000
FXUS65 KGJT 250742
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
142 AM MDT Thu Apr 25 2024

.KEY MESSAGES...

- Afternoon showers and thunderstorms on tap today with some
  high elevation mountain snow showers also possible.

- Unsettled weather continues Friday through the weekend as
  another system and cold front moves through. Accumulating
  snowfall is possible for the highest elevations through the
  period.

- Warm weather returns next week.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 107 AM MDT Thu Apr 25 2024

Some light returns have been showing all morning just to the
west of our CWA. A trough and associated cold front are located
over central Nevada and will keep moving closer as the day
progresses. Those returns will be in our CWA over the next few
hours. Once daytime heating commences, the trough and front get
closer, an increase in showery activity will occur this
afternoon with some thunderstorms expected as well. QG forcing
associated with the cold front, steeper lapse rates, and some
decent CAPE all point to this convection today. CAM guidance is
also on board so we can expect a more active afternoon than seen
lately. While moisture has increased somewhat, drier lower
levels still remain so some gusty outflow winds will be the
rule, might see some small hail under the stronger cells too. As
far as any snow is concerned, snow levels remain around 9K feet
so an inch or two of new snow will be possible as well. Not
expecting any accumulation on roads or pavements as any snow
will quickly melt on those surfaces. Highs today will be about
10 degrees cooler than yesterday thanks to the front moving
through ushering in those cooler temps.

Overnight, some showers will continue in northwest flow as minor
pieces of energy move through the mean flow. Some minor
accumulations of snow will be possible over the highest
elevations along the Continental Divide so yes, Vail Pass may
see a bit of snow but very shortly after sunrise, it will all
melt.

A weak ridge will build in on Friday but with plenty of moisture
remaining, cold air moving in, and favorable wind flow showery
activity will continue. The next, more potent, system will take
the form of a trough with another supported cold front at the
surface. Southwesterly flow around the base of the trough will
keep moisture moving into the region and despite ample cloud
cover, some showers and a few thunderstorms will be possible in
the afternoon once again. Like Thursday, some light snow up high
is possible but minimal accumulations expected. High temps will
be anywhere from 5 to 10 degrees cooler than those seen on
Thursday. The heaviest precip moves in Friday night onwards as
described below.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 107 AM MDT Thu Apr 25 2024

Widespread cloudy conditions will persist across the area with
showers becoming more widespread Friday evening and continuing
through Sunday night. The heaviest precip is expected late
Friday night along the Continental Divide thanks to favorable
windflow/orographics. An area of low pressure will have formed
in the base of the trough and will cause precip to shift to the
San Juans by Saturday morning though all higher terrain will see
some chances for precip. A cold front will move across Utah and
Colorado during the Saturday with a distinct wind shift from
southerly to westerly noted causing high temps to be noticeably
cooler than what we`ve seen lately. Snow is expected above 9K
ft feet during this event and this is where things get tricky.
Any snow falling during the day will have little impact as snow
will quickly melt on pavements and roads. Overnight, some snow
may stick to surfaces so the question is how much. The last few
systems dropped a few inches overnight but shortly after the sun
came up, all snow had melted. Not much impact there. It`s also
important to note that hi-res models are just starting to get
into the picture so some changes in NBM output can be expected.
Models also may not be handling the convection well as they tend
to do in late spring and could be overdoing snow amounts.
Having said all that, snow amounts look to be in the 6 to 12
inch range but we`ll see how things pan out as we get closer to
the event. Will highlights be needed? Quite possibly...

The trough and low pressure will have shifted to the northern plains
states by Sunday but we`ll continue with some showers along the
Divide. Cold air aloft will keep plenty of instability aloft as we
tend to see with these types of systems. Clouds will start to lift
Sunday afternoon, except for the mountains, with high temps already
starting to increase. Quasi-zonal flow then sets up as a shallow and
dry trough lifts into Arizona and New Mexico. This will cause
southwesterly winds to set up and bring another round of warm
temperatures to the region Monday onwards.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1132 PM MDT Wed Apr 24 2024

Scattered to broken skies will remain across the area today
increasing and lowering slowly through the day. Showery activity
will move in for the afternoon with VCSH for the mountain TAF
sites. Ceilings will remain VFR through the period but will
start to drop after 00Z. ILS breakpoints might be met after that
period for KASE and KEGE. Conditions will continue to deteriorate
overnight and tomorrow.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...TGR
LONG TERM...TGR
AVIATION...TGR