Cold advection following a cold front passage brought high wind to northern Johnson County. The highest wind gust recorded was 75 mph at the Buffalo Airport.
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The episode as NWS RIW wrote it up.
Cold advection following a cold front passage brought high wind to northern Johnson County. The highest wind gust recorded was 75 mph at the Buffalo Airport.
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 28, 1:34 AM MST, 2 hours 6 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 234 AM MDT Tue Apr 28 2020 .SHORT TERM...Today through Thursday night We have a few concerns today. First, is precipitation. We currently have some showers working across northern Wyoming as of 1 am, although nothing particularly heavy. A few showers may linger in the eastern zones this morning. We maintained some isolated POPs this morning, but most places should stay rain free as most shifts to the east. The afternoon looks dry at this point. The second concern is enhanced fire weather. The air mass behind the cold front is very dry with dew points falling into the teens. However, temperatures will also average 5 to 10 degrees cooler than yesterday. The best chance for enhanced fire weather will be across southern Wyoming. We already have a fire danger statement in place, and this will be maintained. The third concern is wind. Many areas will have some gusty winds. However, the strongest winds will be found across northern Wyoming, especially in northern Johnson County. They will have the favored northwest flow pattern. In addition, the area will be under the right front quadrant of an 130 to 140 knot jet streak with good downward forcing of 45 to 55 knot 700 millibar winds. As a result, we will upgrade the high wind watch to a warning this morning. Winds should decrease this evening as the jet moves away and winds decouple toward and after sunset. Wednesday at this point looks to be a warm and dry day as ridging builds over the area. Some areas could see highs in the 80s. The main difference is with the ridge over the area, winds should remain light to moderate so fire danger should decrease somewhat. The next system will move in from the west at night. The models tend to be too fast this far out so kept things dry through the night. Thursday looks turn active again as a northern stream shortwave moves into the Wyoming. There are still some differences in the details as to where the best chance of storms would be, as would be expected on Day 3. So for now, we have gone with at least a slight chance for all areas. All models are fairly consistent in keeping areas East of the Divide dry through the morning. This will allow for a warm day for most areas in that location. With the tightening pressure gradient, it will become rather windy for most locations as well. This could cause more rapid snowmelt that could raise levels in creeks and streams, this will have to be watched. .LONG TERM...Friday through Monday A front will be stationary over northern and northwestern portions of the forecast area for the first half of Friday, before quickly progressing to the southeast during the afternoon. Showers will remain confined to the northwest through much of the day. Additional showers will develop over Sweetwater County Friday evening and continue Friday night. Some of this activity could spread into southern Natrona County. This activity will become more of a concern for CYS' CWA Saturday, as a jet streak exits eastward over the Central Plains. Convection will be more widely scattered Saturday, as the region is split between Friday's exiting system and another system coming in for Sunday. The main areas for these showers/storms will be western and southern portions. The nose of the jet will move over southwestern portions by Sunday morning. The left front quad, along with a diffluent flow pattern, could bring more extensive showers and storms. Showers will begin early over areas west of the Divide Sunday morning. Showers and thunderstorms will then spread east of the Divide during the afternoon, and continuing across the area Sunday night. It appears a more robust trough will move over the PACNW/Northern Rockies Sunday/Monday to potentially enhance the convection, by becoming negatively tilted. An associated cold front will be moving through ID Sunday, putting the forecast area in the warm sector. The cold front will blast through much of the forecast area Sunday night, exiting over eastern WY Monday morning. Strong mid level winds of 40-50kt will follow in the wake of the front. These winds could easily mix down to the surface from ongoing showers, in addition to the tight surface gradient. && .AVIATION...For the 12Z TAFS through 12Z Wednesday A line of showers continue over northern portions. These showers are expected to be past KCOD and KWRL by 12Z and will be moving near KCPR through 16Z. Gusty north to northwesterly winds up to 25 kts will occur at most terminals today. Clearing skies have already started this morning and will continue through the rest of the morning. Winds will decrease after sunset, with light winds and mostly clear skies after 00Z Wednesday through the overnight hours. && .FIRE WEATHER... Any showers should end this morning with a balance of the day remaining dry. Temperatures will average about 5 to 10 degrees cooler than yesterday. A gusty wind will occur across much of the area with the strongest winds across Johnson County where high winds are possible. Relative humidity will fall to around 20 percent for many areas with the lowest humidity expected in Sweetwater County where the best chance of enhanced fire behavior will be found. Mixing and smoke dispersal will be range from fair in the west to good to excellent East of the Divide. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 6 AM this morning to 6 PM MDT this evening for WYZ010. && SHORT TERM...Hattings LONG TERM...LaVoie AVIATION...Straub FIRE WEATHER...Hattings
Hazardous Weather Outlook National Weather Service Riverton WY 241 AM MDT Tue Apr 28 2020 WYZ001>020-022>030-290845- 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- 241 AM MDT Tue Apr 28 2020 ...High Wind Warning in effect today for northern Johnson County... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. High wind likely today in northern Johnson County. Please see High Wind Warning for details. Elevated fire behavior possible this afternoon, especially in southern Wyoming. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Thursday...Isolated afternoon and evening thunderstorms. Windy areas. Elevated fire conditions in the south. Still unseasonably warm in many locations. Friday...Scattered afternoon and evening thunderstorms across southern portions. Saturday...Widely scattered afternoon and evening thunderstorms across western and southern portions. Sunday...Morning showers west of the Divide. Afternoon and evening thunderstorms across the area. .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.
1 high wind. Local standard time, as filed.
High winds occurred in northern Johnson County. The strongest wind gust recorded was 75 mph at the Johnson County Airport in Buffalo, Wyoming.
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, April 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: 886273.