FXUS65 KRIW 272200

AFDRIW



Area Forecast Discussion

National Weather Service Riverton WY

400 PM MDT Mon Oct 27 2025



.KEY MESSAGES...



- Rain and mountain snow will continue today though generally 

  becoming lighter through the afternoon. Winter travel 

  conditions remain possible across mountain passes. 



- Light snow is also possible (50-70%) across lower elevations

  of Johnson and Natrona counties late this afternoon through 

  midnight. Natrona County is most favored to see light 

  accumulations, generally under an inch across lower elevations

  (20% chance of totals over an inch).



- Gusty west to northwest winds continue for most areas today, 

  decreasing after sunset.



- Tuesday remains cool before temperatures moderate starting Wednesday.

  Little to no precipitation is expected Tuesday through the 

  end of the week.



&&



.UPDATE...

Issued at 1215 PM MDT Mon Oct 27 2025



We are now on the tail end of this system as the trough axis has 

passed through early this afternoon. Rain and mountain snow will 

generally be on the decrease through the rest of the day as incoming 

moisture wanes. The Bighorns will be one of the last locations to 

hold on to light snow, and the Advisory there will continue through 

the afternoon. As noted below, CAMs are continuing to show light 

snow developing across Johnson and Natrona counties after sunset as 

the trough drops drops to our southeast and wraps additional 

moisture in. Natrona County appears most favorable for light snow 

accumulation between late afternoon and midnight, with amounts 

generally under an inch across lower elevations. Very light snow may 

linger in the western mountains through the night though with little 

to no additional accumulation. Otherwise, precipitation will move 

out after midnight, with a cool and mostly sunny Tuesday in store 

for everyone.



&&



.DISCUSSION...

Issued at 221 AM MDT Mon Oct 27 2025



The broad trough continues to sweep across the northern Rockies

this morning. This is keeping the moisture feed off the Pacific

well placed for lift along local mountain ranges. Models

continue to show elevated lift aloft through the rest of the

day, which will continue to aid in snow production. Peak times

for the northwest mountains should be between now and around

noon, with the focus shifting briefly east to the Bighorns this

afternoon. Additional snowfall accumulations of 3 to 6 inches is

expected before the system moves out tonight. Current warnings

and advisories mesh well with the current timings, so will not

need any adjustments here. As the system moves east this 

evening, a brief period of rain/snow mix will develop for 

Natrona and Johnson Counties, with snow accumulations up to a 

half inch possible.



Winds will also come up across the state today, as the northwest

flow aloft mixes down to the sfc. Widespread wind gusts above 

30 mph are expected, except for the more shaded places across NW

WY. The southern half of the state will see even higher gusts

this afternoon, with frequent gusts 40 to 50 mph likely (>60%).



High pressure builds in for Tuesday, with much colder

temperatures. Highs will struggle to reach 40 degrees, before

falling into the teens and low 20s Tuesday night. H5 ridging

builds across the Rockies midweek, deflecting the next system

into Montana. Right now it would only provide some high clouds

during the day. Models differ on the next system which may pass

through Friday night, with a wide range of strength and moisture

available. Current trend is for a drier passage, with milder

temperatures in the 50s and 60s remaining through the weekend.



&&



.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...

Issued at 359 PM MDT Mon Oct 27 2025



Winds and precipitation chances will continue to decrease from west 

to east through the evening. Winds also decrease through the evening 

at all terminals. KJAC, KCOD, and KCPR will chances for light snow 

showers to start the period. These snow showers through the 

afternoon have been convective in nature with sudden and intense 

reductions to visibility, so brief IFR or even LIFR conditions are 

possible at those terminals through around 04Z this evening.

Conditions should quickly improve, and after 06Z all terminals are 

expected to see prevailing VFR conditions with light winds (less 

than 12kts) and clearing skies through the rest of the 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...

Winter Weather Advisory until 6 PM MDT this evening for WYZ008.



Winter Storm Warning until 6 PM MDT this evening for WYZ012.



&&



$$



UPDATE...Myers

DISCUSSION...Straub

AVIATION...Hensley