059
FXUS65 KRIW 101108
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
508 AM MDT Thu Jul 10 2025

.KEY MESSAGES...

- Widely scattered rain showers will continue over the southern
  half of the forecast area this morning. Isolated showers will
  be possible across areas east of the Divide this afternoon.

- A cold front will move over areas east of the Divide early
  Friday morning, becoming stationary along the Divide. Highs in
  the 70s will be widespread in these areas as a result.

- Dry conditions and a warming trend over the weekend with
  elevated fire weather conditions returning by Sunday.

&&

.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 /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 449 AM MDT Thu Jul 10 2025

VFR conditions expected throughout the period at all TAF sites.
Some ongoing rain showers/ thunderstorms continue west of the
Divide to include KRKS through the morning at 13Z . Increasing
winds up to 18kts at most locations, highest at KPNA up to 22
knots after 16Z-18Z through peak heating until sunset after
01Z-02Z with radiational cooling. The chance of thunderstorms
(around a 1 in 5 up to a 1 in 4 chance) will be found in and
near most mountain ranges, especially East of the Divide. We
have added PROB30 groups for KRIW, KCPR, KLND and KCOD for this
afternoon and early this evening as a result. Any shower or
thunderstorm could bring brief MVFR conditions, but enough
confidence to include in the TAFs at this time. Additional
showers may approach the northern Wyoming sites late Thursday
night but most should hold off until after 12Z Friday.


Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on smoke, icing, and turbulence

&&

.FIRE WEATHER...
Issued at 120 AM MDT Thu Jul 10 2025

Elevated fire weather conditions will return for one more day
today, with critical RH values occurring along eastern portions
of the Bighorn Basin, the Wind River Basin and Sweetwater
County. Winds will not be a contributing factor, however gusty
outflows could occur (20% chance) from showers over the
Absaroka, Bighorn and Wind River Mountains this afternoon.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...LaVoie
AVIATION...Hattings
FIRE WEATHER...Dziewaltowski