Scattered showers, many with no reported lightning associated with them produced wind gusts in excess of 58 mph across portions of southeastern Wyoming. Strongest gust was 68 mph measured near Elk Mountain and Sibley Peak.
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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.
Scattered showers, many with no reported lightning associated with them produced wind gusts in excess of 58 mph across portions of southeastern Wyoming. Strongest gust was 68 mph measured near Elk Mountain and Sibley Peak. A thorough review of lightning data was used to assist and verify if lightning was present in and around the time of the reported wind gusts. Deep inverted V soundings were present in the hours ahead of the event, an indicative sign of strong mixing and wind speeds possible with these cellular storms.
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 Apr 30, 1:30 PM MST, 1 hour 25 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 230 PM MDT Thu Apr 30 2020 .SHORT TERM...(This evening through Saturday night) Issued at 230 PM MDT Thu Apr 30 2020 Forecast concerns today deal with fire weather concerns this afternoon...followed by severe thunderstorm chances Friday and Saturday. Currently...A warm and dry day ongoing this afternoon. Afternoon humidity has fallen into the mid teens across southeast Wyoming as temperatures climb well above average for this time of year. Latest METARS in the Panhandle showing mid to upper 80s widespread. Scottsbluff reporting 89 at 2PM...Cheyenne at 79. Have had a few gusts approaching 25mph in the Panhandle...but they have not been widespread and consistent. So...held off on any fire headlines out there. Will continue to monitor. Attention turns to an approaching cold front that is currently being analyzed over western Montana through southeast Idaho into northern Nevada this afternoon. This front is forecast to move into western Wyoming this evening and over our northern zones Friday morning. GFS forecast soundings showing high based Inverted V soundings for Friday afternoon. Makes sense as we have the very dry lower levels this afternoon. So we may be issuing a few warnings Friday afternoon...mainly for downburst winds. SPC has the area under a Marginal Risk...so the threat is there. Looking at Saturday...front looks to lay along a line from maybe Alliance to Cheyenne. NAM lifted indices down near -5C Saturday afternoon...so pretty unstable across the I-80 corridor from the southern Panhandle to Cheyenne. Did add severe TStm wording in the weather grids for Saturday afternoon...even though SPC shifts the Marginal Risk south into Colorado. .LONG TERM...(Sunday through Thursday) Issued at 230 PM MDT Thu Apr 30 2020 A generally zonal flow will be over the area Sunday and Monday with a couple weak impulses riding across the region and keeping low chances for showers and tstms both days. Upper ridging then builds over the western CONUS Tuesday and Weds and remains in place through Friday which will bring a drier weather regime to the CWA. temperatures look to be pretty close to seasonal averages through the period. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 1104 AM MDT Thu Apr 30 2020 Mainly dry at most southeast Wyoming and Nebraska airports today. Could see a few showers/TStms at KRWL this afternoon that will last through sunset. Better chances for TStms Friday as a cold front moves into the area. && .FIRE WEATHER... Issued at 230 PM MDT Thu Apr 30 2020 Near critical fire weather conditions this afternoon across most of southeast Wyoming and a few areas in the Nebraska Panhandle. Afternoon humidity has fallen into the mid teens this afternoon...but winds have mainly held below critical levels. So held off on any fire weather headlines for the rest of the afternoon. A change in the weather Friday as a cold front approaches from the west. Going to see increased chances for showers and thunderstorms Friday afternoon with fairly widespread wetting rains Saturday. Unsettled weather pattern through the beginning of next week with chances for showers and thunderstorms continuing. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...GCC LONG TERM...RE AVIATION...GCC FIRE WEATHER...GCC
Hazardous Weather Outlook National Weather Service Cheyenne WY 148 PM MDT Thu Apr 30 2020 NEZ002-003-019>021-054-055-095-096-WYZ101>119-012000- 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- 148 PM MDT Thu Apr 30 2020 This hazardous weather outlook is for portions of panhandle Nebraska...western Nebraska...east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...THIS AFTERNOON AND TONIGHT No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A cold front moves into southeast WY and western Nebraska Friday, and stalls along the Laramie Range Friday night and Saturday. There will be enough instability and wind shear to trigger a few strong to severe thunderstorms between 3 PM and 9 PM Friday along and east of the Laramie Range. The main threat will be wind gusts to 60 mph, with hail up to quarter size possible. Isolated strong to severe thunderstorms with small hail and strong winds will be possible Saturday...mainly near the Wyoming and Colorado state line. .Spotter information statement... Spotter activation will not be needed.
The Cheyenne radar (KCYS), 167 km away, was scanning. The volume nearest the first event began at 21:53 UTC.
11 thunderstorm wind. Local standard time, as filed.
Elk Mountain sensor KEHY measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Wyoming Department of Transportation sensor along Interstate 80 about nine miles south of Hanna or nine miles west-northwest of Elk Mountain measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Wyoming Department of Transportation sensor along Interstate 80 roughly three miles northwest of Elk Mountain measured the reported wind gust. Lightning data was not present before and shortly after the wind speeds were recorded.
Wyoming Department of Transportation sensor along Interstate 80 about seven miles northwest of Elk Mountain measured the reported wind gust speed. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Skyline sensor in Skyline measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Wyoming Department of Transportation sensor located about eight miles south of Sibley Peak measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Dodge Creek sensor located about eleven miles south-southeast of Garrett measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Wyoming Department of Transportation sensor along Interstate 80 about fifteen miles east of Sinclair measured the thunderstorm wind gust.
Pine Bluffs Airport sensor measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Wyoming Department of Transportation sensor along Interstate 80 near Quealy Dome or about thirteen miles northeast of Centennial measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
Laramie Airport sensor measured the reported wind gust. A review of available lightning data showed no lightning associated with the parent cell that produced these winds.
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: 880117, 880116, 880114, 880115, 880113, 880106, 880131, 880112, 880110, 880130, 880118.