206
FXUS65 KGJT 251138
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
538 AM MDT Fri Jul 25 2025

.KEY MESSAGES...

- Terrain based thunderstorms and showers decrease in coverage
  west of the Divide today with gusty winds the primary concern.

- Smoke from wildfires in northern Arizona will keep skies hazy
  to smokey across portions of eastern Utah and western Colorado
  today through at least Saturday, resulting in reduced
  visibility and poor air quality.

- Hot, dry, and windy conditions develop by this weekend,
  creating widespread critical fire weather conditions.

- Moisture potentially returns early next week, eroding critical
  fire weather conditions.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 349 AM MDT Fri Jul 25 2025

Skies are quickly clearing as a much drier air mass pushes
eastward due to a low pressure trough moving inland over central
California. This is allowing much drier air to advect across the
western slope from the Desert Southwest as an 80 kt jet streak
and robust shortwave rounds the base of this trough. This jet
streak and shortwave will become more of a player in our weather
on Saturday as southwest winds increase across the region
leading to more widespread critical fire weather conditions.
However, for today, drier air and clearing skies will lead to
less convective showers as most hi-res CAMs are limiting
convection to the San Juans and areas along the spine of the
Divide as much of this moisture is now east of the Divide.
Coverage will be isolated at best, with gusty outflow winds more
likely than wetting rain as chances of measurable precipitation
are very low. With dry conditions and some occasional breezes in
the afternoon, critical fire weather conditions today will be
more localized. However, with the increasing southwest flow, the
HRRR smoke model is predicting more smoke from the Dragon Bravo
Fire on the north rim of the Grand Canyon in northern Arizona to
travel up the Escalante Canyon through much of southeast Utah
and settle into the lower valleys of west-central Colorado,
particularly the Grand Valley resulting in reduced visibility
under hazy and smokey skies and poor air quality.

On Saturday, deeper mixing is expected as this 75 kt jet streak
moves overhead and the robust shortwave allows the low to open
up and track through the Great Basin. The Hot, Dry and Windy
Index has a high probability of exceeding the 90th percentile
across all of eastern Utah and much of western Colorado, with
some areas exceeding even the 95th percentile. Confidence is
increasing that we will see widespread critical fire weather
conditions so decided to issue a Fire Weather Watch for all of
eastern Utah and most lower elevation zones of western Colorado
where the combination of low relative humidity, gusty winds and
dry fuels exceed critical fire weather thresholds. Temperatures
remain near normal for today through the weekend, maybe slightly
above normal where deeper mixing occurs.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 349 AM MDT Fri Jul 25 2025

High pressure situated well to the east and a weak upper level
low over California will keep southwesterly flow over eastern
Utah and the Western Slope. Upper level support for the low will
remain over the area this weekend, shifting a bit to the west
over Utah by Sunday. With a 65kt jet streak to our west, deeper
mixing is expected with some stronger winds mixing to the
surface. Dry conditions will remain in place and with critical
fuels still in place, critical fire weather conditions are
possible through Sunday. Winds look to be a bit less on Sunday
than what is expected for Saturday, but this will be something
to monitor in case Fire Weather highlights are needed for Sunday
as well.

For next week, the high pressure out east starts to retrograde
as an upper level trough approaches from the west. Flow around
these features will tap into some monsoonal moisture and bring
increased chances for more widespread showers and thunderstorms.
Both the EC and GFS are picking up on this possibility with
afternoon and evening convection Tuesday onwards. As always,
this far out some changes with the forecast are expected. High
temperatures will run above normal through Tuesday and will then
drop to normal, or just below, Wednesday onwards.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 538 AM MDT Fri Jul 25 2025

A few high clouds are moving in from the southwest in addition
to smoke from the Dragon Bravo Fire over northern Arizona. Smoke
could potentially result in reduced visibilities through much of
the morning across KCNY, KGJT and KRIL with MVFR conditions at
times. Otherwise, VFR will prevail with mostly clear skies for
much of the area. Breezy conditions arrive this afternoon at
times but gusts should stay below 25 kts for the most part. Some
isolated storms are possible over the San Juans and along the
divide but impacts to TAF sites remain a low probability of
occurrence, so did not mention in the TAF. Light, terrain driven
winds return overnight.

&&

.FIRE WEATHER...
Issued at 349 AM MDT Fri Jul 25 2025

As drier air continues to move in from the west, a downturn in
convection is expected with isolated storms limited to the San
Juans and central Divide. The chance of wetting rain is low with
gusty outflow winds possible. Localized critical fire weather
conditions will occur today with these conditions becoming more
widespread by Saturday. A Fire Weather Watch has been issued
for all of eastern Utah and most lower elevations of western
Colorado as a result, where the combination of gusty winds, low
relative humidity and dry fuels will lead to critical fire
weather conditions. Dry conditions continue Sunday but at this
time, critical fire weather conditions appear more marginal as
wind gusts decrease compared to Saturday. Therefore, did not
include Sunday in the Fire Weather Watch at this time. Moisture
looks to return to the area early to mid next week, which should
lessen fire weather concerns.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Fire Weather Watch from Saturday afternoon through Saturday
     evening for COZ200-202-203-205-207-290-292-294.
UT...Fire Weather Watch from Saturday afternoon through Saturday
     evening for UTZ485>487-490-491.

&&

$$

SHORT TERM...MDA
LONG TERM...TGR/MDA
AVIATION...TGJT
FIRE WEATHER...MDA