Midwest Weekly Highlights - October 11-17, 2006
What A Difference a Week Makes
The changeable nature of autumn weather in the Midwest was never more in evidence than it was the first 17 days of October. The first ten days of the month were highlighted by unseasonably warm weather, and this week had all the marks of early winter with record cold and the first snow of the season in many locations.
Temperatures this week ranged from 7°F below normal in eastern Ohio to 13°F below normal in parts of Wisconsin and Minnesota (Figure 1). The coldest weather occurred the first three days of the period, with temperatures gradually moderating the last half of the period. Temperatures for the month through October 17 now range from near normal in southwestern Missouri to 4°F below normal across the far northern portions of the region (Figure 2).
Precipitation was abundant across much of the region this week, with the exceptions of southwestern Minnesota and northeastern Iowa, and a small portion of southwestern Missouri (Figure 3). The northeastern portion of the region received much of its precipitation the early part of the period as the cold front sweeping through the region produced showers and some thunderstorms, and later snow. Precipitation in the the central and southern portions of the region came the last three days of the period as a low pressure system produced widespread and heavy rain. Precipitation this week ranged from only 10 percent of normal in far southwestern Minnesota to five times normal from the Missouri Ozarks through the Ohio Valley (Figure 4). Some precipitation fell in both areas of Extreme Drought in the Midwest, especially in Missouri (Figure 5), but these areas missed out on the heaviest precipitation.
Goodbye Summer, Hello Winter
As this week began a strong upper level trough was swinging down out of Canada and into the upper Midwest (Figure 6). The first of two cold fronts moved through the Midwest on October 11, dropping temperatures to near to below normal levels (Figure 7). The unseasonably cold air spilled in behind the second cold front which pushed through the Midwest and into the Appalachians by the morning of October 12 (Figure 8). Numerous low temperature and low maximum temperatures records were set across the region October 12-15 (see table below), ending the growing season for most of the region. Records for both daily snowfall amount and earliest measurable snowfall in the season were set at a number of locations in Minnesota, Wisconsin, and Michigan, and as far south as northern Illinois (Figure 9).
Lake effect snow fall was heavy in parts of the Michigan Upper Peninsula and along the western shore of Lake Michigan in lower Michigan. In the western UP, Herman (Baraga County) received 25 inches of snow, Watton (Baraga County), 19 inches; Pelkie (Houghton County), 18-20 inches; Twin Lakes (Muskegon County), 17 inches; and Ironwood (Gogebic County), 16 inches. In lower Michigan, Hastings (Barry County) received 8.0" inches of snow, and the heavy wet snow combined with the strong winds brought down trees and power lines in Barry County.
Most of the temperature records were set on October 12 as the surge of cold air invaded the region. Low temperatures the morning of October 12 ranged from the upper teens to low 20s in Minnesota to the mid 30s along the Ohio River (Figure 10). Temperatures made only a slow rise during the day as the cold air poured in, reaching only the mid 30s in the northern Midwest and the low 50s in the southwest and southern portions of the region (Figure 11). High temperatures on October 12 ranged from 15°F to more than 25°F below normal (Figure 12).
Strong Winds, Severe Storms
The strong low pressure system near James Bay pulling in the cold air also generated strong winds across the upper Midwest. Winds gusted in excess of 40 mph across Wisconsin and Michigan, with South Haven, MI reporting a gust to 62 mph. Some severe thunderstorms developed ahead of the strong cold front on October 11 across Ohio and eastern Kentucky, including one that produced a tornado in central Ohio. The tornado touched down near New Albany, OH (Franklin County), causing damage to several homes.
Concludes With Widespread Rain
The week ended quietly on October 17, with only some lingering light rain over northern lower Michigan and the eastern Michigan UP. By late in the afternoon of October 17, however, the next weather system was poised to enter the Midwest from the Northern Plains. A Snow Advisory was in effect for northwestern Iowa for October 18 in anticipation of a possible 2 to 4 inches of snow.