March Brings Warmer Temperatures for Most of the Midwest

Meteorological spring brought warmer temperatures for the first week of March (Figure 1). All locations in the Midwest recorded above normal temperatures except for central to northern Minnesota, northern Wisconsin and Michigan’s Upper Peninsula, where average temperature departures were near normal to as much as 6°F below normal. As for the rest of the Midwest, average temperature departures ranged from 1-14°F above normal (largest departures in Kentucky). Lee County, Kentucky, clocked in with an average temperature of 55.9°F (14.1°F above normal for the week). Minimum temperatures were widespread 1-6°F above normal, with isolated locations in excess of 6-10°F above normal (Figure 2). Maximum temperature departures were in excess of 10°F above normal for most of the Midwest (Figure 3). There were 139 high max and 29 high minimum daily temperature records broken or tied this week (Figure 4). Modified Growing Degree Day accumulations were less than 100 for the southern extent of the Midwest, but are tracking 100-300 percent of normal for this time of year.

Regional Differences in Precipitation

There were two regions of precipitation in excess of 1 inch this week (Figure 5). The heaviest precipitation fell in the Ohio River Valley, where many areas saw 0.75-2.7 inches of precipitation (0.25-1.75 inches above normal) (Figure 6). Champaign County, located west central Ohio, recorded 2.7 inches of precipitation (2.02 inches above normal). The second region of interest extended from eastern Iowa to northern Michigan, where precipitation departures were over 0.75 inches. Isolated locations in eastern Wisconsin recorded precipitation up to 1.25 inches above normal for the week. Dryness continued in northern Minnesota where less than 25 percent of normal precipitation fell (Figure 7). The central parts of Michigan, northern Indiana, and southeastern Kentucky observed less than 75 percent of normal precipitation. There were 177 daily precipitation records broken or tied this week (Figure 8). Flooding affected southwestern Indiana where many river gauges reported being at the minor flood stage on March 6 (Figure 9). A couple of river gauges in southeastern Illinois and western Kentucky reported moderate flooding.

Snowfall in the Northwestern Midwest

Two bands of heavier snowfall accumulations were recorded (Figure 10). Band 1 stretched from northern Missouri into northern Michigan, where many areas saw 1.5-4 inches (isolated 5 inches in northern Missouri and southern Iowa). Northern Missouri, eastern Iowa, western Illinois, and southwestern Wisconsin saw snowfall totals that ranged 125-300 percent of normal (Figure 11). Isolated locations in northern Missouri saw snowfall totals up to 750 percent of normal. The second band of interest stretched from southwestern Minnesota into Michigan’s Upper Peninsula where snowfall totals were in excess of 1.5 inches. Lake effect snowfall amplified snow totals in Michigan’s Upper Peninsula where Houghton County, Michigan received 15.8 inches. There were 44 daily snowfall records broken or tied in the Midwest this week (Figure 12).

Severe Storms March 5-6

A tornado outbreak occurred on March 5 (Figure 13) - 6 (Figure 14) where there were 35 tornado reports in Iowa, 1 in Indiana, 1 in Wisconsin, 1 in Missouri, and 1 in Ohio. In Iowa, three supercells produced 10 confirmed tornadoes. An EF-4 tornado recorded a path length of 69.5 miles through Madison, Warren, Polk, and Jasper Counties and estimated peak winds of 170 mph. This tornado was responsible for 6 deaths and 5 injuries. An EF-3 tornado hit Wayne and Lucas Counties with estimated peak winds of 138 mph and caused 1 death and 1 injury. There were 4 EF-2, 1 EF-1, 2 EF-0, and another tornado is still being categorized. In Indiana, an EF-0 tornado occurred in Cass County in the middle of the night resulting in damage to homes and agricultural buildings. Combined with the tornado reports, there were 32 hail and 158 wind reports. Locations in Iowa saw hail sizes ranging from golf ball to baseball diameters. There were 20 wind reports in excess of 65 mph and a peak wind gust of 81 mph recorded at the Rockford, Illinois Airport on March 5.