Flash Flood Warning 28, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
139 PM MST Sun Aug 24 2025

.SYNOPSIS...Arizona remains under an active pattern where
showers and thunderstorms are expected each day through mid week,
before decreasing by Thursday into the weekend. Storms will be
capable of producing heavy rain, frequent lightning, small hail,
and gusty/erratic winds. Outside of precipitation chances, look
for near to below normal temperatures each afternoon.

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.DISCUSSION...High pressure centered over eastern Arizona today
will gradually weaken and slide off to the southeast through
mid week as weak troughing continues along the west coast. This
southerly flow pattern will be favorable for continued moisture
transport into our region - and elevated chances for daily showers
and thunderstorms. The main hazards with storms will be locally
heavy rain/flooding and lightning. However, with most unstable
CAPE values approaching 1500-2000 J/kg in Yavapai County this
afternoon and evening, there could also be a few strong/severe
thunderstorms with gusty winds and hail greater than nickel size.
So far this afternoon, the main storm development has been over
and just north of higher terrain of Yavapai and Coconino counties
where moisture values are highest and early day sun destabilized
the atmosphere. Storm motions are slowly toward the north, with
some backbuilding cells noted in the Prescott region. Look for
this activity to continue into the evening, with more isolated
showers or storms overnight tonight. With several days of
elevated precipitable water values expected, we extended the Flash
Flood Watch for the Dragon Bravo and White Sage fire scars
through Tuesday to cover the period with highest chance of seeing
heavy rain over this newly burned area. Daytime temperatures will
be near to a few degrees below normal through Tuesday.

Wednesday into next weekend - as the ridge continues shifting
southeast and the west coast trough moves closer, precipitable
water values begin to fall over northern and central Arizona.
Enough moisture appears to remain Wednesday for scattered storms,
but by Thursday into the weekend storms are looking more isolated
(10-25% chances). Daytime highs remain a bit below normal
Wednesday and Thursday before starting to rebound close to normal
Friday into the weekend.

&&

.AVIATION...Sunday 24/18Z through Monday 25/18Z...Mainly VFR
conditions expected through the period, outside of brief MVFR
conditions in heavier SHRA/TSRA. Expect chances for showers/storms
through 03Z, with -SHRA possibly continuing overnight. Highest
coverage of storms NW of a KPAN-KRQE line. Outside of
gusty/erratic winds with storms, look for west-southwest winds
5-15 mph.

OUTLOOK...Monday 25/18Z through Wednesday 27/18Z...VFR conditions
will continue outside of MVFR ceilings/visibilities in heavier
SHRA/TSRA. Look for daily chances for widespread showers/storms
primarily between 18Z-03Z, with isolated to scattered showers and
thunderstorms continuing both Monday and Tuesday nights. Gusty/erratic
winds possible near storms, but look for south through west winds
5-15 mph otherwise.

&&

.FIRE WEATHER...This afternoon through Tuesday...Daytime highs will
gradually cool over the next several days as humidity increases and
daily precipitation chances continue. Scattered to widespread
showers/thunderstorms expected each afternoon and evening, with a
chance of activity continuing during the overnight periods. Outside
of gusty/erratic outflow driven winds, look for mostly southwest
through west daytime winds 5-15 mph.

Wednesday through Friday...Temperatures will remain below normal
through the end of the week, with a gradual decrease in afternoon
minimum RH values. Scattered showers and thunderstorms are expected
Wednesday, becoming more isolated for Thursday and Friday. Outside
of gusty/erratic outflow driven winds, look for mostly southwest
through west daytime winds 5-15 mph.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday evening for AZZ004>006.

&&

PUBLIC...JJ
AVIATION...JJ
FIRE WEATHER...JJ

For Northern Arizona weather information visit
weather.gov/flagstaff