Weather Service Report


977 
FXUS65 KGJT 030001
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
601 PM MDT Wed Jul 2 2025

.KEY MESSAGES...

- Showers and thunderstorms have begun to develop over higher
  terrain this afternoon. Lightning and outflow winds capable of
  gusting in excess of 50 mph are the primary concerns.

- With rich moisture in place and slow storm motions expected,
  heavy rain and localized flash flooding threats will be on the
  increase today and tomorrow.

- Near to below normal temperatures are expected through Friday,
  then a gradual warming and drying trend will last through the
  holiday weekend.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 328 PM MDT Wed Jul 2 2025

Earlier this morning, widespread cumuli developed along the high 
terrain, and many thunderstorms have begun to form across our 
southern CWA. As cells tap into the steadily increasing moisture, 
expect for additional storm development throughout the afternoon.
Upper-level flow does remain weak given our position under the 
western edge of a broad ridge though. This should limit the lifespan 
of today's storms and keep them fairly slow-moving, similar to 
yesterday. Beyond this, while small hail and gusty outflow winds 
will again be possible today, the 18Z sounding is hinting at an 
environment noticeably lacking in instability. High-resolution 
models yesterday did anticipate a dip in CAPE today, but we are even 
falling short of those estimates. This is partly due to cooling 
surface temperatures from early day cloud cover, and some warming in 
the mid-level atmosphere. PoP's are down as a result, though 
isolated, stronger convection remains possible.

Tomorrow looks to be much more potent for active weather as PWAT's 
quickly rise to 180-210% of normal. This comes with the passage of a 
shortwave trough through the Intermountain West and resultant 
beneficial upper-level support. We'll likely see the bulk of 
moisture move overhead overnight. This actually threatens to inhibit 
the storm setup tomorrow should clouds linger into the morning 
thanks to the added moisture, which is expected as of this moment. 
While this won't change the high likelihood of widespread wetting 
rain, it could considerably alter the organization of tomorrow's 
storms. A more stratiform type event would become more favorable 
should morning cloud cover hamper the development of deep afternoon 
instability. Stronger cells embedded within stratiform rain would be 
possible, albeit more isolated. Should clouds break during the 
morning though, a more convective event would become more probable, 
but with the way models have been trending, this appears to be the 
less likely scenario. Regardless of how storms are characterized 
tomorrow, the widespread nature of precipitation will pose an 
isolated flash flood threat over prone locations. Portions of the 
CWA are under a marginal excessive rainfall risk tomorrow as a 
result.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 328 PM MDT Wed Jul 2 2025

High pressure begins to return to the lower levels on Friday as 
broad high pressure begins to build across the Four Corners, thanks 
to consistent southwesterly flow at all levels. Our brief wet 
spell/cool down will continue Friday afternoon for much of the CWA 
outside of the Four Corners, where warm dry air invades and 
temperatures begin to recover towards three digits. Leftover 
moisture will get reworked on much of our terrain Friday afternoon 
and produce more showers and thunderstorms. Depending on soil 
saturations from Thursday, this could produce some more hydrology 
concerns on a local scale Friday afternoon. For those enjoying 
Independence Day in the wild, staying abreast of local forecasts is 
advised, especially where flood and lightning prone terrain is 
involved. Dry air will continue to spread across the region Friday 
night. Showers and storms should all be wrapped up around midnight. 

High pressure and dry air exert enough influence Saturday to produce 
a mostly hot and dry forecast across the CWA. The terrain 
immediately west of the Divide and north of highway 50 could see an 
isolated shower or two pop up Saturday afternoon. Varying degrees of 
subsidence pose high uncertainty in shower coverage Saturday on the 
terrain. Dry boundary layers will likely keep much of anything from 
reaching the surface, aside from gusty outflow winds. This should 
feel familiar, as we've held on to this same basic regime the past 
week ahead of the current moisture surge.

Sunday and beyond, models are bullish for high pressure building 
over the Southwest. Some extra-tropical moisture starts to bubble 
under the high from the south. This returns non-zero afternoon 
precipitation chances to the CWA Sunday into Wednesday. According to 
guidance, temperatures closer to the high pressure center push well 
above 100 early next week around the Four Corners. Elsewhere, we 
expect temperatures in excess of 7-10 degrees over climatology 
during this warm up. Light winds under the high will keep critical 
fire weather conditions under thresholds, but hot and very dry 
conditions will persist. Showers and thunderstorms that arise will 
continue to produce gusty outflow winds and potential dry
lightning.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 548 PM MDT Wed Jul 2 2025

Today's showers and thunderstorms will gradually diminish across
the region. The most impactful precipitation is expected to end
after 02Z. Isolated showers are possible in the area overnight,
but TAF site impacts are not anticipated to return until 
tomorrow morning and afternoon. After 12Z precipitation will 
begin to move into eastern Utah from the southwest. After 18Z 
impacts spread across the region. Possible impacts with showers
and storms include brief periods of heavy rain, lowered 
ceilings, strong wind gusts, and lightning. 

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...BW
LONG TERM...LTB
AVIATION...TGJT

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Western Regional Climate Center, wrcc@dri.edu