255
FXUS65 KFGZ 022113
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
213 PM MST Tue Sep 2 2025

.SYNOPSIS...Daily chances for showers and thunderstorms are
forecast this week, mainly in southern Coconino and northern
Yavapai counties today. Activity spreads northward and becomes
scattered to numerous across much of northern AZ through Saturday.
Strong outflow winds and localized flash flooding will be the
primary hazards.

&&

.DISCUSSION...Rest of today and tomorrow...There is a lot of factors
at play this upcoming week as we enter the final month of the
monsoon season. Currently, northern AZ sits underneath weakening
high pressure. An inverted trough is propagating around this ridge
and is centered over southwest Arizona. For today, a north-south
moisture gradient is still in place. Scattered storms are
currently in place over the Chuskas, Black Mesa and southern
Coconino county. Through the evening, storm activity is expected
to remain mostly confined south of the Grand Canyon into northern
Yavapai counties, with isolated activity elsewhere. The primary
hazards from storms today are frequent lightning, gusty outflow
winds 40-50 mph, and heavy localized rainfall from training
storms. By tomorrow, the inverted trough continues to propagate
northward. This carries better moisture with it, and brings
chances for precipitation across of much of western Coconino and
Yavapai counties. Enhanced flash flood risk should be expected
each day especially over sensitive terrain features and burn
areas.

Thursday through Saturday...High pressure continues to move away
from northern AZ, leaving behind an airmass of deep monsoonal
moisture with limited capping. This looks to remain in place through
the period and bring chances for scattered to numerous showers and
thunderstorms each day. Recently formed Tropical Storm Lorena may be
a potential factor during this period. The details on this storm are
still very uncertain, however some models are taking it along a
track that will bring impacts to AZ. In addition, some difficult
to resolve daily features such as debris clouds could have
substantial impacts on how active any individual day is. Overall,
the primary hazard each day is heavy rainfall with a continued
enhanced flash flood risk.

Sunday and beyond...Ensemble guidance is in agreement that a west
coast trough will sweep through and act to clear out the moisture
starting Saturday. There is still some uncertainty as to how
sharp this moisture decline will be, but the consensus is that
activity will begin to tick down once again through the start of
next week.


&&

.AVIATION...Tuesday 02/18Z through Wednesday 03/18Z...VFR
conditions are largely expected to continue. Scattered SHRA/TSRA
developing mainly south of a KGCN - KRQE line from 19Z-06Z with a
20-30% chance of SHRA continuing overnight. Main storm hazards
will be outflow winds to 40 kts and brief heavy rain. Outside of
storm activity, winds from the S to SE around 10 kts or less.

OUTLOOK...Wednesday 03/18Z through Friday 05/18Z...Increasing
monsoon moisture will lead to scattered to numerous SHRA/TSRA each
day. Brief periods of MVFR and wind gusts to 40 kts are possible
in/around TS. Otherwise, expect generally S to SW winds around 5-15
kts during the day and light and variable winds overnight.

&&

.FIRE WEATHER...Wednesday and Thursday...Scattered to numerous
showers and thunderstorms each afternoon. Best chances for storms
on Wednesday will be in western Yavapai and Coconino counties,
then along/south of the Kaibab Plateau and Mogollon Rim on
Thursday. Gusty and erratic outflow winds 35 to 45 mph are
possible from nearby thunderstorms. Heavy localized rainfall may
lead to an enhanced flash flooding risk over sensitive terrain.
Away from storms, expect light winds out of south through
southwest 5 to 15 mph each day.

Friday through Sunday...Scattered to numerous showers and
thunderstorms are expected Friday and Saturday, with activity
declining on Sunday. Storms will be most widespread along/south of
the Kaibab Plateau and Mogollon Rim. The primary hazards are
lightning, gusty outflow winds, and elevated risk for flash flooding
over sensitive terrain. Away from storms, expect light winds out
of south through southwest 5 to 15 mph each day.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

PUBLIC...Lewandowski
AVIATION...MCT
FIRE WEATHER...Lewandowski

For Northern Arizona weather information visit
weather.gov/flagstaff