666
FXUS65 KFGZ 132141
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
241 PM MST Wed Aug 13 2025

.SYNOPSIS...Increasing monsoonal moisture and cooler temperatures
set in over the next few days, with the best chances for thunderstorms
being Thursday and Friday. Drier and warmer conditions look to
gradually return by the start of next week.

&&

.DISCUSSION...Today...A ridge that was centered over California the
past few days is continuing to propagte eastward. Northerly flow
has relaxed, and the bubble of moisture pooled in southern AZ is
more able to penetrate along the Mogollon Rim. Dewpoints at KFGZ
this morning were sitting around 10 degrees higher than yesterday
morning. That being said, we still are under an inverted-V
profile. Some localized heavy downpours and flash flooding over
senstive terrain cannot be ruled through the rest of today, but
the primary hazard will be gusty outflow winds. Most Hi-Res
guidance is in agreement that outflow boundaries will propagate
well into the valleys through the evening. Thunderstorms will more
readily spread into Gila and Yavapai counties where much higher
instability is present. Dry surface conditions are still present
north and east of the Rim, and we don`t expect much activity up
there today save some lighter showers.

Thursday...Tomorrow is still on track to be a day with scattered to
numerous activity across most of Northern AZ. A channel remains open
for southerly flow, and PW is expected to peak at about 0.75-0.85
inches. Combined with better surface dewpoints across most of
northern AZ, higher coverage of storms with increased chances of
wetting rains are expected. A similar progression is expected with
storms initiating along the Rim then spreading into the valleys.
Better instability will be present to the northeast of the Rim, and
additional activity is expected there.

Friday...Friday is expected to be similar, but a few forecast
uncertainties have yet to be resolved. A trough will deepen over
California, and some models bring a dry southwest flow aloft that
may hinder convective activity especially towards western AZ.
Additionally, ensemble guidance is hinting at the potential for
overnight showers Thursday-Friday. Lingering debris clouds from
this could be another factor to hinder daytime convection.

Saturday through Tuesday...By Saturday the dry southwest flow from
the trough continues to establish itself. Coverage of storms will
decrease each day, returning to a regime with isolated-scattered
showers. Best chances for preciptation will remain in far eastern AZ
each day.

&&

.AVIATION...Wednesday 13/18Z through Thursday 14/18Z...Mainly VFR
conditions persist with increasing low to mid-level cloud cover by
19Z. Isolated to scattered -TSRA is forecast from 20Z-03Z, mainly
along and south of a KCMR-KFLG-KSOW-KJTC line. Look for cloud-to-
ground lightning, gusty outflows of 20-30 kts, small hail, and
brief periods of heavy rainfall resulting in MVFR conditions in
any storms. Conditions improve after 03Z with SCT-BKN debris cloud
cover. Outside of any outflow gusts from storms, expect west-
northwest winds 15-25 kts through 02Z, becoming light and variable
thereafter.

OUTLOOK...Thursday 14/18Z through Saturday 16/18Z...Scattered
showers and thunderstorms are anticipated across northern Arizona
from ~19Z-03Z for Thursday and Friday. Areas of brief MVFR/IFR
conditions are likely in any storms, along with lightning, small
hail, and gusty and erratic outflows. Storm coverage begins to
decrease on Saturday with drier conditions thereafter. Plan on
southwest winds, 15-25 kts, on Thursday followed by lighter
southwest flow, 10-20 kts, for Friday and Saturday.

&&

.FIRE WEATHER...Thursday and Friday...Monsoonal moisture increases,
resulting in cooler temperatures and scattered showers and
thunderstorms across much of northern Arizona each day. Expect cloud-
to-ground lightning, small hail, gusty and erratic outflow winds of
30 to 40 mph, and brief periods of heavy rainfall. Outside of
outflow winds, anticipate west-southwest winds, 15 to 25 mph with
terrain driven winds each night.

Saturday through Monday...Conditions begin to dry out gradually for
Saturday and Sunday with isolated to scattered thunderstorms mainly
over the high terrain. Temperatures remain near average each day
with minimum humidity of 15 to 25%. By Monday, storm chances are
confined to the White Mountains and eastern Rim as temperatures
become above average once again. Light southwest winds, 10 to 20
mph, are forecast each afternoon with terrain drainage winds each
night.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 7 PM MST /8 PM MDT/ this evening for
AZZ005.

Extreme Heat Warning until 8 PM MST Thursday for AZZ006.

&&

$$

PUBLIC...Lewandowski
AVIATION...LaGuardia
FIRE WEATHER...LaGuardia

For Northern Arizona weather information visit
weather.gov/flagstaff