Midwest Weekly Highlights - March 25-31, 2013
Pockets of Above Normal Precipitation
During the last week of March, the southern Midwest and northern Wisconsin received at least 0.5" of precipitation, while a band stretching from southern Minnesota over to Michigan received very little precipitation throughout the week
(Figure 1). Much of the precipitation reported in the southern Midwest was a result of a large system that moved through on the 24th that brought several inches of snowfall to Missouri, Illinois, and Indiana and significant rainfall to Kentucky (details are in last week's Climate Watch). After the event on the 24th, precipitation was minimal across the region until later in the week when there was some rainfall in the southern Midwest (0.75" to 1.75" in southern Missouri) and mixed precipitation further north (0.5" to 0.75" total precipitation in northern Wisconsin with 1" to 2.5" of snowfall in northern Wisconsin and Upper Michigan) (Figure 2)
(Figure 3). Overall, precipitation was below normal for the Midwest except for the areas with significant precipitation mentioned above (Figure 4). There were several daily precipitation records set on the 25th, which were from the storm event on the 24th, and just a few dozen set after the 26th.
Below Normal Temperatures Continue
Consistent with the rest of the month, average temperatures continued to run significantly below normal during the last week of March (Figure 5). The largest departures of 9°F to 13°F were in northwest Minnesota and southeast portions of the region. Near to just slightly above normal temperatures were only recorded in northern Michigan and northeast Minnesota. Several daily temperature records were set, all of which were record lows.
Even though temperatures were chilly in March, the latest outlook from the Climate Prediction Center indicates a greater chance for above average temperatures over the next couple of weeks (Figure 6). The shift in temperatures may result from a forecasted switch of the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) from the negative phase to the positive phase
(Figure 7). When the AO and NAO are in the positive phase, temperatures are often above-normal in the eastern United States.
In addition to the sprouting of leaves on trees and blooming flowers, another sign of the spring season is more frequent severe weather. During the last week of March, there were a few severe weather reports, all of which were hail reports in Missouri (Figure 8). The hail reports resulted from a low-pressure system that brought severe thunderstorms to much of Oklahoma, northeast Texas, and western Arkansas and Missouri on March 30th
(Figure 9). The largest hail report of 1.5" was in Iron Gates, Missouri (Jasper County).
Drought continues to impact the western Midwest, with extreme drought (D3) still affecting portions of Minnesota and Iowa on the March 26th US Drought Monitor (Figure 10). The only improvement over the last week was in Missouri, where a large portion of the state is no longer depicted as abnormally dry (D0).