150
FXUS65 KGJT 030519
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1119 PM MDT Sat Aug 2 2025

.KEY MESSAGES...

- Showers and thunderstorms will continue across the northern
  and central Divide mountains through this evening, bringing
  frequent lightning, brief heavy rain, winds gusting 40-50 mph,
  and small hail.

- Warm and dry conditions persist into next week. A brief period
  of weaker winds tomorrow will give way to stronger winds and
  a return of widespread critical fire weather conditions Monday
  onward. A Fire Weather Watch is in effect for Monday.

&&

.UPDATE...
Issued at 715 PM MDT Sat Aug 2 2025

Updated to let the Red Flag Warning in effect today expire at 7
pm. Even though relative humidities remain low in some areas,
wind gusts have decreased below critical fire weather
thresholds. Localized critical fire weather conditions will
still continue for another hour before ceasing, with widespread
critical fire weather conditions no longer occurring.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 233 PM MDT Sat Aug 2 2025

The overnight convection that brought thunder to the Grand Valley
early this morning has kept itself together, following a little
upper level wave, as it tracked northeast through the area. The main
convection is focused across the northern and central Divide
mountains, although it extends west along the Roan and Tavaput
ridgelines. These storms have been prolific producers of lightning,
as well gusts 40-50 mph, brief heavy rain, and small hail. This
activity will continue to track northeast, favoring the higher
terrain, through the afternoon and evening. Skies remain mostly
clear across the southern half of the area as drier air surges in
from the west and southwest around the high, now centered over
Southern Arizona. The clear skies are promoting deep mixing, while
is helping to drop relative humidity values below 15 percent across
eastern Utah and portions of far western Colorado. Additionally, the
deep mixing is tapping into stronger winds aloft, courtesy of an 80-
90 knot upper level jet, and bringing them down to the surface.
Gusts across the region this afternoon, outside of those produced by
thunderstorms, will run in the 25-35 knot range. Where combined with
the low relative humidity, and where fuels are critical, this will
result in widespread Critical Fire Weather Conditions. Red Flag
Warnings remain in effect through 7 PM MDT this evening for fire
weather zones along the Utah/Colorado border. In addition to being
dry and windy, highs this afternoon will be near to around 5 degrees
above normal for early August.

Winds will die down this evening, and convection will taper off with
loss of daytime heating. Skies will clear out, and overnight lows
will run near normal for the time of year. A ridge of high pressure
builds in overhead tomorrow, bringing warmer temperatures, drier
air, and weaker winds. Highs will run 3-6 degrees above normal,
while minimum humidities will drop in to the low teens and single
digits for the vast majority of eastern Utah and western Colorado.
The light winds are the one saving grace, keeping critical fire
weather conditions localized. However, it does also set the stage
for another widespread round of critical fire weather conditions on
Monday afternoon, as discussed below in the Long Term section. Model
guidance has next to no chance for precipitation tomorrow, although
an isolated shower or two along the northern Divide is possible
where some deeper surface moisture stays trapped. Sunday night will
run calm, clear, and seasonal.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 233 PM MDT Sat Aug 2 2025

Monday and Tuesday are shaping up to be the most prolific fire
weather days throughout the long-term period with most of the region
reaching single digit relative humidities and 25+ mph gusts in the
afternoon. The GEFS is pinging nearly the entirety of the CWA as
exceeding the 75th percentile in HDWI on Monday and Tuesday.
Portions of the Uinta Basin and the Grand Valley are forecasted over
the 95th percentile of HDWI as well. Should there be one factor
which could inhibit the fire threat, it`s cloud cover. Mild mid-
level moisture may still reside over western Colorado early in the
week, and as of now, this is placing scattered cloud cover over the
majority of the CWA. This could inhibit the afternoon warm-up to a
degree. However, with the potent concoction of summer heat,
extremely dry surface conditions, and increasing gusts, it`s
unlikely that we will avoid hitting widespread fire weather
criteria. As a result, a Fire Weather Watch has been issued for most
zones along and north of US-50 on Monday. Over the next couple days,
keep an eye out for updates as well as potential fire weather
highlights on Tuesday.

Notable fire weather conditions are anticipated to continue
Wednesday through Friday as well, though the potency of these
conditions appears to decrease marginally. This may lead to more
scattered areas of critical fire weather through the week.
Regardless, it`s looking like we are in store for a long stretch of
hot, dry, and windy weather. Stay weather aware and keep up-to-date
with the latest forecasts as this pattern progresses.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1116 PM MDT Sat Aug 2 2025

A few clouds linger across the area this morning but all
convection has died down. VFR conditions will continue for the
next 24 hours under mostly clear skies. Winds will be generally light
through period though afternoon gusts of 20 to 25 kts can`t be
ruled out.

&&

.FIRE WEATHER...
Issued at 233 PM MDT Sat Aug 2 2025

Thunderstorms continue through this evening north of I-70. These
storms have produced significant lightning, brief heavy rain, winds
gusting 40-50 mph, and small hail. South of I-70, drier air is
building in, with winds gusting 25-35 mph. Sunday will see
weaker winds, leading to only localized critical fire weather
conditions. However, strong winds build back for the first half
of next week. A Fire Weather Watch has been issued from 11 AM
MDT to 9 PM MDT Monday.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Fire Weather Watch from Monday morning through Monday evening
     for COZ200>203-290-292.
UT...Fire Weather Watch from Monday morning through Monday evening
     for UTZ485>487-490.

&&

$$

UPDATE...MDA
SHORT TERM...BGB
LONG TERM...BW
AVIATION...TGJT
FIRE WEATHER...TGJT