693
FXUS65 KFGZ 060418
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
918 PM MST Tue Aug 5 2025

.SYNOPSIS...High pressure will dominate the region through the
forecast period, resulting in hot daytime highs and mostly dry
conditions. Slight chances for high-based showers/storms each
day, mainly along the higher terrain. Otherwise, elevated fire
danger will persist with low humidity and breezy daytime winds.

&&

.DISCUSSION...High pressure is currently situated above New
Mexico, allowing a slightly better flow of moisture into Northern
AZ. The PW this morning has recovered from the record low values
in previous days, but still sits right around the 10th-25th
percentile for early August. A few isolated thunderstorms have
begun to fire off primarily along far eastern AZ today, but large
surface dewpoint depressions are keeping activity high-based.
Gusty winds and cloud to ground lightning are the primary hazards
near showers today.

The ridge is forecast to strengthen and wiggle around Arizona,
peaking in intensity by Thursday. A gradual uptick in moisture can
be expected, but there still isn`t too much confidence in an ample
surge of surface dewpoints. Model soundings are also fairly capped
through the week. Right now, it looks like any thunderstorms will
remain isolated and high-based across the higher terrain through
Friday. Persistent troughing over the Pacific northwest will push
against the strong ridge, setting up a tight gradient that will
keep afternoons breezy through Friday. The strongest winds are
expected towards far northwestern AZ each day. After Friday, the
troughing looks to finally propagate away and leaving much weaker
winds.

The strengthening ridge will also bring along very hot temperatures.
An Extreme Heat Warning remains in effect for the Grand Canyon below
4000 ft through at least Friday due to temperatures in excess of
110. Another Extreme Heat Warning will be in effect for
Yavapai/Northern Gila counties below 4000 ft elevation Wednesday
through Friday. Be sure to practice heat safety through the next
several days, which includes drinking plenty of water and avoiding
strenuous activity during the hottest part of the day if possible.

Beyond Friday, some long term model solutions hint at more
widespread showers and storms this weekend. However there is still
a lot of uncertainty in this period, and this may change with
future cycles.

&&

.AVIATION...Wednesday 06/06Z through Thursday 07/06Z...Expect VFR
conditions with localized areas of haze/smoke north of KGCN to
KPGA. Light and variable wind overnight. Southwest winds 10-20
kts gusting near 30 kts redevelop after 17Z Wed and continuing
through 03Z Thu. Isolated -SHRA/-TSRA also redevelop after 18Z
Wednesday, mainly along/north of the Mogollon Rim.

OUTLOOK...Thursday 07/06Z through Saturday 09/06Z...VFR
conditions will persist under variable clouds with localized areas
of haze/smoke north of KGCN to KPGA. Daily chances (10-30%) for
-SHRA/-TSRA between 18Z-03Z are forecast, primarily across the
higher terrain. Daytime winds will generally be west to southwest
at 10-20 kts, gusting up to 30 kts. Light and variable winds
expected during the overnight periods.

&&

.FIRE WEATHER...Wednesday and Thursday...Hot and mostly dry
conditions will persist. Expect slight chances for high-based
showers/storms, primarily across the Mogollon Rim and White
Mountains. Look for southwest through west winds 10-20 mph gusting
around 25 mph both days. Minimum RH values between 10-25%, resulting
in localized near-critical fire weather conditions.

Friday through Sunday...Generally dry conditions on Friday will be
followed by better chances for storms on Saturday and Sunday. Look
for west-southwest winds 10-20 mph with gust to 25 mph on Friday,
with strongest winds expected across western Coconino County.
Lighter winds for Saturday and Sunday at 5-15 mph with a few gusts
to 20 mph. Minimum RH values between 10-20% on Friday with near
critical fire weather conditions. Minimum RH values climbing to 15-
25% on Saturday and Sunday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 8 PM MST Friday for AZZ006.

Extreme Heat Warning from noon Wednesday to 8 PM MST Friday for
AZZ018-037.

&&

$$

PUBLIC...Lewandowski
AVIATION...JJ
FIRE WEATHER...McCollum

For Northern Arizona weather information visit
weather.gov/flagstaff