Midwest Weekly Highlights - January 18-24, 2008

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Cooler Yet

High pressure that built over the eastern Plains helped to drive in persistently cold air from Canada. The entire region was below normal for the third week of January (Figure 1). This is in stark contrast to last week where temperatures were close to or well above normal. Minnesota, Wisconsin, Iowa and sections of northeastern Illinois all saw temperatures dipped down to over 20°F below normal. Missouri, central Illinois and Indiana typically kept their average temperatures around 8°F to 14°F below normal while the eastern half of the region remained closer to normal with average daily temperatures ranged from only 4°F to 8°F below normal.

There were only two instances during the week where precipitation fell and both occurred from weak to moderate clipper systems. The vast majority of the midwest received only 1/10th of the precipitation normally expected (Figure 2). The precipitation fell in snow form along a line stretched from northern Iowa / southern Minnesota through Wisconsin and northern Illinois during a three day period from Monday the 21st through Wednesday the 23rd (Figure 3). Areas where the snow fell received near normal to a slight surplus of precipitation. Missouri, central to southern Illinois, Indiana, Ohio and especially Kentucky fell anywhere from 0.40" to over 1.20" behind their normal (Figure 4). This has now been the second consecutive week with only light to moderate precipitation. There was only a slight improvement seen in the D1 affected areas in northern Wisconsin (Figure 5) when compared to last week. All other drought affected areas remained the same.
 

Another Week with Little Excitement

Week three opened on the heels of a storm system that brought over a foot of snow along the shores of the Great Lakes. High pressure settled into the great plains and with it cold temperatures were brought down from the north and brought widespread cold across the midwest. Wind chills dipped quite low in the early morning hours:

City Location	Wind Chill
Flag Island, Minnesota	-48°F
Warroad, Minnesota	-44°F
Bemidji, Minnesota	-43°F
Spencer, Iowa	-33°F

 
Wind chill values that low are incredibly dangerous. Frostbite is likely and exposed skin can freeze within one minute. The dome of high pressure slowly shifted east through the weekend and through Monday the 21st. A weak clipper moved out of the Canadian prairie provinces that ushered in more cold air from the 21st through the 22nd. The system was able to squeeze out 8"+ in a few locations along a band that stretched from western Iowa through Wisconsin (Figure 6 - Figure 7). No new records were set during this week.

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