February 2007
Midwest Overview - February 2007
A Very Cold February
February temperatures ranged from 4°F below normal in southern Missouri to more than 10°F below normal in a band from eastern Illinois, through central Indiana, and across the southern half of Ohio (Figure 1). Based on preliminary data, February 2007 ranks as the 12th coldest February on record for the Midwest, and the coldest since the Februarys of 1978 and 1979. Embarass, MN plunged to -42°F on both February 4 and February 5, taking honors as the coldest spot in the nation both days.
The largest temperature departures occurred across the central Midwest, coinciding with deep snow cover after a mid-month storm (Figure 2). During the first half of the month, there were frequent outbreaks of Arctic air, but not much in the way of precipitation and snowfall until the blizzard on February 12-14. In the days after this storm, minimum temperatures fell below 0°F for several consecutive days, and maximum temperatures remained in the teens and 20s.
Precipitation was normal to above normal in the Ohio Valley and much of the central portion of the region. Precipitation was two to three times normal from Iowa northward through much of Minnesota (Figure 3). The precipitation in Minnesota, in particular, was welcome as the northern half of the state has been in severe to extreme drought since July 2006. Notable dry areas during February were most of southern lower Michigan, and the southern half of Kentucky. Drought conditions continued to expand in Kentucky during the month as significant precipitation remained along and north of the Ohio River. February snowfall was much above normal from Minnesota through northern Iowa, southern Wisconsin, the northern two-thirds of Illinois, all of Indiana, Ohio, and northern Kentucky (Figure 4). Most of the snow in the central Midwest resulted from the storm on February 12-14, and a second clipper system that dropped another 2 to 4 inches of snow on the same area February 17-18 (Figure 5). Heavy snow in northern Iowa, Minnesota, and Wisconsin came in the last week of the month when two storms dumped one to two feet of snow on these areas (Figure 6).
Seasonal Summary: Winter 2006-2007
One could say there were two distinct winter seasons this year: December/January, and February. Temperatures the first eight days of December were well below normal in the wake of a major storm that hit the central Midwest from November 30 to December 1. However, mild weather quickly took hold, and by the middle of the month there were only traces of snow remaining from the December 1 storm. December temperatures ended ranging from 3°F to 11°F above normal. The largest departures (8°F to 11°F) occurred in Minnesota, northern Iowa, and western Wisconsin (Figure 7).
The warmer than normal weather continued well into January, with temperatures the first ten days of January averaging 16°F to 20°F above normal. Intrusions of colder air began to become more frequent by the middle of the third week of the month, a harbinger of what was to come. As noted above, February was very cold, cold enough to largely offset the warmth of December and January. As a result, temperatures across the southern two-thirds of the Midwest were near to slightly below normal, while across the northern third temperatures were 2°F to 4°F above normal (Figure 8).
Precipitation during the winter was above normal except for the far northern and far southeastern portions (Figure 9). Several major storms hit the region during the winter, starting with the snow and ice storm on November 30-December 1. An ice storm of historic proportions struck Missouri, Iowa, and western Illinois on January 12-14. This was followed less than a week later by a storm which dropped 4 to 7 inches of snow on these same areas. The frequent intrusions of Arctic air from the end of January through early February cranked up the lake-effect snow machine in Michigan as the frigid air streamed over the warmer waters of the lakes. A stormy February continued with blizzards on February 12-14, February 23-25, and another just starting to ramp up on February 28.
SDH