Heavy rains from training thunderstorms produced flash flooding along Cherry Creek that forced a partial closure on Deer Creek Road as Emergency Manager could not keep storm spotting the thunderstorms as road became impassable.
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The episode as NWS CYS wrote it up.
Heavy rains from training thunderstorms produced flash flooding along Cherry Creek that forced a partial closure on Deer Creek Road as Emergency Manager could not keep storm spotting the thunderstorms as road became impassable.
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 Cheyenne, WY wrote its last area forecast discussion before the first event at Jun 19, 10:15 AM MST, 3 hours 10 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 1115 AM MDT Fri Jun 19 2020 .SHORT TERM...(Today and tonight) Issued at 330 AM MDT Fri Jun 19 2020 Upper trough axis extended from the Northern High Plains to the Southern Great Basin. A quasi-stationary front from the Upper Midwest through the Central Plains and Rockies was the focus for clusters of active convection. An inverted low pressure trough extended from the Four Corners to Central WY, with a band of rain showers and embedded thunder across western and northern CO into southwest NE. Skies were mostly cloudy with temperatures from the mid 40s to mid 50s. Winds were variable less than 10 kt. Forecast concerns today will focus on precipitation coverage and amounts as well as potential for strong afternoon convection. Combined large scale lift from the passing upper level trough and surface trough along the Front Range will enhance convective development beginning this morning over and east of the mountains, with likely to categorical PoPs this afternoon. Scattered afternoon thunderstorms will focus along and east of the Laramie Range with mean layer CAPEs from 400-800 j/kg and bulk shear upwards of 25-30 kt. While the threat for severe weather is low today, isolated strong storms with small hail, gusty winds and brief heavy rain will be possible. Model QPF has been consistently between a tenth and half inch. High temperatures today will average about 15 degrees below seasonal normals with 60s to around 70. Scattered showers and isolated thunderstorms will end from west to east this evening with the departing upper trough. .LONG TERM...(Saturday through Thursday) Issued at 330 AM MDT Fri Jun 19 2020 A low amplitude upper ridge to the west will replace the upper trough Saturday, ushering in warmer temperatures and a drier more stable air mass. 700mb temperatures will rise to 8 to 12 Celsius yielding afternoon highs in the mid 70s to mid 80s. Much of the upcoming week will be warm with high temperatures in the 70s and 80s. A west to northwest flow aloft, periodically enhanced by passing weak short wave disturbances will combine with marginal instability and low/mid level moisture to generate mainly diurnal convection each day. Coverage will be widely scattered (20 to 30 percent PoPs). Winds will be light, except in the vicinity of showers and thunderstorms. && .AVIATION...(For the 18Z TAFS through 18Z Saturday morning) Issued at 1115 AM MDT Fri Jun 19 2020 VFR prevailing at all terminals through the period but there will be widely sctd showers and tstms move over the area this afternoon, clearing out of the Panhandle early this evening. Stronger showers could produce gusty erratic winds and brief lower visibilities. Patchy fog also possible Sat morning over the Panhandle. && .FIRE WEATHER... Issued at 245 AM MDT Fri Jun 19 2020 A trough of low pressure along the Front Range and upper level low pressure system moving east through the Central Rockies and High Plains will produce wetting rainfall across much of the area today. Cool temperatures will continue today. Precipitation will end from west to east this evening. Warmer, breezy and drier conditions will return this weekend. Warm temperatures with widely scattered mainly afternoon and evening showers and thunderstorms are forecast next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...MAJ LONG TERM...MAJ AVIATION...RE FIRE WEATHER...MAJ
Hazardous Weather Outlook National Weather Service Cheyenne WY 355 AM MDT Fri Jun 19 2020 NEZ002-003-019>021-054-055-095-096-WYZ101>119-201000- Dawes-Box Butte-Scotts Bluff County-Banner County-Morrill- Kimball County-Cheyenne-North Sioux-South Sioux- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Laramie Range and Southwest Platte County- East Platte County-Goshen County-Central Carbon County- North Snowy Range Foothills-Southwest Carbon County- Sierra Madre Range-Upper North Platte River Basin-Snowy Range- Laramie Valley-South Laramie Range-South Laramie Range Foothills- Central Laramie County-East Laramie County- 355 AM MDT Fri Jun 19 2020 This hazardous weather outlook is for portions of panhandle Nebraska...western Nebraska...east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Numerous showers and scattered afternoon thunderstorms are expected today. Isolated strong thunderstorms producing small hail, gusty winds and brief heavy rain will be possible, especially along and east of the Laramie Range. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY Widely scattered mainly afternoon and evening thunderstorms will develop over and east of the mountains Sunday through Thursday. The threat for severe weather is low. .Spotter information statement... Spotter activation will not be required.
The Cheyenne radar (KCYS), 115 km away, was scanning. The volume nearest the first event began at 20:23 UTC.
1 flash flood. Local standard time, as filed.
Portions of Deer Creek Road was closed due to high rushing water as heavy rains filled the banks of Cherry Creek and made road passage impossible.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2020Every state in 2020This day in weather historyWarnings in Wyoming, June 2020
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: 892043.