753
FXUS65 KFGZ 222245
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
345 PM MST Tue Sep 22 2026

.SYNOPSIS...Increasing moisture will bring chances for showers
and thunderstorms in eastern Arizona today. Precipitation becomes
more widespread Wednesday and Thursday as deeper moisture and a
low pressure system impact the area. Drier conditions are possible
by Friday and the weekend with only slight chances for rain.

&&

.DISCUSSION...Today...An upper low is currently centered over
eastern NV and moving to the northeast. This feature brought a
minor surge in moisture and instability this morning, with weak
isolated showers and thunderstorms across NW AZ. Showers in this
region have ended as the trough lifts northeastward, and a weak
cut-off low will be left behind off the coast of Baja California.
Meanwhile, a shortwave currently located over Mexico will be
slowly drifting northward over the next few days, following a
trajectory into NM and eastern AZ. A much larger surge of moisture
will accompany this feature. PW values this afternoon will reach
above the 95th percentile for this time of year across eastern AZ.
Scattered showers and thunderstorms are firing mainly near the
AZ-NM border as of 1200 MST. This activity is forecast to
increase in coverage and continue through the afternoon and
overnight. A few instances of flash flooding will be possible
across Navajo and Apache counties today.

Wednesday and Thursday...By tomorrow, the main axis of the wave
ripples through our area. Moisture will spread further west, and
shower/thunderstorm chances will extend to Coconino and Yavapai
counties. Further east, rainfall may transition into more of a
stratiform type, however heavy accumulations are still possible.
The WPC excessive rainfall outlook puts most of northern AZ in a
marginal risk for flash flooding tomorrow. On Thursday, the
aforementioned low off the coast of Baja California makes a push
inland. The result will be continued showers and thunderstorms
across much of northern AZ.

Friday and onward...Ensemble guidance tends to bring a downturn in
activity on Friday then more so on Saturday after the wave
departs and brief ridging with drier air remain dominant. By early
next week there is considerable uncertainty hinging on a pair of
tropical systems and a Pacific trough that may form. The current
forecast calls for a widespread area of 30-60% PoPs across
northern AZ on Monday, however there is a lot of room for this to
change.

&&

.AVIATION...Wednesday 23/00Z through Thursday 24/00Z...Mainly VFR.
ISOLD -SHRA/-TSRA continues through 06Z, mainly N/E of KINW. ISOLD-
SCT SHRA/TSRA redevelops after 19Z over the higher terrain, most
numerous S/W of a KGCN-KFLG-KSOW line. Brief MVFR conditions and
gusty erratic winds expected near TS. Otherwise, S winds 10-20 kts
becoming NE-SE 5-10 kts after 03Z.

OUTLOOK...Thursday 24/00Z through Saturday 26/00Z...Mainly VFR. SCT
SHRA/TSRA over the higher terrain on Thursday, becoming ISOLD on
Friday. Brief MVFR conditions and gusty erratic winds expected near
TS. Winds VRB 5-10 kts on Thursday, becoming S-W on Friday.

&&

.FIRE WEATHER...This afternoon through Thursday...Scattered shower
and thunderstorms will continue mainly across Navajo and Apache
counties today. Activity will spread west to include much of
northern AZ on Wednesday and Thursday. Stronger storms will bring
heavy rainfall and gusty/erratic winds. Outside of storms, winds are
south through southwest 10-20 mph gusting to 25 mph today, then
variable at 5-15 mph on Wednesday and Thursday.

Friday through Sunday...Slight chances for showers and thunderstorms
continues Friday, then mostly dry conditions are possible by
Saturday. Rainfall chances may begin to increase early next week,
however there is considerable uncertainty at this time. Winds will
be southwest 5-15 mph on Friday and Saturday increasing to 10-20 mph
on Sunday.

&&

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

&&

$$

PUBLIC...Lewandowski
AVIATION...Humphreys
FIRE WEATHER...Lewandowski

For Northern Arizona weather information visit
weather.gov/flagstaff