A Cold Winter Across Southeast Colorado

It certainly can be said that this past winter was cold across south central and southeast Colorado, as the following preliminary data for Meteorological Winter 2010 (December, January and February) indicates.

In Pueblo, the average temperature for December through February was 27.8 F, making it the 9th coldest winter in the past 121 years, and the coldest since 1988 when the average temperature for the winter was 27.3 F. The coldest winter on record in Pueblo is 1899, when the average temperature was 23.9 F.  In Colorado Springs, the average winter temperature was 27.2 F, making it the 12th coldest winter in the past 115 years and the coldest since 1984 when the average temperature for the winter was 25.8 F.  The coldest winter on record in Colorado Springs is also 1899, when the average temperature was 23.0 F.  In Alamosa, the average winter temperature was 17.5 F, making it the 26th coldest winter in the past 78 years and the coldest since 2008, when the average winter temperature was 11.4 F. The coldest winter on record in Alamosa is 1992, when the average winter temperature was 6.8 F.  

Despite the lack of a major snowstorm, tallies for the winter (December through February) indicate generally above average snowfall for southeast Colorado with Pueblo (19.5) and Colorado Springs (21.0) seeing around 20 inches of snow, which is just over 4 inches above the winter average for both cities.  Total winter snowfall recorded in Alamosa was 11.0 inches, which is around 2 inches (2.1) below average.

The following data and links highlight an interesting comparison on winter temperatures across southeast Colorado and the phase of the "Arctic Oscillation" ( AO ). The AO is refers to opposing atmospheric pressure patterns in the northern middle and high latitudes.  The oscillation exhibits a "negative phase" with relatatively high pressure over the polar region and low pressure at midlatitudes, and a "positive phase" in which the pattern is reversed. In the negative phase, cold arctic air can be more easily transported across portions of mid North America, where as in the postive phase, this colder airmass can be shifted further north and east across Newfoundland and Greenland.

Over this past winter, the AO was characterised as being "highly negative" for the months of December and February, and "slightly postive" in January. This seems to be fairly well correlated with the monthly average temperature anomalies recorded across southeast Colorado.  The monthly temperature anamolies in Colorado Springs for December and February were 5.8 F and 4.0 F below average respectively, with January seeing an average temperature 2.6 F above normal. The monthly temperature anamolies in Pueblo for December and February were 5.9 F and 5.6 F below normal, with January seeing an average temperature of nearly 1.0 F above normal. 

 

http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

 

http://nsidc.org/arcticmet/patterns/arctic_oscillation.html

 

 


 



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