Midwest Weekly Highlights - November 1-7, 2010

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A Cold Start to November

Most of the Midwest dealt with colder than average temperatures the first week of the month. The only exception was the northwestern third of the region, where temperatures ranged from 1°F above normal from northwestern Iowa and northwestern Wisconsin to 9°F to 10°F above normal in extreme northwestern Minnesota. The core of the coldest air was in the eastern portion of the region, where daily average temperatures ranged from 5°F below normal in eastern Illinois to 8°F below normal across much of Ohio (Figure 1). Minimum temperatures, in particular, were much below normal over this region. An area over northeastern Indiana and northwestern Ohio experienced minimum temperatures that averaged 11°F to 12°F below normal (Figure 2). There were a handful of temperature records this week. Record low temperatures were observed on November 1-2 and again on November 6-7.

By the end of this week almost all locations had experienced freezing temperatures at or below 28°F. The coldest morning was the morning of November 6th, when temperatures reached the mid and upper teens in some locations as far south as southern Illinois and Indiana (Figure 3). As a high pressure system moved off to the south and east on November 7th (Figure 4), winds became southwesterly and quickly brought warmer air northward. The week ended with high temperatures on November 7th reaching the 60s all the way into northern Minnesota and east through Illinois.
 

Dryness Persists

Much of the Midwest continued to be dry this week (Figure 5). There were a few notable exceptions, however (Figure 6). An upper level system over the Gulf States early in the week brought heavy rain to parts of southwestern Missouri. As that system finally kicked out to the mid-Atlantic coast on November 4th, precipitation wrapping around the system extended as far east as eastern and south-central Kentucky, where 0.50 to almost 2.00 inches of rain fell. The November 2nd U.S. Drought Monitor continues to depict Severe to Extreme drought throughout the Ohio Valley (Figure 7).
 

First Snow!

Showers developing in the cold unstable air on November 4th were accompanied by some sleet at times in southern Wisconsin and northern and central Illinois, but the more winter-like weather occurred to the east. Very cold air plunging into the Midwest on strong northerly winds brought lake-effect snow to affected areas of Michigan, northern Indiana, and Ohio late on November 5th. A band of snow accumulating 2.0 to 3.5 inches fell over western Porter County, IN with slightly lower amounts over LaPorte County (Figure 8). There were reports of numerous slide-offs and minor accidents because of the snow. Lake-effect snow was reported in northwestern lower Michigan and light snow was observed along the lake south to the Indiana state line. On November 6th, one to three inches of snow fell in northeastern Ohio, with 3.0 inches reported in Chesterland (Geauga County).

-SDH-