National Weather Service Weather Forecast Office

December 2004 – a Review of Weather, Temperatures, and Precipitation for the Quad State Region.

 

Weather Summary for December 2004

 

December ended 2004 with a wide variety of weather.  The active northwest flow from November continued into the first few days of December.  Several upper level disturbances passed southeast over the region touching off showers, some with heavy rainfall.  Between the 5^th and 8^th, most locations received between 1 and 2 inches of rain.  Because there were breaks in the rain, no short term flood products were necessary.  Temperatures were mild with highs reaching into the 60s.  The next storm system passed to our south between the 9^th and 11^th producing another round of showers. Precipitation amounts were light and generally less than one-quarter inch.  Surface high pressure then built into the region providing quiet weather and temperatures more normal for December.

 

The next storm system to affect the region would bring a rather large dose of winter weather.   An area of low pressure developed in the Southern Plains and moved northeast, passing just south of the region on the 22^nd.  Snow, sleet and freezing rain were all reported in the region.  The heaviest snow fell along a line from Poplar Bluff, Missouri, across southern Illinois into southwest Indiana, where 12 to 24 inches was reported.  Amounts tapered off to the north and south of this swath.  Most of the freezing precipitation fell in a line roughly from Murray to Central City, Kentucky.  Holiday traffic literally came to a stop across the region for a period of 24 to 48 hours.  To make the situation worse, arctic high pressure built across the region.  Temperatures plummeted just before Christmas with most locations reporting high temperatures in the teens, and lows below zero.  A warm southerly flow of air returned before the end of the year, pushing highs back up the 50s and 60s, quickly melting the snow and pushing streams to bankfull.   

 

December Temperatures Across the Quad State Region

 

The following table (Figure 1) displays average December 2004 temperatures at five locations across the Quad State Region where this information is consistently collected. For comparison, historical average daily temperatures for December are also given for these locations. The Normal period used to calculate normal high, low, and average daily temperatures and rainfall is currently 1971 through 2000.

 

The high, low and average daily temperatures are averaged for all days of December 2004. Column 5 allows a comparison of the December 2004 average temperature to the highest and lowest December average temperatures recorded during the Normal Period (1971 through 2000). High and Low daily temperatures were not compared.

 

The last column indicates the difference of the December 2004 average temperature from the average December temperature observed during the Normal Period, and the percentile of the December 2004 mean temperature compared to December mean temperatures during the Normal Period.

 

Percentile is the percentage of years during the Normal Period that had mean December temperatures equal to or below the 2004 mean temperature. In most cases, this is based on the entire 30-year Normal Period, but in some cases data was missing that only allowed comparison to 28 or 29 years of the Normal Period. 

 

Figure 1. December 2004 Daily Temperatures (°F) Compared to December Normal Daily Temperatures Based on the Normal Period 1971-2000, at Five Quad State Region Locations.

(source: Midwest Regional Climate Center) 

 

Location	Temp > Normal 2004	High	Low	Mean	1971-2000 Range of Mean Temps * (Normal Period)	2004 Deg from Mean Percentile**
Carbondale IL	Norm > 2004 >	44.3 44.3	25.7 23.7	35.2 34.0	max: 42.4 in 1982 min:  22.3 in 1989	-1.2 °F 29
Cape Girardeau MO	Norm > 2004 >	44.7 44.4	28.3 23.0	36.8 34.0	max: 44.5 in 1971 min:  24.3 in 2000	-2.8 20
Evansville IN	Norm > 2004 >	44.0 42.9	27.7 24.7	36.1 34.1	max: 45.2 in 1982 min:  23.0 in 1989	-2.0 22
Paducah KY	Norm > 2004 >	46.5 45.9	29.0 25.7	38.0 36.0	max: 45.4 in 1971 min:  25.9 in 2000	-2.0 18
Poplar Bluff MO	Norm > 2004 >	46.6 46.2	28.2 27.5	37.6 37.3	max: 44.8 in 1971 min:  26.4 in 2000	-0.3 29

* This column indicates the highest and lowest December mean temperatures observed during the Normal Period of 1971-2000.

** Percentile is calculated as percent of December temperatures during the normal period that were equal to or below the 2004 December average temperature.

 

As Figure 1 indicates, temperatures across the Quad State Region for the month of December were all well below normal. Cape Girardeau was the coldest of the five, at 2.8 degrees below normal, ranking in the 20^th percentile, although Paducah was the lowest based on percentile, at 2.0 degrees below normal and in the 18^th percentile. Evansville was also 2.0 degrees below normal, in the 22^nd percentile.

 

The other two locations – Carbondale and Poplar Bluff – were slightly warmer, at 1.2 and 0.3 degrees below normal, respectively, with both ranking in the 29^th percentile.

 

December Precipitation Across the Quad State Region

 

The next table (Figure 2) displays normal precipitation and the observed precipitation for December 2004. The historical time periods are the same as those in Figure 1. Frozen precipitation – if any – is not available from this data except as liquid equivalent, which is included in the total precipitation for the month.

 

Figure 2. December 2004 Observed Precipitation (inches) and December Normal Precipitation for Five Quad State Region Locations

(source: Midwest Regional Climate Center) 

 

Location	Normal** Record***	2004	2004 Difference	Range (years 1971-2000)	Percentile* (2004)
Carbondale	3.73 12.23 in 1982	2.96	-0.77	max: 12.23 - 1982 min: 0.63 - 1976	43
Cape Girardeau	4.28 12.32 in 1982	2.04	-2.24	max: 12.32 - 1982 min: 0.77 - 1980	27
Evansville	3.54 8.23 in 1982	2.31	-1.23	max: 8.23 - 1982 min: 0.56 - 1976	25
Paducah	4.38 11.53 in 1982	3.32	-1.06	max: 11.53 - 1982 min: 0.63 -1976	45
Poplar Bluff	4.31 11.15 in 1982	2.72	-1.59	max: 11.15 -1982 min: 1.17 -1980	40

* Percentile is the percentage of years during the Normal Period (1971-2000) that had

   total December precipitation less than December 2004 (it ranges from zero to 100).

** Normal is the average December precipitation during the Normal Period: 1971-2000.

*** Record is the highest December rainfall for all years available at the location.

 

As Figure 2 indicates, precipitation for December was below normal at all five locations. This is unusual, considering that a region-wide record snow event occurred in December, to be discussed in the next section.

 

Cape Girardeau had the lowest December precipitation: 2.04 inches – at 2.24 inches below normal, ranking in the 27^th percentile. The other locations ranged from -1.59 inches at Poplar Bluff, to -0.73 inches in Carbondale, and ranging from the 25^th to the 43^rd percentile.

 

December 2004 was relatively dry and cold compared to the normal period.

 

December Record Snowfall

 

Though December was drier than normal, the month saw record snowfall across the Quad State Region. Figure 3 provides information about snowfall at four Quad State Region locations in December 2004.  In all areas, the snowfall was confined to the 22^nd and the early hours of the 23^rd.  One to two feet of snow crippled most areas just before the Holidays.  Several area interstates were closed for a time during and after the event.  The only other weather event of significance during December was flooding in the lower Ohio Valley.  This was due to multiple rain events over the Tennessee and lower Ohio River basins, as well as snowmelt in the Upper Ohio Valley during early December. [information from: 2004 Weather Highlights in Western Kentucky … Southern Illinois … Southwest Indiana … and Southeast Missouri - WINTER SEASON (December 2003 - February 2004)]

 

Figure 3. December 2004 Record Snowfall Data for four Quad State Region

            locations. December precipitation amounts include melted snow.

 

LOCATION	December 2004 Precip.	Departure from Normal	December 2004 Snowfall	Departure from Normal	2004 Snowfall Rank
Paducah	3.32 in.	-1.06 in.	14.2 in.	+12.7 in.	Snowiest
Evansville	2.31 in.	-1.23 in.	22.3 in.	+19.5 in.	2nd Snowiest
Carbondale	2.96 in.	-0.77 in.	13.0 in.	+10.4 in.	Snowiest
Poplar Bluff	2.72 in.	-1.59 in.	11.0 in.	+10.2 in.	Snowiest