413
FXUS65 KTWC 102051
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
151 PM MST Thu Sep 10 2026

.SYNOPSIS...Expect isolated thunderstorms this afternoon and
evening, especially across Cochise county southeast of Tucson.
Heavy rainfall will the primary hazard from storms today. An
increase in thunderstorm coverage is expected south of Tucson
Friday, with a more typical isolated to scattered coverage of
storms anticipated this weekend into next week. High
temperatures will will fluctuate between near normal and a few
degrees below normal.

&&

.DISCUSSION...High pressure is centered over south central
Arizona. Ample moisture is in place with PWATs 25-50 percent
above normal and dewpoints generally in the low 60s. However
even with the moisture in place the proximity of the high will
keep storm activity subdued. CAMs show most storm activity on
the southern periphery of the high over Sonora with isolated
storms along the international border south of Tucson. Isolated
storms will also be possible over the White Mountains where
there are already a few buildups. Instability and surface
heating won`t be enough to overcome the synoptic scale
subsidence for most of the CWA. Storms that do form will be
capable of locally heavy rainfall, which will be the primary
threat.

Friday the high nudges a little further to the east over the
bootheel of New Mexico. This will allow for a little more
activity compared to today. CAMs show isolated to scattered
convection during the afternoon and evening south and east of
Tucson. Heavy rainfall will again be the primary threat with a
more isolated strong wind threat. The 10/12Z HREF paints Santa
Cruz County and southern Cochise County as having the best
chances for heavy rainfall. Probabilities for one inch hourly
rainfall rates are 20-60 percent with the highest probabilities
in Santa Cruz County. Two inch hourly rainfall rates aren`t out
of the question either with probabilities 10-25 percent in Santa
Cruz County Friday afternoon and evening. Expect this heavy
rainfall to lead to isolated flash flooding and rises in area
washes and rivers.

Above normal moisture sticks around through at least next
weekend, if not beyond according to both GFS and Euro ensembles.
This weekend the ridge slowly retreats to the east as a closed low
moves through the Pacific Northwest and into the northern
Rockies. By Sunday the center of the high is over the
southeast U.S., and stays in that relative position into the
middle of next week. With moisture not really decreasing expect
continued daily afternoon and evening thunderstorm activity.
This weekend storm chances will likely be most focused south and
east of Tucson. Early next week with the high retreating
further east NBM PoPs increase and also expand westward with
20-50 percent PoPs from central Pima County eastward.

&&

.AVIATION...Valid thru 12/00Z.
SCT-BKN 7k-10k ft AGL and BKN 14-18k ft AGL this afternoon into
the early evening. Isolated SHRA/TSRA possible south of Tucson
thru 11/03Z with KOLS and KDUG having the best chances to see
storms. Friday afternoon expect an uptick in TSRA coverage, but
still mainly south and east of Tucson. Localized thunderstorm
outflow winds 30-35 kts possible. Otherwise, SFC winds will be
WLY/NWLY 6-10 kts this afternoon and evening, then terrain
driven below 8 kts overnight. Aviation discussion not updated
for TAF amendments.

&&

.FIRE WEATHER...Expect isolated thunderstorms this afternoon
and evening, especially across Cochise county southeast of
Tucson. Heavy rainfall will the primary hazard from storms
today. An increase in thunderstorm coverage is expected south of
Tucson Friday, with a more typical isolated to scattered
coverage of storms anticipated this weekend into next week. High
temperatures will will fluctuate between near normal and a few
degrees below normal. Min RH values mainly 20 to 45 percent in
the valleys and 35 to 65 percent in the mountains over the next
week. RH recoveries will continue to be excellent overnight.
Winds will generally remain less than 15 mph and terrain driven.
Gusty and erratic winds will accompany thunderstorms.

&&

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

&&

$$

Hardin

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