Severe Thunderstorm Warning 110, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
132 PM MST Tue Aug 4 2026

.SYNOPSIS...Chances for thunderstorms will develop each
afternoon and evening this week with day to day variability.
Thunderstorms may produce severe outflow winds with areas of
blowing dust, as well as locally heavy rainfall with a flash
flooding risk. High temperatures will remain a few degrees above
normal through the weekend.

&&

.DISCUSSION...The atmosphere is primed for another day of scattered
strong to severe thunderstorms this afternoon and evening. An
elongated ridge is in place with modest mid-level flow of 20-30
kts at 500 mb. This will lead to 0-6 km shear of 25-35 kts with
CAPE values 1000-1800 J/kg and seasonal PWAT values. Hi-res
guidance shows initial development over the White Mountains and
Sky Islands east of Tucson by mid-afternoon. Current satellite
shows cumulus development over northern Greenlee County. Storms
then progress westward into the lower elevations of Santa Cruz,
Cochise, and eastern Pima Counties late afternoon into the
evening. Tucson will likely be the northern extent of storm
coverage. Heavy rainfall will be a threat in Cochise and Santa
Cruz Counties with HREF one inch in one hour probabilities
within 25 km of a point 20-50 percent between 4PM - 10PM. Areas
that received heavy rain yesterday will also be more likely to
see runoff and flash flooding. Because of this a Flood Watch is
in effect for these areas from 3 PM - 11 PM. With the
aforementioned shear some storms could be rotating, which could
lead to an isolated hail threat and a more widespread severe
wind threat. Model soundings also show a nose of dry air around
400 mb which would act to enhance downdrafts through
entrainment. Because of all of these factors some storms may be
capable of wind gusts 70-80 mph. There is also a small tornado
threat as well with 0-3 km helicity values 150-250 m^2/s^2. The
best environment for a tornado looks to be along the
international border and over Sonora, but confidence is low in
any tornado developing.

Overnight activity looks limited with just some showers over
Graham and Pinal Counties after midnight. This should allow the
atmosphere to reset and be ready for another round of scattered
thunderstorms Wednesday afternoon and evening. Mid-level winds
decreases slightly compared to today with 500 mb winds 15-20
kts leading to 0-6 km shear generally 20-30 kts. Plenty of
instability will be in place along with seasonable PWAT values.
This will lead to a threat of strong to severe winds gusts from
Tucson south and eastward. Locally heavy rainfall leading to
flash flooding will also be a threat with HREF 1 inch in 1 hr
probabilities 30-60 percent south and east of Tucson and 30
percent between Sells and Three Points. Past rainfall from today
and Monday will lead to easier runoff in Cochise and Santa Cruz
Counties with area washes and rivers seeing faster responses
from rainfall.

Looking ahead through the weekend expect daily afternoon and
evening thunderstorms from central Pima County eastward with
typical monsoon threats of isolated severe winds and heavy
rainfall leading to flash flooding. Areas that receive repeat
heavy rainfall each day will be especially susceptible to flash
flooding. The most likely areas where this will happen will be
Santa Cruz and Cochise Counties. There will likely be some day
to day variability. Right now Saturday stands out as a day that
could see enhanced storm coverage and strength due to 500 mb
winds increasing to 25-30 kts. Medium confidence in winds being
this strong even though its a few days out with ensemble
probabilities for winds greater than 20 kts at 500 mb 40-60
percent Saturday.

High temperatures will be 2-7 degrees above normal through the
weekend.

&&

.AVIATION...Valid through 06/00Z.
Scattered thunderstorms expected to develop this afternoon
mainly between 04/22Z to 05/05Z with lingering isolated activity
through 05/07Z. Coverage around KTUS more likely 05/03Z-05/05Z
and KOLS/KDUG 05/00Z-05/06Z. Gusty erratic winds of 35-50 kts
possible with any thunderstorm. Cigs will be BKN 8k-12k ft AGL
this afternoon and evening, slowly dissipating overnight. Expect
another round of TSRA Wednesday afternoon and evening. Outside
of storms SFC winds WLY/NWLY at 8-12 kts with occasional
afternoon gusts to 20 kts. SFC winds light and terrain driven
after 05/05Z. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...An active monsoon period looks favorable this
week with daily chances for showers and thunderstorms each
afternoon and evening, with day to day variability. Minimum
relative humidity values will likely remain above 25-40 percent
through the week with temperatures 2-4 degrees above normal.
Outside of thunderstorms, winds terrain driven to around 10 mph
with occasional afternoon gusts to 25 mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 11 PM MST this evening for AZZ503-504-507-
508-511>513.
Blowing Dust Advisory until 8 PM MST this evening for
AZZ507>509-511>513.

&&

Hardin

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Preliminary Local Storm Report
National Weather Service Tucson AZ
353 PM MST Tue Aug 4 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0930 PM     Flash Flood      9 SSE Sells             31.80N 111.82W
08/03/2026                   Pima               AZ   Emergency Mngr

            Delayed report. Significant flooding along
            San Manuel Rd.

0950 PM     Tstm Wnd Dmg     1 E Sells               31.92N 111.87W
08/03/2026                   Pima               AZ   Emergency Mngr

            Delayed report. Construction pillar damaged
            from thunderstorm winds.

1000 PM     Tstm Wnd Dmg     1 WSW Sells             31.91N 111.89W
08/03/2026                   Pima               AZ   Emergency Mngr

            Delayed report. Building near fire
            department lost siding.

0450 PM     Tstm Wnd Dmg     1 NNW Tombstone         31.73N 110.07W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Batting cage blown into
            desert.

0530 PM     Tstm Wnd Dmg     13 SSE Willcox          32.07N 109.76W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. 14 power poles down in
            Kansas Settlement.

0535 PM     Tstm Wnd Dmg     5 N Huachuca City       31.71N 110.35W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Half of roof blown off
            mobile home.

0540 PM     Tstm Wnd Dmg     6 N Huachuca City       31.72N 110.33W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Several trees down, one on
            home.

0540 PM     Tstm Wnd Dmg     5 N Huachuca City       31.70N 110.34W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Wood fence blown down,
            trampoline blown, carport blown.

0542 PM     Tstm Wnd Dmg     6 SE Sierra Vista       31.51N 110.26W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Tree blown down on power
            box.

0545 PM     Tstm Wnd Dmg     7 SSE Sierra Vista      31.47N 110.29W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Roof damage to main
            structure with roof blown off patio, trees
            down with one large pine tree down onto
            home.

0545 PM     Tstm Wnd Dmg     7 SE Sierra Vista       31.48N 110.25W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Large high frequency ham
            radio antenna damaged.

0545 PM     Tstm Wnd Dmg     8 SSE Sierra Vista      31.47N 110.26W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Roof blown off.

0550 PM     Tstm Wnd Dmg     7 SSE Sierra Vista      31.47N 110.28W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Row of medium sized trees/
            junipers blown down.

0550 PM     Tstm Wnd Dmg     7 SSE Sierra Vista      31.46N 110.29W
08/03/2026                   Cochise            AZ   Emergency Mngr

            Delayed report. Tree blown down and 2 large
            tree limbs blown down.

&&

Preliminary Local Storm Report
National Weather Service Tucson AZ
359 PM MST Tue Aug 4 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0920 PM     Hail             8 SSE Sells             31.81N 111.82W
08/03/2026  M1.00 Inch       Pima               AZ   Emergency Mngr

            Delayed report. Quarter sized hail.

&&