521
FXUS65 KFGZ 071708
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1008 AM MST Tue Oct 7 2025

.SYNOPSIS...Warm and mainly dry conditions continue through
Wednesday. Widespread precipitation then looks to set in for the
end of the week as moisture from now Hurricane Priscilla moves
into Arizona. Areas of flash flooding will be possible, especially
late Friday into Saturday.

&&

.DISCUSSION...Today and Wednesday...Warmer and mainly dry conditions
look to continue through the next couple of days. The only shot
at precipitation during this period looks to mainly be across
eastern Arizona during the afternoon on Wednesday, as moisture
increases from the south and east. Any activity that does develop
should be fairly minimal, with brief heavy downpours being the
main threats.

Thursday through Saturday...Confidence continues to increase in the
the remnants of now Hurricane Priscilla sending a surge of sub-
tropical moisture northward into Arizona by Thursday. Model soundings
show a nearly completely saturated profile from Thursday onward,
with PWATs approaching near-record levels for this time of year
around an inch to 1.40 inches. For context, the 90th percentile
for FGZ is around 0.60 inches for this point in the year and the
record for October 10-12th is near 0.78 inches.

The first wave looks to begin on Thursday, with showers and
thunderstorms developing across much of northern Arizona early in
the day. Coverage then continues to increase through the day, and
likely lasting through the overnight and into Friday. Heavy
rainfall will be the primary threat given the moisture, however
the threat for widespread flash flooding in the initial wave still
remains in question without the large-scale forcing in place yet.

By late Friday, large-scale dynamics look to improve as a strong
trough begins to approach Arizona. This will help to increase
precipitation development Friday night into Saturday, and as a
result, this is the most likely period to see significant rainfall.
Given the abundant moisture and fairly deep warm-cloud layer,
precipitation rates will be very efficient during this time period.

What remains unknown here is exactly where the heaviest area of
precipitation will develop. Much of the operational guidance has a
narrow swath of 2-4 inches of rain developing across northern
Arizona. However, the exact position of this varies between the
guidance. The latest NAM guidance looks to favor areas across
western Arizona, the ECMWF and CMC both favor central and eastern
Arizona, while GFS currently sits in the middle from Flagstaff to
the Four Corners. Outside of this band, around 0.50 inches to 1.5
inches still seem probable.

Flash flooding will be the primary threat during this time period,
given the efficient rainfall rates. However, flooding along some
main steam rivers will be possible later with significant rainfall
amounts in area watersheds. There are many moving parts to the
forecast for this period, so stay tuned for further updates.

Sunday onward...The trough continues to propagate eastward at the
start of next week. Drier air does look to begin to move in aloft,
however the moisture doesn`t look to be completely removed. As a
result, an unsettled pattern looks to remain through at least the
start of next week, with chances for showers and cooler temperatures
continuing.

&&

.AVIATION...Tuesday 07/18Z through Wednesday 08/18Z...VFR
conditions expected through the TAF period. Look for S-SW winds
5-15 kts through 03Z, with light and variable winds returning
afterwards.

OUTLOOK...Wednesday 08/18Z through Friday 10/18Z...VFR conditions
will last through 12Z Thursday, before increased chances of
SHRA/TSRA will likely lead to reduced visibilities and ceilings.
Outside of gusty/erratic winds, look for SE-SW winds 10-20 kts
during the afternoon periods, becoming lighter 5-15 kts overnight.


&&

.FIRE WEATHER...Today and Wednesday...Dry with temperatures slightly
above average today. Isolated showers or storms are possible in
eastern Arizona Wednesday and Wednesday night. Winds S-SW 5-15 mph
today, S-SW 10-15 mph, gusts to 25 mph Wednesday. Minimum RH values
10-20% today, 15-30% Wednesday.

Thursday through Saturday...Unsettled weather through the period,
with showers and thunderstorms at times. Wetting rains are likely,
along with much cooler temperatures and high humidity. Winds SE-S
10-15 mph Thursday and Friday, S-SW 15-20 mph Saturday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

PUBLIC...Humphreys
AVIATION...Konieczny
FIRE WEATHER...JJ

For Northern Arizona weather information visit
weather.gov/flagstaff