Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 231138
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
538 AM MDT Sun Jul 23 2017

.SHORT TERM...(Today through Monday)
Issued at 332 AM MDT Sun Jul 23 2017

A forecast setup featuring slightly suppressed moisture over
eastern Utah and western Colorado will result in similar
conditions today as were seen on Saturday. Analysis of GOES water
vapor and infrared satellite imagery hints at a moisture axis,
roughly positioned from the Sawatch/Elk ranges southwestward
toward Moab and canyon-country in eastern Utah. South of this
feature, slightly higher PWAT values remain and will result in
greater chances for thunderstorms - a few of which could produce
briefly heavy downpours. In the north, another mostly dry day is
expected. Any convection that does develop north of I-70 will
likely struggle to sustain itself, except perhaps in the eastern
Uintas where convective temperatures will be exceeded earliest.
Overall, with a slightly drier airmass in place, Sunday will end
up being the hottest day of the weekend with temperatures running
around 5 degrees above normal area-wide.

Convection will diminish after sunset on Sunday with a mostly dry
overnight expected. The center of a broad, diffuse ridge of high
pressure will consolidate just east of the Continental Divide
on Monday, resulting in a slight uptick in moisture over the
region as southwest flow gently increases. CAM guidance favors the
San Juans for the highest coverage of thunderstorms on Monday,
with a notable increase in activity in the Roan cliffs and and
Tavaputs as well. PoPs have been nudged upward from model blends
in these areas in order to better reflect this idea.

.LONG TERM...(Monday night through Saturday)
Issued at 332 AM MDT Sun Jul 23 2017

High pressure over Utah and Colorado will gradually shift eastward
by Monday evening as a closed low comes onshore NorCal. This
shift of the high pressure will allow more substantial monsoonal
moisture to return through Tuesday. High pressure fights hard
against the trough on the west coast to stay centered across AZ.
NM, TX and OK. The west coast closed low/trough is anticipated to
lift northward by Wednesday/Thursday and allow the center of high
pressure to shift back over the Four Corners. This pattern looks
to be a bit of a repeat of yesterday (Saturday) with slightly
drier air entraining into NE Utah and NW Colorado...keeping
convective activity focused over SE Utah and SW Colorado. This
pattern looks to continue through next weekend.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 525 AM MDT Sun Jul 23 2017

VFR conditions will prevail at all terminal locations through the
afternoon. A few isolated thunderstorms will develop in the
southern mountains of Colorado and may result in a shower or two
at TEX, DRO or GUC. VIS and CIG heights should remain above VFR
thresholds.

&&

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

$$

SHORT TERM...MAC
LONG TERM...JAM/MAC
AVIATION...MAC



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