883
FXUS65 KFGZ 300506
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1006 PM MST Sun Jun 29 2025

.SYNOPSIS...Hot temperatures continue through Tuesday, with
increasing moisture anticipated each afternoon through the end of
the week. Daily chances for showers and thunderstorms increase
each day, with the greatest coverage expected on Wednesday and
Thursday.

&&

.UPDATE...The isolated showers and thunderstorm activity has
begun to decrease over the last couple of hours with the loss of
daytime heating. An outflow boundary continues to move off the
Rim, with some breezy conditions moving into the Verde Valley.
Model soundings show a further increase in mid-level moisture
during the afternoon tomorrow. given that the sub-cloud layer
still remains very dry, little, if any, precipitation is expected
with this activity. Thus, dry lightning and gusty outflow winds
look to be the primary threat once again over the High Country.
The greatest likelihood looks to remain over the White Mountains,
though coverage does look to expand more into the Mogollon Rim
and Chuska Mountains.

Opted to expand PoPs over the higher terrain during the afternoon
tomorrow, based on the latest hi-res guidance and model soundings.

&&

.PREV DISCUSSION /402 PM MST/...High pressure is currently
centered across the Arizona/New Mexico border, resulting in hot to
dangerously hot temperatures across the state. We have an Extreme
Heat Warning in effect through Tuesday evening for the lower
elevations of the Grand Canyon. Even if you`re not hiking down
into the Canyon, be sure to avoid strenuous activity during the
hottest part of the day and stay hydrated!

Despite the mostly dry pattern over Arizona today, there is still
some lingering moisture aloft. This little bit of moisture is
resulting in the increased cloud cover across the higher terrain.
The chances of these clouds producing precipitation that reaches
the surface is very slim, but we cannot completely rule out a
virga shower or a sprinkle this afternoon across the High Country.

Monday will look similar to today with hot and mostly dry
conditions continuing. Look for daytime highs peaking across much
of the state, and just enough moisture to bring in additional
cloud cover and a few stray showers. The White Mountains look to
be the main location for showers/thunderstorms for tomorrow
afternoon.

Tuesday through Thursday...This is when our forecast will get a
little more exciting. Monsoonal moisture looks to ramp up fairly
quickly as the previously mentioned area of high pressure wobbles
towards the Four Corners. This pattern will allow moisture to
funnel in from the south, which is also shown by elevated PWAT
values across central/northern Arizona shown on the recent
ensemble runs of both the GFS and the ECMWF. Although afternoon
highs will gradually cool through the period, daytime heating will
play a big role in the initiation of thunderstorms. It`s worth
noting that hi-res guidance does suggest activity continuing
during the late evening/overnight hours on Tuesday night/Wednesday
morning and Wednesday night/Thursday morning.

Friday through the weekend...A low pressure system that is
forecast to move in across southern California through the week,
will gradually shift the area of high pressure eastward. We could
still see a few lingering showers during this transition, but
overall moisture looks to decrease through the weekend. Another
favorable monsoon pattern could return by next week, but let`s get
through this first round before we get into the weeds of the next
one.

&&

.AVIATION...Monday 30/06Z through Tuesday 01/06Z...ISO -SHRA/-TSRA
possible over the higher terrain 19Z-02Z. Brief MVFR conditions and
gusty, erratic winds possible in and around TS. MVFR VIZ possible in
HZ/FU possible near KRQE from a nearby wildfire. Otherwise, VFR
conditions with winds S-W 5-10 kts.

OUTLOOK...Tuesday 01/06Z through Thursday 03/06Z...SCT SHRA/TSRA
expected each afternoon, mainly over the higher terrain. Brief MVFR
conditions and gusty, erratic winds possible in and around TS. Winds
S/SW 5-10 kts with gusts 15-20 kts each afternoon. Winds S/SE 10-20
kts Monday night into Tuesday morning, mainly across eastern Arizona.

&&

.FIRE WEATHER...Monday and Tuesday...Hot and mostly dry weather will
continue through Monday. Isolated high-based showers or
thunderstorms are possible over the Mogollon Rim and White
Mountains through Monday, increasing in coverage and spreading west
on Tuesday. The greatest risk for dry thunderstorms will be on
Monday and Tuesday. Winds will generally be from the W at about
10-20 mph Monday, shifting to the S on Tuesday. Erratic wind
gusts up to 40 mph possible in/near any thunderstorms.

Wednesday through Friday...Increasing moisture through Thursday with
scattered to widespread showers and thunderstorms. SW through W
winds 5-15 mph with gusts to 20-25 mph each day. Gusty and erratic
winds are likely in the vicinity of storms. Decreased moisture and
thunderstorm chances are forecast Friday into the holiday weekend.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 7 PM MST Tuesday for AZZ006.

&&

$$

PUBLIC...Humphreys/Konieczny
AVIATION...Humphreys
FIRE WEATHER...MCT

For Northern Arizona weather information visit
weather.gov/flagstaff