December 2010 Climate Summary

For a printable version of the climate summary which includes more figures, data tables, and state summaries, click here. 

Temperature Summary

Temperatures across the High Plains Region this month were below normal in the eastern half and above normal in the western half.  The dividing line between the above and below normal temperatures ran from southwestern South Dakota into central Nebraska, and then into west-central Kansas.  December temperature departures ranged from 7 degrees F (3.9 degrees C) below normal in North Dakota to 10 degrees F (5.6 degrees C) above normal in Colorado.

Great Sand Dunes National Park in Colorado recorded its warmest December with an average temperature of 31.0 degrees F (-0.6 degrees C) which was 8.0 degrees F (4.4 degrees C) above normal.  This just surpassed the old record of 30.9 degrees F (-0.6 degrees C) which occurred in 1977 (period of record 1950-2010).  Cortez, Colorado also had its warmest December on record with an average temperature of 36.7 degrees F (2.6 degrees C).  This broke the old record of 36.3 degrees F (2.4 degrees C) which was set in 1980 (period of record 1911-2010).

Precipitation Summary

Southern portions of the Region including Kansas, Nebraska, and eastern Colorado received little to no precipitation this month.  This caused existing drought conditions to persist and led to the development of drought in eastern Kansas as well.  While the southern portion of the Region remained dry, several storm systems impacted the northern portions of the Region this month.  The Dakotas were hit particularly hard by heavy snowfall which set new records and impacted travel.  Several areas of both North Dakota and South Dakota had liquid equivalent precipitation totals which were over 400 percent of normal.  One location which set many records this month was Williston, North Dakota.  Williston had its 3rd wettest December on record with 1.95 inches (50 mm) of liquid equivalent precipitation (period of record 1894-2010).  The current record held with 2.50 inches (64 mm) recorded in 2008.  It also recorded its snowiest December with 35.3 inches (90 cm) of snow (period of record 1962-2010).  14.3 inches (36 cm) of this total fell on December 10th and set the highest one-day total snowfall record for December.  The old record of 11.4 inches (29 cm) was also set in 2008.  Later in the month, on December 21st, a new December snow depth record of 23.0 inches (58 cm) was also set.

Climate Outlook

La Niña conditions were present across the equatorial Pacific this month and are expected to continue into spring 2011.  The temperature outlook indicates a higher probability of above normal temperatures for Kansas, most of Colorado, and a very small portion of southwest Nebraska.  North Dakota and northern South Dakota have a higher probability of below normal temperatures.  Equal chances of above, near, or below normal temperatures are predicted elsewhere in the Region.  The precipitation outlook indicates a higher probability of above normal precipitation for North Dakota, the majority of Wyoming and northwestern South Dakota.  The majority of Colorado, western Kansas, and west-central Nebraska have a higher probability of below normal precipitation.  Equal chances of above, near, or below normal precipitation are predicted elsewhere in the Region.  The seasonal outlooks combine the effects of long-term trends, soil moisture, and when applicable, the El Niño Southern Oscillation cycle (ENSO).  More information about these forecasts can be found here.

Drought Watch

According to the U.S. Drought Monitor, drought conditions deteriorated across the southern portions of the Region this month.  By the second week of December abnormally dry conditions (D0) had expanded north from Oklahoma into eastern Kansas and severe drought conditions (D2) had expanded from eastern Colorado into western Kansas.  In addition, D0 had spread further east in Nebraska.  By the end of the month moderate drought conditions (D1) had developed in eastern Kansas as well.  Only slight improvements were seen in extreme northwestern Colorado where the D0 area was eliminated and in western Wyoming where the D1 and D0 areas were trimmed due to heavy snowfall.  According to the U.S. Seasonal Drought Outlook released December 16th drought conditions across Colorado, Kansas, and Nebraska were expected to persist and the D1 area in Wyoming was expected to improve.