Midwest Weekly Highlights - December 1-7, 2015

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Warm Start to Winter

After one of the warmest November’s on record across the Midwest, warm temperatures continued into December (Figure 1).  Unseasonable warmth blanketed northern Minnesota, northern Wisconsin and the U.P. of Michigan, where temperatures were 9-15°F above normal (Figure 2).  Some areas in northern Minnesota had even greater departures above normal.  Red Lake Falls in Red Lake County, MN was 19.9°F above normal, while the International Falls Airport in Koochiching County, MN was 18.0°F above normal.  Farther south, Iowa was mainly 5-9°F above normal. The rest of the region was generally 1-4°F above normal, with areas near to slightly below normal in southern Illinois and Indiana.
 

Snowy Minnesota, Dry Upper Ohio Valley

While most of the period was dry across the region, a storm on November 30-December 2 brought ample precipitation to portions of the region (Figure 3).  The strongly-occluded low pressure system moved into southern Minnesota on November 30 through the morning of December 1, dumping 6-12 inches of snow across southwest Minnesota and northwest Iowa (Figure 4).  The storm continued into December 2, leaving more than 4-8 inches in northeast Minnesota (Figure 5).  However, warm temperatures melted most of that snow by the end of the period (Figure 6).

Along the cold front, more than an inch of precipitation fell across Kentucky through the morning of December 1 (Figure 7).  However, dry air surged in behind the front through Missouri, Illinois, Indiana, Michigan and Ohio, leaving those areas with minimal precipitation.  High pressure filled in during the remainder of the period, leaving these areas with less than half the normal amount of precipitation for the period (Figure 8).
 

Slight Drought Improvement

Drought improved slightly in the Midwest in the latest Drought Monitor for December 1 (Figure 9).  The remaining slivers of moderate drought in far southeastern Illinois were eliminated, as well as some in southwest Indiana.  Over 18 percent of Indiana remains in moderate drought.  No improvement was made in Michigan and nearly 16 percent of the state remains in drought.  However, the Climate Prediction Center called for an increased chance of above-normal precipitation by the middle of December, which could bring drought relief (Figure 10).

-BJP-