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000
FXUS65 KGJT 131005
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
405 AM MDT Sat Apr 13 2024

.KEY MESSAGES...

- Warm and breezy conditions will prevail today and Sunday, with
  high temperatures around 10 degrees above normal.

- Active weather returns Monday through Wednesday as a pair of
  Pacific storms impact the region bringing showers, cooler
  temperatures and accumulating mountain snow.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 405 AM MDT Sat Apr 13 2024

Light showers were ongoing over the southern and central
Colorado mountains early this morning as a weak mid-level short
wave trough moved northeastward over the Four Corners. Model
consensus indicated the trough axis will shift to the
Continental Divide by 12Z and subsidence in its wake will cause
showers to dissipate by mid-morning. All but the ECMWF indicated
dry weather for the remainder of the day as drier air filters
into the area behind the disturbance. However, can`t entirely
rule out instability showers over the Park Range this afternoon
as ECMWF suggested dry air will take longer to reach the north.

Expect fair weather to continue tonight and Sunday as a closed
low pressure system moves ashore over California`s Bay Area then
to the western Great Basin. A stream of dry air moving from the
eastern Pacific moves through the base of this system, across
the Desert Southwest and into the region. As a result, skies
will be mostly clear tonight and mostly sunny on Sunday.

Dry, breezy conditions this afternoon and again Sunday
afternoon combined with partly to mostly sunny skies will help
keep high temperatures running around 10 degrees above normal,
though not quite as warm as Friday. Lows tonight will be
similarly mild.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 405 AM MDT Sat Apr 13 2024

By Sunday evening, the deep low pressure system will be moving
through the southern Great Basin. It tracks along the Utah-Arizona
Border overnight and continues east along the Colorado-New Mexico
Border Monday pushing a cold front west to east across the region
with it before sliding east of the Divide Monday evening. The low
carries some Pacific moisture with it that along with the frontal
dynamics and jet difluence aloft will support light showers over the
higher terrain starting Monday morning, though little accumulation
is expected with this initial push. By Monday evening as the
influence of this low moves out onto the Front Range, it picks up
deep moisture off the Plains and wraps it through Wyoming into the
northern and Central Colorado Mountains bringing chances for up to
about 12 inches snowfall to these areas generally above 10,000 feet
between Monday evening and noon Tuesday with the higher peaks of the
Park Range seeing 18 inches possible. Confidence in this storm
forecast is increasing as there is good agreement among the
deterministic and ensemble models, and the ensembles are indicating
very low dispersion among their members out into Wednesday. These
late season snow storms tend to produce fewer impacts to area roads,
but that this storm hits overnight Monday into Tuesday morning, plan
for winter driving conditions likely over Rabbit Ears and Vail
Passes. It`s still too early for headlines with this system, so stay
tuned for updates. With the cold front moving through Monday, look
for temperatures to drop eight in the mountains and 15 degrees in
the lower valleys from the weekend highs.

Weak ridging moves in from the west Tuesday to warm the lower
valleys back to about ten degrees above the seasonal normal while
the mountains will remain near normal with lingering light snow
showers. Areas along and south of the I-70 corridor will see
generally warm dry weather through the remainder of the week. The
next low pressure system that drops out of  northern Canada through
the latter half of the week stays well to the north, but pushes a
cold front and much cooler air south. Most of the cooler air stays
east of the region along the Front Range and out on the Plains, but
this system does push the cold front south into the northern areas
of eastern Utah and Western Colorado keeping temperatures in these
areas more near normal into next weekend. We can expect light
mountain snow showers in the northern Mountains with this next
system, but again, lack of moisture with this system will severely
limit any accumulation.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1123 PM MDT Fri Apr 12 2024

Inversions have set up with nocturnal drainage winds across the
region at most TAF sites, the exception being KMTJ where the
southwesterly flow aloft is keeping the winds stronger out of
the south for the next few hours before settling down to the
typical southeasterly drainage winds. Scattered to broken
midlevel clouds continue overnight across much of the region,
but drier air moving in from the southwest will scatter out
ceilings overnight and through the morning with clear skies
returning to much of the area through the day tomorrow. Expect
ceiling to remain above ILS breakpoints through the period. Gusty
west to southwest winds will pick up again through the
afternoon and diminish after 00Z Sunday.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...NL
LONG TERM...DB
AVIATION...DB