Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 221738

Area Forecast Discussion
National Weather Service Flagstaff AZ
1040 AM MST FRI JUL 22 2016

.SYNOPSIS...Scattered showers and storms are expected this
afternoon across much of northern Arizona. Storm coverage will
decrease significantly this weekend as drier air moves in from the
west. Moisture and storm chances will increase again next week
mainly along and south of the Mogollon Rim.



Update to increase thunderstorm chances this afternoon along the
Mogollon rim from Flagstaff southeastward.

.940 am discussion...We have issued an Excessive Heat Warning for
areas below 4000 feet in the Grand Canyon and the Yavapai Valleys.
It runs from now through 7 pm Saturday. Max temps to run from 110-
115, and overnight lows from 74-84.

Satellite pw imagery shows monsoon moisture across all of nrn Az
this morning. Warmer mid level temps are forecast to slowly move
into far western AZ later today. The forecast is on track with no
updates planned.


.Prev Discussion 307 am...The axis of strong high pressure will
shift over or just south of the forecast area today through
Saturday. Moisture will linger across the area today so some
scattered afternoon thunderstorms are expected with the best chance
along and just north of the Mogollon Rim and White Mountains. A few
storms could produce heavy rainfall again today, but should be

By Saturday, some westerly flow will push drier air into
the region with the most pronounced drying from around Flagstaff
northward. This will reduce storm chances across Coconino and
Yavapai Counties. The greatest storm chances will remain over
southern Navajo and Apache Counties where deeper moisture will

Most model guidance shows the ridge shifting back northward as
early as Sunday into midweek. This should allow for some better
moisture and storm chances to gradually return, especially for
areas along and south of the Mogollon Rim and White Mountains.
Depending on where the high eventually sets up, we could see some
east or northeast steering flow off the higher terrain which is
favorable for some stronger storms in the late afternoon and
evening in Gila County and the lower elevations of Yavapai County.
Far northern Arizona (along/north of Grand Canyon to Window Rock)
often remains drier in this pattern. With high pressure in place,
expect hot temperatures in this area, 110+ at Phantom Ranch,
102-104 at Page and near 90 at Grand Canyon south rim.


.AVIATION...For the 18Z package...Monsoon moisture remains. Look
for scattered thunderstorms to develop from KFLG eastward with
isolated storms to the west. VFR conditions will prevail but local
MVFR will be possible in the stronger storm cells. Storm coverage
diminishing after sunset. Aviation discussion not updated for TAF


.FIRE WEATHER...Drier westerly flow will begin a decreasing trend in
thunderstorms today...most notable across the western half of
Arizona. The drying trend continues Saturday when afternoon humidity
will drop into the 15-25% range as temperatures rise well above

Sunday through Tuesday...Decreased thunderstorm chances and warm
temperatures continue Sunday. Moisture may begin to increase from
the Mogollon Rim (Flagstaff area) south from Monday onward.






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