Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 280002
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
602 PM MDT Sat May 27 2017

.SHORT TERM...(Tonight through Sunday night)
Issued at 338 PM MDT Sat May 27 2017

Looking at the latest water vapor imagery this afternoon we can
see the cold front is almost through our forecast area and it
should be clear of the region within the next few hours. Coverage
of convection has been pretty spotty thus far but storms that
have developed have produced periods of brief heavy rain, gusty
winds, and even some lightning. Activity will taper off after
sunset as drier air moves in behind the front and high pressure
begins to build overhead. Though some mid and high clouds will
linger tonight the general clearing of skies will result in
overnight lows being several degrees cooler than last night.

High pressure will continue to move in from the west tomorrow
which will result in a pleasant Sunday. Apart from some isolated
to scattered mountain storms during the afternoon hours, it`ll be
a warm and benign weather day!

.LONG TERM...(Monday through Saturday)
Issued at 338 PM MDT Sat May 27 2017

The ridge will remain overhead as we go into the new work week.
However, height rises are not very substantial with 500mb heights
only peaking at 582-584 decametres. As a result, moisture will be
allowed to trickle in from down south which, when combined with
daytime heating, will lead to orographic showers firing off each
afternoon with the San Juan Mountains being favored for activity.
This ridge will also be "dirty" - as in, skies will not clear
completely and mid and high level clouds will stick around across
much of the forecast area. Regardless of the intensity of the
ridge, temperatures will rebound back to seasonal or slightly
above seasonal values.

Wednesday will be the warmest day of the week with the lower valleys
climbing into the low to upper 80s and the mountains peaking in the
mid to upper 50`s. Wednesday will be the transitional day as the
ridge begins to slide to the east in response to our next Pacific
trough digging into the Great Basin. Extended models are in better
agreement now on what will happen through late Wednesday, but
disagreement returns Thursday and beyond with the GFS continuing
to be the wetter and more progressive solution. One thing both
models agree on, however, is that a shortwave feature will be
ejected out ahead of the main upper level trough on Wednesday
which will be centered in eastern New Mexico/western Texas
Panhandle. The presence of this disturbance will advect
precipitable water values of 0.50 to 0.60 inches (up to 133% above
climo normal) northward. PoP grids remain conservative for the
time being until models can come into better agreement on the
progression of our next storm with just scattered convection in
the mountains and more isolated coverage in the valleys, though
the southern mountains once again look to be favored. One
interesting thing to note is that the Climate Prediction Center`s
6 to 10 day outlook shows a shift towards wetter than normal
conditions for all of Colorado as well as for eastern Utah, so we
could be having a wet start to the normally dry month of June.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 556 PM MDT Sat May 27 2017

Northerly flow is filling in behind a departing cold front.This
northerly flow is supporting isolated thunderstorms which should
diminish this evening as heating of the day dissipates and the
atmosphere begins to stabilize. Otherwise, VFR conditions are
expected to persist through the next 24 hours with mostly clear
skies expected on Sunday.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

$$

SHORT TERM...MMS
LONG TERM...MMS
AVIATION...Larry



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