219
FXUS65 KGJT 262316
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
516 PM MDT Thu Sep 26 2024

.KEY MESSAGES...

- Dry and unseasonably warm conditions are expected for the
  remainder of the week through at least the first few days of
  next week. Near-record highs are expected to continue today
  through the weekend.

- A weak disturbance brings potential for isolated afternoon
  storms over the eastern portions of the southern and central
  Divide mountains tomorrow afternoon. Outside of Friday, dry
  conditions prevail.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 236 PM MDT Thu Sep 26 2024

The blocky pattern across the CONUS continues with a low...ridge
low pattern extending from the EPac through the Southeast. The
northern extend of the ridge over us is getting deformed a bit
by a more robust wave moving through the northern stream near
the Canadian/US border. The interface between this wave and the
ridge has tightened the thermal profile aloft...hence a core of
stronger Southwesterlies. A bit of mositure has been caught up
in this flow and evident on the 12Z KGJT RAOB which has led to
the uptick in cloud cover today. The subsidence inversion over
this moisture should prevent much upscale and not expecting any
shower activity...but late day heating and strong terrain
circulations may have another say. The chance of storms
continues to be hinted at tomorrow along the central and divide
mountains...and farther back into the central San Juans. Large
scale ascent is not very evident but rather isentropic levels
show easterly upslope flow as early as tonight pushing moisture
into this area. A weak low level boundary connected to the
northerly wave looks to dive down the High Plains of CO tomorrow
morning and this added upslope looks to help form these mainly
terrain based storms tomorrow. Coverage looks widely scattered
at best and there could be a few gusty winds in the afternoon
associated with these high based storms which should be ending
through the evening...possibly lingering over the eastern San
Juans toward midnight. Well above normal/near record
temperatures continue.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Issued at 236 PM MDT Thu Sep 26 2024

There remains no big changes to the pattern through the weekend
and really into early next week. The downstream low which will
have absorbed Helene will slowly be filling as we head into
Monday. The upper ridge remains firmly anchored over the 4
Corners region and a more compact cyclone will be heading
lingering near the SoCal Coast. This keeps the hot airmass in
place along with the dry conditions. There is some lingering
moisture over the San Juans going into Saturday which will
likely pops some more convective clouds but confidence extremely
low this will turn into anything of significance. Temperatures
will continue to run some 10 to 15 degrees above normal with 90
degrees expected over many of the lower desert valleys. The
latest 90 degree temperature recorded at GJT is Sept 27th so
this may be pushed back by a few days with records possible
each day through Monday. The early to mid part of next week
will only be slightly cooler. The northern stream looks to be
dipping a bit farther south through the latitudes and finally
being to break down blockier pattern over the southern CONUS.
There may a better chance of perception showing in the
forecast...but not until late in the week. Confidence in models
figuring this out by then is not high.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 515 PM MDT Thu Sep 26 2024

High clouds will continue to stream over the area over the next
24 hours, but will not impact terminals. VFR conditions will
prevail for the next 24 hours, with winds remaining generally
light and terrain driven.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

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