998
FXUS65 KGJT 061719
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1119 AM MDT Mon Oct 6 2025

.KEY MESSAGES...

- High temperatures remain below normal north of I-70 today, and
  will be near-normal elsewhere. A gradual warming trend kicks
  in tomorrow.

- Areas of northwest Colorado will see sub-freezing temperatures
  tonight into tomorrow morning, and a Freeze Watch is in
  effect.

- Drier conditions are expected for much of the week. However, moisture
  returns late this week into the coming weekend, bringing the
  potential for widespread precipitation.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 309 AM MDT Mon Oct 6 2025

Some clouds and a few light showers are lingering along the northern
Divide this early morning, but the remainder of eastern Utah and
western Colorado are under clear skies. With light winds and already
clear skies, temperatures are expected to bottom out near to a few
degrees below normal around daybreak. For the high elevation valleys
of northwest Colorado, particularly along the Yampa River basin,
temperatures are expected to drop near to a few degrees below
freezing. Coverage and duration was not long enough to warrant a
freeze warning tonight.

We remain under broad, weak troughing today, with westerly to
southwesterly flow in control aloft. This will allow for a few
isolated orographic showers over the northern Divide, where just
enough moisture hangs around this afternoon. For the rest of the
region, dry air in place will keep skies mostly sunny and promote
deep mixing. With a 60-70 knot upper level jet still in place, this
mixing could bring down some breezier afternoon wind gusts, on the
order of 20-30 mph. Temperatures will warm a few degrees today
compared to yesterday, mainly for areas along and south of I-70. For
areas north of I-70, today will actually run a few degrees cooler.
The cold front associated with yesterday`s wave has gotten hung up
across the Roan and Tavaput Plateaus, and that`s allowing cooler air
to sneak in across northwest Colorado and northeast Utah. So while
the sunshine will still be abundant, these areas will be in for more
of a brisk fall day compared to areas further south. Tonight, the
longwave trough axis finally tracks east, and we find ourselves in a
col region between this trough and the developing closed low off the
California coast. This will keep weather benign into Tuesday, with
continued clear skies and light winds. Radiational cooling is
expected to be efficient tonight into tomorrow morning, with areas
across northwest Colorado again see temperatures dip below freezing.
These temperatures are expected to be longer in duration and more
expansive in coverage, so a Freeze Watch has been issued.
Temperatures rebound tomorrow, climbing a few degrees above normal
for areas along and south of I-70, and to near-normal north of I-70,
as high pressure begins to take control.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 309 AM MDT Mon Oct 6 2025

Dry southwest flow will continue to advect warmer air across the
western slope as high pressure remains to the southeast across Texas,
building a ridge across the central CONUS. We will see temperatures
return to above normal levels Wednesday and Thursday, on the order
of 5 to 10 degrees. A little bit of moisture will start to work in
under the high, resulting in some isolated storms possible over the
San Juan Mountains. The models are picking up on the development of
what is now Hurricane Priscilla just off the southern tip of the
Baja Peninsula in the eastern Pacific, off the west Mexico coast.
Moisture from this tropical system looks to become entrained in the
southerly flow around the high to our southeast as a deeper trough
moves into the Pacific Northwest, which ejects a shortwave ahead of
it Thursday night into Friday, helping pull remnants of this
tropical moisture northward. PWAT anomalies increase substantially
Thursday to around 200 percent of normal, which may be in the form
of mid and high cloud cover before the lower atmosphere saturates.
Shortwave forcing helps bring this moisture to the surface in the
form of scattered showers and storms Thursday evening into Friday.
Showers become more widespread over the weekend, especially
Saturday, as the PacNW low opens up into a robust trough and tracks
inland across the Great Basin. This trough reaches western Colorado
by Sunday as the remnants of Priscilla become entrained into the
southwest flow. PWAT anomalies increase to over 300 percent of
normal as a result, with more widespread showers expected. This
could be a more stratiform rain event, as instability is limited at
this time, but wouldn`t rule out some embedded thunderstorms.
Precipitation looks to remain rain through Saturday as H7
temperatures remain warm with values in the 6C to 8C range. However,
a cold front associated with the trough passage Saturday night into
Sunday could drive snow levels down to 9500 to 10kft where some snow
could mix in with rain, with all snow at the highest peaks, although
accumulations appear minimal. Much of the area could see some
beneficial rainfall Friday through the weekend with this system.
Temperatures look to cool back to near to slightly below normal by
this weekend given the abundant clouds and moisture.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1118 AM MDT Mon Oct 6 2025

Skies should be mostly clear again today with VFR conditions
expected region-wide. Winds will be mostly calm with some
occasional gusts around 20 kts possible this afternoon at KEGE,
KRIL, and KTEX.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Freeze Watch from late tonight through Tuesday morning for
     COZ002.
UT...None.

&&

$$

SHORT TERM...BGB
LONG TERM...MDA
AVIATION...TGJT