Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 181725
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1025 AM MST Fri Aug 18 2017

.SYNOPSIS...Dry conditions will continue across northern Arizona
through today and much of Saturday. There will be a slight chance
of thunderstorms over eastern Arizona on Saturday afternoon.
Higher chances of showers and thunderstorms then move back north
and west and affect much of the area by Sunday and into next week.

&&

.UPDATE...We added a low chance of thunderstorms over the Kaibab
Plateau this afternoon/evening, and made minor updates to wind
and sky forecasts from now through the overnight period. Visible
satellite imagery shows extensive cumulus clouds have developed
over the Kaibab Plateau, the Black Mesa, and the Chuska Mountains.
A couple of NCAR Ensemble members show brief thunderstorm activity
over the Kaibab this afternoon. Otherwise, the forecast remains
intact.

&&

.PREV DISCUSSION /315 AM MST/...Dry westerly flow aloft will
gradually give way to deep southerly flow over the weekend. This
is due to a stationary low pressure system off the coast of
southern CA and high pressure over Texas and New Mexico. The
gradient between these two systems will increase over the weekend
and into next week, allowing the pool of "monsoonal" moisture to
our south to move back north.

This is a pattern that may favor MCS development and nocturnal
activity as temperatures in the mid-levels are cooler than normal
and shear/steering flow profiles favor redevelopment. This pattern
remains intact through much of next week, before the low opens up
and moves east, allowing drier air to establish itself over the
southwest once again.

&&

.AVIATION...For the 18Z package...VFR conditions through the 24
hour TAF period with winds generally lighter than 10 kts. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Dry conditions will continue again today. Expect
lower than usual humidity for this time of year, along with light
southwest winds and near normal temperatures. Limited moisture
returning Saturday may bring a slight chance of thunderstorms near
the White Mountains.

Sunday through Tuesday...Moisture is forecast to spread farther
north and west with daily afternoon thunderstorm chances developing
over northern Arizona each day.

&&

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

&&

$$

PUBLIC...AT/Peterson
AVIATION...DB
FIRE WEATHER...KD


For Northern Arizona weather information visit
weather.gov/flagstaff


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