Grand Junction, Colorado 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

217
FXUS65 KGJT 200617
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1217 AM MDT Thu Aug 20 2026

.KEY MESSAGES...

- Isolated showers and thunderstorms expected over the high
  terrain Thursday. Main concerns will be gusty outflow winds
  and lightning.

- Triple-digit temperatures on Thursday and Friday in valleys.

- Precipitation potential increases Friday and into the weekend.
  Flash flooding will be possible, especially Saturday.

&&

.DISCUSSION...
Issued at 931 PM MDT Wed Aug 19 2026

A slight lull in the active pattern is expected Thursday as the
southwestern CONUS high drifts northwards and settles near the
Four Corners. Enough moisture remains trapped underneath this
high to keep daily showers along the terrain, but hydrologic
concerns will be on the minimal side. Regardless, anybody near
areas vulnerable to flash flooding should still remain weather-
aware over the next two days should a stray stronger storm
develop. Otherwise, the main point of interest as we close out
the work week will be the abnormally warm temperatures
underneath this high pressure. We hit triple digits in many
valley locations Wednesday, and as it stands now, this should
again be the case Thursday and Friday. Because of the lingering
moisture in the Intermountain West, cloud cover will play a role
in just how hot these temperatures will be allowed to get, but
regardless, look for highs to remain about 10 degrees above
normal until we hit the weekend.

Speaking of the weekend, Saturday marks another ramp-up in wet
weather. This comes as the ridge overhead builds, pushing flow
south- southwesterly and advecting another shot of potent
moisture into the Great Basin. The means the strongest portion
of this moisture plume will reside to our west, yet hydro
impacts become more probable over our CWA during this period
regardless. The extent of those impacts will however hinge on
how far eastwards this plume can reach, a detail that is in
relatively good agreement between the ECMWF and GFS ensembles.
That consensus maintains the plume well into Utah with the more
anomalous moisture (PWAT`s nearing 200% of normal) only really
creeping into the area late Saturday as that moisture rotates
around the ridge to our north. It should be enough to elevate
flash flood potential for most of the region, especially should
morning cloud cover clear enough to support stronger convection,
but storm coverage may be more scattered than widespread. Due
to the projected placement of this shot of moisture, there`s
still wiggle room for models to nudge it further into our CWA,
so don`t count out a more widespread event. As guidance stands
now though, the flash flood risk appears more moderate. Hi-res
models will reveal much more insight into this system, so stay
tuned as we begin to receive this model guidance over the coming
days.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1208 AM MDT Thu Aug 20 2026

Expect generally VFR and light winds through the TAF period.
Isolated showers and thunderstorms will develop on terrain
along and south of I-70 after about 18Z with coverage becoming
more scattered to the south in the San Juan Mountains. Storms
will diminish through the evening, ending around 06Z in the
southern mountains.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

DISCUSSION...BW
AVIATION...DB