Latest ZFP from WFO RIW

		
National Weather Service Local Forecast for Star Valley Ranch
Updated: Thu Jul 10  6:59 pm MT

Tonight... Clear, with a low around 46. West wind 5 to 9 mph
becoming light and variable  after midnight. 

Friday... Sunny, with a high near 82. Calm wind becoming north
northwest 5 to 8 mph in the afternoon. 

Friday Night... Mostly clear, with a low around 49. Northwest
wind 5 to 8 mph becoming light and variable. 

Saturday... Sunny, with a high near 87. Calm wind becoming west
5 to 8 mph in the afternoon. 

Saturday Night... Mostly clear, with a low around 51. West wind
5 to 8 mph becoming light and variable  after midnight. 

Sunday... Sunny, with a high near 90. Calm wind becoming west 5
to 7 mph in the afternoon. 

Sunday Night... Clear, with a low around 53. West wind around 6
mph becoming south southeast after midnight. 

Monday... Sunny, with a high near 90.

Monday Night... Mostly clear, with a low around 52.

Tuesday... A 20 percent chance of showers and thunderstorms
after noon.  Sunny, with a high near 87.

Tuesday Night... A slight chance of showers and thunderstorms. 
Partly cloudy, with a low around 48.

Wednesday... A slight chance of showers and thunderstorms. 
Sunny, with a high near 84.

Wednesday Night... Mostly clear, with a low around 48.

Thursday... Sunny, with a high near 88.

		

Latest AFD from WFO RIW

		
213 
FXUS65 KRIW 102149
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
349 PM MDT Thu Jul 10 2025

.KEY MESSAGES...

- Warm but more seasonable temperatures across the Cowboy State today

- Isolated showers and thunderstorms will be possible this
  afternoon and evening mainly over central and northern WY.

- Cooler temperatures arrive for Friday as a cold front moves through
  the state. Highs may be 10 to 15 degrees cooler than 
  Thursday.

- The frontal passage will bring chances for showers and thunderstorms
  throughout the day Friday.

&&

.UPDATE...
Issued at 1249 PM MDT Thu Jul 10 2025

Showers and thunderstorms that developed over portions of western 
and southern WY this morning have dissipated. Satellite imagery 
shows clearing skies with some isolated convection starting to 
develop over central and southern WY. Coverage will be limited 
mostly to east of the Divide and gradually spread to the east 
throughout the afternoon and evening. The main concern with any 
showers and thunderstorms will be strong gusty outflows of 50 
mph or more. The atmosphere remains fairly dry which may lead to
virga showers and an isolated dry thunderstorm or two. 
Temperatures are still on the warm side with highs in the upper 
80s to low 90s east of the Divide and mid 80s west of the 
Divide. A cold front is nearing the state and is expected to 
start moving into the area by the late evening tonight.

The frontal passage is expected to bring cooler temperatures and 
chances for precipitation. Highs are forecast to be nearly 10 to 15 
degrees cooler than Thursday. Temperatures east of the Divide will 
range in the mid to upper 70s with values in the upper 70s to low 
80s west of the Divide. Shower and thunderstorms will be possible on 
Friday as the front passes with the best chances remaining across 
central and northern WY. Elevated PWAT values do look to possibly 
move into the region for Friday with above normal amounts 
mainly east of the Divide. This may create some brief heavy 
downpours but these are expected to remain fairly isolated. 

The weekend sees warmer and drier conditions return to the area with 
highs reaching the upper 80s to low 90s. The next chance for 
precipitation does not look to arrive until the start of next week 
as a trough moves across the region. Another front moves through the 
area around Tuesday night bringing in a brief period of cooler 
temperatures. The remainder of the week looks to have increased 
chances for precipitation as multiple disturbances move through the 
region.

&&

.DISCUSSION...
Issued at 120 AM MDT Thu Jul 10 2025

Weak showers will continue over the southern half of the CWA this 
morning, as a remnant low approaches the area from southern ID. Any 
rainfall amounts will be very low, a trace to 0.02", along with very 
isolated lightning strikes. Showers will remain isolated over this 
area through the rest of the morning after sunrise, as the low 
reaches far southern WY. The focus for precipitation will shift east 
of the Divide this afternoon, as the low exits over eastern portions 
of the state. Wind gusts of 50 to 55 mph will be the main threat, 
along with some lightning. Instability will be limited, as CAPE 
values will range between 200-500 J/kg. Temperatures will be about 
10 degrees cooler across the CWA as a result of the passage of this 
remnant low. Fire weather conditions will remain elevated as well, 
with critical RH values returning to portions of the Wind River and 
Bighorn Basins and Sweetwater County. 

A cold front will reach northern WY sometime between 06Z and 12Z 
Friday, quickly progressing southward and reaching the Divide by 
15Z. Any precipitation looks to be confined to northern portions 
through much of the day Friday, but could progress into the Wind 
River Basin in the afternoon. Any thunderstorms look to occur along 
the Divide, due to the front. Highs in the 70s east of the Divide 
remains in the forecast, while areas west of the Divide stay in the 
low to middle 80s. Locations in northern Johnson County may not 
reach 70 degrees, which would be a 30 degree dip from yesterday.  

Dry conditions then return for the weekend, with a somewhat 
northwest flow pattern aloft. This will lead to seasonal 
temperatures on Saturday and highs in the 90s return for areas east 
of the Divide on Sunday. Showers and thunderstorms could be possible 
Monday and Tuesday, as another trough drops south from British 
Columbia and bringing the trough/cold front through Tuesday
night.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 335 PM MDT Thu Jul 10 2025

Models remain on track with the cold frontal passage overnight and 
Friday morning. There are slight indications of showers developing 
along and in the wake of the front, however, confidence is low. Most 
likely chances are at KCOD (30% chance), KWRL (20% chance) and KCPR 
(20% chance). Generally, the more likely impact looks to be lowering 
cigs at the aforementioned terminals. VFR conditions look to 
prevail, but for KCOD and KCPR, there is a 20-30% chance of MVFR 
cigs developing behind the front Friday morning. 

Also with the frontal passage, northerly to northeasterly winds are 
expected at most east of the Divide terminals and at KRKS Thursday 
night through Friday morning. Gusts to 20 to 25kts are expected and 
could linger through much of the morning, though do look to 
gradually taper off at most terminals by the later half of the 
morning. Afternoon showers and thunderstorms will then be possible 
for east of the Divide terminals as clearing late Friday morning 
should prompt increasing instability into the afternoon. 

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.

&&

$$

UPDATE...Dziewaltowski
DISCUSSION...LaVoie
AVIATION...Hensley