October 2017 Climate and Hydrology Summary

October 2017

Tulsa: October 2017 was the 47th warmest (63.3°F, tied 1994, 1965; since 1905) and the 13th wettest (7.16"; since 1888) October on record.

Fort Smith: October 2017 was the 42nd warmest (64.4°F, tied 1984, 1915; since 1882) and the 65th wettest (3.29"; since 1882) October on record.

Fayetteville: October 2017 was the 28th coldest (58.0°F, tied 2011, 1967; since 1949) and the 31st wettest (3.86"; since 1949) October on record.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for October 2017 ranged from around 3” to around 12”. The highest rainfall totals exceeding 5” occurred over northeast OK with isolated areas elsewhere. This corresponds to 100% to around 300% of the normal October rainfall for most of northeast OK, with the remainder of the area ranging from 75% to 110%. However, far southeast OK and Carroll County in northwest AR received 50%-75% of the normal rainfall.

Heavy rain fell affected primarily northeast OK in October 2017, leading to some rises along area rivers. Temperatures where near to a degree or two above normal this month across eastern OK and northwest AR.

Moderate flooding occurred along the Black Bear Creek at Pawnee and minor flooding occurred along Bird Creek near Sperry.

According to the Drought Monitor from October 31, 2017, Moderate (D1) drought conditions were present across portions of Le Flore County in eastern OK and Carroll, Madison, Washington, Crawford, Sebastian, and Franklin Counties in northwest AR. Abnormally dry, but not in drought, (D0) conditions were occurring over portions of Ottawa, Delaware, Mayes, Cherokee, Adair, Le Flore, Pushmataha, and Choctaw Counties in eastern OK and Benton, Washington, Crawford, and Sebastian Counties in northwest AR.

According to the Oklahoma Climatological Survey, October 2017 was the 10th wettest for northeast Oklahoma, the 35th wettest for east central Oklahoma, and the 45th driest for southeast Oklahoma. Records go back to 1921. For the Cool Growing Season September 1 - October 31, 2017, northeast Oklahoma ranked as the 37th wettest, east central Oklahoma was the 29th driest, and southeast Oklahoma was the 16th driest period. For Year-to-Date 2017 (January 1-October 31, 2017), northeast Oklahoma ranked as the 8th wettest, east central Oklahoma was the 9th wettest, and southeast Oklahoma was the 31st wettest Year-to-Date.

An area of showers with embedded thunderstorms increased in coverage during the early morning hours of the 4th, developing within a very moist airmass south of a stalled frontal boundary that stretched from southeast KS into northwest OK. This activity spread across primarily northeast and east central OK and northwest AR during the day. The convection was very efficient in producing rainfall due to precipitable water values near 2”, which is about 200% of normal for this time of year. 1.50” to near 2” of rain was measured in an hour within the heavier rain bands. Training storms over Pawnee, Osage, and southern Washington Counties resulted in a total 5”-10” of rain. This lead to flash flooding, with numerous roads closed and a water rescue. Black Bear Creek at Pawnee reached moderate flood stage and Bird Creek near Sperry exceeded minor flood stage due to this rain