High based thunderstorms brought high winds to portions of Teton and Sublette Counties. The wind gusted as high as 60 mph.
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The episode as NWS RIW wrote it up.
High based thunderstorms brought high winds to portions of Teton and Sublette Counties. The wind gusted as high as 60 mph.
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 Jul 25, 5:22 PM MST, 2 hours 23 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Riverton WY 622 PM MDT Thu Jul 25 2024 .KEY MESSAGES... - Showers and thunderstorms possible today, most numerous west of the Divide. Locally heavy rain possible. - Elevated to critical fire weather conditions for portions of central Wyoming this afternoon and evening. - Rain chances Friday through Sunday, along with cooler temperatures. - Warmer and drier starting Monday, with the trend continuing through the workweek. && .DISCUSSION... Issued at 1253 PM MDT Thu Jul 25 2024 The ridge that has brought the warm temperatures to the area begins to shift eastward as an incoming trough moves in from the west. This will bring cooler air west of the Continental Divide today, with seasonal highs, generally in the 80s. For those east of the Divide, the trough will not yet make it over the divide today, so another hot day this afternoon, with highs in the 90s to around the 100 degree mark. The smoke should also get pushed out this afternoon and evening, but may make a return late Friday according to the HRRR. The incoming trough also brings better moisture with it. Again, it will mainly effect west of Divide locations today. Precipitable water (PWAT) values around 1.00 to 1.25 inches will be across western Wyoming today, slowly shifting eastwards through the day. These values are 100% to 200% of normal. As a result, showers and thunderstorms occur across the west today. Widespread 30% to 70% chances through this evening, peaking in the afternoon. Heavy rainfall is the main threat with this convection, though gusty outflow winds 30 to 35 mph are possible. Rain chances spread east of the Divide this afternoon as the trough and its moisture tracks east. Rain chances are more isolated east of the Divide though, as by the time the best moisture moves in, peak heating of the day will limit convection, along with some of the moisture being lost. Latest models put chances at 15% to 40%, peaking late afternoon and early evening. Some showers will likely linger overnight. The other concern today is for fire weather. The incoming trough brings a tighter pressure gradient, with afternoon gusts 15 to 25 mph for the Wind Corridor, up into Natrona and Johnson Counties. With the best moisture remaining west for a majority of the day, relative humidities (RH) will be allowed to drop to the 10% to 15% range of southeast Fremont, Natrona, and Johnson Counties. A Red Flag Warning is in effect for these areas through 11PM (05Z) tonight. Some late storms may continue locally gusty winds even as RHs begin to increase this evening. The earlier storms will likely be on the drier side, with a small threat of dry lightning. That incoming trough pushes the ridge's influence out of the area for Friday, with southwest flow aloft. This allows shortwaves to more easily move over the state. As a result, rain chances continue for Friday. Shower chances begin in the morning, with peak convection occurring in the afternoon. Unlike today, these chances are widespread across the area, with PWAT values 100% to 175% of normal. Locally heavy rain will once again be the main threat, though some strong outflow winds are also possible. Much of a repeat for Saturday, as another shortwave passes through. Friday through Sunday will also be cooler due to the combination of cloud cover, the trough's influence, and rain. Highs around, to a little below normal, are expected. The ridge's influence begins to push back in Sunday, so rain chances remain mainly over northern Wyoming. Monday begins the return of the ridge, with drier air and warming temperatures. This trend looks to continue through the workweek. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 617 PM MDT Thu Jul 25 2024 Mainly VFR conditions expected across western and central Wyoming through the first 18 hours of the 00Z TAF period. Current scattered showers east of the Divide slowly migrate eastward through 26/0600z. Models show another round of showers and thunderstorms entering western Wyoming near 04Z. This second wave will continue to trek eastward overnight and through the early morning hours. More showers and thunderstorms expected tomorrow afternoon, developing between 19Z and 21Z before moving east. Conditions will remain VFR unless a shower or thunderstorms directly tracks over a terminal, dropping VIS to MVFR. && .FIRE WEATHER... Issued at 1253 PM MDT Thu Jul 25 2024 Critical fire weather conditions this afternoon and evening, mainly east of the Continental Divide. Ahead of a plume of monsoonal moisture, winds will increase with frequent gusts 20 to 25 mph while the dry air mass lingers. RH is expected to bottom out in the 10 to 15 percent range during the late afternoon. Any thunderstorms on the leading edge of the front will lack much precipitation, leading to an isolated dry lightning threat, mainly in the 1500 to 2000 LT time range. After 2000 LT, moisture improves as temperatures begin cooling and monsoonal moisture begins moving into basins east of the Divide. Thursday night into Friday will feature higher RHs along with more widespread showers and thunderstorms. && .RIW WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 11 PM MDT this evening for WYZ280-281- 285-289. && DISCUSSION...Wittmann AVIATION...VandenBoogart/Gross FIRE WEATHER...Wittmann
Hazardous Weather Outlook National Weather Service Riverton WY 258 AM MDT Thu Jul 25 2024 WYZ001>020-022>030-261300- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Bighorn Basin-Southwest Bighorn Basin-Southeast Bighorn 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- 258 AM MDT Thu Jul 25 2024 ...Red Flag Warning in Effect for Portions of Central Wyoming Thursday Afternoon and Evening... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and tonight. Near-record heat in Natrona and Johnson Counties. Hot, dry, and breezy conditions combine to create critical fire weather conditions across portions of central Wyoming during the afternoon and evening. Scattered thunderstorms spread into western Wyoming by early afternoon and across the remainder for the region through the evening hours. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. Friday and Saturday...Widespread showers and thunderstorms, especially during the afternoon and evening. Heavy rain is likely with the strongest showers and storms. Sunday...Scattered showers and thunderstorms, mainly across northern Wyoming. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.
Special Weather Statement
National Weather Service Riverton WY
801 PM MDT Thu Jul 25 2024
WYZ012-013-023-024-260230-
Star Valley-Jackson Hole-Teton and Gros Ventre Mountains-Salt River
and Wyoming Ranges-
801 PM MDT Thu Jul 25 2024
...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN LINCOLN AND
SOUTHWESTERN TETON COUNTIES THROUGH 830 PM MDT...
At 759 PM MDT, Doppler radar was tracking a line of strong
thunderstorms nearing parts of Star Valley, moving east at 30 mph.
HAZARD...Wind gusts up to 50 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
This strong thunderstorm will be near...
Turnerville around 805 PM MDT.
Meadow Creek Guard Station around 815 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4349 11104 4356 11067 4300 11061 4249 11076
4245 11104
TIME...MOT...LOC 0159Z 261DEG 28KT 4289 11098
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH
DziewaltowskiSpecial Weather Statement
National Weather Service Riverton WY
836 PM MDT Thu Jul 25 2024
WYZ012-013-023>026-260315-
Star Valley-Upper Green River Basin-Jackson Hole-Upper Green River
Basin Foothills-Teton and Gros Ventre Mountains-Salt River and
Wyoming Ranges-
836 PM MDT Thu Jul 25 2024
...STRONG THUNDERSTORMS WILL IMPACT WESTERN SUBLETTE...NORTHWESTERN
LINCOLN AND SOUTHWESTERN TETON COUNTIES THROUGH 915 PM MDT...
At 834 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from southern Jackson Hole to parts of Star Valley
moving east at 25 mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Strong thunderstorms will be near...
Jackson, Hoback, and Rafter J Ranch around 840 PM MDT.
Lander Peak around 845 PM MDT.
Other locations in the path of these storms include Bondurant.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4357 11038 4309 11015 4244 11036 4240 11095
4304 11080 4352 11091
TIME...MOT...LOC 0234Z 263DEG 24KT 4348 11084 4304 11065 4275 11073
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
DziewaltowskiThe Pocatello radar (KSFX), 167 km away, was scanning. The volume nearest the first event began at 02:42 UTC.
2 thunderstorm wind. Local standard time, as filed.
A 60 mph wind gust was reported at the weather station at the Teton Saddle.
A 59 mph wind gust occurred at the Cottonwood Merna mesonet site to the west of Daniel.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2024Every state in 2024This day in weather historyWarnings in Wyoming, July 2024
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: 1203987, 1203988.