whips the Midwest

A cold and snowy weather pattern emerged across the Midwest for the first week of December.  An intense weather system on December 1-2 produced precipitation across much of the Midwest and ushered in well below normal temperatures across the region (Figure 1). Unsettled weather continued throughout the rest of the week with some part of the Midwest receiving snow each day between December 3-7. 

Precipitation was between 100% to 500% above normal across parts of Minnesota, Wisconsin, and most of Michigan (Figure 2). Most of this precipitation was in the form of snow, with the heaviest totals across Michigan. Northwest winds over relatively warm lake waters led to lake effect snows across much of western Michigan (Figure 3). Over two feet of snow fell in parts of Upper Michigan and northern Lower Michigan (Figure 4). While rain did fall in some of the drier portions of the Midwest, a more persistent wet pattern is needed to alleviate the existing drought conditions. Accumulation was much lighter across the rest of the region, but every Midwestern state saw some snow during the period.  Visible satellite imagery from December 4 showed snow cover over parts of Iowa, Illinois and Indiana, with lake effect snow bands continuing in to Michigan (Figure 5).

Despite the widespread snow, southern portions of the Midwest were dry with parts of Missouri receiving as little as 10% of normal precipitation this week.  This did little to relieve drought conditions in the region (Figure 6). Abnormally Dry (D0) conditions expanded to cover the entire state of Kentucky this week, while over three quarters of the state saw Moderate (D1) drought or higher.  Portions of Missouri, Illinois, and Indiana were also classified as Abnormally Dry (D0), while Moderate (D1) drought expanded across southern Ohio.

Temperatures were well below normal across the Midwest this week as arctic air plunged southward in the wake of the storm system on December 1-2 (Figure 7). Portions of Wisconsin, Illinois, Indiana and Kentucky saw temperatures much as 11°F below normal.  The western portions of the region were the warmest, but were still 2°F to 3°F below normal.    

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