485
FXUS65 KGJT 171121
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
521 AM MDT Tue Jun 17 2025

.KEY MESSAGES...

- Red Flag Warnings remain in effect for southwest Colorado this
  afternoon and evening.

- Temperatures moderate slightly today with isolated showers
  and storms possible over the high terrain along and north of
  I-70.

- After a brief cool mid-week cooldown...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.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 309 AM MDT Tue Jun 17 2025

Water vapor this morning shows an open trough moving through
Utah with ascent ahead of it popping off showers well above the
elevated mixed layer...meaning accas or virga at best under the
radar returns. Satellite imagery also suggests the mid level
front slowly dropping past I-70 also aiding isentropic upglide
to the North. This front will lose it`s southward momentum this
morning and stall over the southern CWA but with little
consequence. Cooler temperatures will move in behind this front
and the trough in general but only drop back toward
climatological normal for mid June. Deep mixing and persistent
dry air will keep a threat of Red Flag conditions in place over
portions of southwest Colorado with localized conditions
elsewhere. These conditions will temporarily ease on Wednesday
in the wake of this trough...unfortunately only to return with a
vengeance later in the week. Not much if any precipitation can
be expected during this time. A few isolated showers/storms
could pop with and just behind the trough passage today but the
main concern will be lightning and new fire starts that may
occur.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 309 AM MDT Tue Jun 17 2025

After a brief midweek cooldown high pressure builds back in
rather quickly across the Southwest. This all changes on
Thursday, as hot, dry, windy conditions return to the CWA. A
digging trough in the West and stubborn ridging over the eastern
U.S. will keep us locked into a persistent fire weather pattern
into next weekend. Strong southwesterly winds will impact the
CWA through next weekend. Some of the strongest winds are
expected Saturday under a potent jet max working from SOCAL
across the Four Corners. Multi-member ensemble guidance is
suggesting winds gusting 35 to 40 mph across the Uinta Basin and
northwest Colorado Saturday. Single digit relative humidities
will almost guarantee significant fire weather conditions
developing under this regime. Deterministic models are hesitant
to eject this trough out of the Great Basin, thanks to the
downstream blocking pattern. Some guidance is hinting at the
West Coast trough digging deep enough to send some Pacific
moisture into the southern counties of the CWA Sunday and
Monday. This doesn`t look like enough for precipitation, but
could raise relative humidities and lower temperatures enough to
make a difference for critical fire weather conditions.
Meanwhile, the jet working through the base of the trough across
the Four Corners is a high uncertainty feature that could have
continued impacts on surface winds at the end of this extended
period. For now, it`s best to count on hot, dry, and windy
conditions continuing under this pattern.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 519 AM MDT Tue Jun 17 2025

Mid to high level clouds will be drifting through with a weak
system today. No impacts to flight criteria is expected with VFR
prevailing. The main concern will be gusty winds developing
through the late morning hours with many TAF sites seeing gusts
at or above 25 mph through sunset.

&&

.FIRE WEATHER...
Issued at 309 AM MDT Tue Jun 17 2025

A system passing through today will push back the heat a bit
but low afternoon humidity and gusty winds remain in place.
Localized critical fire weather conditions up North will be more
widespread across the central and southern Colorado fire zones
where Red Flag Warnings are again in effect. After a brief lull
in critical fire weather conditions on Wednesday hotter and
windier conditions return to end out the week. Several days of
critical fire weather is expected which is likely to stress
fuels across the area. The hot dry and windy index is forecast
to exceed the 90th percentile in many areas during this time.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Red Flag Warning from noon today to 8 PM MDT this evening for
     COZ290>295.
UT...None.

&&

$$

SHORT TERM...15
LONG TERM...LTB
AVIATION...TGJT
FIRE WEATHER...15