February 2006
Midwest Overview - February, 2006
The month of Feburary was cooler and drier than January, as several systems brought renewed opportunities for cold air and snow. The average daily temperature departures across the region for February were still slightly above average across much of the Midwest, ranging from 3°F above normal across northern Ohio, northern Indiana, and northern lower Michigan, to 5°F to 6°F below normal across northern and central Minnesota, where deeper snow cover helped to keep temperatures cooler. The remainder of the Midwest saw daily average temperature departures that hovered between 1°F below normal to 1°F above normal in a band from Iowa across Illinois and into Indiana (Figure 1).
Precipitation for the month was generally below average for a good chunk of the Midwest (Figure 2). The exceptions were across eastern lower Michigan into northern Ohio, where the Super Bowl Sunday snow storm brought above average precipitation. Much of Minnesota, Iowa, and Illinois saw precipitation deficits, with generally 25 to 75 percent of normal. However, many of the weather systems this month seemed to bypass the state of Missouri, where precipitation deficits in this state ranged from a meager 2 percent to 10 percent of normal! Snowfall for the month of February was generally much below average (Figure 3), especially across Illinois, southern Iowa, and Missouri. However, with the change in the weather pattern from January, storm systems tended to track further north, and were generally concentrated along the U.S./Canadian border, giving Minnesota, Wisconsin, and Michigan 150 to 200 percent of normal snowfall for February. Similarly, a few systems tracked further south, across Kentucky and Tennessee, giving these regions 200 to 300% of normal snowfall for February.
Noteworthy events during February included the snowstorm on Super Bowl weekend, a severe weather outbreak coincident with blizzard warnings, and the coldest air of the winter season. The snowstorm on February. 4-5 brought 5 to 8 inches of snow to the eastern parts of lower Michigan, which helped to knock out power to several thousand customers in the Detroit, MI metro area (Figure 4). Cold weather followed on the heels of this system, ending the above normal temperature streaks across many locations in the Midwest. During the week of February 15-21, a powerful area of low pressure moved northeast through the Midwest, along a stationary front roughly located from Kansas City, MO, to Chicago, IL, to Alpena, MI. This storm system brought warm, humid air northward, and dragged much colder air down behind it. The clash of the two very distinct air masses resulted in a few tornado watches across Missouri, Illinois, and Indiana, while heavy snow and blizzard conditions prevailed across Iowa, Wisconsin, and Michigan (Figure 5). Finally, once the system departed, the coldest air of the season followed, bringing sub-zero minimum temperatures as far south as central Illinois and northern Missouri (Figure 6).
Winter 2005-06
The winter of 2005-2006 will likely be most remembered for the radical change in temperatures from December to January, where average daily temperature departures changed by some 20°F during the course of those two months. In the end, the average daily temperature departures for the winter were above normal for the entire Midwest. The largest departures from normal occurred in northern and central Minnesota (+6°F to +7°F), and the smallest departures were found in eastern Kentucky (0°F to -1°F). The remainder of the Midwest saw temperature departures that were some 2°F to 5°F above normal (Figure 7)Precipitation was scarce across southwestern Missouri this past winter, where many locations received only 25 to50 percent of the long-term normal precipitation totals. The only locations that received near or above average winter precipitation was across eastern Wisconsin and much of Michigan, where precipitation totals were 100 to 150 percent of normal (Figure 8). Much of the lack of precipitation can be attributed to a general blocking pattern across the U.S., with a ridge in the southwestern U.S., and general troughiness on both the east and west coasts (Figure 9, Climate Diagnostic Center). This left many of the systems that generate precipitation to skirt the Midwest, save a few major storm systems that produced copious rainfall or snowfall. With the recurrence of above average daily temperatures, snowfall this winter was generally lacking. Missouri, Illinois, and Ohio experienced the least amount of snow this winter, and snowfall amounts were generally 25 to 50 percent of the long-term normals. However, snowfall was closer to normal across Kentucky (75 to100 percent of normal), and the upper portions of the Midwest, from northern Minnesota to northern and eastern Michigan, where locations reported 100 to125 percent of normal snowfall for the winter (Figure 10).