March 18-24, 2007
Midwest Weekly Highlights - March 18-24, 2007
Warm, with Variable Precip Across Region
The trend to a warm month continued this week as much warmer than normal weather remained entrenched in the Midwest. Temperatures ranged from 12°F above normal in southwestern Missouri to 0°F to 2°F above normal from northwestern Minnesota eastward through the northern Great Lakes (Figure 1). This cooler area in the northern Midwest coincided with the area that still had a depth of snow on the ground at the end of the week (Figure 2). On the start of astronomical spring on March 21, Embarass, MN plunged to -21°F, the coldest temperature reported in the contiguous U.S. that day.
Precipitation was from two to five times normal across the central Midwest, from southwestern Missouri into the northern half of Illinois and northeastward through southern lower Michigan (Figure 3). The heavy rainfall also occurred east from Illinois through Ohio. The frequent and often heavy rain in the central Midwest, along with ample winter precipitation, has result led in flooding and increasing concerns by agricultural producers about potential delays in spring planting. Outside of the central Midwest, precipitation was less than 25 percent of normal in much of Minnesota into northwestern Wisconsin, and in southeastern Kentucky. There was little change in the U.S. Drought Monitor status for these areas, with Extreme Drought still entrenched across northern Minnesota. (Figure 4).
The Wet Get Wetter and the Dry Get Drier
Rainfall was concentrated over the central Midwest where frontal systems tended to stall out this week. The first three days of the period were generally fair and pleasant. By March 21, however, strong southerly flow became established over the Midwest, drawing in much warmer, and more humid, air to the region. Showers and thunderstorms developed over the region each day the last four days of the period as a warm front first lifted north through the Midwest, then returned south and stalled out over the central Midwest. Severe weather was largely limited to March 21 as the warm front lifted north through the region. Weak tornadoes were reported in Iowa and Missouri, and there were numerous reports of hail in a number of states and damaging winds in eastern Michigan. The heaviest rainfall fell from late on March 22 through early on March 23 from north-central Illinois east through central Indiana and into west-central Ohio (Figure 5), occurring along a front that had stalled out (Figure 6). Reports of two to three inches of rain were common, causing flooding of many roads. In Lake County, IL two motorists had to be rescued from their vehicles after their vehicles became submerged under eight feet of standing water. A CoCoRaHS observer in Lake County reported a 24-hour rainfall total of 2.82 inches on March 23, with 2.27 inches coming in a two and a half hour period on the afternoon of March 22.
Much warmer air surged into the Midwest the last two days of this week. On March 23 Dayton. OH set a new record high minimum temperature of 56°F, breaking the ld record of 52°F set in 1991. On March 24 the record high minimum temperature of 57°F was tied at Dayton (first set in 1988). Record high minimum temperatures were also set at Columbus OH (58°F, previous record 57°F in 1929) and in Cincinnati (59°F, previous record 52°F in 1979).
Flooding Causes Headaches
The heavy precipitation over the central Midwest, and high river flows combined with ice jams in Minnesota caused flooding problems on numerous rivers and streams. The Minnesota River near Jordan, MN (Scott County) rose above flood stage on March 19, due to high river flow and ice breakup, causing minor flooding. In central Iowa the Des Moines River was near to above flood stage during the week at a number of locations. The Illinois River reached flood stage at Peoria and flood warnings were issued from Peoria south to Havana. Extensive flooding was occurring along White River in east-central and central Indiana, and officials in Hamilton and Marion Counties were making sand bags available to residents. High water in Hamilton County led officials to close portions of 13 roads.
SDH