650
FXUS65 KTWC 092135
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
235 PM MST Thu Oct 9 2025

.SYNOPSIS...Partly to mostly cloudy skies persist across
southeastern Arizona as tropical moisture has set in across
the area. Isolated chances for showers and thunderstorms continue
through Friday, then widespread chances arrive this weekend with
a threat of heavy rain. Rain chances diminish by middle of next
week. Temperatures transition from above normal through Friday to
below normal by the end of the weekend.

&&

.DISCUSSION...Satellite imagery this afternoon showed partly to
cloudy conditions across SE AZ with isolated light showers/virga
moving north. Tropical storm Priscilla was a couple hundred miles
WNW off the srn tip of Baja; newly named tropical storm Raymond
was located offshore of SWrn Mexico and the remnants of post-
tropical storm Octave had weakened between Priscilla and Raymond.
PWATs across the area are still slowing increasing with 1.54" on
the Tucson 18z sounding. Deeper tropical moisture with values over
2" resided over the srn half of the Gulf of CA and srn Sonora MX.

The main short term impacts from Priscilla through Friday will be
over western, central and northern Arizona. Tomorrow will see a
better chance of some showers and thunderstorms for SE AZ with
localized heavy rain developing over western and central Pima
county in the afternoon and moving to the NE across the area into
tomorrow night.

For the upcoming potential long duration rain event for this
weekend into Monday, there is still quite a bit of uncertainty on
precipitation amounts. This is due to timing of the upper level
trof moving into the western CONUS and how much of the moisture
that will be across northern Mexico is pushed into our area.
Can`t get too focused on QPF from one model run with many many
solutions in the ensemble world. Also not as many ensemble
members today are going with insane precipitation totals as they
had in the past two days.

As of today, for precipitation totals for the Saturday thru
Monday time period, the low end scenario (25th percentile) has
0.20" to 0.80" while the high end scenarios (75th & 90th
percentiles) have 2 to 4 inches. The most likely scenario has
1 to 2 inches. Main timing for the heaviest showers will be be
Saturday evening through Sunday night. At this moment of time,
and due to the uncertainty of precipitation totals, held off on
issuing a Flood Watch. WPC Excessive rainfall outlook (ERO) has
a slight risk of rainfall exceeding flash flood guidance Sat
through Monday. See hydrology section for hydro concerns.

Conditions drying out by middle of next week.

Temperatures are expected to trend down with this active pattern.
Highs will transition from 3-7 degrees above normal today and
Friday to below normal by the end of the weekend.

&&

.AVIATION...Valid through 11/00Z.
FEW-SCT clouds at 7K-10K ft AGL and SCT-BKN clouds at 11K-14K ft AGL
thru the forecast period, along with ISOLD -SHRA/-TSRA. SFC wind
ELY/SELY at 8-14 kts with occasional gusts to 20-25 kts. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...High temperatures will be 4-7 degrees above normal
through Friday, falling to 3-9 degrees below normal Saturday into
the middle of next week. Tropical moisture moving northward through
Mexico will result in increasing chances for widespread showers and
isolated thunderstorms through at least early next week. There will
be the potential for widespread rainfall accumulating over several
days, Saturday into Tuesday. Minimum RH values will be at least 25+
percent in the valley`s, with values in the Saturday through Tuesday
time frame at 40+ percent. 20-foot wind speeds will generally be 15
mph or less into the middle of next week and gusts to 20-25 mph.

&&

.HYDROLOGY...Run-off from the rainfall this weekend into early
next week will bring rises to the main stem rivers/creeks across
southeast Arizona with main concerns being the San Pedro river,
Nogales wash/Santa Cruz river. Otherwise the normal dry washes and
low water crossing will have water flowing through them.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

&&

$$


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