Flash Flood Warning 147, NWS Tucson, AZ

680 
WGUS75 KTWC 200314
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
814 PM MST Wed Aug 19 2026

AZC019-200530-
/O.CON.KTWC.FF.W.0147.000000T0000Z-260820T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
814 PM MST Wed Aug 19 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1030 PM MST THIS
EVENING FOR NORTHEASTERN PIMA COUNTY...

At 814 PM MST, Doppler radar indicated thunderstorms produced heavy
rain across the warned area. Up to 1 inch of rain has fallen.
Additional rainfall amounts up to 0.2 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Tucson, Casas Adobes, Drexel Heights, Flowing Wells, Tucson
  Mountain Park, Tucson Estates, Valencia West and Ryan AirField.

This includes the following highways...
Interstate 19 between mile markers 60 and 63. Route 86 between mile
markers 157 and 171. Route 77 between mile markers 70 and 72.
Interstate 10 between mile markers 249 and 260.

This includes the following Flash Flood Prone Locations...
1st Ave north of Fort Lowell Rd, Stone Ave at Mabel St and Camino De
La Tierra at the Rillito River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3228 11091 3225 11097 3217 11098 3213 11099
      3213 11116 3211 11124 3222 11125 3224 11102
      3233 11108 3234 11106 3232 11103

FLASH FLOOD...RADAR INDICATED

$$

JRM

496 
WGUS75 KTWC 200524
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1024 PM MST Wed Aug 19 2026

AZC019-200534-
/O.EXP.KTWC.FF.W.0147.000000T0000Z-260820T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
1024 PM MST Wed Aug 19 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 1030 PM MST THIS EVENING FOR
NORTHEASTERN PIMA COUNTY...

Flash flooding is no longer expected to pose a threat. Please
continue to heed remaining road closures.

&&

LAT...LON 3228 11091 3225 11097 3217 11098 3213 11099
      3213 11116 3211 11124 3222 11125 3224 11102
      3233 11108 3234 11106 3232 11103

$$

CWR

Area Forecast Discussion
National Weather Service Tucson AZ
116 PM MST Wed Aug 19 2026

.SYNOPSIS...An uptick in afternoon showers and storms returns to
Southeast Arizona this afternoon and evening with the strongest
storms capable of producing isolated strong to severe wind gusts,
blowing dust, and heavy rainfall. Blowing dust could impact travel
along and near Interstate 10 and Interstate 19. Moderate to major
HeatRisk continues with forecast high temperatures 5 to 7 degrees
above normal.

&&

.DISCUSSION...So far this afternoon storms were forming in the White
Mountains with cumulus fields developing over the higher terrain
elsewhere. We will see the storms continue to form and gradually
push to the west and south during the afternoon and eventually into
central Pima County in the evening hours. The latest WRF guidance is
not in agreement on the timeline for when storms would potentially
impact the Tucson Metro with the WRF-GFS trending on the later side
and the WRF-HRRR more on the earlier side. To describe how this
difference is manifesting, it looks like the WRF-GFS is picking up
on storm development in Cochise County off the Galiuro, Whetstone,
Dragoon, Rincon, and Catalina Mountains around 3 pm to 5 pm MST
which would send outflows and additional storm development into the
Tucson Metro earlier than the WRF-HRRR that does not have this
development and instead relies on outflows from the south of Tucson
and from storms currently pushing off the White Mountains.
Essentially, we're looking at a two hour time difference depending
on how storm development trends.

The environment is ripe with instability according to the latest SPC
mesoanalysis. As of this writing there is 1500-2500 J/kg of MLCAPE
and around 20-30 kts of effective bulk layer shear as well as DCAPE
of 1400-1600 J/kg. Given this environment and the trends of the
convective allowing models, I think clustering of storms is on the
table along with potentially a few stronger discrete quasi
supercellular storms.

Tomorrow looks a bit similar to today but turning down the intensity
of all of the ingredients a little bit and with storms centered more
over the northern portions of our area including Graham, Greenlee,
and Pinal counties. There will still be showers and storms over the
rest of the southeast Arizona, but that's where I am initially
seeing the best ingredients for stronger outflows setting up.

Otherwise, we look to remain in an active weather pattern into the
weekend as the upper high center moves toward the Four Corners
Thursday into Friday, then into the Rockies by Saturday afternoon.
The Extreme Heat Warning remains in effect through Friday evening,
and we will be monitoring for continuing heat concerns heading into
the weekend.

&&

.PREV DISCUSSION... /issued 1000 AM MST Wed Aug 19 2026/

High resolution guidance as of this writing depict
increasing confidence for storms capable of producing strong, gusty,
and erratic outflow winds, blowing dust, and locally heavy rainfall
this afternoon and evening.

The 19/12Z run of the HREF depicts a high chance (70-90%) for gusty
outflow winds exceeding 35 mph, with a slight chance (10-20%) for
gusts to exceed 55 mph. The Storm Prediction Center (SPC) has
upgraded most of southeast Arizona into a slight risk for
thunderstorms today capable of producing isolated severe wind gusts
which is consistent with the aforementioned wind exceedance
probabilities. Scattered showers and storms forming around Noon MST
will become more widespread and perhaps more organized later in the
afternoon as they propagate west and south toward the Tucson Metro
(most likely around 5 pm to 7 pm MST) and continuing out over Tohono
O'ohdam Nation. Storms will be supported by modest deep layer (0-6
km) shear of around 20-25 kts with mean storm motions of around 10-
15 mph. As always, blowing dust becomes an increasing concern with
gusty outflow winds from organized thunderstorm clusters. But with
the increasing probabilities for gusty winds, my confidence in
organized thunderstorm outflows and potential haboob formation for
today are notably higher than they were at this point yesterday. The
night shift did coordinate with the Phoenix WFO to hoist a Blowing
Dust Advisory for portions of Pima and Santa Cruz counties extending
into Pinal and Maricopa counties. That will be in effect from 3 pm
to 10 pm today. Motorists should use caution driving along the
Interstate 10 and 19 corridors.

Secondarily, we've seen a notable surge of moisture over the past 24
hours. The Weather Prediction Center has upgraded areas from Tucson
metro west from a marginal risk into a slight risk for excessive
rainfall with isolated instances of flash flooding. Surface
dewpoints across the area have surged into the mid/upper 60s over
the past 24 hours. Satellite estimated precipitable water ranges
from about 0.9 inches in the White Mountains and along the
international border in Cochise County to 1.4 inches in western Pima
and southeast Pinal counties with even higher amounts south of the
international border. HREF depicts likely chances (70-90%) for
precipitable water to exceed 1.5 inches this afternoon and evening
as even richer and deeper moisture moves into the area. The deeper
moisture has been a rapidly evolving situation over the last few
days, and in my opinion the guidance is looking a bit more
impressive than yesterday with a slight chance (10-20%) for hourly
rainfall rates to exceed an inch per hour.

&&

.AVIATION...Valid through 21/00Z.
SCT-BKN 7-11k ft AGL BKN-OVC 12-15k ft AGL with scattered to
numerous -SHRA/-TSRA through 20/05Z. Gusty and erratic outflow winds
possible near TSRA with gusts to 40-50 kts. Organized outflows may
produce VSBY less than 1/2 SM in BLDU, especially from KTUS
west and northwest. Winds outside of thunderstorms mainly light
and terrain driven. Tomorrow, scattered -SHRA/-TSRA return after
20/19Z. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Strong thunderstorms will return to Southeast
Arizona this afternoon. The primary concern with storms this
afternoon is that they will be capable of producing organized storm
outflow winds 45-55 mph, potentially producing localized dense
blowing dust. Deep moisture moving into the region from the Gulf of
California will bring about a secondary concern of heavy rainfall
capable of producing isolated flash flooding, especially across
central and eastern Pima county. Otherwise, an uptick in storm
strength and coverage into the upcoming weekend. Hot conditions will
persist this week with an Extreme Heat Warning in effect today
through Friday for portions of the Southeast Arizona. Winds mainly
light and terrain driven. Strong, gusty and erratic winds will
accompany thunderstorms. Minimum relative humidities 15-25 percent
in lower elevations with 25-35 percent in the higher terrain.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...

Extreme Heat Warning until 8 PM MST Friday for AZZ501-502-504>506-509.

Blowing Dust Advisory from 3 PM this afternoon to 10 PM MST
this evening for AZZ501>506.

&&

DVS

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Preliminary Local Storm Report
National Weather Service Tucson AZ
634 PM MST Wed Aug 19 2026

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

0629 PM     Flash Flood      12 NE Green Valley      31.97N 110.86W
08/19/2026                   Pima               AZ   Public

            Swift Water Rescue at 6000 E SAHUARITA RD.

&&

MJS

Preliminary Local Storm Report
National Weather Service Tucson AZ
639 PM MST Wed Aug 19 2026

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

0634 PM     Rain             15 ENE Green Valley     31.95N 110.78W
08/19/2026  E0.96 Inch       Pima               AZ   Trained Spotter

            0.96 inches in 30 minutes.

&&

MJS

Preliminary Local Storm Report
National Weather Service Tucson AZ
644 PM MST Wed Aug 19 2026

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

0637 PM     Hail             5 E Tucson              32.22N 110.80W
08/19/2026  M1.00 Inch       Pima               AZ   Public

            Report of quarter sized hail.

&&

KLM

Preliminary Local Storm Report
National Weather Service Tucson AZ
647 PM MST Wed Aug 19 2026

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

0645 PM     Rain             3 E Tucson              32.20N 110.85W
08/19/2026  E0.25 Inch       Pima               AZ   Trained Spotter

            0.25 inch of rain in 9 minutes.

&&

MJS

Preliminary Local Storm Report
National Weather Service Tucson AZ
648 PM MST Wed Aug 19 2026

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

0641 PM     Hail             5 E Tucson              32.20N 110.81W
08/19/2026  M1.00 Inch       Pima               AZ   NWS Employee

&&

KJS

Preliminary Local Storm Report
National Weather Service Tucson AZ
721 PM MST Wed Aug 19 2026

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

0702 PM     Flash Flood      9 NNE Green Valley      31.96N 110.93W
08/19/2026                   Pima               AZ   Public

            Sahuarita Road East of Country Club Rd
            closed due to flash flooding.

&&

MJS