689
FXUS65 KRIW 111715
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1115 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 /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1115 AM MDT Fri Jul 11 2025

West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals...

Mostly clear skies with only FEW to SCT high clouds this afternoon.
Winds remain mostly light, with gusts briefly reaching 15 to 20kts
at KJAC (30% chance) and more frequent gusts at KBPI and KPNA through
the afternoon. Northeasterly winds this afternoon will favor KRKS
where gusts up to 25kts are expected through around 07Z Saturday.
Light winds are expected overnight with SKC for all terminals
through the end of the period.

East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals.

Behind the overnight cold frontal passage, most terminals will
persist with northeasterly winds, however, wind speeds should
continue to decrease through the early afternoon. Skies remain BKN
to OVC through the late afternoon as well, but breaks in the clouds
are expected to start to develop from west to east. This will allow
for convective initiation during the late afternoon (around 22Z)
over the Absaroka and northern Wind River Mountains. Showers and
thunderstorms will then move east from 22Z through 03Z. Most likely
chances for thunderstorm impacts are at KRIW and KLND (60% chance)
with lesser chances (30%) at KWRL and KCPR. Gusty winds and small
hail are possible with these thunderstorms, particularly for KRIW
and KLND.

Skies quickly clear after 05Z, with light winds and mostly SKC
prevailing through the rest of the period.

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...Hattings
AVIATION...Hensley