083
FXUS65 KFGZ 092358
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
458 PM MST Sun Aug 9 2026

.SYNOPSIS...Warm temperatures continue with isolated to scattered
showers and thunderstorms today. Cooler temperatures and more
widespread showers and thunderstorms are expected beginning Monday
and lasting through at least Thursday.

&&

.DISCUSSION...Strong high pressure will be centered near the four
corners today, with slight weakening and an eastward shift for
Monday. For today, precipitable water values are near normal for
early August with surface dewpoints in the 40s along/north of the
Mogollon Rim and 50s to the south. With daytime heating we will
see scattered thunderstorm development by early afternoon along
the higher terrain, with storm motion toward the west/northwest
toward the lower elevations of Gila/Yavapai later in the afternoon
and evening. While the guidance doesn`t indicate high coverage of
precipitation in these areas (PoP 30-50%), there is a good chance
of gusty outflow winds impacting much of this region this
evening. Isolated severe gusts (58+ mph) will be possible. With
the high still in place, an Excessive Heat Warning remains below
4500 feet for the Grand Canyon and Marble/Glen Canyons until 8 PM
this evening. With slight weakening of the high, and additional
cloud cover, we opted not to extend the warning into Monday.

By Monday, we are anticipating an increase in storm activity that
should last through at least Thursday. High pressure will shift
slowly eastward as a weak trough approaches the west coast. This
will induce more of a south/southeast flow and allow for higher
moisture values to advect into our region. Forecast precipitable
water during this time is near 1.00" along the Mogollon Rim/WHite
Mtns and up to 1.50" for the lower elevations of Yavapai/Gila Co.
With this additional moisture, storms will be more efficient
rainfall producers and the risk of at least localized flash
flooding will be on the increase. In addition, storms may continue
later into the evening and even overnight, especially Tue/Wed
nights. A disturbance is also shown moving up from the south by
several of our models late Wednesday into Thursday which could
increase storm activity further. All in all, things are looking
pretty active Monday through Thursday, then some drier air is
forecast to move in from the southwest by Friday or Saturday and
remain through the weekend. This would likely not shut off
convection completely, but result in less daily coverage.

&&

.AVIATION...Monday 10/00Z through Tuesday 11/00Z...Mainly VFR.
ISO-SCT SHRA/TSRA will decline after 03Z, but additional
SHRA/TSRA possible INVOF KPRC/KPAN through 12Z. Brief MVFR
conditions and gusty outflow winds in excess of 40 kts possible in
and around TS. Winds becoming light and VRB after 03Z. SCT-NMRS
SHRA/TSRA developing again after 19Z, with the greatest storm
activity along and south of a KGCN-KFLG-KJJN line.

OUTLOOK...Tuesday 11/00Z through Thursday 13/00Z...Mainly VFR. SCT-
NMRS SHRA/TSRA each day from 19Z-03Z, especially over the higher
terrain. Brief MVFR/IFR conditions and gusty outflow winds in excess
of 40 kts possible in and around +TS. Otherwise, daytime winds W/SW
5-15 kts, becoming light and VRB overnight.

&&

.FIRE WEATHER...Monday and Tuesday...Cooler temperatures, along with
increasing chance for showers and thunderstorms. Greatest chances
will mainly be over the higher terrain. Heavy downpours, gusty
winds, and hail will be possible in any stronger storm. Outside of
storms, expect variable winds around 5-15 mph.

Wednesday through Friday...Below normal temperatures, with continued
daily chances for scattered to widespread showers and thunderstorms.
Outside of storms, winds will be west/southwest 5-15 mph.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 8 PM MST /9 PM MDT/ this evening for
AZZ005-006.

&&

$$

PUBLIC...JJ
AVIATION...RR
FIRE WEATHER...Humphreys

For Northern Arizona weather information visit
weather.gov/flagstaff