982
FXUS65 KGJT 181112
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
512 AM MDT Wed Sep 18 2024

.KEY MESSAGES...

- Conditions will remain dry and cooler than normal through late
  Friday.

- The next system arrives on Saturday bringing scattered showers
  and a reinforcing shot of cooler air.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 143 AM MDT Wed Sep 18 2024

The system that brought active weather yesterday is lifting out
over the northern Plains. Another low pressure is dropping
southward along the West Coast. In between the two systems is
quiet weather and cooler than normal temperatures. With mainly
clear skies and light winds some locations may see freezing
temperatures this morning. Winds increase later today across
the north along with some cloud cover possible as well.
Tomorrow the low pressure moves over central California giving
us southwest flow aloft. This will warm temperatures by a few
degrees, but conditions remain dry.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 405 PM MDT Tue Sep 17 2024

Models were in good agreement Thursday morning with the Pacific
low turning inland south of San Francisco tracking for northern
Arizona. Though they continue to agree on the track of the low
across northern Arizona before ejecting to the northeast across
the Four Corners and southern Colorado and out onto the Plains,
they diverge on the timing with the GFS and Canadian models
putting the low over the Four Corners Saturday morning and the
European running about nine hours behind. The ensemble means
show a similar timing difference with a lot of dispersion among
the members, so positioning of both models lay within the margin
of error. Guidance is leaning more to the GFS solution with the
faster track. This system carries a little moisture with it,
0.5 to 0.6 inches pwat, enough to spawn isolated nocturnal
storms over the southern and central mountains overnight Friday,
spreading north into the northern Colorado mountains Saturday
morning. Coverage along the Divide in the central and northern
Colorado mountains becomes more scattered to numerous in the
afternoon as moisture from the Front Range wraps around the low.
A few showers may linger along the Divide overnight Saturday
before coming to an end Sunday as the low pushes east out of
Colorado. Beyond Sunday, models diverge wildly, but generally
agree on ridging building in along the Rockies. Temperatures
will be near normal Thursday and Friday, cooling three to five
degrees below normal Saturday with the trough passage and slowly
warming back to normal Monday and Tuesday of next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 511 AM MDT Wed Sep 18 2024

VFR conditions are expected through the taf period. A few sites
may have gusts around 20-30 mph this afternoon. High clouds will
pass north of I-70 today.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...KJS
LONG TERM...15
AVIATION...TGJT