June 2019 Climate and Hydrology Summary

Tulsa: June 2018 was the 55th coldest (77.3°F, tied 1966, 1926; since 1905) and the 22nd wettest (6.92"; since 1888) June on record.

Tulsa: Daily records set or tied this month include a record warm minimum temperature.

Fort Smith: June 2019 was the 67th warmest (77.9°F, tied 1897, 1923, 1950, 1958; since 1882) and the 7th wettest (8.47"; since 1882) June on record.

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

Fayetteville: June 2019 was the 28th coldest (72.9°F; since 1950) and the 3rd wettest (8.93"; since 1950) June on record.

Fayetteville: Daily records set or tied this month include a record warm minimum temperature, a record warm mean temperature, and record daily rainfall.

McAlester: Daily records set or tied this month include a record warm minimum temperature.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for June 2019 ranged from 2” to near 15” across eastern OK and northwest AR. A large portion of the HSA received 5”-8” of rain this month. These rainfall totals correspond to 50%-90% of the normal June rainfall generally west of Highway 75, with far eastern OK and western AR receiving 125%-300% of the normal June rainfall.

Flooding from May 2019 continued into June, with additional heavy rain events through the month causing renewed flooding throughout eastern OK and northwest AR.

Thunderstorms developed during the morning hours of the 3rd across southeast OK within a warm and humid airmass, increasing in coverage as they moved northeast into east central OK and west central AR during the afternoon. Storms continued to redevelop across southeast OK through the afternoon and evening, finally coming to an end by late evening. Additional development occurred across northeast OK during the afternoon hours, spreading into northwest AR during the evening. Rainfall totals ranged from 0.50”-2” across much of southeast OK into west central AR, with pockets of 2”-4”. For northeast OK and northwest AR, rainfall totals were 0.25”-1.5” with isolated 1.5”-2.5”.

As an upper-level low began to approach the region from the southwest, shower and thunderstorms developed across southeast OK, east central OK, and west central AR during the afternoon of the 5th. This activity continued through the evening hours. Scattered light showers affected all of eastern OK and northwest AR overnight. Rainfall totals ranged from around 0.25” to around 1.5” for most of the area along and south of I-40. However, there were localized pockets of 1.5”-3”, and far southeast Pushmataha County/far northeast Choctaw County received 3”-5” of rain.

As the main upper-level low moved into the area on the 6th, convection increased across much of eastern OK and northwest AR during the afternoon and widespread rain continued through the evening. A jet streak lifting east from west Texas interacted with a weak surface trough/convergence zone near I-44, providing a focus for storms. All of the activity moved east and out of the area shortly after midnight. These storms were efficient rain producers since the precipitable water (PWAT) values were high, approaching 2 inches. The high PWAT values combined with slow storm motions resulted in heavy rain and flash flooding. A large portion of northeast OK and northwest AR received 0.75”-4” of rain, with a portion of Washington County, AR receiving 6”-7”. The Tulsa mesonet rain gauge measured 0.68” in just 10 minutes, which is an impressive 4”/hour rate. 3.12” was measured in 1 hour at this site, and 4.06” fell within 3 hours. Several rain gauges across Tulsa measured 2”-3” in one hour, and flash flooding occurred throughout the city. I-244 had to be shut down in Tulsa due to high water and homes near this area were flooded. Numerous road closures were reported across northeast OK and northwest AR from the Tulsa metro area through the Fayetteville metro area. Flash flooding also occurred in areas near the Arkansas River, partly due to the inability to properly drain into the river. This rainfall also resulted in moderate flooding along the Illinois River. The Arkansas River near Muskogee and at Van Buren were still above flood stage from May, but this rain caused the river to rise again to the moderate flood level. Lee Creek at Van Buren also had moderate flooding, with minor flooding along the Poteau River near Panama. Bird Creek saw fast rises, but remained below flood stage.

Thunderstorms moved out of north central OK/central KS into northeast OK during the pre-dawn hours of the 14th. This activity weakened and dissipated as it moved across eastern OK through the morning. A mesoscale convective system (MCS) crossed KS and moved into northeast OK just after midnight on the 15th. The MCS moved across northeast OK and northwest AR during the overnight through morning hours, dissipating by noon. Another, larger MCS moved into eastern OK around midnight on the 16th, and again, weakened as it crossed eastern OK. Most of the rain had dissipated by sunrise on the 16th, though showers continued across southeast OK through mid-morning. Thunderstorms redeveloped near the Red River in southeast OK in the afternoon and continued through the evening before dissipating. Further north, thunderstorms developed near and north of I-44 west of Tulsa during the late afternoon hours. This activity moved northeast along I-44 through the evening, moving into MO by midnight. Meanwhile, new development occurred over northeast OK just after midnight on the 17th. This activity affected northeast OK and northwest AR through mid-morning. By 7 am on the 15th, rainfall totals across northeast OK and far northwest AR were 0.25” to around 1.5”. Over the next 24-hours, an additional 0.25” to around 1.5” fell across northeast OK and northwest AR, with 0.25” to around 1.25” fell over portions of southeast OK. Then, by 7 am of the 17th, locations along I-44 and portions of Choctaw County had received 0.50” to 2.5” of rain, with scattered totals of 0.10” to around 1” elsewhere. This rainfall led to minor flooding along the Neosho River near Commerce.

A potent mid-level vorticity maximum moved from southeast CO into central KS on the 18th, igniting thunderstorms within an unstable airmass over northeast OK during the evening. Most of these storms were north of I-44 until late evening, when the moved east into northwest AR. Meanwhile, a large MCS developed across western OK, which moved into the eastern part of the state during the overnight hours. This line of storms marched east across the entire HSA, exiting the area by mid-morning on the 19th after producing widespread wind damage. Rainfall totals across southeast KS, northeast OK, and far northwest AR were 1”-4”. 0.50”-2” also fell over Choctaw County in southeast OK. Elsewhere, totals were around 0.75” or less. The heavy rain over the Neosho River basin caused another rise along the Neosho River near Commerce, leading to moderate flooding, and minor flooding occurred along the Verdigris River near Lenapah.

Early morning surface analysis on the 22nd indicated a surface low located over the OK/TX panhandles into northeast NM. From the low, a dryline extended southward to far southwest TX and a nearly stationary front was positioned from the low through central KS and into western MO. South and east of these boundaries, breezy southerly winds were helping to keep temperatures warm with dewpoints in the low/mid 70s across eastern OK and northwest AR. Also, ongoing convection along the frontal boundary in KS had put out a southward moving outflow boundary into the HSA. Aloft, an upper-level low continued to drop southeast through NV while a vorticity max had developed over southern TX. The combination of all of these features led to an active weather pattern across the region through the 24th. PWAT values were three standard deviations above normal, up to 2.3”, during this time, meaning thunderstorms were very efficient at producing heavy rain. The vorticity max in southern TX moved into eastern OK during the afternoon hours of the 22nd and into southern MO during the night. The combination of this vorticity max and leftover outflow boundaries from convection in KS allowed for scattered thunderstorm development over eastern OK and northwest AR during the late afternoon and evening hours. Thunderstorm coverage increased again over the HSA after midnight of the 23rd, as the vorticity max slowly moved into MO. During the early morning hours, additional thunderstorms developed along and ahead of a cold front positioned from a surface low in the TX panhandle northeast through central/northern KS. These storms then moved into eastern OK around sunrise on the 23rd and continued across the entire HSA, except for far southeast OK, through late afternoon. By mid-afternoon, new convection began over central OK along the cold front. The leading edge of the thunderstorms moved across east central/southeast OK and northwest AR through the evening hours, with trailing rain lingering for a couple of hours past midnight. There were numerous reports of wind damage and flash flooding across northeast OK, east central OK, and northwest AR. Many roads had water over them. A portion of AR HWY 220 near Devils Den was washed away. Significant street flooding occurred in Fort Smith and throughout Benton and Washington Counties in northwest AR. These rounds of storm activity brought widespread rain to much of eastern OK and northwest AR, with 2-day totals of 2” to 6”. In addition to the flash flooding, several rivers exceeded flood stage. Major flooding occurred along Lee Creek at Van Buren; Moderate flooding occurred along the Neosho River near Commerce, Spring River near Quapaw, Illinois River near Watts, Chewey, and Tahlequah, Arkansas River near Muskogee and at Van Buren, Poteau River near Poteau and near Panama; and Minor flooding occurred along the Caney River near Collinsville, Baron Fork near Eldon, Arkansas River at Ozark L&D

Thunderstorms developed and lingered over Carroll and Madison Counties during the afternoon of the 26th in response to a well-defined mesoscale convective vortex (MCV) over central MO and high instability over northern AR. Rainfall totals were around 1” to around 3” from these nearly stationary storms.

According to the Drought Monitor from July 2, 2019, no drought or abnormally dry conditions were present across eastern OK and northwest AR.

According to the Oklahoma Climatological Survey, June 2019 was the 18th wettest for northeast Oklahoma, the 22nd wettest for east central Oklahoma, and the 12th wettest for southeast Oklahoma. Records go back to 1921. For the Year-to-Date period Jan. 1-June 30, 2019, northeast Oklahoma ranked as the 3rd wettest, east central Oklahoma was the 11th wettest, and southeast Oklahoma was the 11th wettest period. For the last 365 days (July 1, 2018-June 30, 2019), northeast Oklahoma was the 5th wettest, east central Oklahoma was the 9th wettest, and southeast Oklahoma was the 2nd wettest.