881
FXUS65 KFGZ 240537
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1037 PM MST Sun Aug 23 2026

.SYNOPSIS...Moderate monsoon activity will continue through
Monday, mainly along the higher terrain during the afternoon and
evening hours. Then, as high pressure builds over Arizona, hot
weather and a decline in storm activity is expected to develop as
the flow of moisture northward into the region diminishes.

&&

.DISCUSSION...Upper-air analysis shows the 500mb subtropical high
pressure cell centered across central New Mexico, with a
northeastward-moving shortwave trough draped across the Yavapai
and Coconino County border. This system is actively supporting
showers and thunderstorms across western Yavapai and Coconino
Counties, while aiding convective initiation along portions of the
Mogollon Rim.

Moderate monsoon conditions persist today with storms drifting
northeastward on average. The forecast favors high-terrain
locations, with a chance for showers and thunderstorms between
30-60% in the mountains. However, mid-level warming is limiting
deep atmospheric instability, keeping the threat for severe
weather low. Given the presence of slow-moving storms, there is a
low to medium risk for flash flooding. This threat is tempered by
atmospheric moisture (precipitable water) values ranging from
0.75-0.85 inches north of the Mogollon Rim and 0.85-1.15 inches
south of the Rim. Outflow wind gusts between 35-45 mph are
possible in the vicinity of storms.

Storm activity is forecast to decline after sunset. High-
resolution model guidance indicates overnight showers and
thunderstorms may move into the region from the south, impacting
areas west of a Payson to Flagstaff to Page line. Similar
convective coverage is forecast on Monday, though a surge of
moisture northward from the Gulf of California will likely shift
the main axis of high storm coverage into Coconino and Yavapai
Counties, with more isolated activity expected elsewhere.

By mid-to-late week, guidance generally agrees that the
subtropical high pressure circulation will strengthen over
Arizona. This will introduce more stable atmospheric conditions
and a noticeable downturn in storm coverage, leaving only low-
grade monsoon activity through the remainder of the week.
Temperatures are forecast to warm during this period, with daytime
temperatures approaching 10 degrees above normal across much of
the area. Excessive Heat products may become necessary for lower
elevation areas, including portions of Yavapai County and Grand
Canyon country.

&&

.AVIATION...Monday 24/06Z through Tuesday 25/06Z...Mainly VFR
conditions. An outflow boundary moving north from central AZ
could trigger a round of SHRA/TSRA late tonight into early Monday
morning (through around 09Z) along/south of KPRC-KSEZ-KINW.
Otherwise, another round of isolated to scattered SHRA/TSRA is
then forecast to develop Monday afternoon, with highest coverage
west of a KPAN-KPGA line. Brief MVFR conditions and gusty/erratic
wind to 40 kts possible in heavier SHRA/TSRA. Otherwise, look for
south to southwest daytime winds at 5-15 kts, with variable or
terrain wind-driven winds overnight.

OUTLOOK...Tuesday 25/06Z through Thursday 27/06Z...Expect mainly
VFR conditions. Coverage of afternoon SHRA/TSRA decreasing to
isolated Tuesday and Wednesday, mainly over higher terrain.
Outside of gusty/erratic outflow driven winds, look for daytime
winds mainly southwest to west 5-15 kts. Light and variable winds
at night.

&&

.FIRE WEATHER...Rest of today through Tuesday...Expect daily chances
for showers/thunderstorms, with the greatest coverage across the
higher terrain. Activity will ramp up around midday then continue
through the evening hours. Drier conditions are possible starting
Tuesday, with low-grade monsoonal conditions developing. Outside of
gusty and erratic storm driven winds, look for southwest to west
winds generally 10 mph or less during the day and variable at night.

Wednesday through Friday...Drier, low-grade monsoonal conditions
will likely continue, with activity becoming more limited to the
White Mountains. Daytime highs are forecast to become quite hot,
reaching up to 10-15 degrees above normal. Look for southwest winds
5-15 mph each afternoon.

&&

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

&&

$$

PUBLIC...RR
AVIATION...JJ
FIRE WEATHER...McCollum

For Northern Arizona weather information visit
weather.gov/flagstaff