Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 160520
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1120 PM MDT Mon Jul 15 2019

.SHORT TERM...(Tonight through Tuesday night)
Issued at 338 PM MDT Mon Jul 15 2019

Model analyses showed three-quarters to 1 inch of moisture in the
column from north to south across the forecast area this morning.
Combined with steepening lapse rates and weak divergence aloft
associated with a 50-60 kt jet streak, this moisture more than
sufficient to generate the scattered to numerous showers and
thunderstorm observed across the area this afternoon. As day shift
had predicted, heavy rain was observed near Durango this afternoon
with close to 0.80 of an inch of rainfall measured in about 30
minutes. Shower/thunderstorm activity will linger into the
evening, after which diurnal cooling and the loss of divergence
aloft will bring an end of moist convection.

Models indicated the shallow long wave trough off the West Coast
will push over the western U.S. on Tuesday. This will tighten the
height gradient aloft which will lead to breezy southwest winds on
Tuesday. Meanwhile, the moisture feed from the south shifts
eastward allowing drier air to spread into eastern Utah and
northwest Colorado. However, enough moisture lingers along the
Continental Divide to fuel scattered thunderstorms with San Juan
Mountains favored.

Drying continues Tuesday night and expect a diurnal downturn in
shower/thunderstorm activity during the evening with all activity
dying out by midnight.

Temperatures will remain hot with fewer clouds and precipitation
on Tuesday. NBM output was suspiciously cool and adjusted
temperatures upward toward warmer MOS guidance for all locations.
Overnight lows will continue to be mild.

.LONG TERM...(Wednesday through Monday)
Issued at 338 PM MDT Mon Jul 15 2019

Models suggest the drying trend will continue into Wednesday as
the trough over the western U.S. pushes across the northern
Rockies resulting in a more westerly flow aloft. Precipitable
water levels are indicated to drop significantly with values
ranging from near 0.25 to 0.40 inches of liquid by days end. As a
result, afternoon thunderstorms will become more isolated and
largely confined to the San Juan Mountains. Look for little moist
convection on Thursday and Friday as flow continues from the west.
Models, to varying degrees, suggested some moisture return along
the Continental Divide this weekend into early next week so expect
an uptick in activity then. Meanwhile, temperatures should hover
at, or a little above normal during the remainder of the week and
into the weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1117 PM MDT Mon Jul 15 2019

Mainly VFR conditions expected through the taf period for most
sites. There is a slight chance for isolated showers and storms
this afternoon at KTEX, KGUC and KASE. Gusty outflow winds could
occur with the stronger storms.

&&

.FIRE WEATHER...
Issued at 338 PM MDT Mon Jul 15 2019

Dry, breezy and warm conditions are expected to bring critical
fire weather conditions to portions of east-central Utah and
northwest and west-central Colorado Tuesday and Wednesday
afternoon and evening. There is strong possibility these
conditions will spread into southeast Utah and southwest
Colorado Wednesday. Otherwise, expect scattered to numerous
thunderstorms over the mountains this afternoon and evening.
Temperatures will remain above normal while storms decrease during
the remainder of the coming work week.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Red Flag Warning from noon to 8 PM MDT Tuesday for COZ200-202-
     203.

     Red Flag Warning from noon to 8 PM MDT Wednesday for COZ200-202-
     203.

     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening for COZ207-290-292.

UT...Red Flag Warning from noon to 8 PM MDT Tuesday for UTZ487-490.

     Red Flag Warning from noon to 8 PM MDT Wednesday for UTZ487-490.

     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening for UTZ491.

&&

$$

SHORT TERM...NL
LONG TERM...NL
AVIATION...KJS
FIRE WEATHER...NL


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