FXUS65 KRIW 040500

AFDRIW



Area Forecast Discussion

National Weather Service Riverton WY

1100 PM MDT Sun May 3 2026



.KEY MESSAGES...



- Virga showers, moving to the southeast, will end through the

  evening. A brief gust up to 40 mph will remain possible from

  these passing showers. 



- The next weather system moves across the state Monday and

  Tuesday, bringing a better opportunity for rain and snow. 

  Confidence remains low in rainfall and snowfall amounts.



- Freeze Watches now in effect for lower elevations east of the

  Continental Divide Tuesday night into Wednesday morning.



&&



.DISCUSSION...

Issued at 211 AM MDT Sun May 3 2026



The more progressive pattern continues across the northern

Rockies during the next week. Today will start with some high

clouds and warm temperatures reaching the 60s and 70s. The 

approach of the next weather system will bring enough 

instability today for some shower activity along the higher 

reaches of the Absarokas and Bighorns. While moisture has 

started to increase across northern WY in the past 24 hours, 

there still isn't a whole lot to produce much accumulation with 

showers today.



The main system itself will begin to impact Wyoming Monday

morning, as a front sweeps in from the north. The first push

should reach the northern WY/MT border right around sunrise

Monday, and reaches around the Continental Divide by 18Z, before

spreading southwest late in the afternoon. The front will bring

along valley rain and mountain snow behind it, spreading

southward through the day. Most areas should receive a good

wetting rain, but some shadowing across the Bighorn Basin may

keep amounts there to a minimum. With the front stretched along

the southern WY border during the evening, best opportunity for

rainfall would be focused from the Winds east along the Greens 

and Casper Mountain. Rain decreases late Monday night into 

Tuesday, but a brief secondary north wind push will keep very 

light rain/snow going for all except for the Bighorn Basin and 

the NW Parks during the day Tuesday. Current accumulation 

numbers have remained steady for a couple tenths for the 

southern 2/3 of the state, with the highest band near a half 

inch for the Winds east to Casper Mountain. Models have nudged 

amounts downward slightly since yesterday, and with the last 

couple events the models have overestimated final totals, so 

current totals may be a bit high. 



Once this system sweeps southeast early Wednesday, upper level

pattern remains from the northwest, so while temperatures will

return to the 60s and 70s, weak embedded impulses may bring

light heating-of-the-day showers to the northern mountains

through the rest of the week.



&&



.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...

Issued at 1100 PM MDT Sun May 3 2026



VFR conditions to start the period across all terminals. However, a 

nearing cold front will start to bring impacts to terminals starting 

as early as 12-15Z Monday. Northerly terminals such as KCOD and KWRL 

see winds increase around this time along with lowering ceilings to 

near MVFR. Gusty northerly winds of 20-30 knots will gradually push 

south through the day making it to central terminals by around 18Z. 

Development of showers will occur ahead of the front in the 

afternoon with nearly all terminals having a chance around a 20-40% 

for a brief shower from 18Z Monday through 00Z Tuesday. An isolated 

thunderstorm or two cannot be ruled out with terminals west of the 

Divide having the best chances. The main concerns as a result of any 

showers will be gusty outflow winds of 25-35 knots. A second round 

of precipitation looks possible after 00Z Tuesday in association 

with the cold front passage. PROB30 groups have been added to 

numerous terminals with some seeing showers while others may see a 

period of prevailing precipitation to end the 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...

Freeze Watch from late Tuesday night through Wednesday morning 

for WYZ003>006-010-011-017-018-020.



&&



$$



DISCUSSION...Straub

AVIATION...Dziewaltowski