Isolated High Wind event for the I-80 Summit and Foothills.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
Isolated High Wind event for the I-80 Summit and Foothills.
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 May 15, 10:05 AM MST, 57 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Cheyenne WY Issued by National Weather Service Riverton WY 1105 AM MDT Thu May 15 2025 .KEY MESSAGES... - Very windy conditions expected for most of southeast Wyoming and portions of western Nebraska on Thursday. Gusts over 50 mph possible. - Seasonable temperatures into this weekend with isolated thunderstorms returning on Saturday. - Active weather pattern late this weekend and early next week as another Pacific storm system impacts the region. && .SHORT TERM /THROUGH FRIDAY/... Issued at 227 AM MDT Thu May 15 2025 Current KCYS radar loops shows remnant light rain across western Nebraska and far eastern Wyoming as a strong surface low across eastern Nebraska lifts northeast early this morning. The upper level trough, which pushed across the region today, is forecast to stall and become a closed low across the Dakotas today. Models show this system remaining over the Dakotas into tonight and possibly even retrograding westward a bit before it begins lifting northeast into the Great Lakes region into early Friday morning. Expect rain showers to continue early this morning with a brief lull later this morning through sunrise. It continues to look very windy across southeast Wyoming and portions of western Nebraska due to the strengthening surface low to our east. However, 700mb winds are not quite as strong in contrast to 24 hours ago and winds aloft actually strengthen above 50 knots tonight instead of this afternoon. Will continue to keep an eye on the wind prone areas and adjacent High Plains for potential High Wind Watches/Warnings, but strong wind gusts appear to be brief with low confidence in timing. In addition, showers and thunder showers are expected this afternoon behind the main storm system as a secondary shortwave trough moves eastward into Wyoming. Any convective winds associated with shower and thunder shower activity will likely complicate the timing and magnitude of the environmental winds. Expect sustained winds out of the northwest 25 to 40 mph with gusts around 50 mph. Thursday will likely be the coolest day of the week with most of southeast Wyoming in the 50s to low 60s, with low to mid 60s over western Nebraska. Friday looks like the driest day of the next 7 days across the region as a much drier airmass moves into Wyoming as the storm system to our east begins to push into the Great Lakes region. Midlevel subsidence associated with the building upper level ridge should suppress most convective initiation into the evening hours. Otherwise, expect a slight warming trend with 700mb temperatures increasing between 0C to 5C, which should translate to highs in the 60s across southeast Wyoming and upper 60s to lower 70s for western Nebraska. It will remain windy, but winds should start to ease in the mid to late afternoon hours. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 227 AM MDT Thu May 15 2025 Previous forecast on track for most of this weekend with model solutions diverging significantly compared to the last few days regarding the next Pacific storm system for early next week. Expect showers and thunderstorms to return to the region on Saturday as the mid to upper level flow shifts to the southwest with gradually warm air advection and a brief warming trend. High temperatures on Saturday will return to the mid 60s to mid 70s...warmest over the eastern plains. Models show a weak shortwave disturbance lifting northeast ahead of the next Pacific storm system moving into the Great Basin region late on Saturday. This disturbance will help initiate scattered rain showers and widely scattered thunderstorms across southeast Wyoming. These storms will then move northeast into western Nebraska during the evening hours. Although severe storms are not expected at this time, a few stronger storms are possible with gusty winds and small hail the primary threats. For Sunday, we will be tracking the potent Pacific disturbance which is forecast to move across the eastern Great Basin region on Sunday. Models are no longer showing a closed upper level low across the Four Corners region with even the 00Z ECMWF backing off on this solution. All models are now showing the secondary disturbance, which is forecast to dig south out of the Pacific NW, trending much later in terms of timing and not as organized. Therefore, most models eject this system eastward much faster and further south than previous forecasts suggested. Therefore, ensemble guidance has continued to trend lower on QPF and PoP for early next week due to the lack of a closed upper level low to the south of the forecast area. However, will still have to keep an eye on the first upper level trough and associated potent disturbance that lifts northeast across Colorado and the eastern plains Sunday afternoon. Along with scattered to numerous thunderstorms possible with moderate to heavy rainfall, models and ensembles are starting to indicate a severe weather threat for the High Plains (along and east of Interstate 25) with ample 0-6km shear values over 40 knots and MLCAPE of 1000 to 2000 J/kg. Forcing is also evident as the first upper level trough lifts northeast over the area with some cyclogenesis over northeastern Colorado and the southern Nebraska Panhandle, which should also help low level easterly moisture advection into the area as well as low level shear. Kept high PoP above 60% for most of the eastern plains with a favorable pattern for strong to severe thunderstorms and appreciable rainfall amounts. For early next week, models now show drier conditions Tuesday through Thursday with lower coverage of showers and thunderstorms as the upper level flow shifts to the west and the storm track/jet stream shifts north towards the Canadian border. Expect another warming trend with high temperatures back into the 60s and 70s by midweek if current trends continue. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1057 AM MDT Thu May 15 2025 CU field continues to bubble up this afternoon as a wave moves across eastern WY/western NE. Some light showers are developing, but support is a lot less than that of yesterday. Best chances for showers remain toward KRWL/KLAR through this afternoon, but some showers may still reach the remainder of the sites through 00Z. Have added a couple TEMPO groupings for western sites, with PROB30 for KBFF/KCDR until peak heating ends early this evening. Winds will continue to howl through the day, with frequent gusts at 40kts through this evening. Winds will ramp down overnight, but jump back up early tomorrow morning with more gusts above 35kts. The main weather system in the Dakotas tries to wrap back southward Friday morning, and may bring some low clouds and light rain to KCDR, possibly as far south as KAIA through 18Z. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...TJT LONG TERM...TJT AVIATION...WFO-RIW
Hazardous Weather Outlook National Weather Service Cheyenne WY Issued by National Weather Service Riverton WY 425 AM MDT Thu May 15 2025 NEZ002-003-019>021-054-055-095-096-WYZ101>119-161030- Dawes County-Box Butte County-Scotts Bluff County-Banner County- Morrill County-Kimball County-Cheyenne County- Northern Sioux County-Southern Sioux County- 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- 425 AM MDT Thu May 15 2025 This hazardous weather outlook is for portions of panhandle Nebraska...east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Very windy conditions are forecast for most of southeast Wyoming and the higher ridges of the western Nebraska Panhandle. West to northwest winds between 25 to 40 mph are expected with gusts as high as 55 mph at times. Stronger winds are possible along portions of Interstate 25 and the Interstate 80 Summit. Isolated thunderstorms are possible this afternoon and this evening. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY Remaining windy on Friday with drier conditions. Thunderstorms will increase in coverage this weekend and early next week. Some of the thunderstorms on Sunday may become strong to severe across the eastern plains. .Spotter information statement... Spotter activation will not be needed.
Preliminary Local Storm Report
National Weather Service Cheyenne WY
732 AM MDT Thu May 15 2025
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0730 AM Rain 0.1 N Hillsdale 41.21N 104.48W
05/15/2025 M0.65 Inch Laramie WY CO-OP Observer
CO-OP observer called to report 0.65 inches
of rain from last nights storm.
&&The national radar mosaic for the moment the first event began.
3 high wind. Local standard time, as filed.
Mesonet station at Whitaker (KWTR) 0.6 NW of Whitaker gusted 60mph at 12:02 PM MDT.
UPR site UP226 gusted 61mph at 12:43pm MDT.
UR474 Granws gusted 63mph at 1:16pm MDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2025Every state in 2025This day in weather historyWarnings in Wyoming, May 2025
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: 1252356, 1252357, 1252359.