FXUS65 KRIW 240747

AFDRIW



Area Forecast Discussion

National Weather Service Riverton WY

147 AM MDT Fri Oct 24 2025



.KEY MESSAGES...



- Mostly sunny, with mild temperatures and light winds today. No precipitation

  expected. 



- The next weather system brings widespread southwest gusty

  winds over 30 mph starting Saturday afternoon, continuing 

  through Monday. Most widespread gusty winds occur Sunday. 



- Western mountain snow occurs Saturday night through early

  Tuesday morning. Expect winter travel conditions over mountain

  passes from moderate to heavy snowfall and gusty winds. 



&&



.DISCUSSION...

Issued at 146 AM MDT Fri Oct 24 2025



Yesterday was a pleasant autumn day across the area. If that's your 

type of weather, then you're in luck, because today is much the same 

(and if it's not, stay tuned). As the upper low to our south moves 

away from the area, clouds lessen for today, with a mostly sunny 

sky, relatively light winds, and mild high temperatures around 60 

degrees.



The interesting part of the forecast starts Saturday afternoon. A 

longwave trough will begin moving into the area early Saturday. This 

tightens the pressure gradient, with southwest wind gusts 20 to 30 

mph being common over the area. Favored locations, like the Wind 

Corridor from South Pass to Casper, see stronger winds. As the 

trough approaches in the afternoon, stronger winds also look 

favorable for the western mountains, including Yellowstone; gusts 

over 30 mph likely, with areas over 40 mph.



The bulk of this system occurs Saturday night through Monday night. 

The main aspects to it will be wind and mountain snow. Starting with 

wind, like Saturday, gusty southwest winds occur across the area, 30 

to 50 mph. It should be noted that most winds will have continued 

from Saturday afternoon into Sunday afternoon, with no lessening 

winds overnight. Gusty winds will lessen a bit for some locations 

Sunday night, but overall, winds continue through the day Monday.



The other weather element is snow. Quick note, that outside the 

following discussed snow, there will be continuous rain chances (30% 

to 50%) for the lower elevations. Latest snow totals are similar to 

what was seen yesterday, so there is now some consistency, which 

adds confidence to the current snow amount forecast. Highest totals 

are for the Teton, Salt/Wyoming, Gros Ventre, and far western 

Absaroka Ranges, with notable amounts also over the higher 

elevations of the Wind River Range and across the southern half of 

Yellowstone. Forecasted, deterministic mean amounts are 9 to 12 

inches for these mentioned locations. The NBM spread (a 25th to 75th 

percentile difference) is around 6 inches, so about 3 inch buffer to 

those given mean amounts. Notably, there is a greater spread across 

Yellowstone, likely due to model differing in storm track 

(positioning of the jet stream and favored dynamics late Sunday into 

early Monday). The spread there is 8 inches, so plus or minus 4 

inches on the current deterministic forecast. In any case, it is 

likely (75%) that winter highlights will be needed for the 

mountains. Will hold off for now due to lacking confidence in 

potential amounts and will hope that consistency remains with later 

runs today. EFI/SOT (a tool to look at potential for high-end 

events) still has snow amounts in the 50th to 70th percentile, with 

SOT slightly highlighting the Tetons/southern Yellowstone, again 

alluding to the greater uncertainly there, but potential for higher-

end amounts. 



The overall takeaway is that there will be winter weather over the 

western mountains Saturday night through Monday night. Expect winter 

travel conditions, with moderate to heavy snow possible and gusty 

winds bringing blowing snow and reduced visibilities. Notable passes 

include Teton, Togwotee, and Salt River. Conditions improve late 

Monday night into Tuesday morning as snow lessens. Light snow 

lingers through Tuesday morning.



&&



.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...

Issued at 1023 PM MDT Thu Oct 23 2025



Low pressure to the south will move away from Wyoming. VFR

conditions are expected through 06Z Saturday with only passing

high clouds expected. Wind will generally be light and terrain-

driven, under 10 knots.



Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for 

the latest information on smoke, icing, and turbulence

forecasts.



&&



.RIW WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



DISCUSSION...Wittmann

AVIATION...Hattings