Midwest Weekly Highlights - November 1-9, 2008
Balmy Weather Ushers in November
Much of the Midwest enjoyed sunny and unseasonably mild weather the first seven days of the month as strong southerly winds set up over the region. An intense fall storm over the Northern Plains brought rain and an end to the warm weather by the end of the period.
Temperature departures this period ranged from 5°F above normal in the eastern portions of the region to 8°F to 10°F above normal from northwestern Illinois northward through Minnesota (Figure 1). Temperatures the first four days of the month ranged from 5°F above normal in eastern Ohio to 16°F above normal in northwestern Iowa and southwestern Minnesota (Figure 2). Colder air began spreading east and south across the Midwest beginning on November 5.
Most of the region was precipitation-free the first five days of the month, and combined with the sunny, warm weather agricultural producers were able to make significant progress completing harvest. Some showers and thunderstorms occurred in southern Missouri on November 1 in association with an upper level low, and some rain fell in Minnesota, Wisconsin, and Michigan November 2-3 along the front marking the leading edge of the surging warm air. By the end of the period some precipitation had fallen on most of the region, but in most areas it was well below norma (Figure 3). The exception was in Minnesota south into northern Iowa, where precipitation was 200 to 500 percent of normal. The November 4 U.S. Drought Monitor continued to depict Extreme Drought in southern Kentucky, and Severe Drought from central to northeastern Wisconsin (Figure 4). While rain did fall in some of the drier portions of the Midwest, a more persistent wet pattern is needed to alleviate the existing drought conditions.
Basking in the 70s
On November 1 a cold front bisected the Midwest with unseasonably warm air to the south, and cooler but still warmer than normal air to the north (Figure 5). As the centers of high pressure moved to the east coast winds became southerly and the warmer air surged northward. With mostly clear skies on November 3 high temperatures soared into the 70s as far north as central Minnesota and Wisconsin and east to the Appalachians (Figure 6). Maximum temperatures records were set in the western half of the region on November 3 (Figure 7). The warm weather continued through much of the week in the central and eastern portions of the region in advance of the next weather system. Record high temperatures occurred in the Midwest each day from November 4 through November 7 (Figure 8).
Back to Reality
A strong low pressure system developed over the Northern Plains early on November 5, setting the stage for some significant changes to the weather (Figure 9). The storm moved slowly to the northeast into central Minnesota over the next 24 hours (Figure 10). Blizzard conditions developed over the Dakotas, while to the south and east showers and some thunderstorms developed ahead of the advancing cold front. Severe storms erupted over southwestern Missouri during the early morning hours of November 6, including storms that produced two tornadoes. In Barry County, MO an EF-1 tornado produced damage along a seven-mile track. A few boat docks and a boat shed were destroyed, and there was tree damage. Scattered severe storms were also reported in Iowa and Minnesota
Although the heaviest snow with the Northern Plains system occurred in the Dakotas, one to more than four inches of snow accumulated across southwestern Minnesota and extreme northwestern Iowa (Figure 11). Cold air continued to spread east and south, and by November 8 temperatures across the Midwest were generally below normal. On November 8 high remained below freezing across northern Minnesota, and were mostly in the 30s and 40s elsewhere as large low pressure system aloft spun over the Great Lakes (Figure 12). Cold, breezy, and cloudy conditions persisted across the Midwest until the low lifted out to the northeast late on November 9 (Figure 13). Lake-effect snow fell across the Michigan Upper Peninsula, bring the first significant snow of the year to the area (Figure 14). Shingleton, MI (Alger County) reported a storm total of 12.8 inches of snow, and a number of other locations reported more than 10 inches.