000
FXUS65 KGJT 142344
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
544 PM MDT Sun Apr 14 2024

.KEY MESSAGES...

- Warm and breezy weather with near-critical fire weather
  conditions will continue through this evening

- The much discussed Pacific low moves in tomorrow, 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 Monday night
  into Tuesday.

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

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 152 PM MDT Sun Apr 14 2024

Under generally clear skies and gusty south to southwesterly winds,
temperatures have once again climbed 10-15 above the norm for mid-
April, with mid to upper 70s across the lower valleys, 60s for the
higher valleys, and mid to upper 50s for the mountain towns. These
blustery southwest winds will be with us through the rest of the
day, as stronger winds from the jet aloft are mixed down to the
surface. Makes it a great day to go fly a kite! But it also means
that, with very dry air and low relative humidity at the surface,
localized near-critical fire weather conditions are possible, so
it`s worth being mindful of potential spark sources if out enjoying
the lovely weather.

A clear and relatively mild night tonight will give way to
increasing clouds and moisture as the Pacific cutoff low finally
makes it to eastern Utah and western Colorado. The cold front
associated with this system will be on the doorstep around daybreak
tomorrow, and will push its way east over the course of the day.
Temperatures will be significantly cooler, topping out only in the
low 60s for the desert valleys, upper 40s to low 50s for the higher
elevation valleys, and upper 30s to low 40s for the mountain towns.
Overall, a good 5 or so degrees below normal for mid-April, and a
nearly 20 degree departure from highs today. Some light shower
activity will be possible with the front during the late morning and
early afternoon hours, but the dry air at the surface will take some
time to moisten up, meaning virga will be more likely, at least to
start. The low moves east of the Divide late Monday evening, and as
it does so, begins to tap into a deep feed of Gulf of Mexico
moisture over the Plains. It is this moisture, wrapping around the
low, that will bring significant snowfall to the northern and
central mountains Monday night into Tuesday. There is still some
question as to whether all of this moisture will make it into
western Colorado, as afternoon convection on the Plains may siphon
away a good chunk of it before it even reaches the state of
Colorado. If that happens, totals will be less than the current
forecast, but the northern and central mountains can still expect to
see accumulated snowfall by Tuesday morning. With colder air in
place, deep moisture, and favorable northerly to northwesterly flow,
the Park Range is forecast to do especially well, with totals of 6-
12 inches likely, and up to 18 inches possible above 10000 feet. The
Gore, Elk, and Flat Top ranges are looking at slightly less
snowfall, but still within the 6-12 inch range. Some of the lower
elevation Central Mountain Valleys, including Aspen, Snowmass, and
Redstone, are expected to see less 6 inches of snow, but the
uncertainty in the snow level made it difficult to restrict the
advisory based on elevation. Winter Weather Advisories are in effect
for these ranges beginning noon tomorrow and lasting through noon
Tuesday. The biggest push of snow will be between midnight and 6AM
Tuesday.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 152 PM MDT Sun Apr 14 2024

Through the day Tuesday the slightly tilted cyclone Plains
cyclone will move far enough East to pull the TROWAL then
moisture to dry things out over our region. Temporarily anyway.
The northern and central divide mountains are likely to see some
decent QPF as this winds down and the Park Range likely the
winner if it all plays out as the models suggest attm. The one
caveat could be the strength of the Plains convection tomorrow
disrupting the main plume of moisture wrapping back our way.
Transitory ridging Tuesday night becomes zonal on Wednesday
before the effects of a large Canadian Prairies vortex descends
farther into the mid latitudes. This will push a front through
the northern CWA where temperatures will drop back closer to
normal while farther South things stay well above normal to end
out the week. Moisture riding along and over the mid and lower
thermal boundaries will create showery conditions over the
northern valleys and much of the central and northern mountains
Thursday into Friday. With this thermal gradient comes winds and
breezy to windy afternoons can be expected...especially in the
warmer well mixed environments across the central and South.
This pattern remains stagnant until the weekend with the next
upstream system arrives to the Intermountain West to break
things up. This could lead to a more even distribution of
showers across the CWA for the weekend. A lot can happen between
now and then...especially in shoulder season...so confidence to
overly high. Basically cooler wetter North...warmer and breezy
South is the bottom line.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 538 PM MDT Sun Apr 14 2024

Breezy and VFR conditions will continue this evening. Skies will
remain mostly cloud free across the region through the overnight
hours, as nighttime winds subside. An approaching frontal
boundary on Monday will bring winds up from the southwest, with
gusts 25-35 mph for most terminals Monday. Cloud cover will
begin to increase Monday afternoon too, with a few mountain
terminals in northern Colorado beginning to see chances for
rain/snow showers developing at the tail end of this TAF period.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory from noon Monday to noon MDT Tuesday
     for COZ004-010-013.
UT...None.

&&

$$

SHORT TERM...BGB
LONG TERM...15
AVIATION...TGJT