658
FXUS65 KFGZ 272141
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
241 PM MST Fri Jun 27 2025

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

&&

.DISCUSSION...Today through Monday...Weak flow aloft today will give
way as strong ridging sets up over Arizona and New Mexico. A mostly
dry airmass will remain in place, and warm temperatures will be the
primary impact during this period with daytime highs 5-10 degrees
above average by Monday. An Extreme Heat Warning has been issued for
the Grand Canyon below 4000` for Saturday through Tuesday, where
high temperatures are expected to exceed 110 degrees. Physical
activity is discouraged, but any hikers in the Grand Canyon should
be sure to carry adequate food, water, and gear. Exercise enhanced
caution elsewhere especially for those who are sensitive to heat.

Some lingering moisture along the periphery of our forecast area is
bringing a few high-based showers to the White Mountains today.
There will be continued low daily chances for scattered
showers/thunderstorms in this area. Best chances right now look to
be Monday, but some afternoon showers this weekend cannot be
fully ruled out.

Tuesday and beyond...An upper level trough digs down off the coast
of California as the ridge maintains its composure. The trough
meanders eastward, and pushes against the ridge over New Mexico. The
alignment of these features will allow for a strong southerly
moisture surge into northern Arizona. Expect increasing chances for
more widespread showers and thunderstorms peaking on Wednesday-
Thursday, then becoming less widespread into the weekend. There
is some uncertainty as to how persistent the moisture will be
after this initial surge. Some long term models have the ridge
weakening allowing the moisture to clear out. Others maintain the
ridge and keep daily shower/thunderstorm chances in northern
Arizona. Regardless, this upcoming week looks to be quite active.


&&

.AVIATION...Friday 27/18Z through Saturday 28/18Z...VFR conditions
expected with a few isolated high based afternoon thunderstorms
in the White Mountains possible. Winds SW-W 10-15kts, gusts
20-25kts during the day, light and variable or terrain driven
overnight.

OUTLOOK...Saturday 28/18Z through Monday 30/18Z...VFR conditions,
a few isolated high based afternoon thunderstorms possible in
the White Mountains. Winds SW-W 5-15kts, gusts to 20kts during the
day, light and variable or terrain driven overnight.

&&

.FIRE WEATHER...Saturday and Sunday...Temperatures warming to 5
degrees above average over the next couple days. Outside of a slight
chance for high-based showers and thunderstorms near the White
Mountains each afternoon, things remain dry. Winds SW-W 5-15 mph
with gusts to 20-25 mph each afternoon with 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.  By Tuesday and Wednesday a better surge of monsoon
moisture will move in with afternoon thunderstorm chances
overspreading the entire region.  Monday and Tuesday will have a
higher risk for dry lightning as subcloud moisture will still be
relatively dry.  Minimum RH values of 5-15% on Monday will increase
to 10-20% on Tuesday and 15-30% on Wednesday.  Winds SW-W 5-15 mph
on Monday, S-SW 5-15 mph on Tuesday and Wednesday, except near
thunderstorms where local winds will be gusty and erratic at times.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning from 10 AM Saturday to 7 PM MST Tuesday for
AZZ006.

&&

$$

PUBLIC...Lewandowski
AVIATION...Bernhart
FIRE WEATHER...Bernhart

For Northern Arizona weather information visit
weather.gov/flagstaff