765
FXUS65 KGJT 221725
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1125 AM MDT Tue Apr 22 2025

.KEY MESSAGES...

- Temperatures continue to warm up through the week, with
  isolated to scattered mountain showers each afternoon. The
  chance of wetting precipitation remains low with virga and
  gusty winds the likely result.

- Southwest winds increase late this week into the weekend ahead
  of an approaching disturbance, resulting in dry and warm
  conditions and potential for critical fire weather conditions.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 318 AM MDT Tue Apr 22 2025

Instability showers are continuing to move across the Bookcliffs
and Flattops north of I-70 as the frontal boundary appears to be
hung up here. The NAMNest is picking up on this shower activity
pretty well among the hi-res CAMs but having a tough time
finding evidence of anything of note reaching the ground. These
are likely virga showers or just cumulus clouds given the very
dry sub-cloud layer as seen on last evening`s GJT sounding. This
frontal boundary is expected to wash out this morning with steep
lapse rates above 9 C/km and about 100-200 J/kg of CAPE being
enough to generate some isolated to scattered convective showers
with slight chance of a thunderstorm over the western Colorado
Divide mountains. Anticipate less coverage than yesterday with
very little in the way of precipitation with these showers.
Overall, today should continue our warming trend with many lower
central and southern valleys rising into the 70s with 60s across
the northern valleys and 50s in the mountain towns...about up to
5 degrees warmer than yesterday and sitting right around 5 to 10
degrees above normal. Drier conditions can be expected more
often than not as there is little in the way of moisture to work
with. Winds will be less breezy as well given the lack of a jet
streak and shortwave forcing as well as primarily zonal flow,
so critical fire weather conditions this afternoon appear more
marginal and localized. Therefore, opted not to issue any Fire
Weather highlights today.

For Wednesday, the flow becomes more southwesterly as a
shortwave trough drops into the Pacific Northwest. This turning
of the winds will allow for drier air to advect in from the
Desert Southwest, while the Front Range and Plains see a bit of
a Gulf moisture tap. Daytime heating and instability along with
a little moisture added to the air from snow melt should be
enough to generate some convective showers across the mountains
along the Divide once again with very little in the way of
precipitation and more virga resulting in gusty winds due to the
dry sub cloud layer. The best moisture resides on the Front
Range as the Rocky Mountain Divide represents the separation
between drier conditions on the western slope and better
moisture on the Front Range to result in daily storm activity.
Due to the drier southwest flow, we will still see continued WAA
with highs in some lower desert valleys pushing 80 but most
valleys rising well into the 70s. Highs will end up about 10 to
15 degrees above normal.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 318 AM MDT Tue Apr 22 2025

Thursday represents another day of warming temperatures in dry
southwest flow with daytime heating and instability resulting in
isolated to scattered showers/storms over the mountains mainly
along the Divide and across the eastern Uintas due to an
embedded shortwave moving through. The best moisture stays east
of the Divide over the Front Range and our drier southwest flow
seems to prevent this moisture from spilling over. A larger
low pressure trough moves onto the West Coast by Friday and
carves out a deeper low over the Great Basin by this weekend. A
100 kt jet streak rounds the base of this trough, which will
increase the gradient winds across our area for Friday through
Sunday. Given the advection of drier air from the Desert
Southwest and limited moisture, we should see a return to more
widespread critical fire weather conditions due to the gusty
winds and low relative humidity values. H7 winds increase to 30
to 40 kts Friday, Saturday and Sunday...so good chance these
winds mix down to the surface. There is still some discrepancy
among models on the track of this low but it does appear that
changes are in store for late Sunday into Monday as this low
potentially tracks across our area bringing cooler temperatures
and some wetting precipitation. Not holding my breath on this
though as it is still a ways out, but something to keep an eye
on going forward. Regardless, temperatures are expected to be 8
to 15 degrees above normal at least through the coming weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1122 AM MDT Tue Apr 22 2025

Scattered to broken cloud cover has developed over the higher
terrain, but should remain well above any breakpoints. A few
light showers may develop over the terrain this afternoon, but
little in the way of precipitation will make it to the ground.
The main threat will be gusty outflow winds. Beyond that, gusty
westerly winds will pick up over the next few hours, with gusts
up to 25 knots possible. VFR conditions will prevail.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...MDA
LONG TERM...MDA
AVIATION...TGJT