March 22-31, 2010
Midwest Weekly Highlights - March 22-31, 2010
Early Spring Warmth
As March drew to a close much warmer air spread northward through the entire Midwest, with a number of locations reaching 80°F for the first time since last fall. Temperatures the last ten days of March ranged from near to slightly below normal in Kentucky to 7°F above normal in Minnesota (Figure 1). This pattern of near to below normal over the southern Midwest and much above in the north persisted much of the month. Until the end of the month only a handful of temperature records were set in the region. On March 31 numerous maximum temperature records were set in the western half of the region. Pellston, MI reached 78°F on March 31, tying the all time March high temperature record last reached on March 8, 2000.
As far as precipitation was concerned, a southern storm track resulted in a case of feast or famine for the Midwest the last ten days of the month. Precipitation over the southern half of the Midwest was 100 to 200 percent of normal, except for a portion of central Kentucky (Figure 2). In the northern half of the region, precipitation was less than 10 percent of normal for most for the area, and portions of Wisconsin and Michigan received no measurable rain (Figure 3). The March 30 U.S. Drought Monitor (Figure 4) depicted areas of Abnormal Dryness across central Kentucky and north-central Minnesota, as well as northern Wisconsin, the entire Michigan U.P. and the northern portion of Lower Michigan. An area of Moderate to Severe Drought continued to be depicted across northwestern Wisconsin.
Southern Storm Track
Two strong low pressure systems were responsible for the majority of the precipitation the last ten days of March. The first of these moved through the region on March 24-25. Low pressure developed over the Southern Plains in response to an upper level closed low over Oklahoma (Figure 5). Rain spread north as far as southern Iowa and extreme southern Wisconsin on March 24, and east into Ohio on March 25 (Figure 6). Heavy rain in southwestern Missouri on March 25 resulted in flash flooding (Figure 7). A strong cold front pushing through the northern Midwest prevented any further northward movement of the precipitation shield with this low. The low moved through the Ohio Valley and to the mid-Atlantic coast by the morning of March 26. As the cold front followed the storm into the Ohio Valley, rain changed to freezing rain and snow in southern Ohio. Up to an inch of snow was reported north of Cincinnati. The wintry weather was responsible for a number of traffic accidents and delayed school openings on March 26.
After just two days of fair weather, a second storm took aim on the southern Midwest. This system was almost identical in configuration and path to the previous storm. A closed upper low over Oklahoma was reflected by a strong surface low on the Oklahoma-Kansas border on March 27 (Figure 8). Precipitation again developed from Missouri eastward through Ohio (Figure 9). The storm moved slowly through the region until later on March 28, when it accelerated east.
There were only isolated reports of severe weather this week. Severe storms with hail were reported in eastern Ohio on March 22. Thunderstorm winds downed five trees in southern Indiana on March 25, and one inch hail was reported in southwestern Missouri on March 27.
Sunny and Warm
High pressure moved over and then east of the region by March 30, producing southerly winds across the Midwest. Temperatures quickly warmed from the 50s on March 29 to the 70s and 80s on March 31. The warmest weather was found across central and southern Missouri, where high temperatures reached the summer-like mid 80s on March 31 (Figure 10).
Flooding Declines
Dry weather in the upper Midwest allowed river levels to drop in most areas, but moderate to major flooding was still occurring on the Red River in Minnesota and on portions of the upper half of the Mississippi (Figure 11). Minor flooding was occurring on other streams in the western Midwest, and along the Wabash River in Illinois and Indiana (Figure 12).
-SDH-