Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 180545

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
1145 PM MDT Mon Jul 17 2017

.SHORT TERM...(Tonight through Tuesday night)
Issued at 342 PM MDT Mon Jul 17 2017

An upper level trough over the northern Rockies will continue to
suppress the ridge today. Enough moisture lingering will continue the
shower and thunderstorm trend this evening and into Tuesday. Slightly
less moisture over the northern part of the CWA Tuesday so expect
less chance of storms and the better focus for storms to be over
the southern portion. Not much change in the temperature profile
in the short term. Another area of low pressure will spin off the
main trough later today and then intensify Tuesday off the Pacific
Northwest coast. This trough amplifies and helps push the ridge
axis to the east opening the gates for a tap to subtropical

.LONG TERM...(Wednesday through Monday)
Issued at 342 PM MDT Mon Jul 17 2017

The ridge axis center continues to slide slightly east setting up
over KS and OK. The ridge becomes less elongated and more compact.
This setup allows a better tap to the subtropical moisture in
northern Mexico and AZ. Expect showers and thunderstorms to increase
in coverage starting Wednesday. The deep moisture indicated by
precipitable water values reaching around an inch and a quarter
south and near an inch north will mean storms should be efficient
rain producers. There is a threat of storms producing heavy
runoff Wednesday through at least Friday. Max temperatures will
decrease slightly with increases clouds and shower activity. The
pattern persists through the end of the week. The ridge is
flattened by a low pressure system moving over the northern
Rockies this weekend. The plume of moisture is pushed south and
east with slightly dryer air advecting into the area from the
north. deeper moisture will linger over our southern counties
through the weekend. Models indicate a weak disturbance moving off
the more zonal northern Rockies flow and over our northern
counties late in the weekend. Models also indicate a re-
amplification of the ridge over the Great Basin early next week.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1142 PM MDT Mon Jul 17 2017

Scattered showers and isolated thunderstorms will persist through
12Z this morning before ending for a few hours. Another round
develops by 18Z over the higher terrain and will persist through
the late evening hours. Heavy rain, gusty outflow winds to 40 kts,
small hail and dangerous lightning will occur with the stronger
storms. Expect local ILS CIGS in the vicinity of showers and
storms, otherwise VFR pattern remains prominent across eastern
Utah and western Colorado.




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