Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 141747
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1147 AM MDT Thu Mar 14 2024

.KEY MESSAGES...

- Heavy snow is expected in the Uinta mountains through this
  evening. Elsewhere scattered light snow showers are possible
  with minor accumulations.

- Wind gusts of 45-60 mph are possible across portions of
  northeast Utah and northwest Colorado today and tonight.

- Moderate to heavy is expected in the southern mountains today
  through tomorrow. Upwards of two feet is possible.

- Through early next week there may be several rounds of
  precipitation around the Four Corners region due to a stalled
  out low pressure in the Desert Southwest.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 334 AM MDT Thu Mar 14 2024

At this moment there is a closed low pressure over southern Nevada.
It will continue to drop southward today before stalling out. Much
of the influence on our weather today is being driven by strong post
frontal flow in the High Plains and along the Front Range. The
problem with that is downsloping off the Divide, and trying to
figure out how much precip will dry up. There is some consensus
that QPF will generally be low across the northern half of the
area despite a band that has moved in from the east. Minor snow
accumulations on the roads this morning are possible in spots.
Road cameras are showing snow on I-70 from Avon up to Vail Pass.
That could be the case at similar elevations. Conditions should
improve after the sun comes up. The eastern Uintas are favored
in this moist northeast flow therefore expect moderate to heavy
snow most of the day. Portions of northeast Utah and northwest
Colorado will see strong winds today and tonight due to the jet
on that side of the system. Speeds up to 45 mph will be common,
but gusts upwards of 60 mph can not be ruled out.

Several lobes of vorticity coming out of the main low pressure will
rotate in from the south over the next few days. These will focus
showers across the area. Pinning down the exact location and timing
of these will be tough. One that the models have a decent handle on
is late tonight and into tomorrow. This round of showers will be
driven by a strong jet advecting Pacific and Gulf moisture in from
the south. The southern half of the forecast area has the best shot
of seeing showers during this phase of the storm. It is also when
the San Juans could receive moderate to heavy snow. The air mass is
fairly warm so another uncertainty is how low the snow levels drop
especially overnight. The locations of concern are along the
highway 160 corridor. For now the models are showing perhaps
only a few inches by late tomorrow morning. One thing that is
becoming more certain is gusty winds in the Four Corners region
tomorrow with speeds upwards of 45 mph.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 334 AM MDT Thu Mar 14 2024

The cutoff low responsible for this week`s winter storm continues to
play on house money over Las Vegas Friday night. Neither deepening
or filling, according to deterministic models, it just continues to
circulate Pacific moisture into the southern portion of our CWA.
This will keep snow accumulating on our southeast Utah mountains,
the San Juans, and the Uncompahgre Plateau into Saturday evening.
Models then push the low southward and east slightly. This should
help starve the moisture supply enough to smash down the snowfall
rates Sunday, but not quite enough to stop the snow. Light
accumulations will persist on Sunday across the San Juans and the
Central Mountains up north, as the low begins to fill and track
eastward into New Mexico.

Monday and Tuesday see models try to degrade the surface low, but
hang onto the upper level low across the Southwest, where a few
easterly vort lobes track across southern Colorado and deliver
orographic showers to the mountains. Model confidence is pretty low
early next week, with spaghetti plots struggling to find an outcome
for the stubborn upper low trapped under a ridge arcing northward
into British Columbia. Presently, no strong indicator exists for dry
air to scour the residual pool of moisture hanging over the Four
Corners. The GFS tries to finally kick the upper low out when the
subtropical jet pushes north across Baja and Central Mexico
Wednesday. The EC tries to chip away at the British Columbia ridge,
thereby dissolving the upper low. These are highly speculative model
predictions, considering the anomalous conditions preceding this.
Temperatures will trend cold through the weekend with cloud cover in
place across the region. However, some indications exist for a warm
up over the northern half of the CWA through the beginning of the
work week. Potential cloud cover across the southern half of the CWA
will keep the warm up in check, as the upper low refuses to budge.
Needless to say, the evolution of the pattern following this storm
will continue to vex us.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1135 AM MDT Thu Mar 14 2024

With moisture spilling over the Divide on and easterly flow, low
to mid ceilings and light showers with periods of MVFR/IFR
conditions will affect most TAF sites for the next 24 hours.
Gusty east to northeast winds will increase through the
afternoon, and continue overnight before dropping off. Most TAF
sites will see some of these gusty winds, but the northern sites
will have the strongest winds. Snow showers increase over the
southern mountains this evening and will continue Friday as they
push into the central Colorado mountains.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Wind Advisory until midnight MDT tonight for COZ001.
     Winter Weather Advisory until 6 AM MDT Saturday for COZ017-018.
     Winter Storm Warning until 6 AM MDT Saturday for COZ019.
UT...Wind Advisory until midnight MDT tonight for UTZ024.
     Winter Storm Warning until 6 AM MDT Saturday for UTZ028.
     Winter Storm Warning until 6 PM MDT this evening for UTZ023.

&&

$$

SHORT TERM...KJS
LONG TERM...LTB
AVIATION...DB


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