Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 111027
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
327 AM MST Tue Aug 11 2020

.SYNOPSIS...A slight uptick in monsoon activity will take place
through Thursday with generally isolated showers and storms each
afternoon. The most widespread coverage is expected Thursday.
Strong high pressure will build over the region Friday into the
weekend with record high temperatures possible during this time
frame.

&&

.DISCUSSION...The two main stories through the forecast period
will be an increase in monsoon moisture over the next couple days
followed by possible record high temperatures this weekend.

It is another cool morning across the area under light winds and
clear skies. Another warm and breezy day is on tap with high
temperatures similar to what we saw on Monday. Look for another
hot day in the lower elevations of the Grand Canyon with Phantom
Ranch expected to reach 110 degrees this afternoon. Therefore, we
have issued another Excessive Heat Warning which runs from 10am to
8pm MST today. Latest hi-res guidance indicates enough mid-level
moisture and instability will be in place for isolated showers and
storms stretching along the Mogollon Rim and northwest onto the
Kaibab Plateau. The boundary layer will remain fairly dry so it
will be difficult for these storms to produce much rainfall.

Low-grade monsoon conditions look to take place on Wednesday and
especially Thursday as a weak moisture surge pushes northward.
Storm motion looks like it will generally be toward the northeast.
This will favor locations along the Mogollon Rim and into
northeast Arizona. Heights will slowly rise during this period,
but cloud cover and convection will help to limit widespread hot
temperatures.

High pressure will build north and strengthen over the area Friday
into the weekend. This will result in daytime temperatures warming
to around 10 degrees above normal with record highs possibly
falling in some areas. Excessive Heat products will likely be
needed in the coming days. While there will still be some moisture
trapped underneath the high, very warm air aloft will suppress
much of the storm activity. However, a few storms cannot be ruled
out each afternoon over the higher terrain.

There is considerable uncertainty with how the high evolves early
next week, but a more favorable monsoon circulation is still
possible. Stay tuned.

&&

.AVIATION...For the 12Z package...Expect mostly VFR conditions over
the next 24 hours, the exception being possible MVFR conditions in
the stronger showers and thunderstorms across the region today. Look
for scattered showers and thunderstorms north of KGCN and southeast
of KSOW after 18Z with isolated activity over high terrain elsewhere
in the area. Isolated shower activity will move northeast into the
Four Corners area through the evening hours. Light winds this
morning will become southwest at 5-15 kts gusting to 20 kts after
17Z and decrease after sunset. Aviation discussion not updated for
amendments.

&&

.FIRE WEATHER...Look for warm and mostly dry weather today and
Wednesday with breezy west to southwest winds. Chance of showers and
thunderstorms over the high terrain each day. Expect strong outflow
winds and little rain from these storms.

Thursday through Saturday...Increasing clouds Thursday, with showers
and thunderstorms across the higher terrain. Drier and warmer
conditions return Friday and Saturday, with record heat possible
over the weekend.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Excessive Heat Warning from 10
AM this morning to 8 PM MST this evening FOR AZZ006.

&&

$$

PUBLIC...TPS
AVIATION...DB
FIRE WEATHER...DB


For Northern Arizona weather information visit
weather.gov/flagstaff


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