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000
FXUS65 KGJT 151739
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1139 AM MDT Mon Apr 15 2024

.KEY MESSAGES...

- A late winter storm moves over the forecast area today bringing
  much cooler temperatures and rain and snow showers.

- Significant snowfall is possible for the northern and central
  mountains, including Vail and Rabbit Ears passes this
  afternoon through Tuesday afternoon.

- Breezy, milder, and unsettled conditions linger through the
  end of the week.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 326 AM MDT Mon Apr 15 2024

The late season winter storm set to impact the area today,
tonight and Tuesday was centered over east-central Nevada early
this morning. There were a few areas of clouds in the southerly
flow aloft ahead of the system, but otherwise dry and relatively
mild conditions were the rule over eastern Utah and western
Colorado early this morning. Meanwhile, the cold front
associated with this system was oriented north-south along a
line just east of Page (AZ), Price (UT) and Fort Bridger (WY).

Models were consistent in shifting the storm to east-central
Utah by midday, then just east of the Continental Divide in
central Colorado by 00Z/Tue. This will drive the cold front to
the western Colorado border by 12Z and to the Divide by midday.
Dynamic forcing from the surface to jet level indicated as the
storm moves in and as a result, showers become numerous over the
mountains with more scattered coverage over the lower
elevations. Advection of colder air will cause highs to fall by
10 to 15 degrees compared to Sunday`s highs.

Mountain snow picks up tonight as moisture deepens in the area
of wraparound and will continue through midday Tuesday before
decreasing Tuesday afternoon. This phase of the storm will
favor the northern and north-central Colorado mountains
primarily where snow amounts are expected to range from 6 to 12
inches with amounts to near 18 inches above treeline. Current
Winter Weather Advisories appeared to be on track and see no
need for adjustments. The southern half of the forecast area
can expect a downturn in shower activity late tonight with quiet
and milder conditions Tuesday afternoon.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 326 AM MDT Mon Apr 15 2024

The general synoptic pattern Tuesday has a longwave trough
stretching across the CONUS in a zonal flow with ridging off
each coast and shortwave ridges and troughs transiting the
longwave pattern. The last low pressure system will have moved
well to the east over eastern Nebraska and Iowa by Tuesday
evening taking the wrap-around moisture to the east out of the
region with it. The next system to impact eastern Utah and
Western Colorado will be descending out of Canada into the
Pacific Northwest. Though the low associated with this system
will stay to the north along the Canadian Border, weak AR action
slipping in through the Oregon gap with IVT`s raging 100-200
kg/m/s across the northern areas will generate light orographic
showers over the Park Range Wednesday afternoon and evening.
Look for these light orographic showers to spread into the
central mountains Thursday afternoon and into the southern
mountains Friday and Saturday as the mid-level moisture band
gradually drifts south across the region. Snow levels stay
generally around 8,000 feet through the period, a little higher
in the afternoon and a little lower in the early morning, but
little if any snow accumulation is likely with these showers.
The southerly pressure gradient aloft keeps a 50 kt zonal flow
at 500mb across the region through Friday before the gradient
weakens going into the weekend. Look for breezy westerly winds
each afternoon gusting 25 to 35 mph across the region as diurnal
heating and orographic turbulence mix the upper-level winds
down. Temperatures will remain near to slightly above normal
across the northern areas to about ten degrees above normal
across the central and southern areas through the next weekend
into the next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1126 AM MDT Mon Apr 15 2024

A strong system and associated cold front is lifting northward
across eastern Utah and western Colorado this morning. KTEX has
had some passing showers and will have the highest probability
of MVFR or lower conditions over the next several hours. Other
locations will see increasing clouds and possibly a passing
shower but ILS/VFR is forecast to prevail. Through the late
afternoon and evening hours expect lower clouds and
precipitation to expand to several of the eastern TAF sites with
MVFR to LIFR conditions persisting past sunrise on Tuesday.
Winds will remain gusty with this strong system and gusts in the
25 to 40 mph range will occur through the early morning hours.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory until noon MDT Tuesday for COZ004-010-
     013.
UT...None.

&&

$$

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