Midwest Weekly Highlights - September 10-16, 2013

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Mostly Dry

Most of the Midwest was drier than normal in the second week of September (Figure 1). While most of the region was below normal, much of the areas above normal were just a tenth of and inch or two above normal. A few small and scattered areas topped normal by more than two tenths of an inch with one large area in central Minnesota where precipitation totals exceeded 1.50" (Figure 2) bringing departures up to an inch above normal. Drought conditions were largely unchanged from the previous week but concerns about dryness continued to expand eastward (Figure 3).
 

Temperatures Drop

The 7-day average of temperatures was close to normal across the Midwest. Temperatures ranged from 2°F above normal in southwest Missouri to 3°F below normal in Upper Michigan but most of the region was within a degree of normal (Figure 4). The week began well above normal with minimum temperatures on the 11th (Figure 5) ranging from the upper 50s in Minnesota and Wisconsin to the lower 70s in parts of the other seven states. Later in the week temperatures cooled considerably bringing minimum temperatures into the 30s and 40s in most locations (Figure 6). The cooler minimum temperatures brought frosts and freezes (Figure 7) into northern Michigan on the 14th (Figure 6) and northern Minnesota, northern Wisconsin, and Upper Michigan on the 16th (Figure 8). Daily temperature records followed a similar pattern with hundreds of record highs early in the week and dozens of record lows later in the week.
 

Waterspouts on Lake Michigan

At least three waterspouts were confirmed over Lake Michigan near the Wisconsin-Illinois border on the 12th. The waterspouts were photographed by numerous people. Further north, there was also an unconfirmed sighting of a waterspout near Sheboygan.
 

-MST-