December 22-31, 2004
Midwest Weekly Highlights - December 22-31, 2004
Wild Start, Mild End to Last Ten Days of December
A winter storm brought record-setting snowfall to the southern Midwest
just before Christmas, followed by the coldest air of the
season. However, the weather warmed considerably as the new
year approached and record highs were set in a number of Midwestern
locations on New Year's Eve.
Temperatures for the period were below normal in most of the region
(Figure 1). The exception was
in the western two-thirds of
Missouri and far western Iowa where temperatures averaged 1F to 2F
above normal. The coldest weather was in the Ohio Valley in
the area where the heavy snow occurred. Here, temperatures
averaged 7F to 9F below normal as deep snow cover allowed for maximum
cooling at night and dampened the effects of sunshine during the
day. During the period December 22-27, temperatures in the
Ohio Valley averaged more than 18F below normal, with temperatures 8F
to 12F below normal across the rest of the region (Figure 2). In contrast, temperatures were 6F to 18F above normal for the December 28-31 period, with the lowest departures
(cooler weather) found in the Ohio Valley were some snow remained until
late in the period (Figure 3).
There were two distinct areas of heavy precipitation this period, one
in the Ohio Valley where the heavy snow occurred and the other across
the upper Midwest from northern Minnesota eastward into northern
Wisconsin (Figure 4). Most of this was
in the form of snow,
although parts Minnesota received freezing rain and snow late in the
period.
Snowstorm
Creates Travel
Nightmare Before Christmas
As December 22 dawned parts of the Midwest had already been hit with
inclement winter weather. An initial burst of snow associated
with a developing storm in the southern Plains and Gulf states (Figure 5, Unisys)
left 3 to 6 inches of snow on the ground from southern
Illinois across southern Indiana, with yet more, much more snow, on the
way. The snow began to re-intensify during the late morning
of
December 22. Winter weather watches, warnings, and advisories
were in effect in a continuous area from central Texas all the way to
eastern Pennsylvania (Figure 6, SPC). As the storm began to
lift
northeastward, snow fell heavily throughout the afternoon and evening
from southeastern Missouri across southern Illinois, Indiana, and
Ohio. Roads and interstates from southern Illinois through
Indiana and Ohio quickly became snow-covered, and strong winds closed
roads almost as fast as snow plows could open them. By the
morning of December 23, more than two feet of snow covered
south-central Indiana and parts of southwestern Ohio, and a foot or
more was on the ground over southeastern Illinois, the
southeastern half of Indiana and across north-central Ohio (Figure 7 - NWS Lincoln, IL; Figure 8 - NWS Indianapolis, IN; ; Figure 9 - NWS Wilmington,
OH). Heavy snow also fell northward into
southeastern Michigan (Figure 10 - NWS Detroit, MI) and in
western and northern Kentucky (Figure 11 - NWS Paducah, KY).
Freezing rain just fell just
to the east of the heavy snow, producing a band of severe icing that
affected much of central and south-central Ohio (Figure 12, SPC). In the heaviest snowfall areas, winds caused five foot
drifts that closed roads and interstates for days. Interstate 64 in southwest
Indiana was closed for about three days due to extensive drifting. On
Interstate 24 in western Kentucky, a 29-mile long traffic jam formed
from Trigg
County into Lyon County. An
estimated 1,000 people were
stranded in their vehicles overnight. The National Guard was mobilized
for both the Interstate 64 and Interstate 24 incidents. Traffic was
reported stopped on other interstates as well, including the
interchange of Interstates 55 and 57 in southeast Missouri.
Roofs
collapsed on many buildings due to the weight of the
snow. On Interstate 70 in Indiana, traffic was down
to one lane or slowed to a halt in many places.
Some of the heavier storm total snowfalls by state can be seen in (Table 1).
Many locations set one day snowfall records in the affected
area. The 22.3 inches at Evansville was a new 24-hour snowfall record,
as was 14.2 inches at Paducah, KY.
Arctic cold followed the storm. On the morning of December
23rd
Embarrass, MN reported a low of -42F, the coldest in the
nation.
Crane Lake, Tower, and International Falls, MN reported lows
of
-31F. As skies cleared and high pressure built in over the
Ohio
Valley on December
23 overnight temperatures dropped to record levels over the deep snow
pack. On Christmas Eve morning subzero temperatures were recorded as
far south as the Ohio River, while temperatures to -35F were occurring
in northern Minnesota and Wisconsin (Figure 13,
Unisys). In the wake of the storm, Mt.
Vernon, IL
dropped to -13F; Evansville, IN -11F; and Paducah, KY -8F,
all
new records for the date. Just to the north of the snow area
(Figure 14), where little snow was on
the ground, temperatures stayed
near or above 0F. On Christmas night and into the morning of
December 26 a weak low pressure system racing across the Midwest
brought light snow to an area from eastern Iowa south through central
Illinois and Indiana, and Ohio, and northward through Wisconsin and
Michigan.
From
Wild to Mild
The weather began to slowly moderate across the Midwest on December
27-28 as the large arctic high moved off to the east (Figure 15). Strong southwest winds
developed across the region by the 28th and warm air began a rapid
return. By December 30 temperatures in the mid 50s pushed as
far north as Minnesota (Figure 16). Minneapolis tied
its record high for December 30 of 47F.
Temperatures reached 70F in central Missouri and in the mid 60s as far
north and east as east-central Illinois, and a number of locations tied
or broke record highs for this date. Even over the snow
covered Ohio Valley, temperatures topped out in the mid 50s, beginning
a rapid melt of the snow. Further north, the warm air
overrunning cold air near the surface in
northern Minnesota resulted in freezing rain over the northern quarter
of the state as well as parts of western Wisconsin. The warming
continued through New Year's Eve day, and highs 60F or above could be found
as far north as southern Michigan and as far east as west-central Indiana (Figure 17). In the northern
Midwest, cold air was again pushing south through Minnesota accompanied
by several inches of snow, and highs there were only in the
20s.