Midwest Weekly Highlights - April 10-16, 2007
Another Cold Week
Unseasonably cold weather continued into the second week of April, and precipitation was plentiful across the southern third of the region. Precipitation was two to four times normal across the southern third, with very little rain or snow across the far northern portions of the region (Figure 1). The temperature pattern for the week was almost a mirror image of the precipitation pattern, with the largest departures below normal in the southern third of the Midwest (Figure 2). Temperatures there ranged from 11°F below normal in southwestern Missouri to 9°F below normal in Ohio. In the northern Midwest, temperatures ranged from -1°F in extreme northwestern Minnesota to 5°F below normal in southeastern Wisconsin. The southern Midwest was affected by the clouds and precipitation from two major storm system during the week. Snow was again a factor in the central Midwest, with a broad swath of snow 2 to 4 inches from Iowa to Michigan, and more than 6 inches of snow in parts of Iowa, Wisconsin, and northern Michigan (Figure 3). Precipitation this week, as much as 3 inches, helped dry conditions over Kentucky westward to Missouri, where drier weather had been somewhat persistent the past several weeks. However, Extreme Drought conditions over northern Minnesota (Figure 4) saw little relief as the week's storm track kept precipitation well to the south .
The active weather pattern this week further delayed spring planting activities in the central and southern Midwest, and corn planting is running from about 20 percent behind the five-year average in Missouri to about 13 percent behind in Illinois. Corn planting is 1 percent ahead of average in Kentucky.
The Storm Train Rolls On
High pressure was retreating to the east coast on April 10, and another storm system was taking shape over the central Rockies. The storm rapidly intensified over the next 24 ours and by April 11 was parked over northern Missouri (Figure 5). Winter storm watches, warnings, and advisories were posted from Iowa to Michigan (Figure 6). By dawn more than 6 inches of snow had accumulated along the western Iowa-Minnesota border, and another band of 4 to 6 inches accumulated over central Michigan (Figure 7). South of the low pressure center, severe weather developed during the afternoon ahead of the front trailing from the low. Three tornadoes touched down in central Indiana, and there were numerous reports of large hail and damaging winds from eastern Illinois to central Ohio and northern Kentucky.
The low pressure center moved only to near Green Bay, WI by the morning of April 12, and snow was still falling over the eastern Midwest. Snowfall the morning of April 12 generally ranged from 3 to 6 inches from northeastern Iowa across southern Wisconsin and northern Illinois to the northern half of lower Michigan (Figure 8). There were isolated larger amounts, including 9.0 inches in Victory, WI (Vernon County); 7.9 inches in Black River Falls, WI (Jackson County); and 8.1 inches in Beach Park, IL (Lake County - CoCoRaHS report).
The Midwest had less than a one-day respite before the next storm began to take shape over west-central Texas on April 13. This storm followed a more southerly track, ending up in southeastern Arkansas by the morning of April 14 (Figure 9). As a result, most of the precipitation occurred over Missouri, the southern half of Illinois, Indiana, and Ohio (Figure 10). While most of the precipitation was rain, wet snow mixed with the rain from eastern Illinois through central Indiana and Ohio for a time on the afternoon of April 15. This storm rapidly intensified as it moved to the east coast, and produced heavy rain across much of southeastern Kentucky that resulted in widespread flash flooding, washing out and closing a number of roads and forcing the evacuation of some residents.
A Few Records
There were several temperature records set during the week. The most notable of these was a temperature of -3°F recorded in Marquette, MI on April 10. It was a new record low temperature for the date (previous record 3°F in 1979), and the latest ever subzero temperature to occur. The previous record had been set only the day before (April 9) with a reading of -1°F. On April 12, Marquette tied the record low maximum temperature of 28°F, first reached in 1992. On April 13 a record low maximum temperature of 42°F was reached in West Plains, MO, breaking the old record of 48°F set in 1952. In Jackson, KY, a record low temperature of 34°F was reached on April 15, breaking the old record of 37°F set in 1997.