118
FXUS65 KFGZ 021741
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1041 AM MST Tue Sep 2 2025

.SYNOPSIS...Daily chances for showers and thunderstorms are
forecast this week, mainly along and south of the Mogollon Rim
today, with activity spreading northward mid-week. Strong outflow
winds and localized flash flooding will be the primary hazards.

&&

.DISCUSSION...For today, another round of isolated to scattered
showers and thunderstorms are forecast to occur, primarily along
and south of the Grand Canyon, Mogollon Rim, and White Mountains.
This area features the highest surface dew points, with values
forecast to range from 45-55 F during the afternoon hours. Today`s
storms will move to the west-northwest around 10 mph, and the
greatest hazards will be frequent lightning and strong outflow
wind speeds in the 40-50 mph range. The risk of flash flooding is
higher today than yesterday given the general increase in
atmospheric moisture, but is still somewhat low. That said,
localized rainfall amounts over an inch, especially in the event
of training storms, are possible. On Wednesday, chances for
showers and thunderstorms increase further, especially across
northwest Arizona due to the influence of an inverted trough
rotating around the subtropical high.

From Thursday through Saturday, deep monsoon moisture in place
across northern Arizona is expected to bring widespread shower
and thunderstorm activity each day. The primary hazard will
transition to flash flooding from heavy rainfall. Otherwise, high
temperatures will trend cooler, with daytime temperatures around
5-10 degrees below normal by Friday.

Beyond Sunday, ensemble mean forecasts show a general decline in
monsoon moisture as northern Arizona comes under the influence of
a West Coast trough. All of the clusters show this trough, but
they vary in terms of the overall depth and timing. So, while
confidence is high that atmospheric moisture will decline next
week, by how much and how quickly is still uncertain.

&&

.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...Tuesday and Wednesday...Scattered showers and
thunderstorms each afternoon. Best chances for storms are along and
south of the Grand Canyon, Mogollon Rim, and White Mountains on
Tuesday. Shower and thunderstorm chances spread northward on
Wednesday with scattered activity up to the Kaibab Plateau. Gusty
and erratic outflow winds 40 to 50 mph are possible near
thunderstorms. Away from storms, winds are south through southwest 5
to 15 mph each day.

Thursday through Saturday...Scattered to numerous showers and
thunderstorms are expected each afternoon. Activity is most
widespread along/south and west of the Kaibab Plateau, Mogollon Rim,
and White Mountains. The primary hazards are lightning, gusty
outflow winds, and elevated risk for flash flooding over sensitive
terrain and recently burned areas. Outside of any erratic outflow
gusts near storms, expect west through southwest winds 5 to 15 mph
each day.

&&

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

&&

$$

PUBLIC...RR
AVIATION...MCT
FIRE WEATHER...RR

For Northern Arizona weather information visit
weather.gov/flagstaff