October 2015 Climate and Hydrology Summary

October 2015

Tulsa: October 2015 was the 43rd warmest (63.4°F, tied 2011, 1982; since 1905) and the 32nd driest (1.50"; since 1888) October on record.

Fort Smith: October 2015 was the 30th warmest (65.5°F; since 1882) and the 36th driest (1.52"; since 1882) October on record.

Fort Smith:Daily records were set or tied this month include record warm maximum temperatures.

Fayetteville: October 2015 was the 25th warmest (59.2°F, tied 2003; since 1949) and the 17th driest (1.90"; since 1949) October on record.

Fayetteville:Daily records set or tied this month include a record warm maximum temperature.

McAlester: Daily records set or tied this month include record warm maximum temperatures.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for October 2015 ranged from around 0.50” to near 8”. Most of the HSA received 1.5”-3” of rain this October. This corresponds to 25%-75% of the normal October rain across the majority of eastern OK and northwest AR. The exception was southern Pittsburg County, where heavy rain yielded 110% to near 200% of the normal October rainfall.

October 2015 was another dry month across eastern OK and northwest AR as torrential rains remained south in Texas.

According to the Drought Monitor from November 3, 2015, Moderate (D1) drought was occurring over a large part of Pushmataha and northeast Choctaw Counties in eastern OK and southern Madison County in northwest AR. Abnormally dry (D0), but not in drought, conditions were located across the remainder of Pushmataha and Choctaw Counties, as well as southern portion Le Flore, Adair, Delaware, Ottawa, Craig, Mayes, Rogers, Nowata, Washington OK, Osage, Pawnee, Tulsa, Creek, northwest Okmulgee, northwest Okfuskee, northwest Wagoner, northeast Cherokee, Benton, Washington AR, Madison, Carroll, Sebastian, and southern Franklin Counties.

According to the Oklahoma Climatological Survey, October 2015 was the 26th driest for northeast Oklahoma, the 45th driest for east central Oklahoma, and the 42nd wettest for southeast Oklahoma. Records go back to 1921. For the Cool Growing Season September 1 - October 31, 2015, northeast Oklahoma ranked as the 16th driest, east central Oklahoma was the 41st driest, and southeast Oklahoma was the 37th driest period. For Year-to-Date 2015 (January 1-October 31, 2015), northeast Oklahoma ranked as the 21st wettest, east central Oklahoma was the 2nd wettest, and southeast Oklahoma was the 11th wettest Year-to-Date.

Outlook

The Climate Prediction Center (CPC) outlook November 2015 (issued October 31, 2015) indicates an enhanced chance for above normal temperatures and above median precipitation across eastern OK and northwest AR. This outlook is based on both short- and extended range weather forecasts as well as strong El Niño influences.

For the 3-month period November-December-January 2015-16, CPC is forecasting an equal chance for above, near, and below normal temperatures across all of eastern OK and northwest AR except for far southeast OK, where the odds favor below normal temperatures. This outlook also indicates an enhanced chance for above median precipitation across all of eastern OK and northwest AR (outlook issued October 15, 2015). This outlook is based primarily on both statistical and dynamical forecast tools, as well as typical impacts resulting from El Niño conditions.

According to CPC, strong El Niño conditions remain in place. The ongoing El Niño is expected to peak in strength in the late autumn or early winter. There are indications that this event could peak as a very strong (sometimes referred to as a “super”) El Niño, with sea surface temperature anomalies near or exceeding +2.0°C. There is a 95% chance for El Niño to continue through the upcoming winter and it is expected to persist through spring 2016. El Niño impacts are generally most significant in the Southern Plains during the cold season. An El Niño Advisory is in effect.