344
FXUS65 KGJT 181810
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1210 PM MDT Fri Sep 18 2026

.KEY MESSAGES...

- Scattered storms will develop this afternoon with stronger
  storms capable of producing strong outflow winds, small hail,
  and localized heavy rainfall.

- The threat for localized flash flooding will be heightened
  today due to saturated soils and the potential for additional
  heavy rainfall.

- After decreasing precipitation chances this weekend, another
  push of monsoonal moisture arrives by Tuesday.

&&

.DISCUSSION...
Issued at 1152 AM MDT Fri Sep 18 2026

ONE LAST RAINY DAY; DRYING OUT THIS WEEKEND:

A low pressure system will track across the Intermountain west
over the next 24 hours which will break us out of the ongoing
wet pattern. Until then, expect one last day of scattered to
widespread showers and storms. Northeast Utah and northwest
Colorado in particular could be the hot spot for stronger storms
with stronger wind shear and instability expected. Isolated
strong storms cannot be ruled out elsewhere. With stronger
daytime heating expected today, storms will be capable of
producing strong outflow winds, hail, and heavy rainfall. The
threat for localized flash flooding will be heightened due to
antecedent saturated soils and the potential for additional
heavy rainfall.

By Saturday, the passage of a cold front will help scour some
of the moisture from the region, but PWATs will remain around
150% percent of normal. This means that the storm coverage and
the threat for heavy rainfall will decrease, but enough moisture
remains in place to support isolated to scattered convection.
Sunday looks drier yet with PWATs 75-125% of normal. However, we
expect enough remnant moisture for isolated convection over the
higher terrain.

MORE MONSOON NEXT WEEK:

The relatively dry period won`t stick around for long as
moisture- rich southwesterly flow kicks back in Monday PM into
Tuesday. While the details could fluctuate between now and then
with variance amongst and within ensemble families, the general
thought is that wetter weather will return by Tuesday and could
remain in place throughout the week. Early guidance supports
wetter weather, especially south of I-70, but less widespread
than we`ve experienced this week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1209 PM MDT Fri Sep 18 2026

The scattered showers and storms are expected at all TAF sites
this afternoon, with more isolated coverage overnight. There is
a small probability of MVFR if the right storm with heavy
rainfall rates moves across an airfield. Also confidence is low
but will be watching for stratus and/or fog development again
overnight.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

DISCUSSION...KAA
AVIATION...TGJT