December 2010 Climate and Hydrology Summary

December & Year 2010

Tulsa: December 2010 was 34th coldest (38.7°F, tied with 2005; since 1905) and the 20th driest (0.55", tied with 1976; since 1888) December on record. Only a trace of snow was recorded in Tulsa this month.

Fort Smith: December 2010 was the 55th coldest (41.2°F, tied with 1969) and 51st driest (2.14") December since records began in 1882. No snow was recorded in Fort Smith this month.

Fayetteville: A record cold maximum temperature of 28°F was set on December 26. The previous record of 29°F occurred in 2001. A record low minumum tempearture of 9°F was set on December 27th. The previous record of 14°F occurred in 1951.

Both Tulsa and Fort Smith did not receive any measurable rainfall until Christmas Eve, and then rain was only measured on 3 days this month in Tulsa and 5 days in Fort Smith. Over half of the monthly total rainfall at Fort Smith occurred on December 29th, when 1.33" was measured.

Severe weather occurred in eastern Oklahoma and northwest Arkansas on December 30-31, 2010. While not very common, tornadoes can occur during the winter, and unfortunately, a deadly EF3 tornado occurred during this event. Read more about this event here.

Rainfall totals for December 2010 ranged from 0.25" to near 1" across locations northwest of an Okemah to Tahlequah to Bentonville line, with the remainder of the area receiving around 1" to around 3". A few locations in southeast OK even saw 4" to 5" of much needed rain this month. All but far southeast OK received below normal rainfall this month. Most of the area recorded less than 50% of the normal December rainfall, with many locations only receiving 5% to 25% of the monthly normal. The rainfall at the end of the month kept portions of southeast OK near normal up to 200% of the normal December rainfall.

According to the Drought Monitor from December 28, 2010, abnormally dry (D0) and moderate drought (D1) conditions were affecting all of eastern Oklahoma and northwest Arkansas. The expansion of drought conditions was due to the below normal precipitation received this December, which has exacerbated both the long- and short-term rainfall deficits and led to lower lake levels across the area.

According to the Oklahoma Climatological Survey (OCS), northeast OK ranked as the 8th driest December, east central OK ranked as the 25th driest, and southeast OK ranked as the 39th driest since records began in 1921.

Year 2010

Tulsa: The Year 2010 was 33rd warmest (61.3°F, tied with 1986, 1982, 1928, 1927; since 1905) was the 44th driest year (34.47", since 1888), and was the 18th snowiest year (15.4", tied with 1989; since 1900) on record.

Fort Smith: The Year 2010 was the 17th warmest (62.9°F), 38th driest (35.27"), and the 10th snowiest (15.5") year since records began in 1883.

Most of the area received between 30" and 40" of rain this year. This corresponds to near to below normal precipitation (50% to 110% of the normal annual rainfall) for most of the region for the year 2010. While the end of 2010 was dry with no snow accumulations (and under the influence of a moderate to strong La Niña), the beginning of 2010 brought cold temperatures and heavy snowfall events to the region (under the influence of a strong El Niño).

There were 40 tornadoes that occurred this year in eastern Oklahoma and northwest Arkansas. There is 1 additional possible tornado in northwest Arkansas pending further review of the data.

Outlook

The Climate Prediction Center (CPC) outlook for January 2011 (issued December 31, 2010) indicates an equal chance for above, near, and below average temperatures, as well as an equal chance for above, near, and below median precipitation. Short-term computer models continue to indicate that an enhanced chance for cooler than normal temperatures due to a negative phase of the Arctic Oscillation and the North Atlantic Oscillation will offset the enhanced chance for warmer than normal temperatures due to La Niña effects. Therefore, the January outlook indicates equal chances for temperature across the region.

For the 3-month period Jan-Feb-Mar 2011, CPC is forecasting an enhanced chance for above average temperatures. CPC is also forecasting a slightly enhanced chance for above median precipitation across northwest AR, with equal chances for above, near, and below median precipitation across eastern Oklahoma (outlook issued December 16, 2010). The enhanced chance for above average temperatures for the 3-month winter outlook is consistent with La Niña impacts across the southern Plains.

According to CPC, borderline strong La Niña conditions were observed at the end of December. Current computer models indicate that La Niña conditions can still be expected to continue through the remainder of winter 2010-11,and into spring 2011. A La Niña Advisory remains in effect, meaning that La Niña conditions are observed and expected to continue.