Humboldt, Arizona Weather Forecast Discussion

707
FXUS65 KFGZ 161050
AFDFGZ
Area Forecast Discussion
National Weather Service Flagstaff AZ
350 AM MST Tue Sep 16 2025
.SYNOPSIS...Mainly dry conditions and seasonable temperatures are
expected through Wednesday. Moisture begins to increase over the
region later this week, with showers and thunderstorms expected
on Thursday and Friday. Cooler temperatures and unsettled
conditions continue into the weekend.
&&
.DISCUSSION...through Wednesday...High pressure building over the
southwest will lead to warming temperatures and mainly dry
conditions over northern Arizona today. Surface dewpoints look to
have risen a bit over the last few days, especially over central
Arizona, where dewpoints are now 40-50F. Further north, dewpoints
look to remain near 20-30F. Thus, while much of the area will
remain dry, enough moisture does look to be present for a few
isolated showers and thunderstorms. Latest HRRR and U of A WRF
guidance look to favor areas from the eastern Mogollon Rim and
into the White Mountains, but a few stray storms as far west as
the Black Hills looks probable. Any activity that does develop is
expected to be minimal.
Hi-res guidance looks a little less bullish on coverage, which seems
to make sense given an increase in northerly flow aloft ushering in
drier air. So while drier air will be in place, moisture does look
to remain backed against the Mogollon Rim, keeping a few isolated
showers and storms possible to the south in the afternoon.
Wednesday night through Friday...The remnants of Tropical Storm
Mario then look to eject off the Pacific late Wednesday, punting
the ridge further north. This allows for sub-tropical moisture
from the Gulf of California to be advected northward into Arizona
starting Wednesday night.
An area of showers and thunderstorms look to develop over the
southwest as early as Thursday morning, then continue to spread
north and east through the day. However, as of now, a sharp
southwest-northeast moisture gradient looks to setup as the moist
southerly flow from Mario battles the dry northerly flow from the
ridge as it retreats. Thus, the best coverage will mainly be across
western and central Arizona on Thursday.
Further development is expected on Friday with added large-scale
dynamics from Mario and less impacts from the ridge. Thus, a more
area-wide coverage of showers and thunderstorms is expected.
It is still worth nothing that very are many moving parts to this
setup. Any shift in track or timing could alter the outcome. Thus,
while confidence is increasing, there does still remain some
uncertainty in any specific details.
Saturday through Monday...For the weekend, drier and cooler conditions
look to return as an upper-level low off the coast of California
begins to approach Arizona. Uncertainty remains high, with no real
consensus among the operational guidance in the exact track of
this low. Nevertheless, a cool and unsettled pattern looks to
remain for the weekend.
&&
.AVIATION...Tuesday 16/12Z through Wednesday 17/12Z...VFR
conditions. ISO -SHRA/-TSRA possible 19Z-03Z, mainly near a KPAN-
KJTC line. Daytime winds W/SW 5-15 kts, otherwise light and VRB.
OUTLOOK...Wednesday 17/12Z through Friday 19/12Z...Mainly VFR
conditions. ISO -SHRA/-TSRA on Wednesday, mainly near and south of a
KPAN-KJTC line. SCT SHRA/TSRA possible on Thursday, mainly south and
east of a KGCN-KINW-KSJN line. Brief MVFR conditions and gusty winds
possible in and around TS. Daytime winds W/NW 5-15 kts on Wednesday,
becoming W/SW on Thursday.
&&
.FIRE WEATHER...Today and Wednesday...Mostly dry conditions and
seasonal conditions, outside of isolated to scattered thunderstorms
each afternoon along the eastern Mogollon Rim and the White Mountains.
Winds west 5-15 mph today, becoming west/northwest on Wednesday.
Thursday through Saturday...Turning cooler. Chances for showers and
thunderstorms each day, with best chance for wetting rains on Friday.
Wind south through west 5-15 mph each day.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...Humphreys
AVIATION...Humphreys
FIRE WEATHER...Humphreys
For Northern Arizona weather information visit
weather.gov/flagstaff

NWS FGZ Office Area Forecast Discussion