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Powerful Pacific System Impacting the West; First Significant Snow for Portions of the East

Power Pacific system will continue to bring significant impacts for Pacific Northwest into northern California the remainder of the week. Dangerous coastal affects, heavy rain, flooding, strong winds, and higher elevation mountain snow continues. Meanwhile, a storm across the east is set to bring the first accumulating snow to many higher elevations of the Catskills into the central Appalachians. Read More >

 

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August 2017 & Summer 2017

  • Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for August 2017 ranged from around 2” to around 15”. Several areas, especially across east central OK and west central AR, received 8”-15” of rain this month. This corresponds from around 150% to near 600% of the normal August rainfall for a majority of the area. However, a portion of northeast OK only received 75%-100% of the normal August rainfall.
  • August 2017 was unusually wet and mild, with much of the region receiving above normal rainfall and temperatures near to below normal on average this month. The State of Oklahoma preliminarily had the 2nd wettest and 6th coolest August on record. A near total solar eclipse also happened this month.
  • Minor flooding occurred along the Neosho River near Commerce.
  • According to the Drought Monitor from August 29, 2017, no drought conditions were present across eastern OK and northwest AR.
  • According to the Oklahoma Climatological Survey, the 30-day period August 2-31, 2017 was the 9th wettest for northeast Oklahoma, the Record wettest for east central Oklahoma, and the Record wettest for southeast Oklahoma.  Records go back to 1921. For the 60-day period Jul 3-August  31, 2017, northeast Oklahoma ranked as the 17th wettest, east central Oklahoma was the 5th wettest, and southeast Oklahoma was the 4th wettest period.  For the Water Year-to-date, October 1, 2016-August  31, 2017, northeast Oklahoma ranked as the 13th wettest, east central Oklahoma was the 18th wettest, and southeast Oklahoma was the 45th wettest period.
  • On the evening of the 5th, thunderstorms moved into northeast OK and expanded in coverage through the evening hours. A bow echo developed within the thunderstorm complex, bringing several quasi-linear convective system (QLCS) tornadoes to northeast OK, including an EF-2 in midtown Tulsa (more information at https://arcg.is/0LuGH1). The line of storms continued to push southeast and into southeast OK and west central AR by the pre-dawn hours of the 6th. All of the rain then moved south and out of the area by noon. In addition to the tornadoes, this activity brought heavy rain due to a deep moisture axis over the region. Rainfall totals ranged from 0.75” to around 6” across all of eastern OK and northwest AR, with many areas receiving 2”-4”. The highest totals of 5”-6” occurred over northern Osage County. Later in the evening, thunderstorms redeveloped near the Red River along a boundary. This activity continued through the overnight hours before finally coming to an end around sunrise on the 7th. The 24-hour rainfall total from both rounds of precipitation over southeast OK was 1.5”-8”, with all of Choctaw County receiving 2.5”-8” of rain. In the 24 hours ending at 7am CDT August 7, 7.01” was measured 2 miles northwest of Hugo, OK. Numerous roads were reported closed in Hugo. 3.38” was measured 5 miles west of Antlers, OK.
  • Scattered thunderstorms moved south out of KS on the evening of the 10th, affecting northeast OK and northwest AR north of I-40. There were numerous reports of wind damage associated with these storms. A large complex of storms tracking east across OK then began to affect eastern OK a couple hours after midnight on the 11th and reached western AR near sunrise. Rainfall totals ranged from around 0.50” to around 3” for much of eastern OK and northwest AR, with the exception of far southeast OK which remained mostly dry. Portions of the Neosho River basin in southeast KS received 1.5”-4” of rain. As this water flowed south, it caused the Neosho River near Commerce to rise to just below flood stage.
  • An impulse emanating from the Southwest monsoon activity slid over the southern Plains on the 12th, resulting in widespread showers moving east into the area from central OK. This activity affected east central and northeast OK through northwest AR during the morning and afternoon hours, with additional convection spreading into southeast OK and west central AR during the evening. Around midnight on the 13th, elevated showers and thunderstorms began to develop along the I-40 corridor and near the Red River, north of a stalled front over northern TX. An intense band of convection affect locations along the Canadian and Arkansas Rivers in east central OK for several hours during the night. Portions of McIntosh, Haskell, Muskogee, and Sequoyah Counties received 3”-8” of rain. Elsewhere, rainfall totals ranged from a few hundredths to around 3”. The rain finally came to an end by noon on the 13th. Flash flooding occurred across Sequoyah County, with a swift water rescue reported several miles east of Sallisaw, OK, and numerous roads impassable, especially in the Gans and Sallisaw areas. Sequoyah County Emergency Management said a train derailment occurred in Sequoyah County on the 13th, and the derailment was likely due to heavy rain washing away the ground under the tracks. Around 10 cars went off the rails in the morning on Central High Road east of Sallisaw and north of Highway 64, but the two crew members on board were not injured.
  • An MCS developed over the high Plains and eventually merged with other convection lifting north from the TX southern Plains during the evening of the 13th. This system generated an MCV over southwest OK. As the MCV moved east, it enhanced upglide over a surface boundary near the Red River and showers with embedded thunderstorms progressed northeast through the morning hours of the 14th, affecting eastern OK and western AR generally along and south I-44. An upper-level disturbance sliding east over the region fueled another cluster of storms from southeast OK into northwest AR during the evening of the 14th and into the early morning hours of the 15th. Along and south of I-44, rainfall totals were 0.25” to 2”, with isolated areas of 2” to 3”. However, heavier rain during the early morning hours brought 2”-6” of rain to most of Franklin County in west central AR. 5.15” was measured in 24 hours at Ratcliff, AR, 4.90” was measured in Ozark, AR, and 3.42” was measured 1.7 miles east of Charleston, AR. There were reports of water in several homes along AR Highway 23 north of Ozark, AR and a couple of bridges out outside of Branch, AR. The Mulberry River near Mulberry rose quickly above Action Stage, but remained below flood stage.
  • A line of thunderstorms develop near I-35 during the afternoon of the 15th, expanding in coverage as it traversed northeast OK and northwest AR, generally along and north of I-40, during the evening hours. The heaviest rainfall of 0.50” to 3” fell in a band from Creek County to Franklin County. AR Highway 59 was flooded near Natural Dam, AR, with the worst flooding near Cedarville, AR. Sand Springs, OK measured 2.71” in just 40 minutes. A swift water rescue was needed near Krebs, OK. Lee Creek near Van Buren rose above Action Stage, but remained below flood stage.
  • At mid-morning of the 16th, a cold front was positioned from the TX panhandle to central KS, with an ongoing MCS moving eastward across eastern KS into MO. The southern flank of this activity shifted south into northeast OK along an outflow boundary. Additionally, scattered showers developed during the morning and afternoon from southeast OK into northwest AR within an axis of deep layer moisture ahead of the cold front. By mid-evening, a line of thunderstorms had developed along the front from eastern KS into north central OK. This line move southeast across the entire area during the evening and overnight hours, before moving out of southeast OK by mid-morning on the 17th. Rainfall totals were around 0.50” to around 2.5”. The rain over southeast KS and far northeast OK led to minor flooding along the Neosho River near Commerce. The Mulberry River near Mulberry in west central AR rose above Action Stage, but remained below Flood Stage.
  • August 21, 2017 was the first total solar eclipse in the U.S. since Feb. 1979. In Tulsa, the sun was 89% eclipsed during the peak at 1:08pm CDT. The eclipse occurred from 11:39 am CDT – 2:37 pm CDT. There was a noticeable drop in temperature, wind, and solar radiation during the time of the eclipse, as seen in plots of meteorological parameters from three Oklahoma Mesonet stations.
Summer (June-July-August) 2017
  • Tulsa: Summer 2017 was the 35th coldest (80.1°F, tied 1951, 1907, 1912, 1938; since 1905) and the 56th wettest (11.07"; since 1888) Summer on record.