December 8-14, 2004
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. 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.