Area Forecast Discussion
Issued by NWS Grand Junction, CO

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299
FXUS65 KGJT 250632
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1232 AM MDT THU AUG 25 2016

.UPDATE...
Issued at 1230 AM MDT Thu Aug 25 2016

A weak vorticity maxima is lining up very well with convection
this morning occurring in and around the Grand Valley. The HRRR is
also picking up on this too. Upped PoPs over next few hours to
track wave as it moves from west to east with some showers and a
few rumbles of thunder expected.

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 330 PM MDT Wed Aug 24 2016

Residual moisture combined with daytime heating has allowed
isolated to scattered showers and thunderstorms to develop over
the area. Coverage is down from Tue and storms seem to be moving
along at a better pace, but they do seem to be a little more
energetic. Isolated small hail is possible and gusty outflow
winds, but individual storms have generally been short-lived.

As heating fades this evening storms will diminish, with little
activity expected beyond midnight. Look for minimum temperatures
to drop to around normal for late Aug.

A low pressure trough will drop out of the Pacific northwest and
into the northern Great Basin on Thu. As a result, the flow over
our forecast area will become southwest. While this flow will
mostly be weak to moderate, it will open the door to the next weak
surge of moisture from the south. Therefore we can expect an
uptick in showers and thunderstorms, especially during the late
day hours. One embedded weak shortwave will pass over the area in
the late afternoon through the evening. This will act to enhance
the convection. Brief heavy rain and small hail will be possible,
but storm motion should be a little better than on Tuesday.

With the main trough remaining upstream over the Great Basin
some nocturnal showers should hang on throughout the night.

.LONG TERM...(Friday through Wednesday)
Issued at 330 PM MDT Wed Aug 24 2016

The large scale pattern remains fairly static through Friday with
moisture continuing to make its way over the forecast area carried
by the somewhat gentle southwest flow. Therefore look for showers
and thunderstorms to again increase during during the afternoon,
and diminish late in the evening. The weakened Great Basin trough
does lift out and shift east beginning Fri night and into Sun.
This will eventually result in a gradual drying trend, which will
become noticeable on Sun. Until then however, the chance of
showers and thunderstorms will persist Fri and Sat, mainly during
the late day periods. The southern portion of the CWA will be
favored, but activity will be possible over all areas.

On Sunday drier conditions begin to take hold as high pressure
begins to build over the region, and the subtropical moisture
plume will lean over into the central CONUS. Models indicate that
this drier and warmer pattern will then persist through the end
of the long term period. Temperatures will climb to a little above
normal for the first half of the new work week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1145 PM MDT Wed Aug 24 2016

Showers and thunderstorms are tapering off this evening as we
loose the heating of the day. Expect VFR conditions to prevail
overnight with lingering isolated showers for the next few hours.
Moisture will remain in place so anticipate showers and
thunderstorms to develop once again tomorrow afternoon with
initial development over the mountains.


&&

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

$$

UPDATE...TGR
SHORT TERM...EH
LONG TERM...EH
AVIATION...Larry



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