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000
FXUS65 KFGZ 221607
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
907 AM MST Sat Jul 22 2017

.SYNOPSIS...Active monsoon conditions will continue for the next
several days. Heavy rainfall capable of producing flash flooding
remains possible from stronger storms.

&&

.UPDATE...
Satellite imagery showing mostly clear skies across western
Arizona, with mostly cloudy conditions across the Navajo nation.
The amount of precipitable water in this mornings Bellemont
sounding is slightly above normal. So it looks like an active
thunderstorm day across northern AZ, with storms firing first
along the Mogollon rim. The U of AZ WRF does suggest additional
storm activity late this afternoon and evening across the
northeast quarter of Arizona.

&&

.PREV DISCUSSION /320 AM MST/...Monsoon moisture will remain in
place across northern Arizona through Monday with the active
weather pattern continuing. By Tuesday or Wednesday models show a
bit drier and more stable air mass moving across the area with
storm activity becoming more isolated except near the Arizona/New
Mexico border.

For today and Sunday...High pressure aloft was in the process of
becoming centered over the Nevada/Utah border during this
morning. The air mass remains moist across northern Arizona so
look for another round of scattered to numerous showers and
thunderstorms today. The position of the high will result in a
steering flow that will nudge storms southward off the Mogollon
Rim. The result will be a more focused area of shower and storm
activity across a broad area containing Prescott and Payson.
Stronger storms will be capable of producing 1 to 3 inches of
rainfall. On Sunday, the high will wobble across utah with the
flow becoming more easterly. This will probably mean drier air for
the northeast corner of the state and a downturn in activity.
However, from the Mogollon Rim south, the very active weather
pattern will continue with some suggestion by model soundings of a
more unstable environment with an enhanced threat for severe
storms and flash flooding across the region south of the Mogollon
Rim.

On Monday...An upper disturbance will swing across northern
Arizona. Not much upward motion or low-level flow for orographic
forcing with this feature. Looking at model soundings the air
mass will be near saturated through a deep layer. The result will
likely be a good chance of showers, but without decent forcing
for upward motion or sunshine to build instability, more showery
than anything else. At least that`s the way it looks at this
point. Stay tuned.

From Tuesday onward...Models show a drier low-level air mass
moving in from over the eastern Pacific Ocean. Also, a building
high pressure center aloft over Arizona may result in warming mid-
level temperatures. All-in-all it appears that there will be a
decrease in overall activity to mainly isolated except along the
Arizona/New Mexico border.

&&

.AVIATION...For the 18Z package...For the 18Z package...Sct to
numrs shra/tsra and isold +tsra developing by 17z-19z. Highest
coverage along/south of KFLG-KSJN line, with a secondary area west
of KRQE. Coverage gradually decreasing aft 00z-02z. Expect
MVFR/IFR conditions in the stronger storms. Aviation discussion
not updated for TAF amendments.
&&

.FIRE WEATHER...Active monsoon conditions will continue through
the weekend with scattered to numerous showers and thunderstorms.
The best thunderstorm chances will be from the Mogollon Rim
southward. Heavy rain and gusty winds will remain the primary
impact. Expect near average temperatures across the area.

Monday through Wednesday...Active monsoon conditions continue Monday
with high rain chances. A slight downturn in storm chances is
possible by Tuesday and especially Wednesday as a bit drier air
moves in.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

PUBLIC...DL/McCollum
AVIATION...Peterson
FIRE WEATHER...JJ


For Northern Arizona weather information visit
weather.gov/flagstaff