979
FXUS65 KGJT 101013
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
313 AM MST Fri Jan 10 2025

.KEY MESSAGES...

- Cool and sunny today with light winds.

- A frontal boundary brings mountain snow to the CWA tonight and
  Saturday, with Winter Weather Advisories issued for the Flat
  Tops, Park Range, and Central Mountains. 4-10 inches of new
  snow is expected, with some locally higher amounts for the
  northern mountains.

- Mountain snow tapers on Sunday and Monday, with more tranquil
  conditions expected to close out the extended period, barring
  a shift in deterministic model solutions.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 305 AM MST Fri Jan 10 2025

Cool and quiet conditions will prevail today as we remain under the
influence of cold northerly flow stacked through the column. Sunny
skies will take some of the bite out of this chill, but do expect
temperatures to remain at or below climatology for early January
today and likely tomorrow with the arrival of another cold front.
Winds remain light today under the tilted ridge transitioning
through ahead of our next storm. Height falls late tonight will
usher in another round of winter weather for our northern counties,
spreading southward into the rest of the CWA by daybreak. A frontal
boundary loosely organized with the jet streak passing through the
base of the upper level trough will bring along PWAT`s 150-200
percent of normal tonight. Most of this should begin converting to
snow after midnight as forcing and orographics crank up the white
fluff machine. With some cold air in place, SLR`s look more Rocky
Mountain in nature with 15-20:1 expected. This will produce nearly a
foot of snow on some of our higher aspects in the Park Range and
Flat Tops, whereas down south moisture will fade and the Central
Mountains will see on order of 5-10 inches and the San Juans 3-5
inches. Winter Weather Advisories for the Flat Tops and Park Range
continue and we went ahead and added the Central Mountains of
COZ010, including the western approach to Vail Pass, as snow totals
have crept up with each successive model run. Ski traffic will want
to make note of road conditions around Vail and Steamboat Saturday
morning, as some of the more punctuated impacts will arrive with
resort openings. Models have the frontal boundary working through by
lunch Saturday. Some of the best snow rates will likely coincide
with spin-ups along the front. Mountain travelers will want to keep
abreast of changing conditions on roadways, as there will likely be
some brief whiteout conditions in these heavier showers. Post
frontal showers will continue Saturday afternoon and evening, likely
producing an additional couple inches of snow around the mountains.
For now, advisories are expected to drop off around midnight
Saturday night, as snow rates dwindle in the dry air behind the
front. Temperatures in the mountains will remain cool Saturday under
the influence of precipitation, while some of the eastern Utah
Counties and portions of southwest Colorado will get a bit of
sunshine and hit near normal highs.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 305 AM MST Fri Jan 10 2025

Significant accumulating snow will be coming to an end late Saturday
night through early Sunday morning. Having said that, general
troughiness and favorable orographics will allow some light snow and
snow showers to continue through the day Sunday. This precip will be
confined to the higher terrain along the Continental Divide from the
northern mountains down to the San Juans. A somewhat stronger
shortwave will move across the area from north to south during the
day Monday but limited moisture and upper level dynamics will keep
accumulations to an inch or less. This may change as we get closer
to Monday but even if it does, can`t imagine any significant
snowfall amounts out of this wave.

On Tuesday, deterministic models are highlighting a closed low
forming either along or over the southern California coast and then
drifting further west. The low is progged to become cutoff and spin
off the coast for the remainder of the long term period. Previous
runs showed very different solutions with this low but it appears
that model consensus is improving. The end result brings a ridge of
high pressure that remains over our area. The GFS is highlighting a
quick shortwave bringing some chances for precip across the Park
Range Wednesday while the EC keeps the ridge in place. Some
differences remain but the gist looks to be a more quiet period in
store.

Temperatures through the period will remain at or below seasonal
values with a warmup possible Wednesday onwards if the the ridge
builds in as expected.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 941 PM MST Thu Jan 9 2025

Winds are calm and terrain-driven tonight as low-level cloud
cover dissipates across the region. All terminals are at VFR,
and are expected to remain that way throughout the next 24 hours.
Look for BKN to OVC mid-level clouds to begin creeping in from
the northwest towards the end of the TAF period.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory from 11 PM this evening to 11 PM MST
     Saturday for COZ004-010-013.
UT...None.

&&

$$

SHORT TERM...LTB
LONG TERM...TGR
AVIATION...TGJT