November 22-30, 2006
Midwest Weekly Highlights - November 22-30, 2006
Record Warmth
The final week of November featured well-above average temperatures, followed quickly by a dramatic change in airmasses. Temperatures this week were well above normal across a majority of the region. The warmest departures from normal were found across Michigan, Wisconsin, Illinois, Indiana, parts of Iowa and Missouri, where readings generally fell between 10°F to 14 °F above normal. Meanwhile, locations surrounding these states were still above normal, with departures generally from 4°F to 8°F above normal. Only extreme northwest Minnesota was below normal this week (Figure 1).
Numerous record warm temperatures occurred during the final week of November, and these are summarized in Table 1.
The precipitation distribution during the final week of November exhibited a west-east gradient, although many locations experienced above normal precipitation, which set numerous daily records. Precipitation was heaviest across Wisconsin, Iowa, Illinois, and Missouri, where totals were 200 to 300% of normal this week. Elsewhere, much of Ohio, eastern Indiana, and much of Kentucky were well below average, with precipitation totals averaging 5 to 25% of normal (Figure 2). Drought conditions remained unchanged from the previous week, and extreme drought still holds strong across northern Minnesota and parts of southwestern Missouri (Figure 3).
First Came the Rain...
As the Thanksgiving Holiday weekend passed, an upper level trough became established across the western United States, as arctic air from Canada dove down the spine of the Rocky Mountains (Figure 4). This trough and associated cold air, became extremely problematic as the month of November came to a close. An area of low pressure and associated cold front, slammed into what had been record warm temperatures across the Midwest, to produce numerous showers and thunderstorms on the 27th-29th (Figure 5). Precipitation totals ranged from around 0.25", to as much as 1.65" across central Iowa on the 27th alone (Figure 6). Additional showers developed along the arctic front through the morning hours on the 29th, and additional showers and storms were found ahead of the front on the 30th, which also resulted in some isolated severe wind reports across Kentucky (Figure 7). Record rainfall totals were set at Chicago-O'Hare, IL; Springfield, IL; Lincoln, IL; Springfield, MO; West Plains, MO; Vichy-Rolla, MO; Rochester, WI, and a smattering of a few other locations.
...Then The Snow
The cold front responsible for the showery weather shifted eastward, allowing arctic air to dump into the Midwest. However, an upper level disturbance rotating down the back side of the upper level trough spurred a surface cyclone to develop at the tail end of the front. This low became responsible for the first significant snow/ice event for much of the central and southern Midwest. Locations in Missouri experienced up to one quarter inch of ice accumulations before as much as 5-15" of snow fell on top of the ice (Figure 8, National Weather Service, Springfield, MO). Further east, a prolonged period of sleet and freezing rain tortured residents, pedestrians, and motorists across central Illinois, before the precipitation turned to all snow late in the evening on the 30th. Snow accumulations were heavy in spots, including near Peoria, IL where over 10" of snow was reported, and in Princeton, IL, where 18" of snow was reported (Figure 9). For many locations across central Missouri, this was the heaviest one-day snow since March, 2003. Snow total across central Illinois ranged from generally 1-10 inches with isolated higher amounts (Figure 10, National Weather Service, Lincoln, IL).
Impacts from the storm were widespread. In St. Louis, MO, over 500,000 customers lost power due to the combination of ice, snow, and wind, and it may not be restored for a few days. Unfortunately, most of these customers were also victims of heavy thunderstorms that knocked out power during an intense July event.
In Kansas City, MO, a 50-mile stretch of I-70 remained closed on the morning of December 1, as stranded motorists and police cars littered the roadway. Sadly, one person was killed when a snow plow blade struck a vehicle, and then the state trooper who responded to the scene became stranded himself. Yet another motorist was killed on I-44 near Rolla, MO, when he had gotten out of his stranded vehicle and was then broad sided by a five-car accident. The accident was caused by a semi-trailer truck who had slid on the ice, then proceeded through a cable barrier and into the first-responders police car, which then careened into another vehicle and the stranded motorist.
Further northeast, Illinois State University, in Bloomington, IL, was closed on December 1, for the first time in over 20 years on account of the winter storm. Both Northern Illinois and Western Illinois Universities were closed as well, the latter having not been closed in over 100 years! In addition, the University of Missouri-Columbia cancelled classes on December 1 for the first time since 1995.
At Chicago's O'Hare International Airport, a FedEx Cargo plane slid off an icy runway and got stuck in the mud. Fortunately, no injuries were reported. In addition, a Northwest Airlines plane was struck by lightning, while snow was falling, as it was taxiing for departure at O'Hare Airport. Over 350 United Airlines flights were cancelled on Thursday in an effort to allow passengers time to find alternative flights and make preparations for staying another night in the Windy City. On Illinois Route 6, just north of Peoria, the road became a parking lot as stranded vehicles were trapped with snow drifts up to and over their roofs. Approximately 2.4 million customers were without power across Missouri and Illinois through early afternoon on December 1.
Finally, in Milwaukee, WI, a blizzard warning was in effect for the city, as heavy snow of 9-13" combined with wind speeds in excess of 35mph, reducing visibilities making driving treacherous, if not impossible. The blizzard was accompanied by thunder and lightning, forcing schools to close and resulting in several hundred accidents, spin-outs, and crashes. Portions of I-94 were shut down because motorists were unable to make it up a steep incline in the road. However, these motorists also included tractor-trailers and snowplows! Through 11am on December 1, Twin Lakes, WI reported 16 inches of snow on the ground, and in Kenosha, WI, over 17 inches of snow had fallen by early afternoon. A benefit of the snow? Crime was down in Milwaukee, WI during the event.
Meanwhile, as the low tracked up the trailing arctic front, locations in Indiana and Michigan, and eventually Ohio, witnessed the same fate as those living in Missouri and Illinois, and this sets the stage for what will be a very wild beginning to December...
What impacts will the major snowstorm leave behind in the eastern Midwest? Will more snow fall during the first week of December? Find out in next week's edition of the Midwest Climate Watch.
Kruk