591
FXUS65 KFGZ 082319
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
419 PM MST Tue Jul 8 2025

.SYNOPSIS...Hot daytime highs and mostly dry conditions forecast
through the week. Slight chances for showers/storms across the
higher terrain today and tomorrow, becoming more focused across
the White Mountains for the rest of the period.

&&

.DISCUSSION...Showers and thunderstorms have begun to develop
along the Mogollon Rim early this afternoon, with coverage
expected to continue to increase across western Arizona. Given the
dry sub-cloud layer, gusty winds look to be the main threat
across the area. However, a few brief downpours will be possible.

High pressure strengthens overhead on Wednesday, with heights
nearly 600 dam. As a result, hot temperatures are expected across
the region with highs in the upper 80s F to lower 90s F in the
higher terrain and 105-115F in the lower deserts. As a result, an
Extreme Heat Warning is in effect for the lower elevations of the
Grand Canyon as well as lower Gila and Yavapai counties.

A cut-off low off the California looks to eject off the Pacific
and become absorbed by a trough over the Pacific Northwest. As
this occurs, the ridge begins to retreat to the south and allow
for drier to be advected into northern Arizona. As a result, dry
conditions are expected for the vast majority of the area. With
some moisture still trapped under the high, a few isolated
afternoon showers and storms will still be possible, mainly across
the eastern Mogollon Rim and White Mountains. Breezy conditions
also look to develop on Thursday, and with still dry surface
conditions, RH values are low enough to support near-critial fire
weather conditions in the afternoon. Slight cooler, but still warm
temperatures look to ensue but remain hot in the Grand Canyon.
For this reason, the warning has been extended through the
weekend.

As the high shifts to the west, flow aloft will keep advecting drier
air in from the north. However, surface tries to pull moisture
northward into Arizona. Thus, activity may tick up some near the
start of next week, mainly over the higher terrain, but confidence
is low at this point. Looking at the global ensembles, most seem
to agree that deeper moisture will move in near the middle to end
of next week.

&&

.AVIATION...Wednesday 09/00Z through Thursday 10/00Z...Mainly VFR
conditions persist throughout the period with SCT-BKN cumulus
clouds above 10,000 feet AGL. Isolated -TSRA with gusty outflow
winds of 20-30 kts continues through 02Z mainly over the higher
terrain. Conditions clear overnight with light winds under 10
kts. Cumulus clouds build over the high terrain by 19Z with
isolated, high-based -TSRA along a KFLG-KSOW-KJTC line. Outside of
erratic outflow winds, plan on west-southwest winds 10-20 kts.


OUTLOOK...Thursday 10/00Z through Saturday 12/00Z...VFR conditions
continue with mostly clear skies. Conditions become hot and dry
throughout the period with limited thunder activity confined to
the White Mountains. Plan on breezier westerly winds each
afternoon, 20-30 kts on Thursday, followed by 15-25 kts on Friday.

&&

.FIRE WEATHER...Wednesday and Thursday...Hot and mostly dry
conditions are forecast to continue, outside of isolated storms
across the higher terrain. Minimum RH values look to be 10-20% each
afternoon with overnight recoveries between 30-60%. Look for
westerly winds 5-15 mph, but gusty/erratic winds are possible near
storms.

Friday through Sunday...Hot temperatures will continue through the
weekend. Expect daily chances for showers/storms across the White
Mountains, but elsewhere should remain mostly sunny/dry. Look for
westerly winds each afternoon at 10-20 mph on Thursday and gradually
decreasing through the weekend. Minimum RH values between 8-20%.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

Extreme Heat Warning until 7 PM MST Sunday for AZZ006.

Extreme Heat Warning from 10 AM to 8 PM MST Wednesday for AZZ018-
037.

&&

$$

PUBLIC...Humphreys
AVIATION...LaGuardia
FIRE WEATHER...McCollum

For Northern Arizona weather information visit
weather.gov/flagstaff