Phippsburg, Colorado Weather Forecast Discussion

646
FXUS65 KGJT 052141
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
341 PM MDT Fri Sep 5 2025
.KEY MESSAGES...
- Showers and thunderstorms taper this evening, then continue
  again Saturday afternoon with more widespread coverage.
- Higher rainfall rates could produce localized flash flooding
  Saturday on burn scars and other sensitive locales.
- Temperatures will remain around climatology before a warmup
  starts Monday onwards.
&&
.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 336 PM MDT Fri Sep 5 2025
Extra-tropical moisture continues to produce showers and
thunderstorms across the Great Basin this afternoon. Weak steering
winds beneath the high are keeping storm motions mostly north to
south. PWAT values remain high. The mid-day sounding here at Grand
Junction saw a 20 percent jump over 24 hours. Showers today, have
produced measurable rainfall in the saturated conditions. Storms
will continue to form on north aspects and drift south off of
terrain features early this evening. This includes the Colorado
River Valley and southerly aspects of the San Juans, where
thunderstorms have been rather productive along the 160 highway
corridor. Storms will produce gusty outflows and brief downpours
through this evening. Sunset will slow activity down and a few
showers can be expected to linger overnight. Elevated dewpoints and
some cloud cover will keep overnight lows tempered tonight, with
morning lows averaging around 5 degrees above climatology.
The upper level ridge shifts slightly east Saturday. This looks to
force some of the heaviest PWAT values(in excess of 150 percent of
climatology)into the Four Corners and north along the UT/CO border.
Synoptically, the upper level pattern stays basically parked
overhead, including the light steering winds. I would expect the
storm motions to shift a little more northwest to southeast
Saturday. The main concern remains the abundant tropical moisture we
have to work with.  Some localized flooding concerns emerge
Saturday, given the potential for amplified rain rates. With
northwest flow emerging tomorrow, it looks like the best bets for
productive rainfall will remain south of I-70. However, a passing
shortwave late Saturday afternoon will produce some additional
showers for our northern counties. Drier northwest flow behind this
wave is expected to turn the tap off Saturday evening into Sunday.
&&
.LONG TERM /SUNDAY 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 /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1207 PM MDT Fri Sep 5 2025
Showers and thunderstorms continue from the Uncompahgre Plateau
over to the Elk Mountains, and points south late this morning
as a remnant MCV from overnight convection continues to meander
south- southeast. This circulation is already sparking early
thunderstorm development near KTEX and the San Juans and will
likely continue to cause scattered thunderstorms through the
afternoon there as well as south to KDRO as these thunderstorms
exit the high terrain in the northwest to northerly flow.
Elsewhere, lingering higher PWATS will promote shower and
thunderstorm development over the higher terrain during the mid-
afternoon from the Grand Valley into the Elk Mountains, with
showers/storms coming off of the terrain and moving northwest to
southeast into the early evening. Generally where thunderstorms are
expected, ceilings down to 5000 to 8000ft may occur. Otherwise cloud
bases will be 10000ft or higher. Large surface Tdds may support some
sporadic gusty winds with storms as well.
KCNY and TAF sites north of the Flat Tops/northern edge of the CO
plateau will likely stay dry through today with some mild intrusions
of wildfire smoke at the surface. Vis down to 6SM may occur.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...LTB
LONG TERM...KJS
AVIATION...TGJT

NWS GJT Office Area Forecast Discussion