Midwest Weekly Highlights - February 8-14, 2009

A Taste of Spring

The second week in February saw temperatures soar well above normal with precipitation much above normal in most areas.

For the first time since early January, temperatures were well above normal across the entire region this week. Average daily temperatures ranged from 8°F above normal in western Minnesota to 17°F above normal in southern Kentucky (Figure 1). Most of the region east of the Mississippi River experienced departures from 13°F to 16°F above normal. Record high temperatures were recorded from Missouri to Ohio February 9 to February 11.

With the exception of western Wisconsin and southeastern Kentucky, precipitation was from 200 percent to 500 percent of normal this week (Figure 2). Most of the precipitation occurred with a major storm that moved through the Midwest the middle of the week. Significant snow was generally limited to northeastern Minnesota, northwestern Wisconsin, and across the southern half of Iowa (Figure 3). At the end of the week snow depth of 4 inches or more was generally limited to the northern two-thirds of Minnesota, the northern half of Wisconsin, and the northern third of Michigan (Figure 4).

There was little change in the status of drought in the Midwest on the February 10 U.S. Drought Monitor. Dry conditions extended from southeastern Minnesota into the Michigan U. P., with Severe Drought in north-central Wisconsin (Figure 5).
 

Major Storm Rakes the Midwest

The week started out with a day of cooler weather as high pressure drifted across the Midwest, but by the morning of February 9 strong southerly winds became established across the Midwest as a storm strengthened in the Central Plains (Figure 6). High temperatures on February 9 reached the 60s as far north as southern Iowa, northern Illinois, and southern Michigan (Figure 7), the first of three days with unseasonably warm weather in the southeastern half of the region. While the southern Midwest enjoyed mild weather, sub-freezing temperatures resulted in freezing rain across northern Minnesota as precipitation advanced northward. The low pressure system moved northeast into northern Minnesota by the morning of February 10, trailing a cold front through Iowa and Missouri. Favorable upper level wind profiles and warm, unstable air set the stage for severe weather ahead of the cold front. A few severe storms occurred on February 9 with some damage due to high winds. Severe storms erupted again on February 10 in southwestern Missouri, including one that produced tornado, rated EF-1, that damaged two dozen homes and businesses in Springfield, MO (Greene County).

On the morning of February 11 a second and more intense low pressure center had developed along the cold front and was moving northeast through Missouri (Figure 8). Heavy rain was occurring ahead of the low, and severe weather developed east and south of the low's path. Tornado watches, high wind warnings, and flash flood and flood watches were in effect for much of the eastern U.S. (Figure 9). In the 24 hours ending at 6:00 a.m. CST on February 11 the heaviest rain occurred from southwestern Missouri across central Illinois (Figure 10). Two to almost 4 inches of rain fell from near St. Louis, MO to Jasper County, IL (Figure 11). Flash flooding was reported in Missouri and Illinois as a result of the heavy rain as the rain ran off the frozen ground and into rivers and streams. in the following 24 hours the heaviest rain fell across central Indiana into northwestern Ohio and in the thumb of Michigan (Figure 12). Severe storms were widespread from southwestern Pennsylvania through Ohio, Kentucky, and into northern Alabama and Georgia. An EF-1 tornado was reported southeast of Muncie, IN (Delaware County), dislodging a barn roof and damaging the roof of a single family home across the street. Severe thunderstorm winds gusting from 60 to 70 mph toppled trees and power lines and caused building damage throughout the affected areas in Kentucky. Ohio, and Indiana.
 

Strong Winds Blast Eastern Midwest

By early evening on February 11, the storm center moved to northern Indiana, and strong winds circulating around the low lashed Illinois and Indiana Figure sfc. Winds gusted to between 45 and 60 mph during the evening hours, resulting in tree, power line damage and some building damage. As the low moved to northern New York by the morning of February 12 (Figure 13), the strong wind gusts continued across Ohio and much of the northeastern U.S. (Figure 14). Scattered power outages were reported across Ohio as a result of the winds.
 

Snowstorm Dumps on Iowa

Another low pressure system developing in the Central Plains on February 13 produced snow across the southern half of Iowa, with amounts ranging from 2 to more than 8 inches. The heaviest snow fell in southwestern Iowa and across the central parts of the state. This storm lost some of its punch as it moved to the Ohio Valley on February 14, and left only 1 to 2.5 inches across northern Illinois, northern Indiana, and southern Wisconsin, with slightly higher amounts over southern Michigan (Figure 15).
 

Flooding Lingers

At the end of the week many rivers in the Midwest were in flood due to ice jams and the heavy rain during the week (Figure 16).

SDH