November 9-15, 2006
Midwest Weekly Highlights - November 9-15, 2006
Temperatures and Precipitation Near Normal
For the first time in several weeks, temperatures across the Midwest during the second week of November were very close to normal, with just a few areas that experienced cooler than normal conditions. Temperatures ranged from 2°F to 4 °F above normal in Missouri, parts of southern Iowa, much of Wisconsin, Illinois, Indiana, and eastern Ohio, to -2 °F to +2 °F around normal in Michigan, Minnesota, and western Kentucky (Figure 1).
The precipitation distribution during the second week of November was rather heterogeneous, with several stations seeing above average precipitation, and several other stations receiving very little precipitation. Precipitation totals ranged from 5-25% of normal across northern Minnesota, western Missouri, and parts of western Ohio, to 130-200% of normal in very few select locations across the Ohio Valley, primarily in Wisconsin, Illinois, and Michigan (Figure 2). Snowfall was abundant this week across northeast Iowa, southeastern Minnesota, and western Wisconsin, where snowfall totals ranged from 2-12 inches (Figure 3). The snowfall and precipitation, however, did little to alleviate the long-term drought conditions, and extreme drought remains fully entrenched across portions of the Midwest (Figure 4).
Major Winter Storm Stuns the Midwest
A cold front swept through the Midwest on Thursday, November 9, allowing cold air to slowly filter into the northern parts of the region. On Friday, November 10, an area of low pressure scooted northeast along the trailing cold front (Figure 5). This system funneled plenty of warm, moist air northward, and then up and over the cold air in place over southern Minnesota, western and central Wisconsin, and northeastern Iowa. The result was very heavy snow falling in a tremendously narrow axis, known by meteorologists as the "deformation zone." This zone favors enhanced upward vertical motion over a narrow region, resulting in a stripe of heavy snow (Figure 6). At times, the snow was even accompanied by thunder and lightning! When all was said and done, parts of the northern Midwest received between 2 and 16 inches of snow (Figure 7). The heaviest amount was in Osseo, WI in Trempealeau County, where 16.5 inches of snow was measured. Over ten different cities in western Wisconsin reported snowfall totals in excess of 10 inches - a rare event for early November. In fact, the snowfall amounts set many new records, including Rochester, MN with 10.5 inches (previous was 1.8" set in 1946), Rhinelander, WI with 12.5" (was 12.0" in 1991), LaCrosse, WI with 2.9" (was 2.1" in 1916), Eau Claire, WI with 6.5" (was 1.5" in 1984), and finally Waterloo, IA with 1.5" (was 1.1" in 1991).
On the warm side of the storm, record maximum temperatures were set on November 10 in Dayton, OH and Cincinnati, OH. The high temperature in Dayton, OH was 71°F (this tied the record set in 2002), and the high temperature in Cincinnati, OH was 74°F (which also ties the record set in 2002).
Impacts from the early winter storm were quite widespread as drivers faced their first trials of the year with snow and ice-covered roads. In Fond du Lac County Wisconsin, just south of Green Bay, WI, the Sheriff's Department reported 4.5 inches of snow, which resulted in 89 vehicles in the ditch, and 37 accidents. One of the accidents involved a semi-trailer slipping down a hill and toppling across two lanes of traffic, while yet another involved two vehicles in a head-on collision. In addition, due to the weight of the snow on many tree branches, about 100 people lost power on the night of the 10th, but it was eventually restored before daybreak the next morning.
Further west, in central and northern Iowa, over 10 inches of snow fell in Winnebeago County, while Des Moines, IA saw 1-3 inches of snow. The snow impacted travel, including a bus load of students from Faith Baptist Bible College to North Dakota for a basketball game, when the bus slid on a patch of ice and lost control. Three students had to be hospitalized while many others sustained minor cuts and bruises. Another bus of students, en route to St. Paul, MN, from Des Moines, IA were forced to turn around just south of Albert Lea, MN on account of the dangerous driving conditions and heavy snow. Finally, on an interesting note, as the first flakes drifted down over I-80 across central Iowa, within minutes of their initial descent, the season's first wreck on the Interstate occurred, slowing traffic.
The storm system also featured some severe weather, though few impacts were reported aside from the most commonly occurring pea-sized hail covering the ground in locations in eastern Iowa and parts of southern Missouri. Near Chicago, a lightning strike damaged a signal system for a commuter train line, backing up at least 20 trains between Chicago, IL and its western suburbs. In addition, the storm system forced both major Chicago, IL airports to have delays and several cancellations.
On an interesting climatological point, snowfall has been abundant across Canada so far this fall, as evidenced by the NOAA Snow and Ice Chart (Figure 8). If the snow cover across these areas remains through winter, the Midwest will be primed for cold air intrusions in the coming weeks.
November Soaker
The final few days of the second week of November were active, with an important severe weather event in the deep south, and a windy, rainy, and generally raw few days across the central and northern Midwest. A deep area of low pressure moved eastward out of southern Oklahoma on the 14th, providing numerous showers and scattered thunderstorms to southern Missouri and portions of Kentucky (Figure 9). During the day on the 15th, the storm system wound up, on account of a 200 mph jet stream diving into the base of the trough (Figure 10). Strong thunderstorms were found along the cold front in Tennessee and points southward, while a cold rain fell across Missouri, Illinois, Indiana, and Ohio (Figure 11). Windy conditions also prevailed with the storm, with numerous gusts in excess of 30mph common across these states. Lake Michigan wave heights soared to 9-14 feet, crashing into the southwestern portions of the lakes edge, and on the shoreline of the city of Chicago, IL.
Though precipitation lingered into the morning hours of the 16th, precipitation totals from the 15th were quite large, ranging from around 0.50 inches, to as much as 2.38 inches in Lawrence County, IL. Fortunately, however, no major impacts were felt from the storm system, aside from generally miserable outdoor conditions plaguing pedestrians and pets.
The third week of November ends just before the Thanksgiving Holiday. Will the weather cooperate with travel plans, or will they be snarled by another big snow event? Find out in next week's edition of the Midwest Climate Watch.