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Area Forecast Discussion (AFD)

Issued by Grand Junction, CO (GJT)

FXUS65 KGJT 180940

Area Forecast Discussion
National Weather Service Grand Junction CO
340 AM MDT Wed Sep 18 2019

.SHORT TERM...(Today through Thursday)
Issued at 315 AM MDT Wed Sep 18 2019

The last remnant mid level clouds associated with associated with
moisture from yesterday's trough passage will dissipate over the
San Juan mountains this morning. The rest of the day will be dry
with few clouds and gusty southwest winds. The next Pacific storm
will strengthen over the Pacific Northwest this afternoon and
tonight with southwest gradient winds increasing over the area
late this afternoon. 

Overnight the trough will move east into the western Great Basin 
with is closed 500 mb center over northern NV and southwest ID. On
Thursday the polar jet will dip as far south as Las Vegas and then
turn to the northeast over Utah. Moisture will be drawn north over
New Mexico and bring scattered showers and thunderstorms to the
San Juan mountains and lower elevations of the Four Corners
Thursday afternoon.

.LONG TERM...(Thursday night through Tuesday)
Issued at 315 AM MDT Wed Sep 18 2019

The trough coming out of the Pacific Northwest will pass over
northern UT and CO late Thursday afternoon through Friday. The
best weather producing features of this system pass over the area
Thursday night and early Friday morning and produce areas of
precipitation over western CO. A dry slot should stretch over
eastern Utah. Friday evening the trough should be east of the area
and dry air will pour into the forecast area in its wake.

Saturday and Sunday should be dry with a weak transitory ridge
over the area. Then next significant storm will dig south over the
western Great Basin. Model solutions diverge significantly Monday
and Tuesday. The EC moves it to the Four Corners and then lifts
east. The GFS brings a large plume of moisture into the area from
the south with and deep closed low over southern CA. The GFS also
bring remnants of a tropical depression into the area by
entraining it into the moisture plume. Confidence is low at this
point with either solution. 


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 315 AM MDT Wed Sep 18 2019

VFR conditions will prevail for the next 24 hours. Strengthening
southwest winds aloft will produce areas of turbulence over the