443
FXUS65 KFGZ 281708
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1008 AM MST Sat Jun 28 2025

.SYNOPSIS...Warming temperatures and mainly dry conditions continue
through the weekend. Isolated to scattered showers around the White
Mountains through Sunday, then more widespread shower and
thunderstorm activity sets in through the week.

&&

.DISCUSSION...Today through Monday...A ridge will continue to
build across the Desert Southwest through Monday, with a mostly dry
airmass remaining across the region. With the ridge will come
warming temperatures and this will lead to temperatures exceeding
110 degrees in the lower elevations of the Grand Canyon. The peak of
the heat is expected for Sunday and Monday, with temperatures
starting to cool slightly through the rest of the week (more on that
below). The Extreme Heat Warning remains in effect for areas below
4000 feet in the Grand Canyon through Tuesday. While we do not have
headlines up for other parts of the forecast areas, keep in mind it
will still be hot and to use caution if spending time outside. Drink
plenty of water, wear a hat and sunscreen, and try to refrain from
strenuous activity during the hottest parts of the day. Be safe out
there friends!

We still have some lingering moisture off to the east of the area
with some advection into our eastern borders. This may lead to some
isolated to scattered high-based showers or thunderstorms near the
White Mountains this afternoon and again on Sunday afternoon.
Showers will become more scattered over the White Mountains and even
into the eastern Mogollon Rim on Monday as we start to see better
moisture advection in the building southerly flow. Dry lightning
remains possible on Monday across eastern Arizona.

Tuesday through the end of the week...The ridge starts to set up
shop towards the Four Corners, putting it in a more ideal location
for the monsoon. Meanwhile, a trough digs down along the California
coast and looks to be a cut off low. There is also a potential
tropical system that will move near the southern tip of the Baja
California peninsula. So what does this mean for us? We will see a
good influx of moisture from the south through the week, bringing a
good start to the monsoon for this summer. Showers and thunderstorms
will have more widespread coverage by Tuesday with continued showers
and thunderstorms each day through the rest of the week. As we go
through the week, the trough/low starts to weaken. This could allow
for a slight shift to a westerly flow and some slightly drier
conditions but it looks short lived as another trough develops right
behind it. Still time to see how the pattern unfolds but for now
will focus on the increased moisture and the start of the monsoon
this week.

&&

.AVIATION...Saturday 28/18Z through Sunday 29/18Z...VFR conditions.
Isolated high-based -SHRA/-TSRA between 18Z-02Z along and south
of a KPAN-KSOW-KSJN line. S-SW winds 10-20 kts, becoming light and
variable after 02Z.

OUTLOOK...Sunday 29/18Z through Tuesday 01/18Z...Mainly VFR
conditions. Isolated high-based -SHRA/-TSRA between 18Z-02Z each
day, mainly along and south of KSOW-KSJN line. S-SW winds 10-20
kts each day, becoming light and variable each night.

&&

.FIRE WEATHER...Today and Sunday...Warm temperatures and mainly dry
conditions continue. A slight chance for high-based showers and
thunderstorms near the White Mountains each afternoon. SW-W winds 5-
15 mph with gusts to 20-25 mph each afternoon. Gusty, erratic winds
possible in and around thunderstorms. Afternoon minimum RH values 5-
15% both days.

Monday through Wednesday...Monsoon moisture begins to move northward
Monday with a few thunderstorms possible again over the White
Mountains. More widespread coverage on Tuesday and Wednesday. Dry
lightning likely on Monday and Tuesday. Afternoon minimum RH values
5-15% on Monday, increasing to 15-25% on Tuesday, then 20-35% on
Wednesday. SW-S winds 5-15 mph each day with gusts to 20-25 mph.
Gusty, erratic winds possible in and around thunderstorms.

&&

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

&&

$$

PUBLIC...Meola
AVIATION...RR
FIRE WEATHER...Meola

For Northern Arizona weather information visit
weather.gov/flagstaff