Austin, Colorado Weather Forecast Discussion

296
FXUS65 KGJT 061203
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
603 AM MDT Sat Sep 6 2025
.KEY MESSAGES...
- Showers and thunderstorms continue today with more widespread
  coverage.
- Higher rainfall rates could produce localized flash flooding
  today on burn scars and other sensitive locales.
- Temperatures will remain near the climatological mean before a
  warming trend Monday onwards.
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 358 AM MDT Sat Sep 6 2025
Satellite imagery shows the ridge still extending north into British
Columbia dominating our weather pattern advecting much of the
extra-tropical moisture along its western flank up out of the
Great Basin into Idaho, Oregon and Washington. A shortwave
disturbance slowly working its way through the lower Great Basin
into southwestern Utah is keeping nocturnal thunderstorms going
in the Las Vegas area north to Richfield UT. This shortwave
will track northeast across central eastern Utah and
northwestern Colorado this afternoon and early evening pulling
moisture out of northern Arizona into the Four Corners area and
drawing some of the extra-tropical moisture with it out of the
Great Basin into eastern Utah and Western Colorado to keep pwats
in the 0.7-0.8 range across the region for today. Skies are
clearing out across the region and to the west due to the
subsidence under the ridge as it shifts slightly eastward. This
opens the door to strong diurnal heating through the morning to
kick off convection early and to pump more energy into the
atmosphere for stronger convection through the afternoon. Look
for orographic showers to start building on the southern
mountains by mid morning, transitioning into thunderstorms by
noon as they spread to the northeast across the region. These
storms will continue to be slow moving due to the weak flow
aloft, but will track more to the east or southeast with the
westerly shift in the winds aloft. These storms continue to be
capable of producing heavy rain that will pose a greater threat
of flash flooding to the more east-west oriented valleys and
canyons where storm training is more probable. As the shortwave
moves through, convection will diminish from southwest to
northeast through the late afternoon into the evening with
lingering scattered showers over the central to northern
Colorado mountains into the overnight period before the
shortwave exits to the northeast.
Skies will clear out overnight behind the shortwave allowing for
diurnal heating to initiate convection Sunday over the southern
mountains taking advantage of moisture lingering in the area.
Another shortwave will work its way across the areas along and
north of the I-70 corridor Sunday afternoon and evening with yet
potential for a few stronger thunderstorms.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 336 PM MDT Fri Sep 5 2025
On Sunday the region will be under quasizonal flow aloft situated
on the northern periphery of a weak ridge. Dry air working in from
the west will start to decrease the coverage of convection across
the area. There should still be enough moisture for scattered
showers and storms. By Monday that dry air might only allow for
isolated showers. Meanwhile a deep low pressure will approach the
Pac NW keeping the southwesterly flow going. The models show a piece
of that energy breaking off, forming into a separate low and then
tracking over the Great Basin. Unfortunately, there are differences
with the timing and location of that secondary low. If that low
materializes it will cause a shift to southerly flow for our area.
This would pull some deep moisture in from New Mexico towards the
end of next week.
&&
.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 544 AM MDT Sat Sep 6 2025
Mostly clear skies and light winds across the region will give
way to high clouds moving in from the west and convection firing early
on the southern mountains after 15Z. Showers and thunderstorms
will become widespread across the region between 18Z and 00Z
with stronger storm capable of producing frequent lightning,
torrential rain, strong gusty outflow winds and hail. Storms
will diminish after 00Z with isolated showers over the central
and northern Colorado mountains after 06Z. Mountains TAF sites
may see periods below ILS breakpoints with passing storms.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...DB
LONG TERM...KJS
AVIATION...DB

NWS GJT Office Area Forecast Discussion