178
FXUS65 KFGZ 210945
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
245 AM MST Mon Sep 21 2026

.SYNOPSIS...Moisture begins to return to the region by this
evening, with a chance of showers and thunderstorms especially in
northwest Arizona. More widespread precipitation is expected
Tuesday, along with breezy southerly winds. Uncertainty increases
Wednesday onward, but daily shower and thunderstorm chances remain
in the forecast through the work week, highest in eastern Arizona.

&&

.DISCUSSION...After a dry weekend, we will start to see some
changes in the pattern beginning today. An upper low just offshore
the California coast will move just north of Las Vegas by this
afternoon and then northeast through Utah on Tuesday. By late this
afternoon through the overnight hours, an increase in instability
primarily northwest of Flagstaff will result in a 30-50% chance
of showers and thunderstorms. Moisture levels are not impressive
with this initial round of showers, so generally light rainfall
amounts are expected. By Tuesday, precipitable water values
increase significantly across eastern Arizona bringing a 40-60%
chance of showers/thunderstorms. Isolated storms will be possible
farther west. By Tuesday night through Wednesday - a plume of deep
moisture is forecast to move northward into New Mexico, with
eastern Arizona on the fringes of the plume. A disturbance moving
northward out of Mexico should enhance precipitation chances
especially in eastern Arizona - with a marginal risk of flash
flooding included in the latest WPC outlooks now including areas
as far west as Prescott/Flagstaff, though the heaviest rainfall is
expected to be east of the AZ/NM state line. Thursday - weak
troughing off the southern CA and Baja coasts is forecast to shift
northeastward, pulling some deeper moisture farther west to
include most of northern AZ. There is still uncertainty in this
scenario, but Thursday currently looks like the highest rain
chances (30-60%) for areas farther west including Coconino/Yavapai
counties. The overall heavy rain/flood threat is low, with only
isolated areas of heavy rain. Friday through the weekend -
isolated to scattered showers and thunderstorms remain in the
forecast, though the details remain uncertain.

&&

.AVIATION...Monday 21/12Z through Tuesday 22/12Z...Primarily VFR
conditions. ISO-SCT -SHRA/-TSRA returns late this afternoon and
evening, with the best coverage across northern Coconino county.
Winds are SW-W 5-15 kts from 17Z-02Z, light and VRB or terrain
driven overnight.

OUTLOOK...Tuesday 22/12Z through Thursday 24/12Z...Primarily VFR
conditions. SCT-NMRS SHRA/TSRA across Navajo and Apache counties,
ISO-SCT elsewhere. Localized MVFR in heavier precipitation. Daytime
winds are S-SW at 10-20 kts gusting to 25 kts Tuesday, then
light/variable mainly 10 kts or less Wednesday.


&&

.FIRE WEATHER...Today and Tuesday...Shower and thunderstorm chances
return starting this evening. Best chances are across northwest AZ
this evening and overnight, then across eastern AZ on Tuesday. Winds
are south through southwest 10-15 mph on Monday, increasing to 10-20
mph gusting to 25 mph on Tuesday.

Wednesday through Friday...Chances for showers and thunderstorms
continue each day, declining slightly on Friday. The best chances
will be seen across eastern Arizona each day. Winds outside of
thunderstorm activity are forecast to be generally light, 10 mph or
less.

&&

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

&&

$$

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

For Northern Arizona weather information visit
weather.gov/flagstaff