Over an inch of rain in 60 minutes caused flash flooding and debris flows from the Badger Creek burn scar in southern Albany County.
Every event with a place to put it. Tap one for its entry below.
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 CYS wrote it up.
Over an inch of rain in 60 minutes caused flash flooding and debris flows from the Badger Creek burn scar in southern Albany County.
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 Jul 23, 1:58 PM MST, 32 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 258 PM MDT Mon Jul 23 2018 .SHORT TERM...(This evening through Tuesday) Issued at 330 PM MDT Mon Jul 23 2018 Short term issues deal with chances for severe thunderstorms this evening. Currently...Stationary surface front across southeast Colorado up into Albany County near Laramie and then north into the Casper area. Southeast upslope flow has kept low level moisture in the area east of the Laramie Range with broken stratocu over Cheyenne . Latest SPC mesoanalysis showing a fairly uncapped environment with maybe the exception around Cheyenne with the low cloud deck. 20Z surface based CAPE of 2000 to 3000 J/KG with bulk shear around 45kts. Marginal Risk area still looking good from SPC this afternoon. Latest HRRR simulated radar showing potential for severe thunderstorm development across southern Albany County spreading east into Laramie County and Cheyenne after 23Z. Also showing possibility of discreet supercell development near Wheatland and up by Douglas this afternoon. Latest radar showing pretty good verification with cells developing near Shirley Basin and just south of Douglas. So confidence is pretty good on the HRRR solution for this afternoon. A drier day Tuesday as guidance showing most of the PoPs/QPF south in Colorado as the Four corners high is suppressed by low tracking across northern Montana and southern Canada. .LONG TERM...(Tuesday night through Monday) Issued at 330 PM MDT Mon Jul 23 2018 A pretty wet pattern ahead for the CWFA as monsoonal moisture continues to move into the area. This monsoonal moisture is forecast to interact with a surface boundary dropping into the area from the north Wednesday afternoon. All guidance showing fairly widespread precip late Wednesday afternoon into Wednesday evening. This front is not expected to move much through Sunday, only drifting slightly east into the Panhandle Friday, then shifting back west Saturday as an upper level shortwave rides along the front. Four corners high shifts west Monday next week that may cut off monsoonal flow over the area. This will likely bring dry weather back to the area. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1130 AM MDT Mon Jul 23 2018 Scattered showers are ongoing across portions of southeast Wyoming and the western Nebraska Panhandle, mainly east of I-25. Potential for thunderstorms will increase after 20z for areas along and west of I-25, with a threat for hail and gusty/erratic winds. Generally expect VFR conditions to prevail, but brief MVFR cigs/vsbys cannot be ruled out beneath heavier precipitation cores. Showers & storms should diminish after about 03z this evening. && .FIRE WEATHER... Issued at 330 PM MDT Mon Jul 23 2018 Minimal fire weather concerns with monsoonal moisture over area through Sunday. Fairly widespread wetting rains expected each afternoon and early evening. Afternoon humidity expected to stay well above critical levels with good to excellent overnight recoveries. No weather related fire weather concerns at least until next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...GCC LONG TERM...GCC AVIATION...CLH FIRE WEATHER...GCC
Hazardous Weather Outlook National Weather Service Cheyenne WY 1108 AM MDT Mon Jul 23 2018 NEZ002-003-019>021-054-055-095-096-241715- Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne- North Sioux-South Sioux- 1108 AM MDT Mon Jul 23 2018 This hazardous weather outlook is for portions of western Nebraska. .DAY ONE...TODAY AND TONIGHT Scattered afternoon thunderstorms will develop over the southeast Wyoming mountains and foothills, moving into the southern Panhandle along and south of a Scottsbluff to Alliance line. Severe weather is not expected with small hail and downburst winds to 40 mph expected. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY Isolated to scattered mainly afternoon and evening thunderstorms will develop Tuesday through Saturday. Severe thunderstorms are possible Wednesday through Friday afternoon through early evening with large hail and damaging downburst winds. .Spotter information statement... Spotter activation will not be needed. WYZ101>119-241715- 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- 1108 AM MDT Mon Jul 23 2018 This hazardous weather outlook is for portions of east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Scattered afternoon thunderstorms will develop over the southeast Wyoming mountains and foothills, moving east across extreme southeast Wyoming into the southern Panhandle by early evening. Some of these storms could become severe with quarter sized hail and downburst winds to 60 mph after 3 PM this afternoon. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY Isolated to scattered mainly afternoon and evening thunderstorms will develop Tuesday through Saturday. Severe thunderstorms are possible Wednesday through Friday afternoon through early evening with large hail and damaging downburst winds. .Spotter information statement... Spotter activation may be needed this afternoon across extreme southeast Wyoming from Wheatland to Cheyenne and points east to the Nebraska stateline.
Special Weather Statement National Weather Service Cheyenne WY 147 PM MDT MON JUL 23 2018 WYZ101-103-232030- Converse County Lower Elevations WY-North Laramie Range WY- 147 PM MDT MON JUL 23 2018 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL CONVERSE COUNTY UNTIL 230 PM MDT... At 147 PM MDT, Doppler radar was tracking a strong thunderstorm 9 miles south of Laprele Reservoir, or 19 miles southwest of Douglas, moving east at 15 mph. Half inch hail and winds in excess of 40 mph will be possible with this storm. This storm will remain over mainly rural areas of south central Converse County. PRECAUTIONARY/PREPAREDNESS ACTIONS... This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4251 10574 4260 10575 4269 10542 4247 10541 TIME...MOT...LOC 1947Z 266DEG 15KT 4257 10567 Hammer
Special Weather Statement
National Weather Service Cheyenne WY
245 PM MDT MON JUL 23 2018
WYZ104-105-232130-
Shirley Basin WY-Ferris/Seminoe/Shirley Mountains WY-
245 PM MDT MON JUL 23 2018
...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL CARBON AND NORTH
CENTRAL ALBANY COUNTIES UNTIL 330 PM MDT...
At 244 PM MDT, Doppler radar was tracking a strong thunderstorm over
Battle Mountain, or 48 miles south of Casper, moving east at 10 mph.
Half inch hail and winds in excess of 40 mph will be possible with
this storm.
Locations impacted include...
Battle Mountain.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4210 10634 4220 10630 4220 10602 4206 10591
4189 10602 4189 10616
TIME...MOT...LOC 2044Z 290DEG 7KT 4213 10625
HammerThe Cheyenne radar (KCYS), 101 km away, was scanning. The volume nearest the first event began at 21:30 UTC.
1 flash flood. Local standard time, as filed.
Excessive rainfall in 60 minutes over the Badger Creek burn scar caused debris flow/flash flooding along the Laramie River at Jelm/Woods Landing.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2018Every state in 2018This day in weather historyWarnings in Wyoming, July 2018
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: 783120.