Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 180438
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1038 PM MDT WED AUG 17 2016

.SHORT TERM...(Tonight through Thursday)
Issued at 305 PM MDT Wed Aug 17 2016

The atmosphere remains marginally moist and unstable. This
forecast area remains sandwiched between one disturbance moving
into SE Colorado and an approaching one in NW Utah. The resulting
weak high pressure overhead was suppressing convection with most
storms hugging the higher terrain. Storms will have very little
movement. Some heavy showers will result especially in SE Utah
where the moisture is deepest.

Little change expected tonight with a few storms lingering into
the early morning hours. The NW Utah disturbance will weaken as it
approaches the region on Thursday for an expected increase in
thunderstorm coverage mainly over the western portion of the
forecast area.

.LONG TERM...(Thursday night through Wednesday)
Issued at 305 PM MDT Wed Aug 17 2016

Thursday night a cold front will work into the northern forecast
area. This will provide some support for increased storm coverage
in NE Utah and NW Colorado. The front washes out quickly north of
the Roan-Tavaputs-Flat Tops as it slides down the Front Range and
plains.

Friday the upper flow veers to northwest bringing a drying trend
into the weekend. Northern temperatures dip a few degrees on
Friday but recover quickly by Saturday.

Next week the mid range models are showing a different solution
than just 24 hours ago, lowering forecast confidence. Moisture
now works back in from the SW beginning Monday. The mechanism is a
closed low over southern California. Previous models runs kept
this feature lingering along the coast. Today the models are
lifting it into the region. if this solution is correct a trough
passage on Tuesday could produce the best storm coverage. Moisture
remains marginal though, around 0.9 inch precipitable water at
best.

Low amplitude westerlies
will continue over the northern Rockies into early next week,
producing a dry west flow. Subtropical moisture will be suppressed
to our south. So this weak monsoon season is not producing up to
average for this the wettest time of year for the southern and
central zones.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1038 PM MDT Wed Aug 17 2016

Gusty outflow winds will continue through the early morning hours
for some lower valley TAF sites as lingering showers continue to
weaken and collapse, enhanced by terrain-driven downslope winds
through about 09z before letting up. Aside from that, VFR
conditions will dominate. Scattered thunderstorms will form again
initially over the mountains after 17z and spread into the valleys
after 20z with erratic gusty winds the primary impact to TAF
sites. Brief heavy rain is possible under stronger storms, with
KTEX and KASE standing the best chance of rain. Lowered cigs/vsby
expected under heavier showers. Storms are expected to dissipate
after 04z with erratic outflow winds remaining.

&&

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

$$

SHORT TERM...Joe
LONG TERM...Joe
AVIATION...MDA



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