533
FXUS65 KGJT 222324
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
524 PM MDT Wed May 22 2024

.KEY MESSAGES...

- Showers and thunderstorms return Thursday, along with windier
  conditions along a slow moving frontal boundary.

- Partly to mostly cloudy conditions continue Friday and into
  the weekend with the chance for afternoon showers and
  thunderstorms in the mountains.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 136 PM MDT Wed May 22 2024

GOES-East satellite imagery shows some mid and high level clouds
pushing into the region from the northwest this afternoon. This is
out ahead of an approaching and deepening mid-level trough over the
Intermountain West. Southwest flow well in advance of the trough is
helping to boost afternoon temperatures roughly 10 degrees warmer
than yesterday, and much closer to climatological normals. Dry and
mild weather continues tonight, with overnight lows following
similar warming trends.

Accompanying the trough is a strong cold front which is progged to
reach northeast Utah by daybreak Thursday morning. Though moisture
is modest at best, a few showers are possible across the eastern
Uinta mountains within the first couple of hours after sunrise.
After that, the cold front is progged to gradually push through the
CWA over the course of the day on Thursday. Given the aforementioned
limited moisture, shower activity is expected to be mostly confined
to the higher elevations in northwest Colorado and along the
Continental Divide. More notable will be the winds ahead of, and
along the cold front, which will likely gust upwards of 30 to 40 mph
at times, especially during the afternoon. These winds gusts could
even be enhanced further by any virga or dissipating showers. High
temperatures will largely be similar to today, with the exception of
northeast Utah and northwest Colorado where the cold front moves
through earliest. Thus, highs there will be about 5 to 10 degrees
cooler.

The trough and cold front will exit the region to the east Thursday
night, leaving clearing skies and light winds in their wakes. A
cooler air mass overhead and near ideal radiational cooling
conditions will lead to a chillier night, especially for the higher
valleys and across the northern tier where temperatures may near or
even dip below freezing. Otherwise, dry and quiet weather prevails
into the morning hours on Friday.

On a more personal note, today is my last day working at WFO Grand
Junction as I`m moving on to new adventures within the National
Weather Service. It`s been a pleasure serving eastern Utah and
western Colorado for the past 4 years, and I`m honored and proud to
have been given the opportunity to live, work, and play on the
Western Slope. Until next time!

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 136 PM MDT Wed May 22 2024

The forecast area will see a bit of a lull in shower activity
on Friday as the last system pushes farther east and ahead of
the next system upstream to the west. That said, enough moisture
remains to fuel isolated showers/thunderstorms along the
central and northern Colorado portion of the Continental Divide
as the atmosphere becomes conditionally unstable with surface
warming and jet divergence providing the necessary support.
Chances increase Friday night and peak Saturday afternoon as the
trough to the west moves from the Great Basin and over the
forecast during this period. However, there`s a concerning
spread in timing between the ECMWF and the GFS solutions with
the former describing the timing just described. The latest GFS
was markedly slower. It should be noted that due to office
operations, this discussion was prepared in the morning before
the 12Z/ECMWF was available so differences may be overstated.
That said, the forecast for Saturday night and Sunday could be
in flux depending ECMWF adjustments, or lack thereof. The slower
GFS showed a short wave trough trailing the main trough which
is indicated to continue to generate scattered showers for the
northern and central Colorado mountains and the northwest
Colorado Plateau. The ECMWF keeps that energy well north of the
area and as a result, limited showers to Saturday evening with
little chance for additional precipitation beyond the early
morning hours Sunday. However, despite their differences, models
were in agreement with a shallow long wave ridge forming over
the Rockies early next week. Drying under the ridge will end
shower/storm potential for all but mountains forming the
Continental Divide. Given continued showery conditions and in
the absence of warm air advection, temperatures are expected to
hover around 5 degrees below normal through the weekend, but a
warming trend arrives Monday and by Tuesday highs will range
from 5 to 10 degrees above normal.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 522 PM MDT Wed May 22 2024

The main concern over the next 24 hours will mainly be wind
related. Stronger winds aloft will create areas of LLWS
overnight which will eventually mix down to the surface as gusts
of 25 to 40 mph through tomorrow evening. Outflow winds near
showers across northwest Colorado could also produce some
stronger gusts. Otherwise VFR should prevail with low
probability of ILS at KHDN tomorrow afternoon near showers.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...MDM
LONG TERM...NL
AVIATION...TGJT