January Arrives with Frigid Temperatures
Average temperatures ranged from below zero to around 35°F northwest to southeast across the region. The northern halves of Minnesota and Wisconsin averaged temperatures below 5°F, with average temperatures greater than 20°F across and south of northern Missouri, central Illinois, northern Indiana, and southern Michigan. Kentucky averaged the week’s warmest average temperatures ranging between 30-35°F
(Figure 1). The coldest pockets of air impacted northern Minnesota, Iowa, Wisconsin, and far northwest Michigan on the 5th and 6th of January with preliminary temperature records set for 24 hour lowest maximum and 24 hour lowest minimum temperatures across Minnesota, Wisconsin, and Michigan from a cold air outbreak event that swept over much of the region. Average maximum temperatures remained below 30°F in the northwest two-thirds of the region, with the northwest half of the region averaging 9 to 15°F below normal (Figure 2). Average minimum temperatures dropped to 20°F below freezing across northern Minnesota and north-central Wisconsin, gradually increasing to the south and east, but never climbing above 30°F degrees on average across the region (Figure 3). Cold average minimum temperatures across northeast Minnesota, Wisconsin, Iowa, and the upper peninsula of Michigan, averaged 9 to 17°F degrees below normal (Figure 4). Elsewhere, temperatures ranged from 0 to 9°F degrees below normal with warmest temperatures in Kentucky and decreasing to the northwest.
Snow Falls Across the Central Midwest
Accumulated precipitation amounts of 0.5” to 2.5” fell during the first week of January across Illinois, Michigan, Indiana, and Ohio. Southeast Missouri recorded over 3.0” of precipitation. Much of Minnesota, Southwest Iowa, and Northwest Missouri remained dry with less than 0.2” of precipitation recorded (10-25% of mean) (Figure 5). The remaining portion of the region observed 125-300% of mean accumulated precipitation with southeast Missouri experiencing accumulated precipitation values of 300-400% of mean (Figure 6). A weather system moving from the northwest to the southeast across Iowa, northern and central Illinois, northern and central Indiana, and central Ohio resulted in snowfall on the 5th and 6th of January with depths measuring 4” to 7.5” and setting new 24 hour snowfall records (preliminary). Lake effect snowfall 10.0” to 15.0” also fell in regions along the Great Lakes (Figure 7). The storm resulted in accumulated snowfall 200+ percent of mean for these locations. Much of Missouri, southern Illinois, southern Indiana, Kentucky, and Minnesota currently only have accumulated snowfall values up to 50 percent of mean as of January 7, 2015 (Figure 8).