Maher, Colorado Weather Forecast Discussion

469
FXUS65 KGJT 082049
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
249 PM MDT Mon Sep 8 2025
.KEY MESSAGES...
- Expect isolated to scattered afternoon showers and
  thunderstorms focused over the higher terrain the next few
  afternoons with a small chance of storms lingering into the
  early morning hours.
- Thursday and Friday will see widespread showers and
  thunderstorms return with a passing system with temperatures
  cooling below normal.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 248 PM MDT Mon Sep 8 2025
The H500 08/12Z upper air analysis is showing general ridging
over the western NOAM transitioning to a trough over the East.
There is a cyclone that has snuck under the northern extent of
the ridge which is hanging just off the CA/OR coast this
afternoon. This parent low will only progress into NorCal over
the next 48 hours though the trough will carve southward toward
the Baja. This creates an  set up for pulling moisture
northward into the Rockies through the week with a tight
gradient setting up near the CO/UT border...wetter to the East
and drier to the West. The ALPW does show some moisture
advecting northward into the SW Utah as height falls to the West
induce the moist conveyor belt out of the monsoon region.
Convection so far this afternoon is going about as planned
firing mainly on the higher terrain up North and the divide
mountains of the central and south. Some fairly decent shear and
instability are in place but the 18Z RAOB suggest some capping
to overcome. If it does northeast Utah into NW Colorado could
again see some organized storms this evening. The Grand Valley
was awoken overnight by a rogue nocturnal storm and this could
happen again tonight as the back of wave lifts through and an
upper jet begins to nose across eastern Utah. Confidence is not
overly high so PoPs remain low but expect a least a decent ACCAS
field with virga/light showers moving through our CWA during
the morning hours which will blossom into more showers and
storms tomorrow afternoon. PWAT shows a slight increase
tomorrow...though nothing off the charts so coverage should be
similar to today. Drier air filters in behind this overnight and
will have to see if there are any waves or support to keep
nocturnal activity going. Right now it looks dry. Temperatures
stay near to slight above normal the next few days before they
cool down as a wetter forecast arrives.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 248 PM MDT Mon Sep 8 2025
Low pressure digging down the West Coast will bring us one more day
of summer-like conditions Wednesday. The jet streak rounding the
southeast quadrant of the low will send abundant warm air and some
gusty winds across the region. Relative humidities look to stay
above critical fire weather thresholds, but some localized fire
weather could materialize in our desert valleys along the state
line. Pre-frontal showers and thunderstorms are expected too, so
this will likely make fire weather a moot point. 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 TUESDAY/...
Issued at 1133 AM MDT Mon Sep 8 2025
A thin layer of high level smoke is drifting through from
upstream wildfires but this is not impacting surface visibility.
Enough moisture remains in place that afternoon heating will
spark more isolated to scattered showers and storms this
afternoon and early evening. Confidence is not as overly high
but did place PROB30 in the mountain and GUC sites where clouds
are showing some vertical growth. There is also an outside
chance of nocturnal storms forming over the western CWA after
midnight and moving eastward through sunrise.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...15
LONG TERM...LTB
AVIATION...TGJT

NWS GJT Office Area Forecast Discussion