538
FXUS65 KRIW 111120
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
520 AM MDT Fri Jul 11 2025

.KEY MESSAGES...

- A cold front will bring a chance of thunderstorms and cooler
  temperatures today, mainly East of the Divide.

- Mainly dry for the weekend with hot temperatures returning,
  especially on Sunday.

- An approaching weather system will bring a chance of
  thunderstorms for the middle of next week.

&&

.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 /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 520 AM MDT Fri Jul 11 2025

Windy to start the TAF period, as a northerly wind associated with a
cold front moves through the area. Winds decrease through the
morning. There could be some showers/storms behind the front, from
roughly 16z until 03z. These chances are mainly for locations east
of the Continental Divide; have included PROB30 groups to account
for the 20% to 30% chances.

At KJAC, there is lower confidence in wind direction starting about
18z. Possible directions could range from 260 to 320 degrees through
the afternoon. Have gone with the middle, 280, for the TAF. There
could also be occasional gusts 15 to 20 mph through the afternoon.

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...
None.

&&

$$

DISCUSSION...Hattings
AVIATION...Wittmann