163
FXUS65 KGJT 242036
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
236 PM MDT Fri May 24 2024

.KEY MESSAGES...

- The potential for showers and storms increases this evening
  and continuing through tomorrow. Gusty winds will be possible
  with these showers and storms.

- Mountain snow is possible generally above 9 kft with the
  impacts to the roads occurring tonight and tomorrow night.
  Highest chances for upwards of several inches of snow will be
  in the northern and central mountains.

- Temperatures will run below normal through the weekend then
  increase next week. Precipitation chances remain low through
  mid week.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 236 PM MDT Fri May 24 2024

A trough of low pressure continues to approach from the west
this afternoon, dragging through the Great Basin this evening. A
modest uptick in midlevel moisture paired with a weak ripple
embedded in the southwest flow aloft has led to the development
of isolated showers in the last few hours, focused north of
I-70. Persistent dry air in the lower levels, as noted in our
12Z sounding at GJT, has mainly resulted in virga showers which
has enhanced winds at the surface. The Eagle Airport reported a
peak gust of 38 mph. Outside of these high-based showers there`s
been an increase in mid and high clouds across the northern
two-thirds of the forecast area while the Four Corners region
remains mostly sunny. As a result, some occasional gusts down
south of 30 to 35 mph will be possible through this evening. The
trough digs into western Utah tonight before it lifts across
western Colorado and eastern Utah on Saturday. Broad scale
ascent becomes maximized during the 12Z - 18Z timeframe on
Saturday with the best shower coverage expected across mainly
the north as a result before activity becomes more convective in
nature Saturday afternoon. CAM guidance is pinging on a notable
band of showers extending from Baggs, WY to the Tavaputs Plateau
mid Saturday morning as the weak cold front associated with
this system begins to dig into the region. Snow levels will
drive down to 9-10kft with the front so previous forecasts of
upwards of several inches of snow remains likely. As the cold
front works farther southeast throughout the day showers and
storms will reach south of I-70 with storms becoming capable of
producing gusty outflow winds and perhaps some graupel or small
hail. Elsewhere outside of Saturday`s shower activity will be
dry under partly sunny skies. The trough axis slides east of
the Divide on Saturday evening with showers tapering off from
west to east in response.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 236 PM MDT Fri May 24 2024

Showers rapidly diminish west to east Sunday morning under
subsidence as ridging moves in from the west behind the
trough/frontal boundary moving out onto the Plains. Sunday
afternoon will see some lingering scattered showers over the
northern Colorado mountains with isolated showers in the central
mountains ending by evening. Temperatures Sunday will run a
little below normal under a northwesterly flow. Monday into the
middle of the week looks to be mostly quiet with the ridge and
mostly clear skies moving in overhead, and temperatures rising
to five to ten degrees above normal for late May. Winds will be
light terrain driven through the period with the weak westerly
flow aloft. Weak lower level south to southeasterly flow along
the Front Range may be enough to push some moisture up to the
Divide to feed a few isolated showers along the Divide each
afternoon, in the southern mountains Monday, spreading north
into the central and northern mountains Tuesday and Wednesday.
In the latter half of the week, models concur on a low pressure
system dropping into the Pacific Northwest pushing the ridge
east out onto the Plains and putting eastern Utah and Western
Colorado under an increased southwesterly flow aloft and gusty
southwesterly afternoon winds at the surface. Models diverge on
how deep they dig the associated trough into the Great Basin
much as they have with the last few troughing systems. With the
last system, the solutions that forecast the deeper trough were
the better forecasts that brought a cold shot of northern air to
the region with temperatures well below normal. Current
guidance is keeping the system more to the north with unsettled
weather in the northern mountains and temperatures near normal,
which is reasonable for the end of May, but we can`t rule out
another deep trough to the west and a cold shot dropping
temperatures ten degrees by the end of the week with unsettled
weather spreading south into the central and even southern
mountains. The ensembles indicate wide dispersion in the
solutions mid-week and beyond expressing the low confidence in
the forecast for the latter half of the week, so you`ll just
need to stay tuned for updates on the extended period to see how
this plays out.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1124 AM MDT Fri May 24 2024

Expect VFR conditions with increasing clouds ahead of the next
system through the next 24 hours. Look for isolated to scattered
showers to move in from the northwest overnight becoming
scattered along and north of the I-70 corridor after about 15Z.
Included vicinity showers from KCNY and KASE northward late in
the TAF period with showers becoming predominant at KVEL after
16Z. Conditions will remain above ILS breakpoints through the
TAF period.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...MMS
LONG TERM...DB
AVIATION...DB