981
FXUS65 KFGZ 291753
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1053 AM MST Tue Sep 29 2026

.SYNOPSIS...Widespread showers, along with increased thunderstorm
activity, is expected today, continuing the heightened risk of
flooding. A Flood Watch remains in effect for northern Arizona
through this evening. Chances for showers and thunderstorms
continue across eastern Arizona on Wednesday, before warmer and
drier weather returns Thursday and into the weekend.

&&

.DISCUSSION...The mid/upper-level trough with a closed low at its
base is starting to push into Arizona as tropical moisture
continues to sit across northern Arizona. Meanwhile, Hurricane
Polo is moving across Baja California. Radar shows heavier
showers and thunderstorms are developing across eastern AZ, and
this will be pushing W to NW across the State today as the trough
and closed low move eastward today. This will support impactful
weather across northern AZ today, with a greater focus over
eastern AZ this evening and Wednesday.

From this morning through Wednesday morning, the low is forecast
to move across northern Arizona. As it does so, additional
atmospheric moisture from Hurricane Polo will be entrained into
the low. With increased synoptic-scale forcing associated with the
passing low, greater storm activity and higher rainfall rates are
forecast. High-resolution model guidance continue to highlight
the eastern Mogollon Rim and White Mountains as the area with the
highest flood risk with 24 hour rainfall totals up to 3 inches. Another
signature of an inch or greater is starting to appear in the 3-hr
QPF HREF guidance near the UT and AZ border, near Lake Powell,
this afternoon and early evening hours so this will be a trend to
watch. We will also see higher 0-6km Bulk Wind Shear, with values
ranging from 40-60 kts. Despite the strong shear, forecast CAPE
values at or below 600 J/kg may limit the overall severe
thunderstorm threat, though isolated severe storms cannot be ruled
out given the benefit of forcing from the low. So, all things
considered, we are looking at a moderate/high risk of
flooding/flash flooding, with a lower risk of strong storms
producing large hail and severe wind gusts. A Flood Watch remains
in effect for northern Arizona through Tuesday evening.

On Wednesday, the low center moves into New Mexico, with chances
for showers and storms primarily remaining across eastern
Arizona. High pressure is forecast to bring a return of dry
weather, with daytime temperatures warming to near average on
Thursday and into the weekend.

&&

.AVIATION...Tuesday 29/18Z through Wednesday 30/18Z...The most
widespread SHRA/TSRA will favor areas north/east of a KGCN-KFLG-
KPAN line this afternoon where MVFR and local IFR conditions can
be expected. Further west, coverage will be more scattered, but
another round of TSRA is expected to develop during the
afternoon/early evening hours bringing periodic MVFR/IFR
conditions. Moisture wrapping around the low pressure system
tonight will bring another round of SHRA with some embedded -TSRA
aft 06Z persisting into Wednesday morning. Expect areas of
MVFR/IFR overnight with some local LIFR possible in areas of fog.
Winds today will be easterly at 5-15 kts, becoming light and
variable overnight.

OUTLOOK...Wednesday 30/18Z through Friday 02/18Z...SHRA/TSRA will
continue on Wednesday afternoon primarily along and east of a
K0V7-KKINW line where MVFR to IFR conditions are possible. A few
showers lingering over the White Mountains Wednesday evening with
showers ending Wednesday night. Elsewhere should see improving
conditions through the afternoon Wednesday. Winds Wednesday
becoming W/NW around 5-15 kts, decreasing after sunset.

&&

.FIRE WEATHER...Today through Wednesday...Precipitation chances
will remain high today with widespread wetting rain and isolated
embedded thunderstorms across the region, becoming more focused
over eastern Arizona this evening into Wednesday. This will
present a moderate flood and burn scar flash flood risk. Western
Arizona will start drying out Wednesday. Winds N-NE 10-20 mph
today, NW-N 5-15 mph on Wednesday.

Thursday through Saturday...Dry with no precipitation across the
state, minimum RH drops to the 20s and 30s percent by Saturday.
Daytime high temps will also become near to slightly above normal
across western AZ and near to just below normal for eastern AZ.
Winds light and variable 5-10 mph Thursday, light and variable most
areas Friday/Saturday with the exception of some winds E 5-15 mph
along the Rim.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Flood Watch through this evening for AZZ004>018-037>040.

&&

$$

PUBLIC...Schank
AVIATION...MCT
FIRE WEATHER...Schank

For Northern Arizona weather information visit
weather.gov/flagstaff