Damaging Winds in Wyoming, April 11, 2026

Area Forecast Discussion
National Weather Service Riverton WY
1159 AM MDT Sat Apr 11 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms are expected through this evening
  as they move from southwest to northeast across the area.
  Strong wind gusts of 40 to 60 mph are possible with this
  activity.

- Elevated to near critical fire weather conditions are expected
  through the afternoon across much of central Wyoming.

- Scattered showers and thunderstorms are again expected on
  Sunday, though less widespread with the best chances across
  western Wyoming. Elevated to near-critical fire weather
  conditions will continue for much of the area.

- The unsettled pattern will persist through next week, with
  mild afternoon temperatures and several chances for moisture.
  A late week system may return cold morning temperatures
  (15-25 degrees) to lower elevations.

&&

.UPDATE...
Issued at 1157 AM MDT Sat Apr 11 2026

Convection is beginning to increase across western and southern
Wyoming late this morning as a shortwave arrives ahead of an
approaching upper low. Continued diurnal heating will allow MLCAPE
values to build to 100-500 J/kg across the area, with showers and
thunderstorms expanding in coverage from west to east over the next
couple of hours. The main concern with this activity will be strong
outflow wind gusts given the relative dry, well-mixed boundary layer
(DLCAPE values of 500-1000 J/kg). This risk will extend through mid
evening, with the last storms expected to exit the area between 9 PM
and midnight.

&&

.DISCUSSION...
Issued at 145 AM MDT Sat Apr 11 2026

As an advancing trough makes it to northern California today,
southwest flow aloft increases across Wyoming, bringing better
moisture to the area. In addition, a trough in advance of the main
system passes through today. These factors combine to bring
increased precipitation chances today, with showers being able
to produce rain that reaches the ground. The main push of this
shortwave starts late this morning, with shower and thunderstorm
chances increasing from the southwest through the afternoon,
and then decreasing from the southwest to northeast between
about 6pm and midnight. Everywhere will have a chance for rain
today (snow levels around 9000 feet). The best chances will be
west of the Continental Divide, where the better moisture will
be. The current forecast depicts of blend of hi-res models, with
the reality being that it is nearly impossible to determine
exactly where a shower or storm could occur today, but they will
be around. Everywhere has at least a 20 percent chance, though
actual chances vary to be as high as 80 percent (mainly west of
the Divide). Many models seem to depict a cluster of rain
showers over Sweetwater County this afternoon, so confidence in
rain is better there. The main hazard with any showers or storms
would be outflow gusts, which could be up to about 60 mph.

The other hazard today will be wind, and some fire weather concerns
with it. Moisture does increase today, especially west of the
Divide, but minimum humidity values around 20 percent are likely for
basins east of the Divide, driest for Johnson County. It is also
going to be windy today, a result of a tightening pressure gradient.
Gusts 25 to 40 mph will be common, and for these drier places, near
critical fire weather conditions could occur.

For Sunday, precipitation chances remain (though much more limited
compared to today), mostly along and west of the Divide, though some
"spill-over" is likely. Current projected positioning of the
incoming low would favor the western mountains (i.e. Absarokas,
Tetons, Yellowstone) the most. Gusty southwest winds 25 to 40 mph
continue during the day as well, so elevated to near critical fire
weather conditions remain a concern.

For Monday and Tuesday, the model trend continues to be for a weaker
and drier system, unfortunate news for those wishing for
precipitation. Liquid totals have dropped once again, with very
limited chances for low elevation basin locations. Elevated to near
critical fire weather looks to continue as well as gusty winds occur.

Looking further ahead, there is growing confidence in a colder system
towards the end of next week (Thursday-Saturday). This system has
the potential to bring morning low temperatures in the low 20s, with
multiple mornings in a row under 30 degrees. This is a heads up to
those with sprinklers or vulnerable vegetation.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1059 AM MDT Sat Apr 11 2026

VFR flight conditions are largely expected through 18Z Sunday with
scattered shower and thunderstorm chances this afternoon. At all
terminals, there is a 30 percent chance of thunderstorms beginning
as early as 19Z at KJAC followed by all other terminals. Because
showers and thunderstorms will move southwest to northeast, it is
expected that west of the Divide terminals (KJAC, KRKS, KPNA, and
KBPI) will generally see chances before east of the Divide terminals
(KRIW, KCPR, KCOD, KLND, and KWRL). Showers or thunderstorms should
also end from southwest to northeast between 01Z and 04Z. Gusty 40kt
to 50kt winds are possible at any terminal in or with nearby showers
or thunderstorms. Isolated severe gusts near 60kts cannot be ruled
out. MVFR conditions will be possible in the heavier showers and
thunderstorms with occasional mountain obscurations.

Gusty southwest winds are also expected outside of any showers or
thunderstorms with gusts generally between 25kts and 35kts. These
gusty winds should diminish around or shortly after sunset with
relatively light winds overnight at most terminals. KCPR is the
exception with winds remaining breezy the entire TAF period.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

UPDATE...Myers
DISCUSSION...Wittmann
AVIATION...Gerhardt

Hazardous Weather Outlook
National Weather Service Riverton WY
154 AM MDT Sat Apr 11 2026

WYZ001>020-022>030-121300-
Yellowstone National Park-Absaroka Mountains-Cody Foothills-
North Bighorn Basin-Southwest Bighorn Basin-Southeast Bighorn 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-
154 AM MDT Sat Apr 11 2026

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...Today and tonight.

Showers and thunderstorms move across the area mid-morning through
late this evening. Gusty winds up to about 60 mph are possible.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Daily precipitation chances through the next week. A cold weather
system Thursday and Friday is likely to bring below freezing
temperatures.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service Riverton WY
1240 PM MDT Sat Apr 11 2026

WYZ023-024-111915-
Star Valley-Salt River and Wyoming Ranges-
1240 PM MDT Sat Apr 11 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN LINCOLN COUNTY
THROUGH 115 PM MDT...

At 1240 PM MDT, Doppler radar was tracking a strong thunderstorm over
Thayne, moving north at 30 mph.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

This strong thunderstorm will be near...
  Star Valley Ranch and Freedom around 1245 PM MDT.
  Stewart Peak around 1255 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4310 11105 4313 11104 4306 11070 4284 11102
      4285 11104
TIME...MOT...LOC 1840Z 199DEG 26KT 4293 11104

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

Gerhardt