Dec 8-14 temp Dec 8-14 precip Dec 8-14 snow
Dec 8-12 temps

Midwest Weekly Highlights - December 8-14, 2004

Winter Weather Begins to Make Presence Felt in the Region

Although mild weather continued into the early part of the week, winter weather gradually took hold over the Midwest, with the most significant impacts around the Great Lakes.  However, the early part of the period was very mild, and temperatures for the week ranged from near normal in the Ohio Valley to as much as 8F to 10F above normal across the northwestern third of the region (Figure 1).  Most of the southwestern two thirds of the Midwest had very little precipitation this week (Figure 2), which allowed river levels in Illinois and Indiana to drop and fields to dry out after the heavy rainfall in late November and the first week of December.  Much of the precipitation in the northeastern Midwest and Great Lakes was lake effect snow (Figure 3) that developed as the first significant cold air of the season plunged through the Great Lakes and Midwest.

A Mild, then Wild, Start

As the week began high pressure centered over Tennessee began to return mild air to the western half of the region.  Temperatures during the first four days of the week were as much as 15F above normal across the northern Midwest (Figure 4).  Temperatures began to cool slightly on December 10 as a low pressure system brought some rain and drizzle to the lower Midwest.  The low intensified as it moved into the eastern United States and generated strong winds across the Midwest.  By December 11 a second low was entering the northern Plains.  This low intensified as it moved over lake Superior on December 12, producing strong winds and dragging in much colder air behind it (Figure 5). Winds gusted to between 40 and 50 mph as far south as central Illinois and Indiana, causing numerous power outages and causing damages to roofs and buildings. Gusts reached 71 mph near Welch, MN and 58 mph in Door County, WI.  The winds toppled at 25-foot Christmas tree at the Governor's residence in St. Paul., MN and also knocked down a 20-foot-high scaffolding onto five parked cars in Minneapolis, flattening their front ends.  The strength and duration of the winds produced waves 14 to 18 feet on Lake Michigan and prompted lake shore flood warnings along the western Michigan shore south to LaPorte and Porter Counties in Indiana.  In Grand Haven, MI, Ottawa County sheriff's deputies were unsuccessful in warning  thrill-seekers to stay off Lake Michigan piers.  People in wet suits and with surfboards were seen flinging themselves off the pier into the water.  The high winds and waves were accompanied by temperatures in the mid 20's at the time.  Deputies indicated that they would not be able to launch any rescues in the dangerous conditions.

Lake Snow Machine Switches to "ON"

The much colder air streaming over the relatively warmer waters of the  lakes initiated a lake-effect snow event from Lake Superior to Lake Erie.  Marquette, MI set a new daily snowfall record  for December 13 with 16.8 inches, shattering the old record of  7.4 inches in 1973.  Lake effect snow warnings were issued all along the lakes from Superior to Erie (Figure 6). Snow piled up along the western and southern shores of Lake Michigan, from Traverse City to South Bend, Indiana (Figure 7) with the heaviest amounts generally from 4 to 8 inches.  Maps of the snowfall are available from National Weather Service offices in Grand Rapids, MI and North Webster, IN.  The heaviest lake effect snow, however, fell on northeastern Ohio.  Pierpont, OH in Ashtabula County reported a total of 24 inches of snow on the ground on December 14, and 10 to 18 inches of snow was common throughout the county. Hambden Township in Geauga County  reported 22.6 inches on the ground on December 14, and Chardon reported 19 inches on the ground.  Heavy snow also accumulated in Lake, Medina, and Portage Counties.

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