817
FXUS65 KFGZ 031101
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
401 AM MST Wed Sep 3 2025

.SYNOPSIS...Daily chances for showers/storms remains in the
forecast through Saturday, before we quickly dry out across the
state Sunday onward. There still remains uncertainty with
available instability and the trajectory of Tropical Storm Lorena,
so confidence is iffy on rainfall amounts especially for later in
the week. Either way, gusty winds and localized flash flooding
will be the primary hazards.

&&

.DISCUSSION...Although we had a rather slow start to monsoon
season this year, we are quickly ramping up here in the final
month of the season. Model guidance suggest high pressure slightly
wobbling eastward through the next couple of days, keeping a good
influx of moisture into the state. Another primary source of
moisture through the next several days will be Tropical Storm
Lorena. According to the National Hurricane Center, this storm
will creep towards the northern portion of the California Baja
through Saturday.

For today, precipitation chances look best along and west of
Fredonia-St. Johns line, which matches nicely with the day 1
marginal risk for excessive rainfall from the Weather Prediction
Center. As far as timing for showers/storms today, hi-res guidance
suggests light activity picking up as early as 8 AM MST, but the
bulk of the precipitation looks to pick up any time after 12 PM
MST (noon). We could see showers/storms persist through the
evening and overnight hours, and Yavapai County seems to be
highlighted to receive a cluster of storms just after midnight.

Thursday through Saturday...we expect moisture to continue to
increase across northern Arizona, as Tropical Storm Lorena inches
closer to the States. Model guidance hasn`t agreed well on the
trajectory of this system yet, but the GFS is certainly the more
favorable solution for widespread showers to reach our CWA for the
end of the week. The majority of our CWA remains under a marginal
risk for excessive rainfall (from WPC) Thursday through Saturday,
but as confidence grows in the path of this Tropical Storm, we
could see a slight risk get introduced into our CWA.

Despite our extended forecast usually holding the least
confidence, models seem to be in good agreement that Arizona will
quickly dry out Sunday onward. Initially we look to fall under a
zonal flow and ultimately cutoff any lingering moisture, but then
a trough will further clear us out in the beginning of next week.

&&

.AVIATION...Wednesday 03/12Z through Thursday 04/12Z...VFR
conditions expected through much of the TAF period, but brief MVFR
conditions possible in heavier SHRA/TSRA. Showers and
thunderstorms will be greatest between 18Z-03Z along and west of a
KGCN-KSOW line. Gusty/erratic winds between 30-40 kts possible
near storms. Otherwise, expect winds 5-15 kts varying in
direction.

OUTLOOK...Thursday 04/12Z through Saturday 06/12Z...Daily
SHRA/TSRA expected through the outlook period. Outside of brief
MVFR ceilings and visibilities in heavier storms/showers, look for
VFR conditions to persist. Gusty/erratic winds between 30-40 kts
possible from outflows. Otherwise, look for south through west
winds 5-15 kts.

&&

.FIRE WEATHER...Wednesday and Thursday...Scattered to widespread
showers forecast each afternoon, with light activity continuing into
the evening hours. Heavy rainfall, small hail, gusty winds, and
frequent lightning will be the main hazards. Heaviest storms look to
be along and south of a Fredonia-St. Johns line. Due to the uptick
in moisture, look for minimum RH values between 20-45%. Outside of
gusty/erratic outflow winds, expect winds 5-15 mph varying in
direction.

Friday through Sunday...Potential for showers/storms forecast
through Saturday, before much drier conditions return on Sunday.
Outside of storm driven outflow winds, look for westerly winds 5-15
mph. Minimum RH values look to be between 25-55% Friday and
Saturday, becoming 20-40% on Sunday.

&&

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

&&

$$

PUBLIC...Konieczny
AVIATION...Konieczny
FIRE WEATHER...Konieczny

For Northern Arizona weather information visit
weather.gov/flagstaff