Flash Flood Warning 100, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
227 PM MST Wed Aug 5 2026

.SYNOPSIS...Expect thunderstorm activity 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 an isolated flash flooding
risk. High temperatures will remain a few degrees above normal
through the weekend.

&&

.DISCUSSION...Current satellite shows a cumulus field over
central/eastern Pima County, Santa Cruz County, and parts of
Cochise and Graham Counties with an isolated thunderstorm over
northern Greenlee County and the Santa Ritas. This likely means
there is very little CIN left and with more surface heating the
atmosphere will be ready for convection.

All the ingredients are in place with seasonable PWAT values,
MLCAPE of 800-1800 J/kg, and effective bulk shear 20-30 kts.
Storms will continue to develop over the White Mountains early
this afternoon and over the Sky Islands by mid-afternoon. Storms
then move into the lower elevations and progress westward
through the late afternoon and evening. Storms could reach
Tucson as early as 5 PM, but between 6-8 PM looks more likely.
Storms will be capable of strong to severe wind gusts with an
isolated storm or two producing a 70+ mph wind gusts. Model
soundings show a dry nose just above 500 mb that could enhance
downdrafts and the 05/12Z HREF has a 30 percent chance for 50 kt
winds within 40 km of a point for central/eastern Pima County
and southern Pinal County this evening. This is being driven by
a couple HREF members that shows storms over Tucson that produce
a strong outflow that moves through the metro and then into the
Tohono O'odham Nation and Pinal County late this evening. If
this does happen expect blowing dust along I-10 in Pinal County.
Locally heavy rainfall leading to flash flooding will also be a
threat from central Pima County eastward late this afternoon
and evening. Most storms will be capable of one inch per hour
rainfall rates with isolated areas approaching 3 inch totals
through midnight. Because of this a Flood Watch has been issued
from 4 PM to 11 PM from central Pima County east to western
Cochise County including the Tucson metro and Santa Cruz County.

Overnight convection looks limited after midnight with maybe a
isolated showers over central or western Pima County. Thursday
thunderstorm coverage and intensity looks to be a little less
than today. 0-6 km shear values will be around 15-20 kts, but
there will be plenty of instability and moisture values will be
seasonable. CAMs show initial development over the White
Mountains and Sky Islands of Cochise and Graham Counties, then
spread into the lower elevations mainly south and east of
Tucson. Storms will be capable of strong outflow winds, with a
few storms possibly producing severe wind gusts. Storms will
also be capable of heavy rainfall with an isolated flash
flooding threat.

Friday into early next week the high remains in a favorable
position for daily afternoon and evening thunderstorms with some
day to day variation in coverage and strength due to the
strength of the high. Friday into Saturday the ridge increases
in strength which will lead to a 2-3 degree warmup compared to
today and Thursday. This could lead to a downturn in monsoon
activity Friday. Saturday ensembles and deterministic models
show an increase in mid-level flow, which could lead to an
increase in storm coverage and intensity even with the stronger
ridge in place. After Saturday heights decrease and
temperatures drop to around normal next week.

&&

.AVIATION...Valid through 07/00Z.
Scattered thunderstorms expected to develop this afternoon
mainly between 05/22Z to 06/05Z with lingering isolated activity
through 06/08Z. Coverage around KTUS more likely 06/01Z-06/06Z
and KOLS/KDUG 05/23Z-06/04Z. 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 Thursday afternoon and evening south and
east of Tucson. 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 06/05Z. 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. Today storms
will be capable of heavy rainfall and strong to severe wind
gusts. A Flash Flood Watch is in effect from 4 PM to 11 PM.
Minimum relative humidity values will be 20-40 percent into
early next week with temperatures 2-7 degrees above normal.
Outside of thunderstorms, winds terrain driven to around 10 mph
with occasional afternoon gusts to 20 mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 11 PM MST this evening for AZZ502>504-507-
513>515.

&&

Hardin

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Preliminary Local Storm Report
National Weather Service Tucson AZ
608 PM MST Wed Aug 5 2026

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

0557 PM     Non-Tstm Wnd Gst 4 ENE Safford           32.85N 109.63W
08/05/2026  M69 MPH          Graham             AZ   ASOS

            ASOS station KSAD Safford Regional Airport.

&&

Preliminary Local Storm Report
National Weather Service Tucson AZ
628 PM MST Wed Aug 5 2026

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

0618 PM     Hail             19 E Tombstone          31.76N 109.75W
08/05/2026  M1.00 Inch       Cochise            AZ   County Official

            Quarter size hail via photo.

&&

JRM

Preliminary Local Storm Report
National Weather Service Tucson AZ
642 PM MST Wed Aug 5 2026

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

0640 PM     Rain             1 WSW Patagonia         31.54N 110.76W
08/05/2026  M0.42 Inch       Santa Cruz         AZ   Mesonet

            0.42 inches of rain in 5 mins. 0.6 inches in
            10 mins.

&&

JRM

Preliminary Local Storm Report
National Weather Service Tucson AZ
656 PM MST Wed Aug 5 2026

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

0656 PM     Rain             3 S Thatcher            32.79N 109.77W
08/05/2026  M0.51 Inch       Graham             AZ   Mesonet

            0.51 inches of rain in 10 mins.

&&

JRM

Preliminary Local Storm Report
National Weather Service Tucson AZ
739 PM MST Wed Aug 5 2026

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

0738 PM     Hail             6 SE Sierra Vista       31.50N 110.26W
08/05/2026  M1.00 Inch       Cochise            AZ   Trained Spotter

            Trained spotter reported between dime and
            quarter sized hail.

&&

DVS