368
FXUS65 KFGZ 130916
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
216 AM MST Sat Sep 13 2025

.SYNOPSIS...Cooler temperatures and lighter winds arrive for the
weekend. Isolated showers and thunderstorms will linger over far
eastern Arizona today, with dry conditions elsewhere. Expect a
gradual warming trend through much of next week, with low storm
chances limited to the White Mountains area. Storm chances may
spread over much of the area by late week.

&&

.DISCUSSION...A fairly strong trough for mid September is moving
eastward into NW Arizona and Utah this morning. Moisture out ahead
of the trough continues to flow into far eastern Arizona with much
drier air spreading into central/western parts of the state.
Strong unidirectional wind shear and instability continue to
produce isolated strong thunderstorms over Apache County as of 2
AM. Some of the storms have shown supercell characteristics, with
some storm splitting as well. This threat will persist for several
more hours until around 10 AM MST before enough dry air spreads
across even far eastern AZ to mostly end storm chances. Elsewhere,
a nice weekend is shaping up as mild daytime temperatures and
lighter winds are expected as the trough moves over and then east
of the state. With the rather dry air and lighter winds, morning
low temperatures Sunday/Monday will be much cooler with 30s
forecast at some of the high elevations spots (Flagstaff, Tusayan,
Bellemont, Window Rock) and a couple of the coldest places could
even touch the freezing mark.

Monday through Wednesday - gradually increasing heights as high
pressure builds from the southeast. A fairly light southwest to
west flow aloft so winds will be lighter, mainly in the 5-15 mph
range. Daytime temperatures will be warming back up a few degrees
above normal. Dry conditions are forecast for most areas, though
just enough moisture may move back into the White Mountains region
for a low chance (10-30%) of a shower or thunderstorm each
afternoon.

Toward the end of next week - another west coast trough is
forecast to develop which could induce a more southerly flow and
moisture advection into Arizona. The precipitable water forecast
from the grand ensemble using inputs from EC/GEFS/GEPS goes from
around 0.30" early in the week to 0.90" by Friday at Flagstaff.
Values in Yavapai County increase to 1.0" to 1.4" by Friday. The
chance of showers and thunderstorms returns to our forecasts from
the Mogollon Rim southward by Thursday and then spreads across
the entire area Friday and Saturday. Daytime temperatures are also
forecast to drop back toward normal by the end of the week.

&&

.AVIATION...Saturday 13/12Z through Sunday 14/12Z...Mainly VFR
conditions expected. Isolated SHRA/TSRA through this afternoon
generally east of a KSOW-0V7 line, otherwise dry. Winds light and
variable, becoming SW 10-15 kts gusts 20-30 kts after 15-18Z and
then diminishing after 02Z.


OUTLOOK...Sunday 14/12Z through Tuesday 16/12Z...VFR conditions
expected. Isolated thunderstorms near White Mountains Monday (10%
chance). Winds SW 5-15 kts Sunday, SW 5-10 kts Monday. Light and
variable or terrain driven during overnight hours.

&&

.FIRE WEATHER...Saturday and Sunday...Seasonably cool and turning
dry. Winds are southwest through west 10 to 15 mph with gusts to 20
to 25 mph on Saturday, then southwest 5 to 15 mph on Sunday.
Isolated storms on Saturday confined to areas right along the UT and
NM state lines, dry on Sunday.

Monday through Wednesday...Mostly dry with seasonal daytime
temperatures. Minimum RH is generally 10-20%, locally higher at high
elevation sites. Daytime winds are southwest through west 5 to 15
mph. Chance for isolated showers and thunderstorms in the White
Mountains each day.

&&

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

&&

$$

PUBLIC...JJ
AVIATION...JJ
FIRE WEATHER...JJ

For Northern Arizona weather information visit
weather.gov/flagstaff