306
FXUS65 KGJT 191745
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1145 AM MDT Sat Sep 19 2026

.KEY MESSAGES...

- Saturday will see isolated to scattered showers and storms
  with moisture on the downward trend for the rest of the
  weekend.

- A few storms may strong to severe this afternoon. Also
  localized heavy rainfall could result in flash flooding.

- Another push of moisture on Tuesday and Wednesday brings
  precipitation chances back into the forecast for the region.

- Daytime highs this weekend and into next week will be
  relatively seasonable, if not below at times.

&&

.DISCUSSION...
Issued at 1123 AM MDT Sat Sep 19 2026

TAIL END OF THE MOISTURE:

A low pressure will track just north of the area area today and
tonight. This low is providing several rounds of forcing, which with
moisture in place has resulted in showers and storms. Those chances
continue through tonight as the low clips the northern CWA. During
the afternoon shower coverage will be highest in the eastern tow
thirds of the area and tonight the highest chances will be along and
north of I-70. Marginal shear will be present once again this
afternoon so that along with cape around 500-1000 j/kg a few
storms may be strong to severe. The main threats would be large
hail and damaging winds. Given PWAT values are still 150 percent
of normal and saturated soil there is a potential for heavy
rainfall and therefore flash flooding.


DRYING OUT:

The low pressure tracks to our east tomorrow and dry air moves in
from the northwest. There may still be enough lingering moisture for
showers mainly over the higher terrain, but those chances are low.
The same can be said for Monday as well.


PRECIPITATION CHANCES RETURN:

The next system of interest will be a low pressure that makes
landfall in California. It will progress eastward and tap into the
moisture that will be shunted to our south tomorrow. The low is
expected to become an open wave and move through the area relatively
fast. The result from the wave will be scattered showers and storms
across the area on Tuesday and Wednesday at the least. The wave will
provide shear so some of the storms could be strong to severe. Also,
freezing levels may come down enough to coat the highest peaks with
snow. The uncertainty is will the wave push the moisture to our
south or will it linger in portions of the area. If it does get
pushed southward how quick will it return. Confidence in the
forecast mid to late week is low attm.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1123 AM MDT Sat Sep 19 2026

Scattered showers and storms continue to develop across the area
this afternoon and evening, except the for far southern CO/UT and
eastern UT airfields where drier air will be filtering in...limiting
the coverage of storms. VFR should prevail otherwise over the next
24 hours.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

DISCUSSION...BS
AVIATION...TGJT