289
FXUS65 KFGZ 212116
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
216 PM MST Tue Jul 21 2026

.SYNOPSIS...Deep monsoonal moisture will remain over the area
through at least mid week, with a slight decrease later in the
week. With this moisture comes the daily threat of thunderstorms,
along with the risk for locally heavy rainfall and flooding. Daytime
temperatures will remain at or below normal much of the week, with
hotter temperatures toward the weekend.

&&

.DISCUSSION...An upper level disturbance is moving northwest into
east central Arizona now and then into north central Arizona
tonight. While there was a slower start to convection over much of
our area today, the deep moisture and instability in place is
allowing numerous storms to develop. The greatest coverage is over
eastern Arizona, spreading westward and impact the rest of
northern Arizona later in the afternoon and evening. The primary
threat continues to be heavy rainfall and flash flooding,
especially considering the wet ground conditions and many
streams/rivers are already flowing and elevated. For this reason,
there is a Flash Flood Watch in effect through late this evening
for all of our forecast area excluding the far northeast corner.
There continues to be a localized strong wind/hail threat today,
especially over northeast Arizona through the early evening. As
the disturbance moves northward Wednesday, scattered thunderstorms
are expected in the afternoon, especially over the higher terrain
with a somewhat lower threat of heavy rainfall. From Thursday
into the weekend, the center of high pressure to our east is
forecast to shift toward Arizona. While moisture levels will drop,
there will still be enough for daily scattered storms over the
higher terrain, but more isolated for the valleys. Temperatures
will also begin to heat up to above normal levels. Temperatures by
the weekend may approach warning levels for the lowest elevations
of the Grand Canyon so we`ll keep an eye on that.

&&

.AVIATION...Tuesday 21/18Z through Wednesday 22/18Z...Isolated -SHRA
through 20Z, then scattered to numerous SHRA/TSRA developing once
again and moving westward. Stronger storms will be capable of
producing hail, wind gusts to 45 kts and brief MVFR and IFR
conditions. Activity decreasing in coverage after 03-06Z Outside
of storms, winds light and variable.

OUTLOOK...Wednesday 22/18Z through Friday 24/18Z...Look for
SHRA/TSRA activity through the period, most numerous during the
afternoon/evening hours. Coverage of SHRA/TSRA decreasing a bit by
Thursday and mainly focused over higher terrain. Stronger storms
will produce brief MVFR and IFR conditions, gusty winds to 40 kts
and hail. Outside of storms, surface winds light and variable.

&&

.FIRE WEATHER...Today through Thursday...A medium to high grade
monsoon environment continues today. Most storms will produce
wetting rain and any stronger storms may produce flash flooding,
hail, and wind gusts to 50 mph through this evening. Activity
slightly declines in coverage/intensity on Wednesday, then more so
on Thursday. Scattered thunderstorms are still expected each
afternoon/evening, with continued threat of localized flash
flooding. Winds are generally light through the period outside of
outflow and thunderstorm activity.

Friday through Sunday...Chances for showers and thunderstorms
continue, though coverage will be more isolated to scattered.
Generally light winds outside of outflow and thunderstorm activity.
Most storms will produce wetting rain and any stronger storms could
produce localized flash flooding. Expect a warming trend and minimum
RH down to 20% for the lowest elevations.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM MST /11 PM MDT/ this evening for
AZZ004>009-012>018-037>040.

&&

$$

PUBLIC...Zanker
AVIATION...Lewandowski
FIRE WEATHER...Lewandowski

For Northern Arizona weather information visit
weather.gov/flagstaff