January 2007
Midwest Overview - January, 2007
A Warm January
The month of January, 2007, was quite warm for most locations across the Midwest, but not as warm as one year ago when numerous all-time records were set (January 2006 review). Nevertheless, January started out with temperature departures that were well above seasonal averages, and it wasn't until the final week of the month when routine arctic blasts roared through the region, bringing Midwesterners back to reality. For the month as a whole, temperature departures were warmest across the northern and eastern portions of the region, and coolest across the soutwest areas (Figure 1). In Minnesota, Wisconsin, and Ohio, departures were 5-7°F above average, with a cooling gradient to the southwest. Much of Iowa, southeastward through Illinois and into Indiana saw departures of 3-5°F above normal, and southwestern Missouri saw departures that were actually somewhat below average, on the order of 1-3°F.
For the most part, January, 2007, will be remembered for not only being warmer than average, but also much wetter than average. Numerous strong storm systems rolled through the region during the month, many of which had little cold air to tap and so the precipitation primarily fell as rain. An amazing band of precipitation totals greater than 5 inches (some 2 to 3 times the average monthly January total) extended from extreme southeast Missouri northeastward into southern Illinois, most of Indiana, and parts of western and northern Ohio (Figure 2). Precipitation totals dropped off markedly as one headed northwest into the upper Midwest, where drought remains a serious problem. In this area, precipitation totals were generally less than one inch, some 30-50% below normal for the month. Finally, snowfall during the month was generally below average for a good portion of the Midwest, although a few larger systems did produce measurable snow and ice across the region. Snowfall amounts were generally 2-4 inches across Illinois, southern Missouri, and southern Indiana and Ohio, while a bandof 10-15 inches was found across Iowa northeast into Wisconsin and Michigan (Figure 3). The most snowfall, in excess of 45 inches, was found across the Upper Peninsula of Michigan.
Warm, Rainy Start...Cold, Snowy End
After a warm December, the second month of climatological winter started out equally warm, with temperature departures well in excess of 10°F across most of the Midwest (Figure 4). Little in the way of major weather systems impacted the Midwest during the first week, but that would all change during the second week of January. An area of low pressure moved out of the Southern Plains States on January 14-15 (Figure 5) and scooted northeastward along a trailing arctic cold front. This set the stage for what would eventually turn out to be a historical ice-storm for parts of the region, especially Missouri, southern Iowa, and western Illinois. Parts of southern Missouri saw 3-6 inches of sleet, and 1-2 inches of ice (Figure 6). The tremendous ice accumulations snapped numerous power lines across the state, sending over 160,000 persons into the dark, where they remained without power for up to as many as 5 days. The massive ice-storm also featured several hundred vehicle accidents, which resulted in over 20 deaths in the Midwest alone. As if this wasn't enough, another potent winter storm brought 4-7 inches of snow on January 20, which did not help the recovery efforts across the region. A swath of snow from this system was found across Missouri, Iowa, Minnesota, and Wisconsin (Figure 7). Finally, as the month of January closed, numerous arctic air invasions were beginning to occur, and each was seemingly more potent than its predecessor. Daytime temperatures struggled to get out of the single digits above zero on the 30th, and nighttime lows dipped well below zero across the northern Midwest...perhaps a precursor to what the early parts of February, 2007 had in store.
Kruk