673
FXUS65 KGJT 111113
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
513 AM MDT Mon Aug 11 2025

.KEY MESSAGES...

- Localized critical fire weather conditions will be possible
  over the Four Corners region of southwest Colorado today
  with a reprieve through the coming week.

- Near normal temperatures again today will return to well above
  normal by midweek.

- Mountain thunderstorms will be possible over the central and
  south on Tuesday with lightning and gusty winds the main
  threats.

- Warm conditions continue into much of the coming week with
  some hint of better moisture being drawn northward into the
  region mid to late week to promote an increased coverage of
  showers and thunderstorms.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 248 AM MDT Mon Aug 11 2025

Northerly flow is in place aloft in the wake of a passing trough
and amplified ridging along the Pacific Coast. Water vapor
imagery shows a weak wave dropping into our northwest CWA in
this flow but with very little moisture to work with attm it
should move through almost unnoticed. Satellite imagery shows
the Lee and Stoner fires still active into the early morning
hours. The smoke from these fires will be the biggest impact to
start the day. HRRR models the thicker concentrations moving
down the Colorado River Valley into the Grand Valley and at last
check outside it is verifying. The Cortez area is also seeing
some impacts to visibility and likely air quality. With
northerly general flow remaining in place the southern and
central valleys of western Colorado will once again be impacted
tonight. Temperatures begin a trend upward today with plenty of
sunshine and a dry airmass in place. Slightly above normal today
gains a few more degrees on Tuesday. Moisture transport on
theta surfaces near 315K show a southeast flow pulling post
frontal mositure from the lee side of the divide through
northern New Mexico up into southwest CO tonight. Models are
latching onto this moisture and producing convection over the
high central and southern mountains tomorrow afternoon. Gusty
outflow winds and new lightning starts will be more of a threat
than wetting rainfall.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 248 AM MDT Mon Aug 11 2025

High pressure will remain over Nevada at the start of the long term
period. Concurrently, a plume of deeper moisture will start
streaming up from the south but anticyclonic flow around the
high will keep this moisture over Arizona and New Mexico.
Midweek onwards, an upper level trough will start working on the
high, forcing it to move to the Four Corners region. Both the
GFS and EC ensembles are suggesting this movement will allow the
moisture to our south to finally reach our CWA. The NBM is
picking up on this moisture bringing 40% chances for some
isolated to scattered convection from the central mountains down
to the San Juans. Coverage increases Thursday as a weak
shortwave moves through the area and works on this increasing
moisture. Chances increase to 60% for the San Juans and 20 to
40% for the remaining higher terrain across the CWA. PWAT
anomalies also increase Thursday through Saturday. Some timing
differences can be found between the EC and GFS with the onset
of this increase but the general gist remains the same. By
Friday afternoon, anomalies will reach around 150% of normal
which, if true, will be welcome relief after our prolonged dry
spell. A second wave is progged to move through on Saturday and
should work on the moisture bringing another round of showers
and storms to the region. As far as high temps are concerned,
they`ll start increasing day by day maxing out on Thursday
before dropping some on Friday thanks to the increased cloud
cover precip.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 513 AM MDT Mon Aug 11 2025

VFR conditions are expected to prevail at most TAF sites over
the next 24 hours under mainly clear skies. The biggest
challenge will be where and how impactful wildfire smoke will be
across central and southwest portions of the CWA. The plumes
should take up a northeast trajectory according to smoke models
and will watch webcams and obs and amend as necessary...with
KGJT the most probable this morning.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...15
LONG TERM...TGR
AVIATION...TGJT