390
FXUS65 KGJT 190524
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1124 PM MDT Mon Aug 18 2025

.KEY MESSAGES...

- Hot and dry conditions remain in place under high pressure. A
  few very isolated storms are possible over the San Juans.

- Models continue to highlight moisture increasing towards the
  end of the week, increasing chances for precip.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 246 PM MDT Mon Aug 18 2025

High pressure is building in but just enough moisture and
instability remains in the atmosphere to allow some convection
to fire. Models continue to indicate the San Juans being the
best the area for this convection and a few storms have formed
down there this afternoon. Might see a few more storms fire in
that general area but this convection will remain very isolated
in nature. Elsewhere, hot and dry conditions are the rule.
Tomorrow, the San Juans have a 20% chance to see some isolated
convection with just some Cu buildup expected for the higher
terrain. Warm air will continue advecting into the CWA causing
high temps to jump another 5 to maybe 10 degrees above normal.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 246 PM MDT Mon Aug 18 2025

By Wednesday high pressure will be well established over the region
therefore temperatures will be near record values. This means desert
valleys getting into the 100s and mountain towns in the 80s. Like
previous days the San Juans may have enough moisture for afternoon
showers and a few storms. Elsewhere conditions appear to remain dry.
Counter clockwise flow around the high will advect moisture into the
area on Thursday and Friday. This should contribute to more showers
and storms especially over the high terrain. Confidence is low on
the coverage and rainfall amounts. It is common for the moisture to
take a few days to reach down to the surface. Warm temperatures may
also inhibit precipitation from reaching the ground. This weekend the
high pressure sinks to the south, which allows the moisture
advection to continue. The PWAT values show that the peak moisture
will be on Saturday, so expect more widespread showers. As with most
moisture surges the morning cloud cover will dictate how much
instability can be reached by the afternoon. This in turn is the
difference between light showers and strong storms with heavy
downpours.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1122 PM MDT Mon Aug 18 2025

Aside from some lingering mid-level clouds along the Divide,
skies are clear across the region. Winds will remain light and
follow typical terrain driven patterns over the next 24 hours,
with VFR conditions prevailing. Low to mid level clouds and a
stray shower or two will be possible over the southern and
central mountains tomorrow afternoon, but are not expected to
impact terminal operations.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...TGR
LONG TERM...KJS
AVIATION...TGJT