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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 are:

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.

National Weather Service Offices with additional detail, including photos of the snow and its impacts, on this storm include:

Paducah, KY
Indianapolis, IN

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.