FXUS65 KGJT 220418
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1018 PM MDT Fri Aug 21 2026

.KEY MESSAGES...

- Monsoonal moisture will cause precipitation chances to become
  more widespread Saturday. 

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

- Temperatures gradually cool off for the weekend and into next
  week but still remains above normal. 

&&

.DISCUSSION...
Issued at 1014 PM MDT Fri Aug 21 2026

COOLER & WETTER WEATHER THIS WEEKEND:

High pressure will continue to be centered over our region through 
the weekend. Clockwise flow around this system will favor moisture 
advection into our CWA. Hence, precipitation chances will become 
more widespread Saturday under dominant southwesterly flow. 
Deterministic models are hinting at PWATs at 150-180% of normal 
during this time period. Storms are expected to favor the higher 
terrain initially, but adjacent valleys could also get in on the 
action as storms begin to move off the terrain. Models also seem to 
be hinting at a shortwave disturbing the driving flow Saturday, which 
would mean additional lift in an already saturated environment. 
This will subsequently increase flash flooding and debris flow 
concerns. Continue to be weather aware and have multiple ways to 
receive watches and warnings. 

Afternoon storm chances will be around Sunday as well while the 
increased atmospheric moisture remains in place. However, storm 
chances will be mostly confined to the higher terrain as no 
additional lift is anticipated from synoptic forcing. With that 
being said, flash flooding and debris flow concerns persist through 
at least Sunday as localized heavy rainfall remains a possibility.

Daytime highs cool by about 5 degrees for the weekend, but still 
remain above normal for this time of year.  


NEXT WEEK: 

The environment continues to be saturated into next week which will 
keep afternoon thunderstorms in the forecast daily for the higher 
terrain. It is unclear how precipitation chances will pan out for 
the lower valleys at the moment. As more HiRes guidance becomes 
available, we will likely have a better grasp on what's to come. 

Daytime highs hold steady as we move into next week with most 
locations seeing similar temperatures as the weekend. These values 
will still be above normal but not quite into record breaking 
territory anymore.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 519 PM MDT Fri Aug 21 2026

VFR conditions will likely prevail through the TAF period. Some
light rain showers are still ongoing this evening, but will
begin to gradually diminish after ~01Z. Gusty outflows have
already been observed this evening at some terminals and
continue to be a threat with decaying storms. Winds will resume
a light and terrain driven pattern by the overnight hours.
Saturday will see shower and storm chances beginning around 18/19Z
at most terminals. Localized heavy rainfall is possible with
storm activity which could have an impact on visibility at 
certain terminals.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

DISCUSSION...BS
AVIATION...TGJT