Phippsburg, Colorado Weather Forecast Discussion

256
FXUS65 KGJT 060039
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
639 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 /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 627 PM MDT Fri Sep 5 2025
Scattered showers and thunderstorms will continue this evening
with most activity ending shortly after sunset. Gusty winds to
35 mph and brief heavy rain could result in MVFR conditions with
reduced visibility and lower ceilings. VFR conditions should
prevail for the most part including overnight. A disturbance
will push through Saturday afternoon, with more widespread storm
activity possible after 17Z Saturday through the evening. Higher
terrain appear favored initially but most TAF sites could see
impacts at some point Saturday afternoon with brief heavy rain,
frequent lightning and gusty outflow winds possible with storms.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...LTB
LONG TERM...KJS
AVIATION...TGJT

NWS GJT Office Area Forecast Discussion