Midwest Overview - October 1-8, 2002

A variety of weather visited the Midwest the first week of October. Early in the week, a stalled frontal system in the upper Midwest provided the focus for heavy showers and thunderstorms. The result was a band of 2 to 4 inches of rain from western Iowa through southern Minnesota, northern Wisconsin, and the Michigan UP (Figure 1). The influence of the front was very evident in the temperature departures for the week (Figure 2), with departures ranging from 6 to 8 degrees below normal in Minnesota to 8 to 9 degrees above normal in Ohio. The heavy rain prompted flash flood warnings in a number of these areas. Further south and east, the remnants of Hurricane Lili brought widespread rain to the southeastern half of the Midwest, but much less than had been orginally expected (Figure 3). The cold air to the north finally drove through the Midwest on October 4, sweeping the moisture with Lili to the east. Cool and very dry air settled in over the Midwest on October 5-7. The combination of high pressure, clear skies, and light winds resulted in freezing temperatures in much of the upper Midwest on the morning of October 7 (Figure 4), and scattered patchy frost in areas as far south as central Illinois and Indiana. However, temperatures the last three days of the week were near to only slightly below normal.