147
FXUS65 KGJT 150409
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
909 PM MST Thu Nov 14 2024

.KEY MESSAGES...

- Warm and windy conditions Friday ahead of an approaching
  frontal boundary will push temperatures 5-10 degrees above
  climatology, with winds gusting 30-40 mph around the region.

- Weak snow showers Friday night and Saturday will deliver some
  light accumulations to our northern mountains.

- Another disturbance Monday and Tuesday will deliver more
  measurable snow to the mountains.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 319 PM MST Thu Nov 14 2024

Water vapor satellite shows a well defined jet stream digging out a
positively tilted trough down the West Coast this afternoon. This
comes on the backside of a flattened ridge centered over the Great
Plains. Some weak moisture is riding over the top of the ridge, but
cloudless conditions are well established here across the CWA. This
will help with another night of cool autumn temperatures. The caveat
here will be whether we are able to mix things up earlier in the
morning as the potent jet streak works overhead, along with some
insulating cloud cover. Regardless, looks like we`ll be nearly as
cool around the area as we were this morning.

By daybreak Friday morning, a closed surface low materializes over
the Great Basin, with a substantial jet streak skirting the
southeast quadrant. This jet streak will work northeast across the
Four Corners through the day Friday with 110-130kts across southwest
Colorado by Friday afternoon. While the weak moisture plume hangs
back to the west along the frontal boundary, warm, dry and windy
conditions will greet most of us on Friday. Afternoon highs will be
5-10 degrees over climo. The strongest winds will remain south of I-
70, with borderline wind advisory conditions around the Four Corners
in the afternoon. Held off on an advisory at the moment with
coverage just not justifying a highlight. Areas up the hill from the
US491 corridor and in the Paradox Valley can expect some wind gusts
near 45 mph from lunch time through early evening. Winds will taper
some along the foothills and valleys Friday evening, but remain
gusty on the terrain for much of the night Friday. A mostly dry
frontal boundary works into eastern Utah Friday evening with a deep
pool of cold air behind it that stretches well to the south. Winds
remain southwesterly Friday night, but the cold pocket digging into
SOCAL/AZ will serve up enough cold air advection for impacts
discussed ahead in the long term. This will also help a few pockets
of moisture along the frontal boundary deliver some weak snow
showers to some of our mountain zones in the northern half of the
CWA before daybreak Saturday.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 319 PM MST Thu Nov 14 2024

Long term models remain on track with regards to the trough over the
weekend. This elongated trough will start splitting Saturday
afternoon as a closed low forms at the base of said trough. As this
occurs, upper level support moves to the Plains which will keep the
most active weather in that area. We might see a few showers as the
trough moves through thanks to some midlevel convective instability
but that will be about it. Speaking of, the NBM is showing a skiff
of snow for the northern mountains so not much to speak of.
Deterministic models are showing a little better coverage but the
end result is still the same...not much QPF. What we will
experience, however, will be much cooler temperatures as H7 temps of
0 to 2C on Friday will drop to around -9C by Saturday. This will be
reflected at the surface with highs dropping 10 to 15F from highs on
Friday. This temperature drop will be seen across the entire CWA.
The CWA will remain under a col for the rest of the weekend as the
closed low moves along the US/Mexico border before shifting
northeast towards the Texas panhandle Monday morning. The next
shortwave then starts dropping down from the northwest and this is
where discrepancies start showing up. By Monday evening, the EC
keeps digging the trough down into the UT and NM before closing off
an area of low pressure. The GFS brings the trough through as
northwesterly flow sets up allowing some orographics to setup and
bring light snow to the northern mountain ranges through Wednesday
morning.  Models do agree, however, that a high amplitude ridge axis
sets up to our west Wednesday night and persists into the weekend.
Temperatures will generally be cool through the period starting
around seasonal norms dropping becoming 3 to 5 degrees below normal
for much of next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 908 PM MST Thu Nov 14 2024

VFR conditions are expected through the period. Winds aloft will
increase tonight so low level wind shear is possible at some
sites. Those winds will reach the surface tomorrow afternoon so
gusts of 25-35 mph are expected.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

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