Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 312137
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
337 PM MDT WED AUG 31 2016

.SHORT TERM...(This evening through Thursday night)
Issued at 335 PM MDT Wed Aug 31 2016

High pressure centered over the Central Rockies will be shifting
east tonight as a Pacific trough moves onshore. A few weak
showers and thunderstorms will persist this evening over the
higher mountains with one or two drifting over the valleys. HRRR
model showing showers lingering through the early morning hours
along weak instability axis near the San Juans. RAP coming in
drier for the overnight hours, which pairs well with the medium
range runs for this timeframe. So will linger activity through
midnight, before shutting things down for the night.

As the trough moves inland on Thursday, moisture will be drawn
northward across southwest Colorado and eventually up into the
central zones by late in the day. Diurnal heating and slight
increase in speed sheer, as winds aloft strengthen with the
approaching trough, will be enough to kick off at least scattered
showers and thunderstorms. Storms will becoming better organized
as the day wears on with a few heavy rain producing cells
expected, especially over the San Juans and near the Four Corners
where the best moisture will reside. Precipitable water values
climb to around an inch over the Four Corners by Thursday
afternoon.

Showers and thunderstorms remain in the picture through the night
Thursday night as the trough moves into the Great Basin and
moisture continues lifting north across the region. Embedded waves
in the flow and lingering outflow boundaries will provide
additional focus for convection throughout the night.

.LONG TERM...(Friday through Wednesday)
Issued at 335 PM MDT Wed Aug 31 2016

Friday will see a few showers early in the morning with conditions
stabilizing a bit through midday. Once atmosphere recovers,
another round of showers and thunderstorms will develop with
decent support from energy kicking out of the base of the trough.
Have continued to ramp the chance of precipitation up as
confidence grows.

General southwest flow pattern holds into the weekend with showers
and thunderstorms decreasing in coverage, but sticking around
nonetheless. Southern zones will remain favored in this pattern.
Beyond this weekend, the ECMWF is advertising drier west to
southwest flow over the region, whereas the GFS remains a little
more persistent, holding onto the southwest component and hinting
at showers lingering over the high country. Based on recent
history, will side with the GFS and keep at least a slight chance
of showers in the forecast into next week, mainly over the
mountains.

No major swings in temperatures expected through the period with
MOS guidance in the ballpark.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1056 AM MDT Wed Aug 31 2016

VFR conditions are expected to prevail today under mostly sunny
skies. Isolated to scattered storms will develop after 17z over
higher terrain favoring the San Juans. Brief MVFR conditions may
occur at KTEX and KDRO under brief light to moderate rain, with
little impact to other TAF sites aside from gusty outflow winds.
Expecting most activity to end after 03z Thursday with VFR
conditions and mostly clear skies tonight through Thursday
morning.


&&

.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&

$$

SHORT TERM...JDC
LONG TERM...JDC
AVIATION...MDA


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