Midwest Weekly Highlights - November 15-21, 2005

---

Winter Arrives After One Last Severe Weather Blast

The period of November 15-21 started with the third and final tornado and severe weather outbreak this month. One person died and dozens were injured when dozens of tornado events were reported, including several long track significant tornadoes with substantial damage resulting. Substantial precipitation exceeding 4 inches in places fell with the same system through southern Missouri, Illinois, and Indiana (Figure 1). Both the northern Ohio Valley and Great Lakes areas received well over 200% of normal precipitation for the week (Figure 2). After the intense low pressure system pulled out of the Midwest, a very strong surge of colder than normal air arrived in the Midwest, leading to a week that was 4-8°F below normal in most of the region (Figure 3) despite starting with a very warm day during the severe weather outbreak. After the low pressure center pulled cold air south from central Canada, lake effect snows were prevalent for several days, dropping up to 2 feet of snow in the Upper Peninsula of Michigan, and lesser amounts over much of the northern Midwest (Figure 4). Snow flurries were noted as far south as Champaign, IL, home of the Midwestern Regional Climate Center. It appeared at the end of the period that we had abruptly transformed from early autumn to mid-winter conditions.
 

Tornadoes Hit Central-South Midwest

A high likelihood of severe weather was predicted by the Storm Prediction Center (SPC) for Tuesday, November 15 (Figure 5, SPC). This situation was similar to earlier in the month, with a strong surface low pressure center (Figure 6, College of DuPage - COD) traveling under an area of favorable jet stream support (Figure 7, Climate Diagnostic Center). By mid-afternoon, two lines of severe thunderstorms had formed ahead of the cold front (Figure 8, University Corporation for Atmospheric Research - UCAR), raking the area with wind, hail, and two dozen tornadoes in the Midwestern region alone (Figure 9, SPC). One person died in the F4 rated Madisonville, KY tornado, and dozens of houses were destroyed. The storm with the tornado can be seen in the upper part of Louisville radar at the time (Figure 10, UCAR). Madisonville, KY is located only 50 miles south of the location where 23 died on the 6th, and newspapers reported that the only family that lost a house in the first storm lost another family member's house in this latest storm.
 

Cold Dry Air Shuts Off the Severe Weather Season

The period ended with a plunge into intensely cold conditions. Lake effect snow showers streamed across the lakes (Figure 11, COD), with some places in northern and western Michigan and northwestern Ohio receiving 6-18 inches of snow. Low temperatures dipped into single digits and even below zero territory for the first time this year over a wide portion of Minnesota, Iowa, and Wisconsin (Figure 12, Unisys). Four people died in car accidents on snow-slicked roads in Minnesota.