029
FXUS65 KGJT 180557
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1157 PM MDT Fri Jul 17 2026

.KEY MESSAGES...

- Showers and thunderstorms will continue each afternoon and
  evening through at least early next week.

- Main threats with these storms include lightning, localized
  heavy rainfall, and gusty outflow winds (35-45 mph).

- These storms have the ability to produce flash flooding and
  debris flows in vulnerable terrain, including areas near and
  downstream of burn scars.

&&

.DISCUSSION...
Issued at 1005 PM MDT Fri Jul 17 2026

The current upper level pattern is characterized by a stagnant high
pressure system. This will lead to many rinse and repeat days when
it comes to the forecast. Current guidance continues to suggest PWAT
values around 150-200% of normal for the next few days. This will be
enough moisture to support daily showers and thunderstorms each
afternoon and evening through the weekend for the CWA. It is also
becoming more possible that we hold onto this moisture into early
next week as well. A majority of these storms will initialize over
the higher terrain before spreading through the valleys as outflows
develop. Additional development is also possible where these
outflows collide with each other and the higher terrain, leading to
pop up thunderstorms. The primary threats with these storms include
lightning and heavy rain, in addition to small hail and gusty
outflow winds (35-45 mph). Although we welcome much of this rainfall
with open arms, localized heavy rainfall could result in flash
flooding and debris flows. This is especially of concern over highly
sensitive areas like recent burn scars. The hydrology section below
discusses the risk in greater detail.

As previously mentioned, these storms have the ability to pop up
rather quickly, so be sure to monitor the forecast and have multiple
ways to receive weather alerts. This is especially important if you
are visiting or reside below terrain that is vulnerable to flash
flooding.

QUICK NOTE ON TEMPERATURES + NEXT WEEK:

As for daytime highs during this time period, we have increased
cloud cover to thank for temperatures near normal for the
foreseeable future for much of the region. Next week`s convection
looks to follow similar patterns as this week. Although, there may
be slight variations in where the storms materialize and drift off
the terrain. As HiRes guidance becomes available for that time
period, we may gain a better grasp on the "when and where".

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1142 PM MDT Fri Jul 17 2026

Still have some light shower and isolated thunderstorm across
northwest Colorado and southwest Colorado/southeast Utah with
midlevel ceilings and a few gusts to 25 kts. Look for these
storms to continue to diminish over the next few hours. Showers
will develop over the higher terrain after 15Z with
thunderstorm becoming dominant after 18Z. Convection will work
down into the valleys through the afternoon, and begins to
diminish after 00Z becoming more stratified showers after 03Z,
much like this evening. The main threats with convection will
be lightning, gusty outflows (30-40kts), and brief periods of
MVFR in heavy rainfall.

&&

.HYDROLOGY...
Issued at 1047 AM MDT Fri Jul 17 2026

Anomalous moisture has become established across portions of
eastern Utah and western Colorado. Rainfall rates of 1-2 inches
per hour will be possible with the stronger storms. These rates
could lead to flash flooding and debris flows especially over
recent burn scars.

Storms over the last few days have helped prime lower levels of
the atmosphere and saturate the ground where rain was observed.
Several locations across southwest Colorado reported over 0.5
inches of rain within 30 minutes; which is more than sufficient
to create issues in our steep, rocky terrain that is already
susceptible to flash flooding. This environment also triggers
heightened awareness over recent (or actively burning) fires,
due to the burnt ground`s inability of absorbing moisture under
heavy rainfall. As such, we continue to emphasize the potential
for flash flooding and debris flows in this regime.

As a reminder: Keep an eye on our forecasts through the end of
the week and stay tuned for updated hydrology alerts if
visiting or if you reside below vulnerable terrain to flash
flooding and/or debris flows. Storms across the west develop
quickly, leaving little room for lead time in flashy terrain.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

DISCUSSION...BS
AVIATION...DB
HYDROLOGY...ERW