Midwest Weekly Highlights - December 1-7, 2005

---

The first week of December featured some of the coldest weather of the last three decades for the first week of the month.  Temperatures the first week of December ranged from 8°F below normal in northern Michigan to 20°F-22°F below normal throughout Iowa. The core of the greatest departures from normal extended from southern Minnesota to northern Missouri and east through the northern half of Illinois (Figure 1).

Precipitation was well above normal from southwestern Minnesota through western Iowa, but across most of the Midwest precipitation was generally light and well below normal for the week (Figure 2).  The precipitation in Iowa resulted from a storm on November 30 into early December 1 which dropped 3 to 5 inches of snow across Iowa, with lighter amounts across Wisconsin, Illinois, and Indiana (Figure 3).  A second clipper system scooted through the Midwest on December 3-4, dropping several inches of snow from Minnesota through central Illinois and Indiana (Figure 4). Persistent cold northwesterly flow across the the Midwest switched on the lake-effect snow machine in the Michigan Upper Peninsula and along the lee shoreline of Lake Michigan in lower Michigan (Figure 5).  At the end of the week snow cover in the Midwest extended south to a line roughly from Kansas City, MO to Columbus, OH.

Temperatures in much of the Midwest were in the upper 50s on November 29, but since then (through December 7) most of the nine-state Midwest region with the exception of southern Missouri and Kentucky did not see temperatures above freezing.  A series of progressively colder air masses spread across the region, reinforced by snow cover as far south as central Missouri and central Illinois.  Numerous record low maximum temperatures and record low temperatures were established the last three days of the period, with December 7 being the coldest day (Figure 6).  Some of the records set during these three days are:

December 5

Station	Record Type	Value	Old Record
Moline, IL	Low Maximum	13°F	20° in 1917
Dubuque, IA	Minimum	-9°F	0°F in 1992
Dubuque, IA	Low Maximum	7°F	15°F in 1955
Springfield, IL	Low Maximum	19°F	23°F in 1895
Lincoln, IL	Low Maximum	17°F	27°F in 1964

December 6
 

Station	Record Type	Value	Old Record
Cedar Rapids, IA	Minimum	-9°F	-4°F in 1898
Moline, IL	Minimum	-4°F	-2°F in 1886
Cleveland, OH	Minimum	7°F	7°F in 1977
Rockford, IL	Low Maximum	12°F	14°F in 1984

December 7

Station	Record Type	Value	Old Record
Cedar Rapids, IA	Minimum	-19°F	-14°F in 1976
Lincoln, IL	Minimum	-3°F	-2°F in 1977
Lincoln, IL	Low Maximum	9°F	13°F in 1950
Peoria, IL	Low Maximum	12°F	12°F in 1977

On December 7 a storm system developing over Texas and Oklahoma took aim on the Midwest (Figure 7), and during the day heavy snow spread into western Missouri.  Kansas City, MO received 10 inches of snow for the day, a new 24 hour snowfall record. By the end of the day a variety of winter weather advisories and watches were in place through Missouri, Illinois, and Indiana in anticipation of the storm. Details on this storm will be included in the December 8-14 Climate Watch.