February 1-7, 2007
Midwest Weekly Highlights - February 1-7, 2007
Into the Deep Freeze
The Midwest experienced the coldest weather of the season the first week of February, and in many areas it was the coldest weather experienced in the past several years. Temperatures this week averaged 16°F to 20°F below normal from northern Illinois and Indiana northwest through Wisconsin and Minnesota (Figure 1). South of this area, temperatures ranged from 8°F to 14°F below normal. The warmest area in terms of departure from normal was northern Michigan and the eastern Upper Peninsula, where lake-effect snow and cloudiness moderated the normal daily swing in temperatures and average daily temperatures there were only 6°F to 8°F below normal.
Precipitation was below normal in most areas this week with the exception of lake-effect snow areas in Michigan and in central Minnesota (Figure 2). Even though snow fell in a good portion of the Midwest this week (Figure 3), snow was not heavy in most areas and seasonal snowfall is running below normal. By the end of the week much of the Midwest had snow cover with the exception of Missouri and the southern third of Illinois (Figure 4). Snow cover across most of Minnesota and Wisconsin, however, was well below normal for this time of the season. In Minnesota, snow cover is significantly less than the historical median for the date with the exception of far southern counties. For many central and north central Minnesota counties, snow depths are near all-time lows for this time of year.
Multiple Surges of Arctic Air
On the morning of February 1 the first of several Arctic cold fronts was entering the northern Midwest (Figure 5). By the morning of Groundhog Day, February 2, this first front had pushed all the way into Texas and the next surge of cold air was poised along the U.S. Canadian border (Figure 6). Temperatures across much of the Midwest did not climb above freezing the remainder of the week, and most of Minnesota, Wisconsin, and Michigan did not see temperatures higher than the single digits. The coldest days of this period were February 3rd and 4th, when maximum temperatures across Minnesota, Wisconsin, and northern Iowa remained well below zero (Figure 7). The bitterly cold temperatures were also accompanied by strong winds which produced dangerous wind chill values across much of the region. Wind chill values in northern Minnesota were reported from -30°F to around -50°F on February 4th and 5th. School districts across Ohio cancelled classes on Monday, February 5 due to the dangerous wind chill readings. The Milwaukee Public School District, the largest in Wisconsin shut down for the day. Schools also closed because of the cold in parts of Minnesota, Michigan, and Illinois.
In northern Michigan, the first week of February 2007 was one of the top ten coldest start to the month for a number of locations, and a few records were set. Several low maximum temperature records were set on February 4 in Michigan. Muskegon, MI reached only 4°F, breaking the 95 year-old record of 8°F (set in 1912). Marquette, MI reached only -9°F on February 4, shattering the previous record of 5°F set in 1994 (record go back to 1961). Youngstown, OH dropped to a record -5°F on February 5, breaking the old record of -3°F set in 1996. On the morning of February 6, Flint MI tied its record low of -5°F, first set in 1948. Also on February 6 Mansfield, OH dropped to -6°F, tying the record first set in 1988.
The coldest spot in the nation on February 4th and 5th was Embarrass, MN which plunged to -42°F on both days.
Snow Piles Up In Michigan
The cold Arctic air streaming across the open and relatively warm waters of Lake Michigan caused a prolonged period of lake-effect snow along the western shores of Lake Michigan on February 2nd and 3rd. More than a foot of snow piled up just west of Grand Rapids, and blizzard conditions were also experienced across much of southwest Lower Michigan, especially southwest of a Muskegon to Lansing line. Lake-effect snow also occurred in northern Lower Michigan near Traverse City and in the eastern UP.
Clipper System Brings Swath of Snow
On February 6 a low pressure system was located in South Dakota and moving southeast along the western boundary of the cold air (Figure 8). The "Alberta Clipper" produced snow from Minnesota southeast through Iowa, Illinois, Indiana, Ohio, and Kentucky. Amounts generally ranged from 2 to 5 inches, but there were amounts locally up to 7 inches reported in Illinois and Indiana (Figure 9). Cincinnati, OH received 6.3 inches of snow, a new daily snowfall record for the date, breaking the old record of 5.5 inches set in 1972. In Illinois, the snow began during the early morning hours, severely impacting the morning commute in Chicago. With temperatures in the single digits, salt and calcium chloride applied to the roads was generally ineffective. There were hundreds of accidents reported, including one with a fatality, and trips of a few miles were taking an hour or more. During the early afternoon, a crash on I-294 (Tri-State Tollway) involved 20 to 30 vehicles, including six semi tractor-trailers. Lanes were closed up to three hours. Flight delays and cancellations were reported at both major Chicago airports.
In the Midst of Winter, a (Brief) Taste of Spring
While most of the Midwest was experiencing bone-chilling cold on February, the circulation associated with the clipper system pulled very warm air into southwestern Missouri. While it was 10°F and snowing in central Illinois, it was sunny and 67°F only 300 miles to the southwest in Springfield, MO. High temperatures reached the mid 60s in central Missouri and the mid 40s along the Mississippi River (Figure 10). Record high temperatures were set at West Plains (66°F, old record 65°F set in 1999), and in Vichy (65°F, old record 58°F set in 1950). However, the warmth was short-lived, and on February 7 high temperatures were back down in the 30s across Missouri and in the single digits and teens across the remainder of the Midwest.
SDH