182
FXUS65 KRIW 232202
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
402 PM MDT Thu Jul 23 2026

.KEY MESSAGES...

- Monsoon moisture will be slightly decreased today, but still
  in abundance for showers and isolated thunderstorms this
  afternoon. Lack of upper level support will keep chances
  limited to the higher elevations and foothills today,
  primarily along and east of the continental divide. Localized
  flooding is somewhat possible along the eastern portions of
  the Absarokas and Wind Rivers if storms produce heavy rain on
  top of saturated soils.

- High pressure builds across the Rockies for this weekend,
  bringing another round of heat to the state. Areas of northern
  and central Wyoming could again reach the upper 90s and low
  100s from Friday through Monday.

- Lingering monsoon moisture and weak disturbances from the
  Great Basin will continue to bring isolated showers and
  thunderstorms over western and northwest WY as well as other
  higher elevations this weekend into early next week.

&&

.UPDATE...
Issued at 206 PM MDT Thu Jul 23 2026

Convection is well under way this early to mid afternoon across
western and central WY, with most of the storms across southern
and central WY. Still expecting more development over the
eastern portions of the Absarokas, Bighorns, and Wind Rivers,
moving to the southeast, as a shortwave trough rides over the
ridge axis just to our west. The 18Z KRIW sounding not only
shows a very moist lower atmosphere, but a significant cap
around 500 mb which would limit the vertical extent of any
convection. A new-ish flood watch remains in effect through 8
PM for some areas due to the possibility of heavy rain failing
on now- saturated soils. However, the ground seems to be taking
in quite a bit of precipitation giving the lack of localized
flooding the past two days. Otherwise, welcome showers and
thunderstorms are expected through sunset this evening, moving
toward southeast WY.

The upper-level ridge axis will slide eastward over western WY
on Friday, keeping relatively light winds over the area. A weak
shortwave trough is expected to move from the northern Great
Basin toward NW WY during the afternoon, bringing isolated
showers and thunderstorms to west-central WY, then into northern
WY during the evening hours. Locally moderate rain and gusty
winds up to 30 mph are possible from 4 to 8 PM Friday due to
possible thunderstorms. With the ridge axis moving into WY
Friday, temperatures are expected to climb about 7 to 10 degrees
Friday afternoon, ranging from the upper 80s to upper 90s. Even
warmer temperatures are expected on Saturday, with the
expectation that another shortwave trough will bring increasing
afternoon cloudiness and scattered showers and thunderstorms
late in the day.

&&

.DISCUSSION...
Issued at 247 AM MDT Thu Jul 23 2026

After a day of scattered to numerous showers and thunderstorms
yesterday, the overall threat for precipitation decreases some
for Thursday. The shortwave trough that swept across the state
yesterday is moving into eastern WY, taking most of the
thunderstorm activity with it. WV imagery shows the main
moisture pool shifting east with it, while a push of drier air
moves in from the west. The lack of midlevel energy and the
decrease in moisture will keep thunderstorm activity much more
isolated today, mainly along the higher elevations of the
Absarokas and Winds. With PW values holding near 1.00 late this
afternoon, will likely continue the Flash Flood Watch through
this evening, but only for those mountain ranges, after
yesterday`s saturating rainfall keeps some watershed prone for
more runoff.


The H5 ridge builds across the Rockies for the weekend, centered
still on the Four Corners region. Temperatures jump nearly 10
degrees from Thursday to Friday, with highs in the upper 80s to
the mid 90s. Saturday will see continued warming, with highs
from the mid 90s for western valleys and south WY, to upper 90s
and low 100s for northern and central WY. Monsoon moisture will
still be able to draw into the state, but will be decreased
enough to limit shower activity to higher elevations. The
flooding risk will these will also be much lower. This warmer
pattern with more isolated daytime showers on higher elevations
look to remain the trend well into the upcoming week.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 400 PM MDT Thu Jul 23 2026

VFR conditions prevail this afternoon and evening, with brief
MVFR conditions possible east of the Continental Divide due to
isolated thunderstorms. Abundant mid-level clouds continue,
with isolated thunderstorms through 24/0300Z, mainly east of
the Continental Divide affecting TAF sites such as COD, LND, and
CPR. It`s continues to look unlikely that that locations in the
middle of basins (such as WRL and RIW) receive any rain today,
but there is a small chance (around 10%). Unlike yesterday
(Wednesday) evening, any isolated storms should quickly end
around their more typical time this evening - shortly after
sunset. The air mass dries slightly on Friday, with notably
warmer temperatures but continued small chances (10 to 20%) for
isolated showers and thunderstorms.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 8 PM MDT this evening for WYZ002-003-005-007-
015.

&&

$$

UPDATE...McDonald/Wittmann
DISCUSSION...Straub
AVIATION...VandenBoogart