Clark, Colorado Weather Forecast Discussion

737
FXUS65 KGJT 091746
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
1146 AM MDT Tue Sep 9 2025
.KEY MESSAGES...
- Expect isolated to scattered afternoon showers and
  thunderstorms focused over the higher terrain through
  Wednesday with a small chance of storms lingering into the
  early morning hours.
- Thursday and Friday will see widespread showers and
  thunderstorms return with a better chance of wetting rains.
  Temperatures will cool to below normal levels.
&&
.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 346 AM MDT Tue Sep 9 2025
As the back edge of a shortwave continues to lift through
northeast Utah and northwest Colorado, showers and storms
continue to pop up as enough instability and lift remain. Once
again, thunderstorms developed across east-central Utah and
tracked into the Grand Valley of west-central Colorado during
the early morning hours. These storms have since weakened
considerably with some light rain and gusty winds but lightning
was fairly frequent with this convection earlier with some
pockets of heavy rain rates, although the storm motion was
fairly quick, so precipitation amounts were around 0.20 or less.
These showers will be more isolated through sunrise with accas
left in its wake, an indicator of instability. PWAT continues to
increase ever so slightly today with CAPE between 300 and 500
J/kg. There looks to be some CIN as well though so some areas
may continue to remain capped, so will likely need to overcome
this to realize stronger convection. Regardless, scattered
showers and thunderstorms are expected to develop over the high
terrain by afternoon with some storms spreading over the valleys
late in the day. Looks like similar coverage to yesterday with
gusty winds and frequent lightning the primary concerns with
pockets of wetting rain possible but less likely as low levels
remain dry. The HRRR is more aggressive with convection this
afternoon while the NAMNest is less so and keeps activity mainly
over the high terrain. Something to keep in mind. Conditions
look to dry out behind this wave tonight as southwest flow
increases ahead of a low pressure system that develops out west
over Northern California, pumping dry southwest flow into the
Desert Southwest and Great Basin. There is nothing definitive to
suggest that convection will continue overnight tonight like the
last couple nights but something to monitor.
On Wednesday, conditions start off dry with breezy southwest
winds across eastern Utah and western Colorado near the UT-CO
border ahead of this low. High pressure remains to our southeast
over eastern New Mexico, which does allow monsoonal moisture to
push across southwest Colorado up the central Divide late Wednesday
afternoon and evening. This will result in a bit better coverage
of storms late in the day on Wednesday. Increasing clouds and
moisture should put a damper on near critical fire weather
conditions which could be localized due to the gusty winds along
the UT-CO border. Chance of wetting rain increases for the San
Juans and central mountains by late Wednesday afternoon and
evening due to this increasing moisture but imagine gusty winds
will remain primary threat with storms until better moisture
arrives Thursday. Temperatures will remain warm and above normal
through Wednesday, before a cooldown arrives.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 248 PM MDT Mon Sep 8 2025
High pressure over the Great Plains will stall advancement of
the low out of the Great Basin on Thursday. The jet remains
overhead, so additional moisture filters in, creating more
widespread shower activity on Thursday. Temperatures will remain
warm, but also muted by cloud cover and showers. By early
Friday morning, the low ejects eastward putting the CWA under
jet exit region forcing and abundant moisture. This should bring
widespread showers and thunderstorms to most of the CWA
Thursday night and Friday. Cold air behind the front begins to
invade and afternoon highs Friday should feel rather fall-like,
especially with the damp conditions. Conditions in the wake of
the front turn more progressive Saturday, with zonal flow
producing additional precipitation chances on the terrain
Saturday. Temperatures remain mild through the weekend, before
warming some early next week. Transitory ridging will quiet
things down on Sunday, before another weak disturbance delivers
some additional shower activity Monday. While I`m sure warm
conditions return this fall, there certainly is a seasonal shift
arriving with this system.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1141 AM MDT Tue Sep 9 2025
Scattered afternoon thunderstorms are possible at most terminals
this afternoon but will favor the mountain terminals. Lightning,
gusty winds, and small hail are the main thunderstorm threats
today. Otherwise, scattered could cover with periodic wind
gusts up to 20 knots highlight this afternoon`s forecast.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...MDA
LONG TERM...LTB
AVIATION...TGJT

NWS GJT Office Area Forecast Discussion