000
FXUS65 KGJT 202010 CCA
AFDGJT

Area Forecast Discussion...CORRECTED
National Weather Service Grand Junction CO
210 PM MDT Sat Jul 20 2024

.KEY MESSAGES...

- Daily showers and thunderstorms can be expected, though storm
  coverage will gradually decrease each day and begin to favor
  the mountains.

- Gusty outflow winds, lightning, and brief moderate to heavy
  rain will be possible with storms. Localized flash flooding is
  possible down south.

- Wildfire starts from lightning remain possible into the new
  week as storms remain high based.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 208 PM MDT Sat Jul 20 2024

Drier weather has prevailed across the north as expected today,
thanks to the advection of drier air from the northwest. Down
south has been a different story as we`ve seen convection re-
develop over the higher terrain. The atmosphere remains juicy as
moisture stays pooled across southwest Colorado in particular,
leading to some drift of showers and storms into the adjacent
valleys. Not much wind with storms thus far but the potential
for gusty outflows remains possible in addition to periods of
moderate to heavy rain. Similar to the last several days, the
threat for localized flash flooding prevails as storms continue
to train, so something to monitor over the coming hours. With
the loss of daytime heating this evening, convection will begin
to taper off from north to south. However, a weak shortwave will
brush southwest Colorado tonight, seeing showers linger near the
Four Corners into Sunday. The ridge amplifies farther north on
Sunday, advecting additional dry air into the region, with PWATs
projected to drop back to slightly below normal. Even so, there
will be plenty of pockets of moisture lingering down south and
along the Divide, so look for another round of showers and
thunderstorms to develop by midday Sunday. Once again, storms
will be capable of producing gusty outflow winds and we can`t
rule out brief heavy rain. Outside of storms, look for dry
weather with passing clouds. Temperatures will continue to trend
slightly above normal through the period.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 208 PM MDT Sat Jul 20 2024

The area of high pressure that has influenced our weather for many
days now will continue to do so through much of the long term
period. This high pressure will remain to our west which will keep
generally northerly flow across the region. This will keep the
deeper moisture to our south so while we will still see afternoon
and evening convection, heavy rainers will be less of a concern.
Even so, in this type of environment even brief, heavy rain could
cause some concerns in those particularly flashy areas. As far as
actual moisture, PWATs Monday through Wednesday will be around 0.4
inches while Thursday and Friday we`ll see a bump into the 0.8 to
1.0 inch range. The reason for the increased moisture towards the
end of the week is an approaching trough from the PacNW that is
forecast to flatten the high pressure. Both the GFS and EC are
indicating this occurring while ensemble clusters are also
forecasting this trough moving through. As the high begins to break
down, flow will become more south through southwesterly allowing
monsoonal moisture to return. Thus, an increase in PoPs and
convective coverage which the NBM looks to be handling quite well.

All that being said, we`ll see convection firing off the terrain
Monday through Wednesday with the usual gusty outflow winds, small
hail, and brief, heavy rain possible. Thursday will see a small
increase in coverage but the bigger push of moisture won`t occur
until Friday. For Friday then, we`ll see an uptick in coverage and
also QPF. Of course, the usual caveat applies and that being this
far out, some changes can be expected especially for Thursday and
Friday.

As far as temps are concerned, we`ll see generally seasonal highs
Monday with a warmup midweek before dropping back down to more
normal highs heading into the weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1107 AM MDT Sat Jul 20 2024

Expect scattered showers and thunderstorms to develop over the
higher terrain this afternoon with better coverage for areas
south of I-70, namely KTEX, KDRO, KGUC, KASE and KEGE. VFR
conditions should prevail but brief reductions to MVFR is
possible in any shower/storm. Gusty outflow winds to 40 mph
possible near any showers/storms. Winds potentially pick up this
evening but should become light and terrain driven after 06Z
Sunday. A few showers will linger over the San Juans into Sunday
morning with dry weather prevailing elsewhere until activity
re-develops Sunday afternoon.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...MMS
LONG TERM...TGR
AVIATION...TGJT