Midwest Weekly Highlights - December 1-7, 2003

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The winter begins…

The Midwest enjoyed a tranquil start to the first week of December and the start of meteorological winter. Temperatures ranged from 8F above normal in northwestern Minnesota to 5F below normal in eastern Ohio (Figure 1).  The upper Midwest – the northeastern half of Minnesota, Wisconsin, and Michigan -saw very little precipitation this week. In contrast, an area encompassing western Minnesota, the western half of Iowa, and far northwestern Missouri received more than twice the normal precipitation.  The remainder of the region received from 30 to 80 percent of normal precipitation (Figure 2).

High pressure overspread the Midwest behind on December 1 and 2, although by late on December 2 clouds were spreading into Missouri, Iowa, and Illinois as a low pressure system developed in the central Rockies.  Snow developed over Iowa and Missouri late on the 2nd, and by the morning of December 3 four to eight inches of snow covered central Iowa, with one to three inches over portions of northwestern Missouri (Figure 3). As this system moved east, warmer air was drawn into the Midwest mostly light rain fell across eastern Missouri, much of Illinois and Indiana. This system moved off to the east late on December 4, pulling some colder air in behind it. At the same time, an Alberta Clipper was diving southeast out of the northern plains.  A broad area of light snow accompanied this system as it moved into the Ohio Valley. The heaviest snow, generally 4-6 inches, fell in a band from north-central Illinois through northwestern Indiana into northwestern Ohio.  Some amounts in this band were:  Monmouth, IL - 5.0”; Monee, IL – 4.7”; Fort Wayne, IN – 4.7”; Francesville, IN – 4.8”; Plymouth and Decatur, IN – 6.0”; Van Wert, OH – 6.5”; Stow, OH – 9.9”. By the morning of December 6 this system had moved well to east and merged with a second system in the southeastern United States to produce a December nor’easter along the eastern seaboard (Figure 4).