October 2012 Climate and Hydrology Summary

October 2012

Tulsa: October 2012 was the 23rd coldest (60.7°F, tied with 1936, 1911; since 1905) and the 62nd driest and wettest (2.75", tied 2008, 1977; since 1888) October on record.

Tulsa recorded its earliest freeze on record October 7, 2012. The previous record earliest freeze was October 8, 2000 and 1952.

Fort Smith: October 2012 was the 48th coldest (62.0°F, tied 1974, 1968; since 1882) and the 57th driest (2.65"; since 1882) October on record.

Fayetteville: October 2012 was the 11th coldest (56.1°F, tied 1970; since 1949) and the 27th driest (2.98"; since 1949) October on record.

October 2012 was the first time Tulsa, Fort Smith, and Fayetteville had their monthly average temperature below normal since September 2011.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for October 2012 ranged from less than 0.10” in southern Tulsa, northern Okmulgee, and eastern Kay Counties to around 5” in northern Tulsa, Rogers, and eastern Franklin Counties. Most of the HSA received 0.5” to 3” of rain this month. Only Rogers, northern Creek, northern Tulsa, southeastern Ottawa, eastern Benton, and Carroll Counties received above normal rainfall this October, while the remainder of the area saw less than 75% of the normal rainfall for October. Eastern Kay, southern Tulsa, western Wagoner, and northern Okmulgee Counties in eastern OK were very dry, only getting 5% or less of the normal rainfall this month! There was a very large rainfall gradient across Tulsa County due to the heavy rain event on October 13th.

According to the Drought Monitor from October 30, 2012, all of eastern OK and northwest AR was in Severe to Exceptional drought. Exceptional (D4) drought was occurring over portions of Osage, Pawnee, and southern Washington Counties in eastern OK. Extreme (D3) drought was present across portions of Osage, northern Washington, Tulsa, Nowata, Rogers, Wagoner, Muskogee, western Haskell, Latimer, eastern Pushmataha, and Le Flore Counties in eastern OK, and eastern Washington, southern Carroll, Madison, Sebastian, and southern Franklin Counties in northwest AR. Severe drought (D2) conditions existed across the remainder of the area.

In 2012, Tulsa, Fort Smith, and Fayetteville all had their RECORD warmest January 1 - October 31 period for their respective periods of record.

Outlook

The Climate Prediction Center CPC outlook for November 2012 (issued October 31, 2012) indicates a slightly enhanced chance for above normal temperatures across all of eastern OK and northwest AR. This outlook also indicates an enhanced chance for below median precipitation for northeast and east central OK and northwest AR and equal chances for above, near, and below median precipitation across southeast OK and west central AR. This outlook is based on short- and extended-range computer models.

For the 3-month period Nov-Dec-Jan 2012-13, CPC is forecasting an equal chance for above, near, and below average temperatures across eastern OK and northwest AR. This outlook also calls for a slightly enhanced chance for below median precipitation north of I-40 and equal chances of above, near, and below median precipitation south of I-40 (outlook issued October 18, 2012). This outlook is based primarily on dynamic computer model output and long term trends.

According to CPC, ENSO neutral to borderline El Niño conditions continued through October. Computer models indicated that sea surface temperatures in the equatorial Pacific Ocean will either remain steady or increase slightly, leading to weak El Niño conditions, during the upcoming winter. An El Niño Watch remains in effect.