981
FXUS65 KGJT 101151
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
551 AM MDT Fri May 10 2024

.KEY MESSAGES...

- Snowfall will favor the eastern Uinta mountains in northeast
  Utah and the higher elevations of the San Juans and central
  Colorado mountains through Saturday.

- Snow amounts in excess of 6 inches have a 40 percent
  probability of occurring over the highest peaks of the San
  Juans mountains over the next 36 hours...with lesser
  probability of at least 20 percent along the Elk and West Elk
  mountains. Main travel corridors are expected to mostly remain
  wet during the day.

- Unsettled conditions will persist through the weekend along
  with a slow warming trend...however temperatures will remain
  below normal. Above normal temperatures return next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 356 AM MDT Fri May 10 2024

Satellite imagery indicates clouds and showers wrapping around
the center of the low pressure system that appears to be
centered somewhere over southeast/east-central Utah. Webcams
indicate the best snowfall rates falling over Monarch Pass and
the central spine on the eastern fringe of our CWA as expected.
Further west, scattered convective showers are developing over
the San Juans and moving into the central mountains, tracking
over lower elevations as they do but precipitation rates appear
light at this time with roads at the higher passes remaining wet
at this time, most likely due to the mild antecedent conditions.
These showers are brief and expect more of the same as we head
into the day today. Snow accumulations thus far have been around
2 to 4 inches at best across the eastern Uintas and portions of
the West Elks and Sawatch, really closer to the eastern side of
our zones bordering PUB. This is as expected with limited impact
on our side with wet roads during the day.

There appears to be two circulation centers with this
retrograding low under the Rex Block, one over east central Utah
currently as of this morning and another that will develop over
southern Nevada as the low retrogrades and the east-central Utah
circulation sort of fizzles out by this afternoon. This along
with steepening lapse rates especially across the Four Corners
should allow for more convection this afternoon to develop over
southwest Colorado and track into the central mountains and
around the low to the north across northwest Colorado and
northeast Utah by this evening. Expect scattered to widespread
showers with embedded thunderstorms. Milder temperatures should
keep snow levels above 9000 feet but any convection could lower
snow levels and increase rates at times, although with the
convective nature of showers and quicker motions, these
conditions should be brief. Another 2 to 4 inches of snow
remains possible in the higher elevations with passes remaining
wet. A brief pause in shower activity looks to be seen this
evening across the south but redevelops as the low center shifts
closer across southern Utah by Saturday morning prior to
daybreak. Some hi res CAMs are picking up on increasing
convective showers Saturday morning across southeast to east-
central Utah and spreading into southwest and west-central
Colorado by Saturday afternoon as the low moves northeast across
southeast Utah to west-central Colorado with the trough axis
moving overhead. More widespread shower and thunderstorm
activity is expected on Saturday as this happens. Temperatures
will continue to warm though with another 2 to 4 inches of snow
possible at the highest elevations of the San Juans and central
mountains, mostly above 10,000 feet with limited impacts at pass
level and some wetting rain among some of the lower elevations.
Despite the slowly warming temperatures each day today through
the weekend, temperatures will still remain below normal.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 356 AM MDT Fri May 10 2024

The back edge of the trough will be moving eastward, crossing
the Divide Saturday evening before subsidence takes hold by
Sunday morning with northerly flow on the backside of the
exiting trough. A ridge of high pressure tries to build across
the Great Basin into the Intermountain West Sunday, but
additional shortwaves will move through the unsettled northerly
flow, allowing for continued development of afternoon convective
showers, favoring the higher elevations of western Colorado
mostly along the Continental Divide. Conditions should be
mostly dry though across eastern Utah and far western Colorado,
especially lower elevations. An additional couple of inches of
snow will be possible at the higher peaks but, again, little to
no impact is expected.

Unsettled northerly flow will keep showers in the forecast for
Monday morning but a weak transitory ridge will build in from
the west for the afternoon. This advection of drier air will
see showers taper off in coverage, though scattered activity will
continue over the mountains. For Tuesday and Wednesday,
moisture will once again be on the rise as a trough of low
pressure begins to dig into the Intermountain West. This will
kick the ridge east and see flow aloft shift to the
west/southwest. Winds don`t look to increase too much ahead of
this system but, by the midweek point, scattered to potentially
numerous showers and some storms can be expected. The trough is
projected to drop through the area from the north Wednesday
night into Thursday, potentially trying to close off another low
over the Desert Southwest with a Rex Block trying to form once
again over the west by the end of next week. This is still a
ways out and a lot can change but it does look to remain
unsettled through next week as well.

Temperatures through the period will start off below normal on
Sunday given the unsettled pattern. A gradual rebound will
occur with a slow warming trend as we head into the new work
week and the flow begins to shift to a more mild component. High
temperatures should rise to around 5 degrees above normal next
week with slightly cooler than normal highs for the mountain
areas. A similar trend is expected for low temperatures through
the period. A brief cooldown is possible Wednesday into Thursday
if that trough moves through the area from the north.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 551 AM MDT Fri May 10 2024

Scattered showers and isolated thunderstorms will continue
through the morning over the San Juans with isolated showers
across the central and northern mountains as moisture rotates
around the low. Coverage of showers is expected to increase this
afternoon with isolated thunderstorms possible and occasionally
breezy conditions especially near any showers. Expect VFR
conditions for much of the period with MVFR at times in any
shower activity.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...MDA
LONG TERM...MMS/MDA
AVIATION...MDA