A cold front swept across Wyoming and brought high winds to portions of west and central Wyoming. High winds ranged from 56 to 83 mph from Teton to Natrona counties.
Every event with a place to put it; 5 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 RIW wrote it up.
A cold front swept across Wyoming and brought high winds to portions of west and central Wyoming. High winds ranged from 56 to 83 mph from Teton to Natrona counties.
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 Nov 15, 2:53 AM MST, 2 hours 2 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 253 AM MST Sun Nov 15 2020 .SHORT TERM...Today through Tuesday night We will split the discussion between West and East of the Divide, due to the contrast between these regions. West of the Divide...After a break this evening, another wave is moving into the area with snow breaking out again. This one does not have quite the support as the one Saturday, but it will still have an effect. Like yesterday's system, the steadiest snow will fall toward the front end of the storm with the warm advection through early afternoon. Low level flow then turns more west to northwest and snow will become more orographically oriented with showers and banding. Although there will be moderate levels of snow, impacts should not be quite as bad as the previous system since there will be somewhat less wind. In addition, it will be warmer at times this afternoon and with temperatures possibly rising above freezing at times in the valleys it could limit accumulations a bit on paved surfaces. Amounts look reasonable, so we made only minor tweaks. Some areas of the Tetons will likely see some warning level amounts, but this would likely occur above pass level and in places that want the snow. We did add Yellowstone Park to the advisory as well, although mainly for the southern portions of the park as amounts should drop off fairly quickly as you move further northward. Some snow showers will continue into Monday as well, although they will end from south to north as the jet retreats to the north as ridging builds into the area from the west. Snow will end across the area by Monday night. Tuesday at this point looks like the nicest day of the period, with ridging over the area and mild temperatures. The next Pacific system will begin to approach the area Tuesday night. However, most of the models have slowed the progress of the next system and given the fast bias of most of the American models with Pacific systems, we lowered PoPs to slight chances for later at night. It would not surprise me to see any snow hold off until Wednesday with this system. East of the Divide...Like yesterday, the main concern here shifts to wind. We will still have the potent 120 knot jet over the area. However, the ability to mix the mid level winds to the surface looks more limited today and the strongest 700 millibar winds will be in the morning and then decrease as we head toward peak heating. They will likely be stronger than guidance, but far short of warning criteria. Even in areas that have warnings, it does not look as windy as the past couple of days. A place like Wyoming Boulevard may have a 60 mph wind gust, so we will leave them in effect for now. The rest of the period should be more tranquil, as the jet shifts to the north and ridging builds into the Cowboy State. The result will be less wind and gradually warming temperatures, with some of the warmer spots seeing high temperatures climbing into the 60s on Tuesday. With southwest flow, there will continue to be a gusty breeze in areas favored by this, like Casper. However, with the jet far to the north, high winds are not expected at this time. .LONG TERM...Wednesday through Saturday The pattern then changes Wednesday, as the ridge shifts over the Upper Midwest and the flow aloft turns to the southwest. A longwave trough over the EPAC/West Coast will weaken and fill, as it moves onshore. The jet supporting this system will move over the region, which could bring the next round of high winds. Likely areas will be the Wind Corridor, including southern Lincoln County, as well as the east slopes of the Wind River Mountains. Strong downsloping winds could be possible here and impact the Lander Foothills. This system will also bring the next round of Pacific moisture with it, mainly impacting northwestern portions with light snow. The timing of the associated cold front remains in flux, but snow levels look to drop to 6000 feet through the afternoon. Expect this activity to continue into Thursday, as the flow turns more zonal. Breezy to windy conditions and cooler temperatures will continue across the area Thursday, in the wake of the cold front. Strong winds do not look likely, despite the core of the jet being overhead. This will be a similar situation to today (Sunday). Zonal flow will continue over the area, as the jet energy exits eastward over the Northern Plains and Great Lakes. Overall, conditions will be cool and dry across the Cowboy State. By Saturday, a trough will strengthen and dig as it moves onshore over CA. This system will come in phase Saturday, with a weak trough moving over the Northern Rockies. Most of the impacts, however will be over CYS's area. && .AVIATION...For the 12Z TAFS through 12Z Sunday West of the Continental Divide...KBPI/KJAC/KPNA/KRKS Terminals: The heaviest snow will fall between 14Z and 19Z at KJAC, with IFR conditions expected in heavier snow showers. KBPI and KPNA will see snow showers and MVFR to occasional IFR ceilings and visibility after 15Z, with snow showers lingering longer at KPNA. Winds at KJAC and KRKS may gust to 30kt during the late morning and afternoon. Frequent mountain obscurations can be expected after 09Z. Snow should end by 06Z Monday for KJAC. East of the Continental Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals: VFR conditions will prevail through the forecast period. Strong gusty winds will increase late this morning for KCOD and KCPR with gusts to 40 to 50kts possible. KRIW may see a strong NW wind during the afternoon for a few hours. Gusty winds diminish after 02Z. && .FIRE WEATHER... Another weather system will move into western Wyoming and bring another round of snow through tonight and possibly into Monday. Meanwhile, areas east of the Divide should remain mainly dry with near normal temperatures. Breezy to windy conditions will again develop with high winds possible from Muddy Gap through Natrona County. However, winds do not look quite as strong as yesterday. Relative humidity will remain above critical levels. Mixing and smoke dispersal will range from poor in the west to good from Sweetwater County through Natrona County. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 AM MST Monday for WYZ001-012>014- 023-024. High Wind Warning until 6 PM MST this evening for WYZ019-020. && SHORT TERM...Hattings LONG TERM...LaVoie AVIATION...Fisher FIRE WEATHER...Hattings
Hazardous Weather Outlook National Weather Service Riverton WY 259 AM MST Sun Nov 15 2020 WYZ001>020-022>030-161000- 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- 259 AM MST Sun Nov 15 2020 ...Winter Weather Advisories in effect for far Western Wyoming through Sunday Night... ...High Wind Warning for southeast Fremont and Natrona counties through this evening... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Snow will continue across the far western valleys and mountains. Please see winter weather advisory for more information. High wind is expected across southeast Fremont into Natrona County. Please see the high wind warning for more details. Also strong winds are possible in the Absarokas, Cody Foothills and eastern slopes of the Wind River Mountains. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Wednesday and Thursday...A chance for snow across the far west. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions, according to standard operating procedures. TEAM RIVERTON
Special Weather Statement National Weather Service Riverton WY 248 AM MST Sun Nov 15 2020 WYZ003-160100- Cody Foothills- Including the cities of Clark, Cody, and Meeteetse 248 AM MST Sun Nov 15 2020 This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...West winds 25 to 35 mph with gusts to 50 mph. Locally higher gusts near Clark. * WHERE...Cody Foothills * WHEN...Today. * IMPACTS...Mainly to transportation along Highway 120. There could be control issues especially for light and high profile vehicles, including campers and tractor trailers. * ADDITIONAL DETAILS...Please keep two hands on your steering wheel in case of a sudden, strong wind gust. WYZ016>018-160100- Upper Wind River Basin-Wind River Basin-Lander Foothills- Including the cities of Dubois, Riverton, Shoshoni, and Lander 248 AM MST Sun Nov 15 2020 This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...West to northwest winds increasing to 20 to 30 mph with gusts to 45 mph. * WHERE...Wind River Basin and Lander Foothills. * WHEN...Today, especially in the afternoon. * IMPACTS...Mainly to transportation. There could be control issues especially for light and high profile vehicles, including campers and tractor trailers. * ADDITIONAL DETAILS...Please keep two hands on your steering wheel in case of a sudden, strong wind gust. WYZ027>030-160100- South Lincoln County-Rock Springs and Green River-Flaming Gorge- East Sweetwater County- Including the cities of Kemmerer, Cokeville, Rock Springs, Green River, and Wamsutter 248 AM MST Sun Nov 15 2020 This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...West winds increasing 25 to 35 mph with gusts to 50 mph. The strongest winds are expected east of Rock Springs. * WHERE...Sweetwater and southern Lincoln Counties * WHEN...Today, with the strongest winds in the afternoon. * IMPACTS...Mainly to transportation. There could be control issues especially for light and high profile vehicles, including campers and tractor trailers. * ADDITIONAL DETAILS...Please keep two hands on your steering wheel in case of a sudden, strong wind gust.
The national radar mosaic for the moment the first event began.
5 high wind. Local standard time, as filed.
A measured 83 mph wind gust was recorded by the mesonet station UYDDX at 1 mile west of Grant Village in Yellowstone National Park.
A measured 62 mph wind gust was reported at the mesonet station WY61 I25-Hat Six, four miles southeast of Evansville, Wyoming.
A measured 59 mph wind gust was reported by the mesonet station W47 2.1 miles southwest of Casper, Wyoming.
Mesonet station CAMW4, Muddy Gap, 7 miles southwest, reported a measured 72 mph wind gust.
A measured 65 mph wind gust was reported, 14 miles west-southwest of Buffalo, Wyoming at the SPKW4 mesonet station.
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, November 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: 930416, 930426, 930428, 930422, 930423.