July 2017 Climate and Hydrology Summary

July 2017

Tulsa: July 2017 was the 46th warmest (83.6°F, tied 1939, 1919; since 1905) and the 57th driest (2.23"; since 1888) July on record.

Fort Smith: July 2017 was the 36th warmest (83.4°F, tied 1956, 1941; since 1882) and the 32nd wettest (4.53"; since 1882) July on record.

Fort Smith: Daily records set or tied this month include a record daily rainfall.

Fayetteville: July 2017 was the 28th coldest (77.7°F, tied 2008, 2002, 1990; since 1950) and the 28th driest (2.19", tied 1950; since 1950) July on record.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for July 2017 ranged from 0.50” to around 12”. The highest totals of 6”-10” occurred over west central AR and 6” to around 12” across southeast OK, with isolated pockets of 5”-8” elsewhere. The highest rainfall areas received 125% to near 400% of the normal July rainfall, with the remaining area receiving 90% to around 25% of the normal July rainfall.

Several rounds of heavy rain impacted primarily southeast OK during July 2017, with much of the remaining portion of the region receiving below normal rainfall.

A line of thunderstorms developed over central OK during the afternoon of the 2th. These storms moved east, affecting all of eastern OK and northwest AR through the afternoon and evening hours. Storms lingered across far southeast OK through the overnight hours. Rainfall totals ranged from around 0.50” to around 5”. Most of Choctaw County received 3”-5” of rain, with a few other isolated pockets of heavy rainfall elsewhere. Some urban flash flooding occurred in Tulsa and Bartlesville. The rain exited the region by noon on the 3rd. A few hours later, additional thunderstorms developed just south of the KS-OK state line. These storms affected northeast OK through the mid-evening hours before another line of thunderstorms moved into the area from north central OK. Once again, all of eastern OK and northwest AR was affected by the line of storms through the overnight and early morning hours. By sunrise on the 4th, only a few showers lingered near the mesoscale convective vortex (MCV) generated by the squall line. Rainfall totals ranged from 0.10” to around 2.5” for most of eastern OK and northwest AR, though south central Osage County ended up with 2”-6” of rain. The City of Hominy, which received 4.57” of rain, reported waist deep water in town.

Scattered showers continued over northeast OK and northwest AR during the morning and lasting through the evening of the 4th as the MCV moved slowly across the area. This brought an additional 0.10”-2” of rain. Just before midnight on the 5th, thunderstorms developed near the Red River in southeast OK near a frontal boundary and under the influence of the low-level jet. This activity continued through the mid-morning hours of the 5th. This activity produced very heavy rain, 2”-8”, primarily during the pre-dawn hours over Pushmataha and Choctaw Counties. This precipitation, on top of the previous days’ rainfall, resulted in minor flooding along the Kiamichi River near Antlers (see preliminary hydrograph at the end of this report) and flash flooding in Pushmataha and Choctaw Counties.

During the afternoon and evening of the 8th, widespread thunderstorms developed near a cool front and affected northeast OK and northwest AR. A cluster of storms then intensified near the front in northwest AR after midnight on the 9th and moved southward. Training of storms over west central AR resulted in 2”-5” of rain over Sebastian, Crawford, and Franklin Counties, while elsewhere, rainfall totals were around 2” or less. Around sunrise, additional storms fired up over northeast OK. This activity moved southeast, bringing 0.25” to around 1.5” of rain to northeast OK through west central AR.

According to the Drought Monitor from August 1, 2017, D0 (abnormally dry conditions but not in drought) were present across portions of Okfuskee, Okmulgee, Creek, Tulsa, Pawnee, Osage, eastern Kay, and Washington Counties in eastern OK.

According to the Oklahoma Climatological Survey, July 2017 was the 47th driest for northeast Oklahoma, the 33rd wettest for east central Oklahoma, and the 7th wettest for southeast Oklahoma. Records go back to 1921. For the Year-to-Date period Jan. 1-July 31, 2017, northeast Oklahoma ranked as the 12th wettest, east central Oklahoma was the 10th wettest, and southeast Oklahoma was the 31st wettest period. For the last 365 days (Aug 1, 2016-Jul 31, 2017), northeast Oklahoma was the 33rd wettest, east central Oklahoma was the 48th wettest, and southeast Oklahoma was the 38th driest.