746
FXUS65 KGJT 271953
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
153 PM MDT Mon May 27 2024

.KEY MESSAGES...

- Clouds and isolated showers over the southern mountains will diminish
  after sunset tonight.

- Above normal temperatures will last through mid week, with a
  brief cool down to near normal values late in the week.

- Conditions will be generally dry and breezy, with chances for
  isolated to scattered showers and storms over the higher
  terrain possible most afternoons.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 152 PM MDT Mon May 27 2024

With high pressure building in overhead and the ridge axis just to
the west this afternoon, mostly sunny skies and near to above normal
temperatures are in control. Pockets of 700-500 mb moisture remain
over the southern half of the area, where scattered to broken clouds
and a few isolated showers have popped up over the last few hours.
This activity, confined to where daytime heating can work on that
pool of moisture, will remain generally south of the Highway 50
corridor this afternoon, and is expected to dissipate after sunset.

As the next Pacific trough moves onto the West Coast this evening,
it will nudge the ridge eastward, with the axis forecast to pass
overhead tonight. This will favor clear skies and calm winds,
allowing temperatures to drop to near normal values despite
increasing warm air advection aloft. These cooler temperatures won`t
last long tomorrow morning, as warmer, more moist southwest flow
kicks in aloft behind the ridge axis. Forecast highs tomorrow will
run 5-10 degrees above normal, with upper 80s to low 90s forecast
for the desert valleys, upper 70s to low 80s across the higher
elevation valleys, and 50s to low 60s for the mountain towns. The
increasing moisture aloft and a weak shortwave expected to track
across the Four Corners will bring slightly increased shower and
storm coverage for tomorrow, most favoring the Divide mountains. Dry
air at the surface will limit the amount of precipitation that makes
it all the way to the ground, keeping the main threats gusty outflow
winds, lightning, and perhaps some small hail. These showers and
storms are expected to once again diminish after sunset with the
loss of heating. Tuesday night will be milder, as warm, moist
southwest flow remains ahead of the approaching Pacific trough.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 152 PM MDT Mon May 27 2024

The ridge axis continues east of the Divide on Wednesday with
southwest flow increasing as a trough moves into the Pacific
Northwest. The trough will move across the north Wednesday evening
into Thursday morning across Montana and North Dakota, as well as
the bordering Canadian Provinces, turning our flow more zonal. It
will drag a cold front across the Plains with the back edge trailing
into eastern and central portions of Colorado Thursday and Friday.
Temperatures will continue to warm up Wednesday with highs near 90
in the Grand Valley and low 90s for the lower desert valleys of east-
central and southeast Utah. 80s should be seen in the remaining
lower valleys. So highs will be around 5 to 10 degrees above normal
and Wednesday does appear to be the warmest day this week.
Temperatures cool a bit, especially up north due to the cold front
and trough passage Thursday and Friday, with highs returning closer
to normal, with better chances of below normal up north and above
normal down south. The models and NBM solutions are not indicating
much in the way of precipitation for the western slope during this
period, with the high terrain of western Colorado along the
Continental Divide more favored for afternoon storms, isolated to
scattered in coverage. Most areas should remain dry and breezy with
the passage of the northern system and diurnal heating.

By the weekend, a ridge of high pressure tries to build in,
resulting in drier conditions and temperatures warming back above
normal heading into early next week. The GFS is indicating another
trough moving across the north and bringing more widespread showers
late Sunday but the ECMWF indicates this trough staying well to the
north to not impact us much at all. The NBM follows the drier trend,
so will stick with that for now until better consensus is reached.
Heading into the first week of June, it looks like the typical June
ridge of high pressure wants to build and amplify across the area,
which would result in a more drier and warmer forecast. So will have
to wait and see how models trend as confidence beyond Saturday is
low due to inconsistencies.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1146 AM MDT Mon May 27 2024

VFR conditions will prevail with SCT to BKN cumulus over the
southern mountains and mostly sunny skies elsewhere. Occasional
breezy conditions are possible during the afternoon, but winds
should generally remain light and terrain driven. Isolated
storms are possible over the San Juans but are not expected to
impact TAF sites.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...BGB
LONG TERM...MDA
AVIATION...MDA