A cold front moved across Wyoming and mixed strong mid level winds to the surface. Wind gusts of 63 mph were reported at both the Sweetwater County and Natrona County airports as the front passed.
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The episode as NWS RIW wrote it up.
A cold front moved across Wyoming and mixed strong mid level winds to the surface. Wind gusts of 63 mph were reported at both the Sweetwater County and Natrona County airports as the front passed.
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 Apr 18, 1:27 PM MST, 31 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 227 PM MDT Tue Apr 18 2023 .DISCUSSION...(This evening through Tuesday) Issued at 218 PM MDT Tue Apr 18 2023 A large trough has begun moving across Wyoming today, with a distinct shortwave trough bringing a round of showers and thunderstorms for the lower elevations, in addition to snow in the mountains. Instability is marginal this afternoon and evening (around 150 to 300 J/kg of CAPE); however, strong synoptic lift will aid in development of widespread showers and a few thunderstorms with small hail. A strong pressure gradient with strong mid-atmosphere flow will contribute to gusty westerly surface winds, especially in the vicinity of showers. The strongest storms could contain damaging winds with gusts around 60 mph; however, these storms will be isolated in nature, and mainly confined to Natrona to Johnson Counties. Winter Weather Advisories remain in effect for the western Wyoming mountains through the early AM hours Wednesday. Mountain passes (including Teton, Togwotee, and South Pass) will see light snow accumulations, and those traveling over passes will want to be prepared for winter driving conditions, given strong winds creating blowing snow and low visibility through sunrise Wednesday. The region remains under the influence of a longwave trough Wednesday through Friday, with temperatures 10 to 15 degrees below average. Cold air aloft will aid in afternoon shower development each day, with light snow accumulations possible in the mountains daily. Lower elevations could see see isolated showers each afternoon, but accumulations for most locations will be minimal. Saturday will be a transition day as the trough exits and northwesterly flow develops aloft. Mountain snow showers continue to be possible, but lower elevation temperatures are forecast to recover to near seasonal normals by Sunday and into early next week. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday) Issued at 1153 AM MDT Tue Apr 18 2023 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals. Convective showers have developed over southwest Wyoming late Tuesday morning in association with shortwave energy and aided by jet streak dynamics aloft. IFR/MVFR conditions already occurring at KBPI and KPNA, with the possibility of MVFR at KJAC through mid-afternoon. KRKS could see brief MVFR with rain showers, but the better chance exists to the north where snow showers are the more likely result. Isolated thunderstorms would be most likely through about 22Z/Tuesday. A cold front pushes east late in the afternoon with gusty west-northwest wind developing at all but KJAC where southerly wind persists. Combined with the precipitation lifting north around 00Z/Wednesday, conditions improve to VFR and dry out early Tuesday evening. One concern would be snow showers wrapping back into KJAC late tonight as low pressure develops over Montana. Mountain tops obscured through at least 12Z/Wednesday. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals. VFR conditions prevail, but scattered rain showers and even isolated thunderstorms become more common as the afternoon wears on. There could be brief MVFR with the heaviest showers, but these will not be widespread. The showers track north and are mainly confined to the northern-third of the state by 02Z/Wednesday. Surface wind speeds increase steadily late this afternoon and evening, especially behind cold frontal passage around 00Z/Wednesday. KRIW is favored in this pattern and gusts to 35kts are possible. KCPR sees southwest wind increase to 25-35kts late tonight as the other terminals begin a downward trend. A mid-level low develops over eastern Montana this evening and wraps moisture back across the north overnight and into Wednesday morning. Impacts would be minimal, but KCOD and KWRL would be the most likely candidates for lingering showers. Mountain tops frequently obscured until 12Z/Wednesday. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued AT 218 PM MDT Tue Apr 18 2023 Winds gusts in the 30 to 50 mph range will continue into the early overnight hours this evening, along with widespread rain and snow showers. Given the weather system moving through, winds remain elevated overnight, and many locations will not experience their typical weakening of winds overnight. Snow showers will decrease in coverage by sunrise Wednesday; however, there will be continued chances for light snow showers in the high terrain through the day Wednesday (and each afternoon this week). Temperatures will be about 10 to 15 degrees below normal through Friday, rebounding to near normal by Sunday. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 1 AM MDT Wednesday for WYZ001-012- 014-015. && DISCUSSION...VandenBoogart AVIATION...CNJ FIRE WEATHER...VandenBoogart
Hazardous Weather Outlook National Weather Service Riverton WY 135 PM MDT Tue Apr 18 2023 WYZ001>020-022>030-191300- 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- 135 PM MDT Tue Apr 18 2023 ...Winter Weather Advisory Continues for the Northwest Mountains through Tuesday Evening... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...This Afternoon and Tonight. Snow continues across the northwest mountains through the evening. See Winter Weather Advisory for more details. Isolated thunderstorms over southwest, central, and northern Wyoming are likely to produce small hail along with occasional gusty outflow wind. Areas outside of thunderstorms will also see gusty west wind from late afternoon through the evening. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Thursday and Friday...Unsettled weather expected across the region with below normal temperatures and accumulating mountain snow, most likely Thursday. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report wind gusts over 50 mph and hail of any size to the National Weather Service.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
A wind gust of 63 mph was reported at the Sweetwater County airport.
A maximum wind gust of 63 mph was reported at the Natrona County airport.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2023Every state in 2023This day in weather historyWarnings in Wyoming, April 2023
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: 1096773, 1096774.