September 2017 Climate and Hydrology Summary

September 2017

Tulsa: September 2017 was the 43rd warmest (75.0°F; since 1905) and the 34th driest (1.80"; since 1888) September on record.

Fort Smith: September 2017 was the 38th warmest (76.0°F, tied 2010, 1914, 1898; since 1882) and the Record driest (Trace, previous record 0.05" in 1928; since 1882) September on record.

Fayetteville: September 2017 was the 31st warmest (69.6°F, tied 1969; since 1949) and the 10th driest (1.50"; since 1949) September on record.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for September 2017 ranged from 0” to around 4”. Portions of far east central OK, southeast OK and west central AR received no measureable rainfall this month. This corresponds to 0% to near 75% of the normal September rainfall for a majority of the area. Only small portions of Osage, Kay, Pawnee, and Nowata Counties received near normal September rainfall.

It was a well below normal rainfall month across eastern OK and northwest AR. Fort Smith, AR only received a trace of rain making this the record driest September since records began there in 1882! Southeast OK also ranked as the driest on record, with two Mesonet stations receiving no rain at all. Three devastating hurricanes, Harvey, Irma, and Maria, impacted the U.S. this month, but did not affect eastern OK and northwest AR.

According to the Drought Monitor from October 3, 2017, D1 (Moderate) drought conditions were present across portions of Rogers, Mayes, Delaware, Wagoner, Cherokee, Adair, Muskogee, McIntosh, Le Flore, Pushmataha, and Choctaw Counties in eastern OK and Benton, Carroll, Washington, Madison, and Sebastian Counties in northwest AR. D0 (Abnormally Dry but not in drought) conditions were occurring over portions of all counties in eastern OK and northwest AR except Creek, Okfuskee, and Okmulgee Counties.

According to the Oklahoma Climatological Survey, September 2017 was the 18th driest for northeast Oklahoma, the 8th driest for east central Oklahoma, and the Record driest for southeast Oklahoma. Records go back to 1921. For the 60-day period August 2-September 30, 2017, northeast Oklahoma ranked as the 35th wettest, east central Oklahoma was the 22nd wettest, and southeast Oklahoma was the 30th wettest period. For Water Year 2017 (October 1, 2016-September 30, 2017), northeast Oklahoma ranked as the 19th wettest, east central Oklahoma was the 32nd wettest, and southeast Oklahoma was the 38th driest Water Year.

Water Year 2017 (Oct. 1, 2016-Sep. 30, 2017)

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for Water Year 2017 ranged from around 35” to around 60”. The majority of the area received 40”-50”. This corresponds to 75% to 150% across the counties that border KS and a few areas elsewhere, while the majority of eastern OK and northwest AR was 50% to 100% of the normal water year rainfall

In Tulsa, OK, Water Year 2016-17 ranked as the 5th warmest Water Year (63.4°F; since records began in 1905-06) and the 37th wettest Water Year (41.98”; since records began in 1893-94).

Fort Smith, AR had the 2nd warmest Water Year (64.8°F, tied 1931-32; since records began in 1882-83) and the 44th wettest Water Year (44.87”; since records began in 1882-83).

Fayetteville, AR had the 2nd warmest (59.4°F, tied 1990-91) and the 19th wettest (49.97”) Water Year since records began in 1949-50.