516
FXUS65 KGJT 012112
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
312 PM MDT Mon Jul 1 2024

.KEY MESSAGES...

- - A Flood Watch for southeast Utah and southwest Colorado
  remains in effect through 6 PM this evening. Localized
  flooding remains a concern under thunderstorms, as deep
  monsoonal moisture clears the region.

- Cooler and drier conditions return Tuesday with chances for
  terrain based showers and thunderstorms along the Continental
  Divide and our southern mountains.

- Warmer and drier weather brings the return of critical fire
  weather conditions Wednesday and Thursday.


&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 258 PM MDT Mon Jul 1 2024

A sharp moisture gradient hangs southwest to northeast across the
northwest tier of our CWA this afternoon. Dewpoints in Blanding, are
20 degrees greater than Moab to the north. This boundary has been
the difference in fair weather cumulus sprouting in the remnant
moisture and thunderstorms capable of heavy downpours and flash
flooding. The better convection has set up closer to this sharp
moisture gradient that is drifting east and southward through the
evening. Our Flash Flood Watch is expected to drop off at 6pm MDT as
the threat of flooding quickly diminishes this evening with the
departure of PWAT values some 200 percent of normal. Storms will
continue to fire on the terrain as this boundary works through the
region this evening. Gusty winds, small hail, and heavy rainfall
rates can be expected, mostly on the Colorado side of the state
line. Precipitation chances will stick around during the overnight
hours as we clear the abundant moisture from the terrain. Dry air
begins to invade from the northwest tomorrow. However, enough
moisture should remain to keep a shower or thunderstorm in the
forecast along the Continental Divide and terrain south of the
Colorado River tomorrow afternoon. These storms aren`t expected to
pack as much moisture and will likely be gusty affairs with some
small hail mixed in. Afternoon highs will remain milder tomorrow
too, as we get a taste of lower humidity in the northwest flow.
Clearing skies Tuesday night and lower dewpoints will allow
overnight lows to come back down to seasonal normals.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 258 PM MDT Mon Jul 1 2024

On Wednesday high pressure begins to nose over the West Coast while
a trough dives into the Northern Rockies and Northern Plains. This
leaves us under northwest flow aloft that will be pumping in much
drier air. This essentially pushes the monsoon moisture into the
Desert Southwest and Mexico. On Thursday the trough intensifies into
a closed low pressure over the central US. The models are suggesting
that the far northeast corner of the CWA gets clipped with some
moisture due to that system. Although they do not generate any QPF,
so we keep conditions dry for most of the area. Meanwhile the ridge
over the West Coast, which is where the heat will reside, expands a
bit to the north. For our area high temperatures on Thursday will
actually be near normal to around 5 degrees below normal. Over the
weekend the ridge nudges eastward slightly, but overall remains
anchored. Models are hinting at several shortwaves diving in from
western Canada essentially keeping the ridge in place to our west.
By early next week not much changes with the pattern. Perhaps the
ridge nudges to the east some causing our temperatures to come up a
few degrees. Given the general position of the ridge dry northwest
flow persists and therefore we are expecting mostly quiet
conditions.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1121 AM MDT Mon Jul 1 2024

Another round of widespread showers and storms is expected today
and tonight. These showers will be capable of heavy rain and
gusty winds generally up to 50 mph. Brief MVFR/IFR conditions
are possible. With a front moving through the area and showers
around the typical drainage winds may be disrupted tonight.

&&

.HYDROLOGY...
Issued at 258 PM MDT Mon Jul 1 2024

A Flash Flood Watch is expected to expire this evening for
southeast Utah and southwest Colorado. Localized flooding
potential will remain a threat under strong thunderstorms this
evening. Drier conditions return Tuesday with the departure of
the rich monsoonal moisture, thereby taking much of the flash
flood concern off the table.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Flood Watch until 6 PM MDT this evening for COZ009-011-012-014-
     017>023.
UT...Flood Watch until 6 PM MDT this evening for UTZ022-028-029.

&&

$$

SHORT TERM...LTB
LONG TERM...KJS
AVIATION...TGJT
HYDROLOGY...TGJT