151
FXUS65 KGJT 101758
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1158 AM MDT Mon Jun 10 2024

.KEY MESSAGES...

- Showers and storms continue today, favoring the southern
  mountains and the Divide. Gusty outflow winds will be the
  primary threat from storms.

- Temperatures will cool slightly today, then inch upward by
  Wednesday, with highs nearly 15 degrees over normal expected
  Wednesday afternoon.

- Drier weather is expected from Tuesday onwards. Active weather
  returns late week as the next system arrives Friday, along
  with some temperature relief.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 315 AM MDT Mon Jun 10 2024

A weak circulation spinning over the Front Range has fueled
isolated showers early this morning and this will continue
throughout the day as another round of scattered showers and
thunderstorms is expected. These upslope conditions have
resulted in an uptick in mid- and upper-level moisture while dry
air continues to plague the lower levels of the atmosphere, as
evident by the prominent inverted-V on the 00Z GJT sounding.
Even so, this does still translate to PWATs that are well above
normal with dewpoints projected to reach the mid to upper 30s
for much of the region this afternoon. Slightly better forcing
from the surface low itself paired with additional moisture
advection will result in better thunderstorm coverage today,
particularly across the southern Colorado mountains, though
instability remains marginal at best. So, similar to yesterday,
activity will favor the higher terrain with gusty outflow winds
being the primary concern. However, brief periods of moderate to
even heavy rain cannot be ruled out. Even though much of the
storms will be anchored to the terrain, outflow boundaries from
collapsing storms will help fire off storms in the valleys later
on in the day. Another area of focus for precipitation today
will be our far northern zones where the base of a trough
pushing through Wyoming will help fuel isolated to scattered
storms.

Shower and thunderstorm activity dwindles after sunset as the
northern trough and eastern low both exit towards the Plains.
This will allow high pressure to build overhead across eastern
Utah and western Colorado for Tuesday. While daytime heating
will act on residual moisture to fuel orographically-driven
convection Tuesday afternoon, dry weather is expected elsewhere.
After a slightly cooler day today, temperatures will once again
rebound back to several degrees above normal for Tuesday.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 315 AM MDT Mon Jun 10 2024

Strong zonal flow across the northern CONUS will hold the storm
track and any chance of cooler air well away from our area to start
this period. We will be looking at a hot a dry mid week forecast as
the SubTrop High squeezes into the 4 Corners Region...caught between
another closed Baja system and a Southern Plains low. Highs both
Wednesday and Thursday look to be around 10 to 15 degrees above
normal in most areas with triple digits pushing back into the lower
desert valleys. Very dry air moving into the area will help the
atmosphere heat up but also radiate efficiently at night with some
relief as lows drop into the 60s. Moisture will begin to move back
into the region Thursday night as the upstream low begins to kick
eastward into the Desert Southwest. PWAT anomaly is 1-2 StdDev by
Friday as the upper low moves into the Great Basin. There is still a
bit of discrepancy between global models on whether the main
circulation of this low stays to our South...or lifts across if in
the GFS camp. Either way the trough will provide some large ascent
for storm formation in the afternoon and a cooler wetter forecast is
in the cards for now. However this push of moisture is brief and the
storm progressive so feel the lower levels won`t have a lot of time
to saturate. This means a high based storm mode with gusty outflow
winds would be the main threat...though under the right outflow
boundary conditions a few stronger organized storms might be able to
produce some heavier rainfall rates. In the GFS solution another
decent lee side fropa event will provide upslope moisture
convergence along the divide and it blows up storms there by late
afternoon with the northern trough solution. Confidence will need to
increase before messaging any threats. Dry weather returns for the
weekend as another anomalous weather pattern sets up across NW NOAM
with a digging trough dipping across the PacNW into the
Intermountain West. Warm and breezy Southwest flow will be the end
result for our CWA in this pattern.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1154 AM MDT Mon Jun 10 2024

Showers and storms will develop over the mountains this
afternoon. Brief moderate rainfall rates and gusty outflow
winds are possible. KDRO, KGUC and KTEX have the highest
probability of these storms moving over the airfield but
confidence still not high enough to go beyond VCTS attm.

&&

.HYDROLOGY...
Issued at 337 AM MDT Sun Jun 9 3374

Hydrographs continue to trend downward today as the snowpack
has largely dwindled and temperatures cool compared to this
weekend. As a result, all ongoing advisories are still on track
to be discontinued later on this afternoon and evening. Even so,
please continue to use caution when walking near riverbanks.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...MMS
LONG TERM...15
AVIATION...TGJT
HYDROLOGY...TGJT