April 1-7, 2008
Midwest Weekly Highlights - April 1-7, 2008
Another Active Week
Heavy rain and heavy snow made their marks during the first week of April, with few signs that the active weather pattern would abate.
The was a marked difference in temperature departures the first week of April. Temperatures over the southwestern third of the region ranged from 1°F to 5°F below normal, with the largest negative departures found over Missouri (Figure 1). In contrast, temperatures averaged 3°F to 4° above normal across northeastern Wisconsin and northern Michigan, and 1°F to 2°F above normal across southeastern Ohio and eastern Kentucky.
On the whole, precipitation was above normal in the Midwest this week, with only a narrow band through the central Midwest getting less than normal precipitation (Figure 2). Precipitation was three to five times normal for the week in the southern third of the region, and two to four times normal in the northern third. Most of the precipitation in the northern Midwest fell as snow, and snowfall for the week was 500 to 700 percent of normal (Figure 3). The heavy precipitation in the northern third of the region will help improve the somewhat dry conditions still existing there. On the April 1 U.S. Drought Monitor a small area of Moderate drought was depicted over west-central Minnesota (Figure 4). However, the heavy late week precipitation in that region occurred after the Drought Monitor was issued.
Heavy Snow in the UP
On the morning of April 1 the storm that brought March to a close had intensified as was over the central Great Lakes. Heavy lake-effect snow piled up in the Michigan UP, with as much as two feet in the central UP along the shore of Lake Superior (Figure 5). Eight to 10 inches fell across much of the region, with a small core of 18 to 24 inches in Marquette County (Figure 6). Marquette, MI received 15.8 inches of snow on April 1, a new record for the date.
More Heavy Rain for the Soggy South
High pressure over the Midwest provided a day of generally nice weather on April 2, but late in the day another storm was taking shape over the Central Plains and by the morning of April 3 rain had already spread eastward into the Ohio Valley (Figure 7). Over the next 24 hours heavy showers and thunderstorms rolled across the Missouri Ozarks into western Kentucky, southern Illinois, and southern Indiana. Two to four inches of rain fell across much of this area between the morning of April 3 and the morning of April 4, with isolated amounts in excess of 6.50 inches. Severe storms were reported across southern Missouri and Illinois on April 3, with most from reports of hail. A few thunderstorms with damaging winds were reported in Kentucky. The heavy rain caused another round of flash flooding and road closures in these areas, and exacerbated flooding already in progress on rivers and streams. A two-year old child died in Kentucky when her mother lost control of her car after driving into high water. Much of this same region has received 12 to more than 15 inches of rain in the past five weeks (Figure 8). At the end of the week stream flows were well above historical averages across much of the Ohio Valley (Figure 9).
The weekend of April 5-6 brought pleasant spring weather to all but the far northern portions of the Midwest. Sunny and warmer weather spread across the southern two-thirds of the region, with high temperatures in the 60s as far north as central Minnesota and northern Wisconsin on April 5 (Figure 10).
Northern Minnesota Buried in Snow
While much of the region enjoyed the spring weather on April 5-6, a cold front stalled over northern Minnesota, keeping temperatures there in the 30s and 40s. On April 6 a compact wave of low pressure developed along the front (Figure 11), and resulted in very heavy snow in a narrow band that stretched from eastern North Dakota across the Iron Range of northern Minnesota (Figure 12). The snow began late on April 5, and continued through much of the day on April 6. Snowfall amounts across northern Minnesota were generally in the 6 to 12 inch range, but portions of St. Louis County received more than two feet of snow. 26 inches were reported in Babbitt, MN, and 32 inches accumulated near Virginia, MN. This was the largest ever April multi-day snowfall in the Iron Range. The heavy wet snow caused trees and powers lines to snap, resulting in power outages to thousands of customers. In northeastern Minnesota additional travel problems occurred as the snow became mixed with sleet and freezing rain.
SDH