January 1-10, 2002: A Strong Warm-Up Occurs.

A large high pressure center dominated the central U.S. from January 1 to 6, allowing a Pacific air mass to moderate under days of solar radiation. Strong warm advection from the west commenced with the dry passage of a warm front on the 7th, culminating in record warmth in the northwestern Midwest on the 8th and 9th. While the average temperatures for the period January 1-10 were below normal in Kentucky, most of the Midwest was well above normal, reaching more than 12°F above normal in Minnesota (Figure 9). On the record warm days, the maximum temperatures were more than 30°F above normal over wide areas of Minnesota, Iowa, and Wisconsin (Figure 10). Record highs were reported on January 8 at Des Moines, Cedar Rapids, Waterloo, Mason City, Lamoni, and Sioux City, IA; and St. Cloud, Rochester, and International Falls, MN. On January 9, record highs were set at Rockford, IL; Des Moines and Mason City, IA; Minneapolis and Duluth, MN; Eau Claire, La Crosse, Green Bay, Appleton, Oshkosh, Wausau, and Rhinelander, WI; and Marquette, Sault Ste. Marie, Alpena, and Muskegon, MI. Record high minimum temperatures were also set on the 9th at Rochester, MN, and Milwaukee and Madison, WI. Many non-first order stations also set records throughout the northwestern Midwest. A passage of a weak low center through the Ohio Valley brought an end to the record warmth on January 10, but temperatures remained well above normal.

A strong low pressure area circled to the south and east of the Midwest on the 6th and 7th, bringing the most notable precipitation to the region during the first 10 days of January (Figure 11). However, most of the region received less than 25% of normal precipitation for the first 10 days of January (Figure 12). A very light snow shield wrapped around the northern and western side of the storm, accounting for all of the snow during the period except for some lake effect (Figure 13). Away from the lake effect belts, the Midwest is greatly deficient in snow fall and snow cover this season. Chicago, for instance, has received only 1.7 inches in total during this snow season. The lack of snow has had a negative impact on winter wheat in the Midwest and Great Plains. In addition, soil moisture recharge has been considerably curtailed in the northwestern third of the Midwest, although there is still time to make up for this before the growing season.