November 1-7, 2007
Midwest Weekly Highlights - November 1-7, 2007
Mild Start, Chilly End
The period of quiet weather that ushered out the month of October continued into the first week of November. During the first five days of the month temperatures ranged from almost 5°F above normal in western Minnesota to 6°F below normal in southeastern Ohio (Figure 1). However, actual maximum and minimum temperature readings the first five days of the month were fairly uniform across the region. Highs were generally in the 50s to low 60s, rising to the low and mid 70s along and south of the Ohio River on November 5 (Figure 2). Lows started out in the 20s and low 30s on November 1, rising to the mid 40s across the southern two-thirds of the region on November 5. The coldest air of the season plunged south through the Midwest on November 5, dropping temperatures to well below normal levels for the rest of the period. When all was said and done, temperatures for the week ranged from 1°F to 2°F across Minnesota and northwestern Wisconsin to 6°F below normal in southeastern Ohio (Figure 3).
The first week of November was generally dry across the region with two notable exceptions. Precipitation was 75 percent of normal across central Kentucky, and well above normal across the Upper Peninsula of Michigan (Figure 4). Precipitation was also near normal in far northeastern Ohio. Rainfall in Kentucky resulted from showers and thunderstorms developing ahead of the cold front on November 5. Heavy snow fell across the Michigan UP as the cold air streamed across the relatively warm waters of Lake Superior. There were only minor changes in drought conditions across the Midwest this week. Abnormally dry conditions expanded slightly in Missouri, and decreased in southern Indiana and Ohio (Figure 5).
Cold Brings End to Growing Season
High pressure settled into the Midwest on November 1 behind a cold front that moved through the region on October 31. Clear skies and calm air allowed overnight temperatures over the central portions of the region to plunge into the mid 20s, producing the first hard freeze of the fall for many locations from northern Michigan through southern Illinois the morning of November 2 (Figure 6). After a brief two-day warm up, the coldest air of the season knifed south through the region (Figure 7). Low temperatures on the morning of November 7 ranged from the mid teens in Iowa and Minnesota to the low 20s along and south of the Ohio River (Figure 8). Cloudy skies associated with the departing low pressure system over Quebec held temperatures generally above freezing across southern lower Michigan and Ohio.
First Major Snow of the Season
Strong northwesterly winds generated by the intense low pressure system generated significant lake-effect snow across the Michigan UP and northern Wisconsin on November 5 and 6 (Figure 9). The snow was heaviest across the Michigan UP, where it fell at the rate of an inch an hour or more. Marquette, MI received 12 inches of snow, and 9 to 12 inches was common across the UP (Figure 10). Interestingly, the week of November 4-10 was Winter Hazards Awareness Week in Michigan. Snowfall across northern Wisconsin ranged from 3 to 7 inches. One half to one inch of snow also fell across extreme northern Minnesota and 2 to 4 inches of snow fell in northwestern lower Michigan. The heavy snow in the Michigan UP forced authorities to close Highway 17 north of Sault Ste. Marie because of the heavy, wet snow and wind. South of the snow areas, high wind advisories were in effect. The high winds generated by the low pressure system caused scattered power outages in Michigan and Wisconsin. Muskegon, MI record a wind gust of 58 mph on the morning of November 5, and winds across much of the upper Midwest were gusting in excess of 45 mph.
Scattered Severe Storms in Southern Midwest
The cold front that marked the leading edge of the cold air triggered showers and thunderstorms as it pushed through Kentucky and Ohio on November 5. The severe storms were concentrated in northern Kentucky and southwestern Ohio. Most of the severe weather reports were for hail from 0.75 to 1.25 inches. In Mount Carmel, KY (Fleming County) two people were injured when they were blown off a scaffolding during a severe thunderstorm.
SDH