150
FXUS65 KGJT 190458
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1058 PM MDT Wed Jun 18 2025

.KEY MESSAGES...

- After a seasonable day today more hot, dry, and windy
  conditions return Thursday and persist into the weekend
  bringing widespread critical fire weather conditions.

- Triple digit highs will spread across a majority of the desert
  valleys Thursday into Friday.

- Southwest winds increase Friday and Saturday with potential
  for gusts to exceed 45 mph, in addition to the dry and hot
  conditions.

- Temperatures cool back down closer to normal Sunday into early
  next week.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 305 PM MDT Wed Jun 18 2025

With high pressure currently sitting over the region, winds have
been less windy than previous days with less heat as well. This
will all change quickly as we transition into Thursday and
Friday with the high pressure ridge shifting east and a low
pressure trough moving into the Pacific Northwest. This sets up
a strong southwest gradient overhead between both these systems.
Winds will pick up on Thursday afternoon with gusts in the 25 to
35 mph range with relative humidity in the single digits.
Decided to upgrade the Fire Weather Watch to a Red Flag Warning
where these conditions are met and fuels are critical. Excluded
the far eastern zones though as coverage does not appear
greater than 50 percent and conditions are more borderline.

Thursday also looks to be the hottest day of the week as well
as high temperatures rise 10 to 15 degrees above normal. High
temperatures will rise into the triple digits for west-central
Colorado and eastern Utah valleys. Current forecast has max
temperatures reaching 105 in east-central and southeast Utah
with potential for up to 108/109 in Mexican Hat. This brings
heat risk levels up to high but with temperatures this hot,
decided to issue a Heat Advisory for Thursday afternoon and
evening for the desert valleys of east-central and southeast
Utah as this is a highly recreated area as well.

By Friday, a strong jet streak parks itself over Utah,
increasing the southwest gradient winds even more. Potential
exists for winds to gust 40 to 50 mph with more widespread
critical fire weather conditions across the entire CWA. The Hot,
Dry and Windy Index indicates much of the area seeing a greater
than 90 percent chance of exceeding both the 75th and 90th
percentile. Therefore, issued a Fire Weather Watch for Friday
and Saturday, beginning at 9 am and continuing through midnight.
There may not be much in the way of relative humidity recovery
overnight but winds decrease enough to warrant ending each Fire
Weather Watch by midnight both days. With potential for winds
up to or exceeding 45 mph, wind advisories may be needed. Will
let later shifts re-evaluate this potential.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 305 PM MDT Wed Jun 18 2025

A slow-moving, high-amplitude trough begins to set up across
the Great Basin late on Friday. Moisture from this system will
stay confined mostly towards the center of the low across the
PacNW, whereas we will be trapped under anomalously dry
southwesterly flow. As the trough pushes further into the
Intermountain West, the pressure gradient overhead should
tighten, meaning we will experience a boost in our winds
(potentially exceeding Wind Advisory criteria) for our valleys.
Due to this setup, critical fire weather conditions remain
favorable throughout the weekend. GEFS members are in strong
agreement regarding region-wide Hot, Dry, and Windy Index values
exceeding the 75th percentile on Saturday. Additionally, lower
elevation locations such as the Grand Valley and the Uinta Basin
are likely (>90% chance) of exceeding the 90th percentile in
the Hot, Dry, and Windy Index. This is all to say that a Fire
Weather Watch has been issued for Saturday. Stay tuned for
further updates as we may need to consider fire weather
highlights for Sunday as well.

While the environment loses some potency in terms of its
support for critical fire weather beginning Monday, we may not
be completely out of the weeds just yet. Northeastern Utah and
northwestern Colorado are expected to remain hot and dry, but a
stream of moisture from the south may provide some relief to the
southern portions of our region. Ensembles have yet to pinpoint
the trajectory of this surging moisture, so it is difficult at
this moment to determine how this will impact our CWA, but we
will continue to monitor this feature over future model runs.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 1057 PM MDT Wed Jun 18 2025

Winds will remain light and terrain driven through 12z, then
will start to increase through the morning. Southwesterly winds
gusting 20-25 knots are expected during the afternoon. Clear
skies and VFR conditions will prevail for the next 24 hours.

&&

.FIRE WEATHER...
Issued at 305 PM MDT Wed Jun 18 2025

A prolonged period of critical fire weather conditions are
becoming more likely late this week and into the weekend. High
pressure over the southeast CONUS and a strong upstream low
pressure system stalling over the West will allow a strong
southwest pressure gradient to linger over the Intermountain
West. Windy conditions will combine with low humidity until
this upstream system moves through...which may not occur until
well into next week. Higher confidence exists in this potential,
especially for Friday and Saturday as the Hot, Dry and Windy
Index has a 90 percent or greater chance to exceed the 75th and
90th percentiles for much of the region. Therefore, upgraded the
Fire Weather Watch to a Red Flag Warning for Thursday
afternoon/evening and issued a Fire Weather Watch for both
Friday and Saturday, beginning 9 am until midnight both days.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Red Flag Warning from noon to 8 PM MDT Thursday for COZ200-202-
     203-207-290-292-294.
     Fire Weather Watch from Friday morning through Friday evening
     for COZ200-202-203-205-207-290>295.
     Fire Weather Watch from Saturday morning through Saturday
     evening for COZ200-202-203-205-207-290>295.
UT...Red Flag Warning from noon to 8 PM MDT Thursday for UTZ486-487-
     490-491.
     Fire Weather Watch from Friday morning through Friday evening
     for UTZ486-487-490-491.
     Fire Weather Watch from Saturday morning through Saturday
     evening for UTZ486-487-490-491.
     Heat Advisory from noon Thursday to midnight MDT Thursday
     night for UTZ022-027-029.

&&

$$

SHORT TERM...MDA
LONG TERM...BW
AVIATION...TGJT
FIRE WEATHER...TGJT