426
FXUS65 KGJT 072136
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
336 PM MDT Tue Oct 7 2025

.KEY MESSAGES...

- Temperatures trend 5-10 degrees above average Wednesday and
  Thursday.

- Isolated showers and thunderstorms possible over the San Juans
  Wednesday afternoon.

- Models continue to advertise well above average precipitable
  water for the region Thursday and beyond, leading to
  widespread rainfall.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 331 PM MDT Tue Oct 7 2025

High pressure remains in control across the West. Skies remain clear
too, with a few sprigs of cumulus on the terrain to the west of the
Divide. The return moisture on the west side of the high that models
promised yesterday has yet to materialize today. Hurricane
Priscilla`s trajectory northward will potentially send some more
moisture into the region on Wednesday. However, it appears to only
skim our southern counties on the Colorado side. Subsidence will
continue to keep things quiet on the West Slope with temperatures
trending 5-10 degrees above climatology beneath the southwesterly
flow pumping in ahead of a PACNW low dropping into the West. The
southwesterly jet max working across the Great Basin Wednesday
afternoon will stir up surface winds. Breezy afternoon conditions
can be expected. Some isolated convection on the San Juans is
possible, but most of the region remains dry.

Wednesday night, cloud cover will continue to invade the Four
Corners thanks to extra-tropical moisture from Priscilla. A few
showers will likely develop over southwest Colorado  and southeast
Utah by daybreak Thursday. Dewpoints start to respond to the inbound
moisture too. Overnight lows will remain above normal thanks to the
warmer and wetter airmass Thursday morning.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 331 PM MDT Tue Oct 7 2025

A rainfall event is expect to occur during much of the long term
forecast period as a surge of moisture associated with Hurricane
Priscilla becomes embedded in southwesterly flow around a trough
along the Pacific coast, and advects into our region. Elevated
moisture begins moving into the southern half of our CWA Wednesday
night, but on Thursday this moisture spreads across the region from
south to north. By Thursday evening PWAT anomalies of 200% of normal
or greater are expected across the CWA. Anomalies may even peak at
around 300% of normal Friday into Saturday. Moisture decreases
significantly on Sunday, but may linger into next week as well.
Friday and Saturday will be the biggest days in terms of
precipitation, with widespread rain expected through both days,
including during overnight hours.

Although it seems stratiform precipitation is the general forecast
with this event, the development of thunderstorms is not out of the
question. Despite the abundance of atmospheric moisture, synoptic
forcing does not seem incredibly significant. Much of the PVA from
the trough stays to our north, and it is unclear if the positioning
of any jet streaks will be favorable for increased support. However,
if upper level support does increase, the chance of thunderstorms
and flash flooding would increase too. Daytime heating should be
limited by increased cloud cover, but any breaks in cloud cover
could also lead to an increased potential for thunderstorms. On
Friday high temperatures look to drop by 5 to 10 degrees with the
increased cloud coverage, leading to just below normal highs through
the long term period.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1128 AM MDT Tue Oct 7 2025

Other than some stronger afternoon wind gusts over the higher
terrain, winds will be light. Generally clear skies are expected
through the afternoon, but cloud cover may increase over the
southern Colorado mountains tonight. VFR conditions are expected
to prevail.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...None.
UT...None.

&&

$$

SHORT TERM...LTB
LONG TERM...GF
AVIATION...TGJT