Allentown, Arizona Weather Forecast Discussion

826
FXUS65 KFGZ 250959
AFDFGZ
Area Forecast Discussion
National Weather Service Flagstaff AZ
300 AM MST Thu Sep 25 2025
.SYNOPSIS...Another warm day is expected today, but then scattered
showers and thunderstorms will form by afternoon. These showers and
thunderstorms will become more widespread by tonight and then will
persist through at least Sunday. Some stronger storms may contain
large hail, damaging winds, the threat of flash flooding, and even
the threat for tornadic activity. Please heed any warnings you
receive and take them seriously.
&&
.DISCUSSION...A closed low just south of San Francisco this morning
will slowly move into the Imperial Valley by Friday morning. This
low will then move even slower, reaching Yuma Saturday morning, then
toward Prescott Sunday morning. The low then moves out of the region
by sometime on Monday.
The trajectory of this low will allow another northward incursion of
the Monsoonal moisture pool for most of the state, but especially in
the eastern third of the state. More importantly, the significantly
colder temperatures aloft will destabilize the atmosphere. The days
spent on the eastern side of the low will also have a fair amount of
shear and large helicity values, making for a potentially dangerous
situation.
So, multiple days and nights of showers and thunderstorms are a
given, but the ingredients for severe weather are also present from
about tonight through Saturday night. Isolated storms containing
large hail, damaging winds and even tornadic activity cannot be
ruled out. Training storms will also enhance Flash Flood risk, but
storm motion may minimize that risk for most areas.
Finally, by the start of next week, this low moves away from
Arizona, with warmer and drier conditions taking over.
Again, this is a multiple day period with a moderate threat of
damaging thunderstorms, take any warnings seriously.
&&
.AVIATION...Thursday 25/06Z through Friday 26/06Z...Mainly VFR.
Brief periods of MVFR and gusty, erratic winds expected in SCT
SHRA/TSRA after 20Z, mainly north and east of a KCMR-KPAN line.
Winds E/NE 5-10 kts overnight, becoming S 5-15 kts after 18Z.
Locally gusty NE winds downwind of the terrain overnight.
OUTLOOK...Friday 26/06Z through Sunday 28/06Z...Brief periods of
MVFR and gusty, erratic winds possible in SCT SHRA/TSRA each
afternoon and evening. Otherwise, VFR conditions with daytime winds
S/SE 5-15 kts.
&&
.FIRE WEATHER...Thursday and Friday...Expect scattered showers and
thunderstorms this afternoon becoming more widespread tonight
through Friday. Some storms may become severe. Winds away from
storms will be southerly at 5 to 15 mph.
Saturday through Monday...Periods of showers and thunderstorms will
continue through Sunday, with coverage becoming isolated on Monday.
Daytime southerly winds at 5 to 15 mph each day.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...Peterson
AVIATION...Humphreys
FIRE WEATHER...Peterson
For Northern Arizona weather information visit
weather.gov/flagstaff

NWS FGZ Office Area Forecast Discussion