Flagstaff, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

710
FXUS65 KFGZ 052349
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
449 PM MST Fri Sep 5 2025

.SYNOPSIS...Scattered showers and thunderstorms are expected
through Saturday. Dry air starts to move in on Sunday delivering
isolated activity through early next week. Fall-like weather is
expected to set in mid to late next week with low chances for
showers and thunderstorms returning.

&&

.DISCUSSION...Monsoon moisture will hang around through Saturday
with decent chances for showers and thunderstorms continuing. A
drier westerly flow will develop on Sunday and last through at
least Tuesday. Enough moisture will linger for a slight chance of
showers and thunderstorms but our expectation is that it will
remain mainly dry. By mid to late next week forecast models
diverge, and to put it simply, they range from wet to dry to
severe thunderstorm potential. We`ll need to get closer in time
to start making that call.

For tonight...Diminishing showers and thunderstorms but with
isolated activity continuing through the night. The thunderstorm
complex we saw Friday morning through the early afternoon will
squash most daytime heating across northwest Arizona and from
Interstate-40 southward, so any activity in these locations will
be low key. Further north there`s just not enough moisture for
more than a stray shower or two.

On Saturday...Monsoon moisture will remain in place. We will see
the more typical daytime heating and midday through early evening
thunderstorm development. Activity will start mainly over the
high terrain first then progress to the lower elevations. No
widespread flash flood or severe weather threat is anticipated.

For Sunday through Tuesday...A drier westerly flow will develop
across northern Arizona. The result will be some drying but with
enough moisture lingering for isolated showers and thunderstorms,
mainly toward the Arizona/New Mexico border. Turning a bit warmer.
In general, winds will remain on the light side as pressure
gradients will remain weak.

From Wednesday onward...Revisit the end of the first paragraph in
this discussion, forecast chaos. We have fair confidence that
breezes will strengthen and temperatures will cool resulting in a
fall-like feel as a trough moves across the western states. But
as far as the remainder of the forecast, please check back. The
position of the eventual trough will be critical as to how much
moisture, if any, gets pulled across Arizona.

&&

.AVIATION...Saturday 06/00Z through Sunday 07/00Z...Mainly VFR
expected with brief/localized MVFR in SHRA/TSRA. Isolated
SHRA/TSRA this evening and overnight. Gusty outflow winds
20-35kts ahead of TSRA as well as localized gusty erratic wind in
immediate vicinity of TSRA. Otherwise expect winds W 5-15 kts
daytime with light and variable or terrain driven winds overnight.
Another round of scattered SHRA/TSRA develops again Saturday after
18Z.

OUTLOOK...Sunday 07/00Z through Tuesday 09/00Z...Mainly VFR
expected with brief MVFR in SHRA/TSRA. Scattered SHRA/TSRA through
around 03Z Sunday. Only isolated SHRA/TSRA over higher terrain on
Sunday afternoon and evening. Expect gusty outflows 20-35 kts
ahead TSRA as well as localized gusty erratic wind in immediate
vicinity of TSRA. Otherwise expect S-W winds 5-15 kts daytime,
light and variable or terrain driven overnight.

&&

.FIRE WEATHER...Saturday and Sunday...Scattered showers and
thunderstorms expected on Saturday, however things become more
isolated and confined to the higher terrain Sunday as a trough
moving in from the West Coast dries things out. Main hazards will be
heavy rainfall, frequent lightning, and gusty/erratic winds. Outside
of storms, expect westerly winds at 10-20 mph. Min RH`s Saturday 25-
35% high deserts, 45-55% mountains and forests.  Min RH`s Sunday
drop to 25-35% area-wide.

Monday through Wednesday...No showers or thunderstorms expected on
Monday as dry air moves into the area. A little more moisture moves
in on Tuesday and Wednesday and may produce an isolated storm over
the Mogollon Rim and White Mountains. Winds S-SW at 10-20 mph on
Monday and Tuesday, increasing S-SW 15-25 mph on Wednesday. Minimum
RH values drop to the 15-30% range each day.

&&

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

&&

$$

PUBLIC...McCollum
AVIATION...JJ
FIRE WEATHER...Bernhart

For Northern Arizona weather information visit
weather.gov/flagstaff