Midwest Weekly Highlights - January 1-10, 2011

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A Quiet Start to January

The first ten days of January were uneventful across the Midwest. Temperatures and precipitation were both mostly below normal. Snowfall was generally limited to lake-effect areas until January 10th, when snow spread across the western half of the region.
 

Cold Weather Continues

A generally persistent northwest flow of air associated with an upper level trough of low pressure aloft over the Midwest (Figure 1) kept temperatures near to below normal throughout most of the region (Figure 2). Temperatures were 1°F to 2°F above normal in western Missouri and Iowa. The coldest portions of the region were northern Minnesota, where temperature departures ranged from 4°F to 6°F below normal, and in eastern Kentucky were departures were 3°F to 4°F below normal. There were numerous record highs and record high minimum temperatures recorded the first two days of the month in the eastern portion of the region.
 

Dry Weather Persists

Precipitation was well below normal across most of the region this period (Figure 3). Western Iowa and Minnesota recorded from two to three times the normal precipitation, but most of that occurred on January 1st and January 9th. Otherwise, only light snow dusted the Midwest the first ten days of the month with the exception of the usual lake-effect areas (Figure 4). Snowfall totaled 45 inches in the Keweenaw Peninsula of Upper Michigan where it snowed almost continuously for seven straight days. The South Bend, IN airport measured 32.6 inches in 24 hours and 38.6 inches for a lake-effect storm event on January 7-8. At the end of this period snow cover was four inches or more across northern Iowa, the northern three-quarters of Wisconsin, and all of Minnesota (Figure 5). Snow depths of four inches or more were also observed along the western shore of Lake Michigan and in northeastern Ohio.

There was little change in the U.S Drought Monitor as it continues to depict dry conditions in the Ohio Valley, Indiana, southern Missouri, and far northeastern Minnesota (Figure 6).
 

More Snow on the Horizon

A developing low pressure system brought heavy snow to the extreme western portions of the region on January 9th, and by the morning of January 10th more than six inches of snow had piled up in western Iowa and southwestern Minnesota (Figure 7). The low was expected to move steadily eastward, and winter weather advisories blanketed the central Midwest in reaction to and in anticipation of the snow with this system (Figure 8).

-SDH-