October 2010 Climate and Hydrology Summary

October 2010

Tulsa: October 2010 was 45th warmest (63.2°F, since 1905) and the 23rd driest (1.23", since 1888) October on record.

Of the 1.23" of rain that fell at Tulsa, 0.98" of that fell on one day, Oct. 9, 2010.

Fort Smith: October 2010 was the 47th warmest (63.8°F) and 38th driest (1.70") October since records began in 1882.

Showers and thunderstorms that affected eastern OK and northwest AR on the 25th were the start of a large severe weather outbreak that occurred across the Midwest and Southeast US on Oct. 26-28. These storms were associated with one of the lowest pressures ever recorded in the continental US from a non-tropical system.

All of eastern OK and northwest AR received below normal rainfall this month, with most locations receiving less than 50% of the normal October rainfall. Portions of northeast OK and eastern Carroll County were the driest, recording only 5% to 25% of the normal October rain.

According to the Drought Monitor, portions of Pushmataha, Latimer, Le Flore, Okfuskee, and Creek Counties were experiencing abnormally dry conditions by the end of October. This is an improvment over the drought conditions at the end of September since the rain this October fell primarily on those areas experiencing the worst drought conditions.

According to the Oklahoma Climatological Survey (OCS), northeast OK ranked as the 11th driest October, east central OK ranked as the 23rd driest, and southeast OK ranked as the 24th driest since records began in 1921.

Outlook

The Climate Prediction Center (CPC) outlook for November 2010 (issued October 31, 2010) indicates an enhanced chance for above average temperatures and an enhanced chance for below median precipitation. For the 3-month period Nov-Dec-Jan 2010-11, CPC is forecasting an enhanced chance for above average temperatures and a slightly enhanced chance for below median precipitation (outlook issued October 21, 2010). The enhanced chance for above average temperatures and below median precipitation for the 1- and 3-month outlooks are consistent with a La Niña impacts across the southern Plains.

According to CPC, La Niña conditions strengthened during late September and early October and are currently of moderate strength. For this time of year, the observed ENSO indices are close to a record. La Niña conditions typically peak near December, and current computer models indicate that these conditions will strengthen and at least last through winter 2010-11,and very likely into the spring. A La Niña Advisory remains in effect, meaning that La Niña conditions are observed and expected to continue.