459
FXUS65 KGJT 132149
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
349 PM MDT Thu Jun 13 2024

.KEY MESSAGES...

- A storm moving eastward across the Desert Southwest approaches
  the region tonight. Lift and moderate moisture ahead of this
  system is expected to bring a chance for light showers and
  isolated thunderstorms late tonight for portions of the Four
  Corners region.

- Showers increase Friday with the the San Juan and central
  Colorado mountains favored Friday afternoon/evening.

- Temperatures cool off Friday but rebound Saturday and into
  next week. Above normal heat combined with dry and breezy
  conditions from Sunday onwards is likely to bring critical
  fire weather conditions.


&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 349 PM MDT Thu Jun 13 2024

The forecast area was under a ridge of high pressure this
afternoon ahead a low pressure system circulating over the
coast of southern California. Temperatures have climbed well
above normal again this afternoon with Grand Junction tying the
record for this date at 101. Clouds were increasing ahead of
the low and a few light showers/virga had developed over the
Four Corners region and the San Juan Mountains.

This activity is expected to diminish this evening, but will be
redeveloping later tonight as the SoCal low moves to western
Arizona. As the low moves northeastward on Friday, shower and
thunderstorms will increase with the San Juan Mountains and the
central Colorado mountains favored, especially during the
afternoon. Increased clouds combined with shower activity will
bring some relief from the unseasonably hot conditions
experienced over the past several days.

The trough axis shifts east of the Continental Divide Friday
evening bringing subsidence aloft which, when combined with
diurnal cooling should bring an end to showers/thunderstorms by
late evening. Thereafter, expect decreasing clouds and
moderately cooler overnight lows.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 349 PM MDT Thu Jun 13 2024

A shortwave ridge of high pressure will slide overhead Saturday
behind the exiting low pressure trough from Friday. There looks to
be enough residual moisture with a little bit of lift to allow for
some isolated showers or storms to pop off the higher terrain
particularly across the north and along the divide. Not expecting
much though as drier southwest flow begins to infiltrate the area
but any shower activity may generate more virga and gusty winds as a
result than wetting rain. Meanwhile, low pressure troughs will be
rolling over the Pacific Northwest and lifting northeast into the
Intermountain West and northern Rockies this weekend through the
coming week. We will see the upper level jet and perhaps a frontal
boundary lay across the north, which should result in a tightening
gradient with increasing southwest winds. So expect breezy
conditions across northeast Utah and northwest Colorado this
weekend. These breezy and dry conditions expand further southward
and become more widespread Sunday into early next week as the jet
dips further southward.  This will lead to potential critical fire
weather conditions and start getting into the areas where our fuels
are deemed critical and ready to burn.  The status of other zones
may change, which would then expand the coverage of potential fire
weather highlights. These hot, dry and breezy conditions look to
last at least through Tuesday before we see a bit of a reprieve
from the heat and some cooler temperatures mid week due to the
influence of the passing trough and front to our
north...although no precipitation is expected as we are on the
wrong side of that upper level jet. After our brief cooldown,
temperatures look to spike back up late next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1147 AM MDT Thu Jun 13 2024

VFR remains the rule today as high pressure remains overhead.
Another round of gusty west through southwest winds is expected
today reaching 20 to 30 mph at times. Clouds will increase in
the afternoon and evening hours as the next system approaches
from the southwest. Some midlevel ceilings are possible heading
towards Friday morning.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...NL
LONG TERM...MDA
AVIATION...NL