599
FXUS65 KGJT 232333
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
533 PM MDT Sun Aug 23 2026

.KEY MESSAGES...

- Monsoonal moisture in place will keep scattered shower and
  thunderstorm chances in the forecast today.

- Heavier rainfall could lead to localized flash flooding over
  burn scars and susceptible terrain.

- Temperatures near to around 5 degrees above normal are
  expected through early next week, followed by a gradual warmup
  to close to 10 degrees above normal.

&&

.DISCUSSION...
Issued at 1232 PM MDT Sun Aug 23 2026

Shortwave troughing working across the northern Rockies this
afternoon is providing some lift to the monsoonal moisture in
place across the region. Convection thus far, has been richest
across the San Juans where a concentration of showers and
thunderstorms have developed this morning. This activity is
expected to continue through the afternoon. Some rain is making
its way to the surface, but rainfall remains sporadic. Some
heavier showers could pose flash flooding issues this afternoon,
as afternoon heating amplifies storms. Shortwave energy will
continue to drag across the region into the evening hours,
likely keeping a few isolated showers going into the overnight.
Showers will lose much of their stamina after sunset, so
expecting for more stratiform shower activity during the late
evening to overnight hours, winding down before daybreak. While
moisture takes a slight downturn on Monday, there will still be
ample fuel for another afternoon of mountain showers and
thunderstorms. Once again, some showers could pose a threat for
flash flooding near burn scars and sensitive slot canyons,
arroyos, etc.

Above normal moisture sticks around Wednesday and beyond, as
the high gradually shifts back into the Desert Southwest.
Forcing will be somewhat lacking, with only the occasional
shortwave rotating around the periphery of the high. This means
that most afternoons will see isolated to scattered showers and
thunderstorms develop over the higher terrain, with occasional
periods of focused convection coinciding with a passing wave.
So long as surface levels remain saturated, heavy rain and flash
flooding will remain concerns, particularly for burn scars, slot
canyons, and flashy creeks/dry washes. Additionally, gusty
outflow winds and lightning will be daily threats. Temperatures
will start around 5 degrees above normal, but will gradually
warm through the week under the influence of the high. By the
end of the coming workweek, look for highs to be 5-10 degrees
above normal.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 529 PM MDT Sun Aug 23 2026

Scattered showers and thunderstorms continue to be around for
some terminals, but storm activity will gradually diminish after
sunset. Winds around storms could get gusty as well as the
additional wind threat from nearby outflows. Winds will resume
terrain driven patterns overnight. Cloud cover will likely
linger into the morning hours as we have been seeing the past
few days. Shower and storm chances return Monday afternoon,
particularly for the high terrain terminals. All that being
said, VFR conditions will prevail.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

DISCUSSION...TGJT
AVIATION...TGJT