Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 161456
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
856 AM MDT Wed May 16 2018

.UPDATE...
Issued at 856 AM MDT Wed May 16 2018

Upgraded the Fire Weather Watch to a Red Flag Warning for Thursday
as models and forecast have been consistently showing critical
fire weather conditions being met for those western Colorado zones
where fuels are critical. Coverage of Red Flag conditions has
actually increased compared to yesterday, so confidence is high.

&&

.SHORT TERM...(Today through Thursday)
Issued at 317 AM MDT Wed May 16 2018

Today is sizing up to be another dry and warmer than normal day. A
sharp ridge will build over the area ahead of a developing low
pressure system moving onshore over central California. Southwest
winds at the surface and aloft will begin increasing late this
afternoon as the pressure gradient tightens and a moderately
strong jet stream begins to spread overhead.

Thursday will see stronger southwest winds and continued dry and
warmer than normal conditions. The Pacific storm will move into
the Great Basin and a jet maxima will be oriented southwest to
northeast over the Four Corners. The jet overhead will only range
in speed between 50 and 60 mph but vertical mixing should bring
enough wind aloft to the ground in the afternoon to continue the
Fire Weather Watch for potential for critical fire weather
conditions across much of the area. See the fire weather section
below.

.LONG TERM...(Thursday night through Tuesday)
Issued at 317 AM MDT Wed May 16 2018

The Pacific low pressure system will settle over the western Great
Basin Thursday night, but quickly begins to fill in on Friday
before ejecting to the east Friday night. With little moisture to
work with, shower and thunderstorm activity won`t be very
extensive, largely confined to the higher terrain both Friday and
Saturday afternoon and evening. The pattern becomes weak and
chaotic on Sunday, before another low moves off the eastern
Pacific for the early part of the coming week. Consequently,
expect more of the same weather wise, with warm afternoon
temperatures and modest moisture resulting in isolated to low end
scattered showers and thunderstorms over the higher terrain. The
ECMWF and GFS weren`t in great agreement with positioning of the
low and moisture flux over the area Monday and Tuesday. GFS
appears the more plausible solution with the low moving into the
western Great Basin once again resulting in a dry southwest flow.
In contrast the ECMWF places a weaker low over southern
California allowing for a broad influx of moderate moisture from
the Mexican Plateau. Given model differences will continue with
the low PoPs over the higher terrain early next week. Temperatures
will remain unseasonably warm during the period, but at this point
it doesn`t look like the area will see record setting warmth.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 317 AM MDT Wed May 16 2018

VFR conditions will prevail over the entire area for the next 24
hours under nearly cloudless skies.


&&

.FIRE WEATHER...
Issued at 856 AM MDT Wed May 16 2018

Critical fire weather conditions will occur on Thursday as
another Pacific storm moves into the Great Basin, bringing
stronger southwest winds and dry conditions across much of the
area. A Red Flag Warning is in effect for late Thursday morning
through Thursday evening for much of western Colorado in areas
where fuels are deemed critical.

Winds will lessen by Friday but remain breezy at times with some
moisture increasing across the north through the weekend,
lessening fire weather concerns there. However, much of the area
will still be dry through Friday.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Red Flag Warning from 11 AM to 9 PM MDT Thursday for COZ200-202-
     207-290>295.

UT...None.
&&

$$

UPDATE...MDA
SHORT TERM...CC
LONG TERM...NL
AVIATION...CC
FIRE WEATHER...CC



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