Midwest Overview - March 22-31, 2003

Most of the Midwest enjoyed mild weather spring weather during most of this period. Average daily temperatures the last ten days of the month were 4 to 8F above normal (Figure 1). The temperature pattern the second half of the month reversed pattern the first half of the month (Figure 2), going from well below normal to well above. The result was that temperatures for the month ranged from 3F above normal in Kentucky to 4F below normal in northern Minnesota, Wisconsin, and the Michigan UP. (Figure 3).  High temperatures during this period were 10 to 15 degrees above normal.  Marquette, MI tied the record for the highest minimum temperature on March 23rd (34F) and on the 24th set a new record of its highest minimum temperature with a reading of 43F.  On the 24th a high temperature record was set at Flint, MI (70F), and tied in Lansing.  The mild weather completed the melting of much of the snowcover in the upper Midwest. The runoff from the melting snow and the potential for ice jams due to higher than normal spring ice cover prompted a flood watch to be issued for the Sturgeon River in the Michigan UP and for low lying areas near other smaller rivers and streams. On Lake Superior, the first downbound ships of the season were due at the Sault Ste. Marie Poe Lock on March 26th.  By March 27, however, winter had returned to the upper Midwest. A strong spring storm in the plains produced heavy snow in northern Minnesota, Wisconsin, and the Michigan UP, prompting the issuance of winter weather-related watches and warnings throughout the region.  By the morning of March 28, 4 to 8 inches of snow covered the ground in northern Wisconsin, northeast Minnesota, and the Michigan UP, with some locations reporting as much as 12 inches (Figure 4).  Strong winds produced by the storm resulted in gale warnings being posted for western Lake Superior.

Some light showers dotted Iowa, northern Illinois and southern Wisconsin on March 24 as a weak cold front slipped through the Midwest. As the front stalled near the Ohio Valley some strong thunderstorms developed over eastern Missouri and southwestern Illinois, resulting in some locations picking up one to two inches of rain. The most significant precipitation during the period came on March 27-28 as the strong spring storm lumbered northeast through the region.  South of the area of snow, a wide band of showers and some thunderstorms stretched into southwestern Missouri, but rainfall was generally not enough to make up the month’s deficit..  The late season snowfall did boost precipitation amounts in the northern Midwest, and March precipitation was above normal over the northern two-thirds of Wisconsin and the Michigan UP (Figure 5). Much of the remainder of the Midwest received less than 75 percent of normal precipitation.