017
FXUS65 KTWC 082147
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
247 PM MST Wed Oct 8 2025

.SYNOPSIS...Increasing moisture will bring partly to mostly
cloudy skies and isolated chances for light showers and
thunderstorms through Friday. Then more widespread chances for
showers arrive this weekend along with a threat of heavy rain.
Temperatures transition from above normal during the work week to
below normal by the end of the weekend.

&&

.DISCUSSION...Moisture continues to increase across the area well
in advance of Tropical Storm Priscilla, which was located a couple
hundred miles WSW of the southern tip of Baja CA. As TS Priscilla
continues to move WNW of Baja CA, moisture continues to increase
with PWATs Friday in the 1.25" to 1.60" range which is 250% to
300% above normal for this time of year. However the bulk of the
deeper moisture from Priscilla will be west of the area thanks to
the western edge of the subtropical ridge being overhead. In any
event through Friday, expect partly to mostly cloudy skies with a
10%-30% chance of showers and thunderstorms.

Southeast of TS Priscilla, off the coast of southern Mexico, is
an area of disorganized showers and thunderstorm which may become
the next tropical system. Along the west coast will be a deepening
upper level trof which will advect this deeper moisture into
southeast Arizona, bringing a significant rainfall event for the
area starting Saturday and continuing to Monday. WPC 4-day QPF
numbers has widespread 1.5" to 3" with isolated to 6". Wrn Pima
county will see lesser totals. Some of the ensemble members of
the GEFS and EPS still showing insane higher QPF totals. All of
this potential rain will lead to hydrologic concerns for the
mainstem rivers and creeks across SE AZ.

Conditions start to dry out Tuesday but still enough moisture
around for a few showers.

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

&&

.AVIATION...Valid through 10/00Z.
SCT-BKN clouds at 7K-10K ft AGL and BKN-OVC clouds at 11K-14K ft
AGL thru the forecast period, along with SCT -SHRA and ISOLD -TSRA.
SFC wind ELY/SELY at 8-14 kts with occasional gusts to 20-25 kts at
most locations, with gusts up to 30 kts in the upper Gila River
Valley near KSAD. 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. This increase in moisture will raise
min RH values to 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 through early next week
and gusts to 20-25 mph, with the potential for some gusts to around
30 mph in the upper Gila River Valley.

&&

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

&&

$$

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