Across Johnson County, two to four inches of rain fell from May 27th through May 28th. This caused rapid rises of creeks and streams as well as the Middle Fork of the Powder River.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS RIW wrote it up.
Across Johnson County, two to four inches of rain fell from May 27th through May 28th. This caused rapid rises of creeks and streams as well as the Middle Fork of the Powder River. The river gauge at 10 miles upstream of Kaycee peaked at 10.3 feet, which is 2.3 feet above flood stage. In Kaycee, minor flooding occurred, especially around the fairgrounds but no damage was reported. Moderate flooding also occurred downstream of Barnum, but no damage was reported.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Riverton, WY wrote its last area forecast discussion before the first event at May 27, 10:55 AM MST, 1 hour 5 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 1155 AM MDT Mon May 27 2019 .SHORT TERM...(Today through Wednesday night) A shallow frontal boundary will make its way southward east of the Divide this morning, becoming stationary along the Divide by midday. Rain chances will increase throughout the day, becoming definite across northern and central portions by the afternoon. Heavy rain with patchy fog is possible across Natrona and Johnson counties this afternoon. The QPF amounts did not change much from previous runs so we continued the Flood Watch for these areas and the eastern Bighorns. This evening snow level will begin to drop to 8000-8500 feet which will bring a short period of heavy snowfall to the Wind River, Absaroka, and Bighorn Mountains. Total snow amounts in the Winds and Absarokas look to be around 12 to 16 inches with the higher terrain seeing amounts in the 20s. The Bighorn's totals are a bit higher at 15 to 20 inches with some areas getting into the 30 inch range. We have issued Winter Storm Warnings to cover these areas, including specifics of elevations above 8000 feet and that South Pass will only see 3 to 5 inches. Most of the snow should change back to rain by noon Tuesday. Rain will shift southward Tuesday as the upper level low in northern Colorado continues its trek east. This will increase chances for rain across central Wyoming through Tuesday afternoon. The environment appears to remain stable through the day so precip should remain stratiform in nature with a light chance for an embedded shower in the mid afternoon. Rain will tapper off from northwest to southeast Tuesday evening as the upper low pushes into the central plains. Wednesday will see clearing skies with drier and warmer conditions as some weak high pressure moves in from the west. .LONG TERM...(Thursday through Monday) Large-scale pattern on Thursday is expected to feature upper high over the northern High Plains and weak upper trough across the Intermountain West. The upper trough is expected to slowly progress eastward through the period with the trough axis expected to push across the area over the weekend. Isolated to scattered showers and thunderstorms will be confined to the west up to the eastern foothills of the Divide Thursday afternoon and evening. This activity will increase in coverage and spread into central areas Friday and Saturday as the upper trough moves into the Great Basin. A stronger upper trough pushing into the northwest U.S. on Sunday should gives this pesky trough the boot, with it accelerating across the Divide into the High Plains on Sunday. Chances of showers and thunderstorms will remain across the area on Sunday with a somewhat drier westerly flow prevailing on Monday - slight chances of thunderstorms mainly over the high terrain. High temperatures will generally be slightly below seasonal normals through the period with valleys and basins mostly in the 60s to lower 70s and mountains mostly in the 50s. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday morning) Issued at 1155 AM MDT Mon May 27 2019 Rain will occur over many areas through tonight with MVFR to IFR conditions prevailing at many terminal sites. Expect mountains to be frequently obscured today and tonight. Isolated thunderstorms will be possible through 02Z, with the best chances in west and southwest WY. Tonight the rain will be mainly along and east of the continental divide with MVFR to IFR conditions continuing through 15Z Tue. In the west, after 02Z, scattered rain showers will occur with areas of MVFR conditions. Please see individual terminals for more details. Please refer to Aviation Weather Center products for more information on icing and turbulence forecasts. && .FIRE WEATHER... Issued AT 1155 AM MDT Mon May 27 2019 A cold front across Wyoming will produce widespread rain, heavy at times through Tuesday evening, especially east of the Divide. The heaviest rain is likely to fall between midday Monday until about sunset Tuesday with 1.5 to 2.5 inches falling in Johnson and Natrona counties. Widespread one-half to one inch amounts are expected in many other locations. Temperatures will be cooler than normal today with cloudy skies across the state. Tuesday will find a gusty north wind of 20 to 35 mph across northern Wyoming. && .RIW WATCHES/WARNINGS/ADVISORIES... Flood Watch from noon MDT today through Tuesday afternoon for WYZ009>011-020-022. Winter Storm Warning from 6 PM this evening to noon MDT Tuesday for WYZ002-008-009-014-015. && SHORT TERM...Hulme LONG TERM...Meunier AVIATION...Lavoie/Swanson FIRE WEATHER...Swanson
Hazardous Weather Outlook National Weather Service Riverton WY 322 AM MDT Mon May 27 2019 WYZ001>020-022>030-280930- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Big Horn Basin-Southwest Big Horn Basin- Southeast Big Horn Basin-Owl Creek and Bridger Mountains- Bighorn Mountains West-Bighorn Mountains Southeast- Northeast Johnson County-Southeast Johnson County- Teton and Gros Ventre Mountains-Jackson Hole- Wind River Mountains West-Wind River Mountains East- Upper Wind River Basin-Wind River Basin-Lander Foothills- Green Mountains and Rattlesnake Range- Natrona County Lower Elevations-Casper Mountain-Star Valley- Salt River and Wyoming Ranges-Upper Green River Basin Foothills- Upper Green River Basin-South Lincoln County- Rock Springs and Green River-Flaming Gorge-East Sweetwater County- 322 AM MDT Mon May 27 2019 ...Flood Watch from Noon Today through Tuesday afternoon for Johnson and Natrona Counties... ...Winter Storm Warning from 6 PM this evening to Noon Tuesday for the Absaroka, Wind River and Bighorn Mountains... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Rain likely with high elevation snow. Snow levels will lower to near 8000 feet across central Wyoming tonight with heavy, wet snow developing in the mountains. Rain could be heavy at times across central Wyoming. Rainfall amounts of 1 to 2.5 inches are possible across central Wyoming, with the heaviest amounts expected across Johnson and Natrona Counties. Please see Winter Storm Warnings and Flood Watches for the latest information. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Tuesday...Areas of moderate to heavy rain continuing across the lower elevations of central Wyoming with heavy wet snow in the mountains. Precipitation tapering off north to south Tuesday night. Thursday through Sunday...Isolated to scattered afternoon and evening thunderstorms. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
NCRS employees reported minor to moderate flooding along the Middle Fork of the Powder River downstream from Barnum. The flooding remained over rural areas and caused no damage.
NCRS reported the Middle Fork of the Powder River out of its banks in a few locations around Kaycee. The flooding was minor and no damage was reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2019Every state in 2019This day in weather historyWarnings in Wyoming, May 2019
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 822494, 822493.