Midwest Weekly Highlights - November 10-16, 2008

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More Like What November Should Be

After a very mild start to the month, this week's weather was more typically November in the western two-thirds of the region, while mild weather persisted in the east.

Temperature departures this week ranged from 0°F to 3°F below normal from Illinois westward, with the coolest area in northeastern Missouri (Figure 1). Temperature departures in the east ranged from -1°F to 0°F in Indiana to +3°F to +4°F in Ohio and Michigan.

Precipitation was much above normal this week in two distinct bands across the Midwest (Figure 2). The first was from western Iowa east-northeastward into the Michigan U. P., and the second was east of a line from southern Illinois to southeastern Michigan. Precipitation in both of these areas was as much as three times normal for the week. In the northern half of Minnesota into northwestern Wisconsin precipitation was only 10 to 50 percent of normal. Southwestern Missouri received 50 to 75 percent of normal precipitation. The areas that received the precipitation this week are also the same areas experiencing severe drought depicted on the November 11 U.S. Drought Monitor (Figure 3).

Snowfall this week was mostly limited to lake-effect snows in the lee of Lake Superior and Lake Erie. Some snow fell from northwestern Iowa to southeastern Michigan early in the period (Figure 4).
 

A Taste of Winter

A low pressure system that began to develop on November 10 in western Texas gathered strength as it moved to central Kansas on November 11 (Figure 5). Rain spread across the Midwest on November 11, with some snow and mixed precipitation in the northern sector of the storm. Winter weather advisories were posted for Much of northern Iowa and southern Minnesota (Figure 6). One to two inches of snow accumulated across northwestern Iowa and southern Minnesota, with freezing rain from southern Minnesota into western Wisconsin. The freezing rain was responsible for numerous accidents, including one which resulted in a fatality in southern Minnesota. A teenager was killed in Le Sueur County when his car slid into a snowplow.
 

The Winds of November

A series of cold fronts were lined up to move through the Midwest the remainder of the week. The first of these pushed through the region on November 14 (Figure 7), accompanied by light showers in the north, and heavier rain south. A low pressure system in the Gulf of Mexico on November 14 moved northeast along the front and rapidly intensified over the Appalachians by the morning of November 15 (Figure 8). Heavier rain fell north and east of the low from southern Illinois into southern Indiana, and across the eastern half of Kentucky into southeastern Ohio. One-half to one inch of rain fell in these areas, with isolated amounts from 1.50 to 2.00 inches (Figure 9).

Lake-effect snow developed along the southern and eastern shores of Lakes Superior, Michigan, and Erie on November 16 as strong northwesterly flow developed over the relatively warm lake waters. Snowfall amounts in northeastern Ohio exceeded 5 inches in Ashtabula County on November 16 (Figure 10), with another 24 hours of lake-effect snow expected.

SDH