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Latest ZFP from WFO RIW
	
National Weather Service Local Forecast for Star Valley Ranch
Updated: Fri Jul 11 11:13 pm MT

Overnight... Clear, with a low around 47. Calm wind becoming
east southeast around 5 mph. 

Saturday... Sunny, with a high near 85. Calm wind becoming west
5 to 9 mph in the afternoon. 

Saturday Night... Mostly clear, with a low around 51. West
northwest wind 5 to 7 mph becoming calm  in the evening. 

Sunday... Sunny, with a high near 90. Calm wind becoming west
around 6 mph in the afternoon. 

Sunday Night... Mostly clear, with a low around 52. West wind
around 6 mph becoming light and variable  in the evening. 

Monday... Sunny, with a high near 90. Calm wind becoming west 5
to 9 mph in the afternoon. 

Monday Night... Mostly clear, with a low around 53. West wind 6
to 8 mph becoming south southeast after midnight. 

Tuesday... A 20 percent chance of showers and thunderstorms
after noon.  Sunny, with a high near 89.

Tuesday Night... A 10 percent chance of showers and
thunderstorms before midnight.  Partly cloudy, with a low around 51.

Wednesday... A 10 percent chance of showers and thunderstorms
after noon.  Sunny, with a high near 85.

Wednesday Night... Mostly clear, with a low around 49.

Thursday... Sunny, with a high near 87.

Thursday Night... Mostly clear, with a low around 51.

Friday... Mostly sunny, with a high near 88.

	

Latest AFD from WFO RIW
	
054 
FXUS65 KRIW 120345
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
945 PM MDT Fri Jul 11 2025

.KEY MESSAGES...

- Cooler temperatures overnight into Saturday morning. 

- Rain showers diminish and push southeast out of the area with
  improving skies and dry conditions overnight into Saturday. 

- Dry and warming trend return for the weekend and into the 
  start of next week with the potential for fire weather 
  conditions by Monday.

&&

.UPDATE...
Issued at 1236 PM MDT Fri Jul 11 2025

A cold front has moved across much of the Cowboy State overnight. 
The frontal passage has brought relief to the recent heat that 
enveloped the region over the past week. Highs today will reflect 
this relief with temperatures in the mid to upper 70s east of the 
Divide and upper 70s to low 80s west of the Divide. Scattered 
showers and isolated thunderstorms moved across northern WY this 
morning but have now dissipated. Another round of showers and 
thunderstorms is expected to develop this afternoon. The best 
chances of seeing a shower or thunderstorm look to be east of the 
Divide, especially across central WY. CAMs have highlighted portions 
of the Wind River Basin, eastern Sweetwater County and southern 
Natrona County. Overall, dynamics are not overly impressive but 
there does look to be some favorable components that may lead to a 
strong or near severe storm. CAPE values are marginal ranging from 
500 to 1000 J/kg with some shear present but not overly 
impressive. PWAT values look to be above normal with values 
ranging from 0.75 to 1.00 in. These dynamics will lead to the 
possibility of a few hazards as a result of any strong storms 
that develop. These hazards look to be hail, strong gusty 
outflow winds, and isolated heavy downpours. Very isolated flash
flooding cannot be ruled out, especially in poor drainage 
locations but the overall concern for this is not very high. As 
mentioned earlier, CAMs highlight central WY especially portions
of the Wind River Basin. SPC's day 1 outlook supports this with
a sliver of marginal chances for severe thunderstorms being 
drawn across central WY into southwestern WY. Showers and 
thunderstorms look to start developing shortly after noon over 
northern WY and gradually tracking southeast through the 
remainder of the afternoon and evening. Convection moves out of 
the area around sunset with quiet weather prevailing overnight 
through the weekend.

The weekend sees warmer and drier conditions return to the area with 
highs reaching the upper 80s to mid 90s. These warm temperatures and 
dry conditions may lead to fire concerns by Monday. Winds are 
looking to increase Monday along with low min RH values and warm 
temperatures. These components may lead to portions of the state 
seeing elevated to near critical fire weather conditions. This 
possibility will continue to be monitored as we head into the 
weekend. 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 259 AM MDT Fri Jul 11 2025

When I was surfing the net before I left for work, I happened 
upon an old commercial I have not seen since my youth, many eons
ago. It is for the antacid Rolaids. And the question asked in 
it is: How do you spell relief? And the answer is spelled out: 
R-O-L-A-I-D-S. And this relates to this question, how do you 
spell relief from the heat? And the answer is C-O-L-D F-R-O-N-T.

A cold front is currently moving through the area, having 
passed through the humble Riverton weather abode a bit ago with 
wind gusts close to 50 mph with the strong cold advection. Both 
Greybull and Buffalo have gusted over 50 mph as well. These 
strong wind gusts should slowly end though. The big change today
will be much cooler temperatures that will move in today East 
of the Divide, where some locations will be up to 20 degrees 
cooler than yesterday, with a place like Buffalo struggling to 
get out of the 60s. It will feel more like May than July. It 
will remain warm West of the Divide though, with temperatures 
close to yesterday's highs though. As for convection, we do have
some instability but not a ton, maximum CAPE values max out at 
around 1000 J/Kg in some of the mountains but it is generally 
around 500 J/Kg or less. Lifted indices generally drop down as 
low as minus 2. Much of the area, except for southwestern 
Wyoming, may see a shower or storm but the chance is generally 
at most 1 out of 4, with up to a 2 in 5 chance in some of the 
mountain ranges. Most of this looks like an early show, with 
most over around 6 pm and all over by sunset.

The weekend at this point looks relatively uneventful with mainly 
dry conditions under northwest flow. Many people will be suffering 
from temperature whiplash though with near to above normal 
highs returning Saturday and especially Sunday with widespread 
90s in the lower elevations East of the Divide and some 
locations getting close to 100. Fire weather concerns look low 
though with wind remaining light to moderate. 

Active weather then begins ramping up again starting Monday. On 
Monday a shortwave will approach the area and bring a chance of
showers and storms, mainly across northern portions of the 
state. This will also tighten the pressure gradient across the 
area and bring a gusty wind which will likely increase fire 
weather concerns, especially in southern Wyoming. Following 
that, a more potent cold front will drop southward into the area
and bring a better chance of showers and storms, possibly both 
on Tuesday and into Wednesday. Details on which day will be 
wetter and details of where the storms may fire are still highly
uncertain though. Cooler temperatures will also move in for 
midweek as a trough lingers across the area. So, it looks like 
we will be riding the temperature rollercoaster as we head into 
through the middle of July.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 945 PM MDT Fri Jul 11 2025

VFR conditions expected throughout the entirety of the period.
All rain showers have pushed southeast of the CWA with dry
conditions through the weekend. Light winds overnight with
clearing skies west to east of the Divide. Winds increase after
18-19Z due to daytime heating and mixing to the surface. Gusts
up to 18kts at JAC/PNA/CPR and up to 25kts at RKS/BPI through
01Z with radiational cooling towards sunset and overnight into
Sunday morning. Few to scattered high clouds remain throughout
the period with more ample sunshine than previous days, with no
other weather elements expected at this time. 

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...Hattings
AVIATION...Lowe

	

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