Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 182013

Area Forecast Discussion
National Weather Service Grand Junction CO
213 PM MDT Wed Apr 18 2018

.SHORT TERM...(Tonight through Thursday night)
Issued at 152 PM MDT Wed Apr 18 2018

The ridge axis of high pressure is almost directly overhead
bringing the sunny skies and warming temperatures to the region.
This will be short-lived though as the next system continues to
move closer to the region. For the rest of the day, a few high
clouds will move overhead and that will be about it. High
temperatures will be a bit below seasonal normals.

By Thursday, the closed low will be over Nevada but the pressure
gradient will already be tightening. While wind speeds look to be
sub-advisory level, gusts of 25 to 35 mph, sometimes higher, will
occur in the afternoon. Humidities will remain low so the red flag
warnings continue. Two new zones have also been added as described
below. Temperatures will also continue to rise as wind flow will
be almost directly from the south ushering in warmer air. These
winds will tap into some moisture but models still in disagreement
where this moister air will set up. GFS still keeps the moisture
over the Front Range while the EC and NAM want to put it right
along the Continental Divide. Where this moistures sets up will
make all the difference as to where the heaviest precip will fall.
However, no precip expected until early Friday morning.

.LONG TERM...(Friday through Wednesday)
Issued at 152 PM MDT Wed Apr 18 2018

So by early Friday morning, the NAM is highlighting precip over
the central and southern mountains. By mid-morning, the low will
have moved further east causing this line of heavier precip to
shift to our northern mountains and front range. As the low
continues to move over our area, the models are picking up on
wraparound moisture making it as far down as the Book Cliffs and
possibly areas even further south than that. The big question is
snow. At the start of the event, snow levels will be fairly high
thanks to the warm air advection. They will drop to around 9 to
10K feet as the storm progresses so some snow accumulation (maybe
significant) is possible. Right now, amounts are in the advisory
level (6 to 12 inches) but will hold off on highlights to allow
another look or two at the latest guidance. Really want to see all
the models lining up with respect to track of the low and where
the precip will fall.

By Saturday afternoon, the low will have moved to the Plains as
nicer weather starts to move in. Temperatures will rebound as we
return to partly cloudy skies. The next chance for any precip
looks to be Monday afternoon as a weak trough slides by to our
north. As most energy stays over Wyoming and Montana, precip
amounts look to be minimal at best.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1116 AM MDT Wed Apr 18 2018

Sunny skies will be the rule today though a few high clouds will
enter from the west later on this afternoon into the evening
hours. A few gusts up to 20 mph may occur from time to time but
generally they`ll be light and variable. Winds will pick up again
but this should occur around 18Z tomorrow, give or take.


Issued at 152 PM MDT Wed Apr 18 2018

Red Flag Warnings remain in effect tomorrow as gusty winds move
back in along with dry humidities. Did add CO Fire zones 292 and
294 as latest updates indicate fuels in those areas are also
critical. Some concern that increased cloud cover may inhibit the
winds somewhat but with such dry conditions in place, better safe
than sorry. Remember, when red flag warnings are issued open
burning is highly discouraged as any fire starts will be
difficult, if not impossible, to contain.



CO...Red Flag Warning from noon to 9 PM MDT Thursday for COZ200-202-



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