Midwest Overview - February 1-7, 2003

Precipitation activity revived in the northern Midwest during the first week of February, as a strong weather system followed by several days of lake effect snow helped to establish a substantial snow cover. The storm passing on February 2 and 3 left most of the Midwest with some precipitation, including a swath of south central Minnesota through Minneapolis that received 0.50 to 1.00 inch of liquid water equivalent and the Upper Peninsula of Michigan, which received more than 1.00 inch of liquid water equivalent (Figure 1). The storm track area received more than 300% of normal for precipitation between February 1st and 7th (Figure 1a). Two feet of snow was quite common in the UP of Michigan, while a foot or more fell along the Minnesota / Wisconsin corridor affected by the storm (Figure 2). As is commonly the case, to have enough moisture for large scale precipitation, temperatures were several degrees Fahrenheit above normal over most of the Midwest (Figure 3). The precipitation received did result in the drought status of the UP of Michigan being reduced to abnormally dry from the status of moderate drought (Figure 4, National Drought Mitigation Center). However, the overall pattern of drought in the Midwest changed little, although the excellent snowfall did help to ameliorate some of the negative impacts of the recent snow drought on winter recreation.

The largest amount of snow for the system on February 2 and 3 occurred well to the north of the surface low, where a training band of snow across Minnesota and Wisconsin kept bringing more and more snow to the same swath (Figure 5, UIUC Dept Atmos Sci). As a new cold front approached on the 3rd, a very narrow but intense line of convective showers developed in the warm sector, bringing a quarter inch or more of heavy rain in less than an hour and then moving onward (Figure 5a, National Weather Service). In Michigan, classic lake effect snow bands formed (Figure 6, NWS), and many areas in the UP of Michigan, and even some places in northern Lower Michigan, have 1-2 feet or even more snow on the ground. At the end of the period, a low passing to the south brought some significant precipitation to southern Missouri and Kentucky, and some light snow further north. The low also brought stronger winds in its wake, intensifying the lake effect again on the 7th. Along I-94 east of Benton Harbor, MI, reduced visibility and slippery roads resulted in a 90 vehicle pile-up, with one fatality.