Flash Flood Warning 4, NWS San Diego, CA

392 
WGUS76 KSGX 112302 RRC
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
Issued by National Weather Service Los Angeles/Oxnard CA
402 PM PDT Tue Aug 11 2026

CAC065-073-112312-
/O.EXP.KSGX.FF.W.0004.000000T0000Z-260811T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-San Diego CA-
402 PM PDT Tue Aug 11 2026

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHEASTERN RIVERSIDE AND
NORTHEASTERN SAN DIEGO COUNTIES...

The heavy rain has moved out of the area. However, additional
isolated showers are possible in the next few hours. Please continue
to heed remaining road closures and keep in mind that mudslides and
rockslides can occur many hours after the rain has ended.

&&

LAT...LON 3343 11637 3354 11643 3359 11630 3354 11617
      3348 11608 3342 11609 3337 11611 3333 11620
      3338 11634

$$

Cohen/Lund

Area Forecast Discussion
National Weather Service San Diego CA
1214 PM PDT Tue Aug 11 2026

.SYNOPSIS...
Another round of monsoon thunderstorms is expected for the mountains
on Tuesday with locally heavy rainfall rates. An isolated storm or
two may pop up over the mountains again Wednesday, but otherwise
drier conditions are expected for late week into the weekend. A
cooling trend will bring below normal temperatures to the region
from Wednesday onward along with breezy conditions for the mountains
and deserts. For the coastal basin, the marine layer is expected
to deepen each day through the weekend.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

Today through tomorrow night...

Recycled monsoonal moisture is continuing to stream up over the
region out of the southeast around the high positioned over the
desert southwest. Given the amount of instability and abundance of
moisture, there will be around a 40 to 50 percent chance of
afternoon showers and thunderstorms developing, with the San
Bernardinos mostly at play. Some of these storms will be capable of
producing rainfall rates of 0.50 inches per hour. Expect that some
of these storms will also produce strong and gusty winds due to
outflows and high DCAPE values exceeding 1000 J/kg. There could also
be some small hail associated with these storms. This will continue
into the evening hours, with storms beginning to move towards the
northeast by later in the day as mid-level flow begins to shift to
being more out of a southwesterly direction. There may also be
some isolated areas of flash flooding as a result of the storms,
as they may rapidly intensity along the mountain/desert interface,
especially where there are currently some SBCAPE values of 4000
J/kg, with temperatures/dews of low 90s over low 70s within the
Coachella Valley. These showers and storms will likely make their
way into the high deserts with skies continuing to clear as these
showers/storms dissipate and move out of the CWA. The marine layer
will be rather dispersed and then fill back in by late into the
night. As troughing continues to influence the region from
upstream, with should allow bases to slightly rise into the
morning hours tomorrow.

Thursday through Wednesday...

Troughing from upstream will continue to influence the region with
gradually cooling temperatures through the end of the week, and
temperatures becoming as much as 10 degrees below the seasonal
average for some areas. This will also increase surface gusty winds,
especially during the afternoon for the high deserts, and mountain
canyons/passes by later in the week, with gusts approaching 60 mph
within Gorgonio Pass. There will also become more persistence with
onshore flow, with the marine layer becoming more prevalent
overnight and into the morning hours. Going into early next week,
ensembles reflect a breakdown of the troughing over the E Pacific
waters and thus a return to more seasonal temperatures, while
remaining dry.

&&

.AVIATION...
101800Z....Coast/Valleys...Ongoing high cu AOA 20,000ft MSL through
Wednesday. VFR through this evening before low clouds develop again
tonight. Bases will be slightly higher, likely 1200-1500ft MSL after
03z Wed. Bases may lift from closer to 1000 to around 1500 MSL
through 12z, and will spread up to 20 miles inland. Intermittent
CIGs possible at inland TAF sites, KONT and KSBD between 12-15z. Low
chances (10%) of impacts at inland TAF sites from nearby TSRA.

.Mountains/Deserts...Scattered TSRA over mountains and
locally in deserts through this evening. Bases around 9000ft MSL
with tops to 50000 feet with any storm. Any TSRA could produce
lightning, strong up/downdrafts and associated VIS reductions.
Otherwise, SCT-BKN clouds mostly above 15,000ft MSL through today.

&&

.MARINE...
No hazardous marine conditions are expected through Saturday.

&&

.BEACHES...
High tides will exceed 7 feet this evening and again Wednesday
evening between 800-930 PM, resulting in minor tidal overflow of low-
lying areas along the beach. Surf will be low and is not expected to
add much to the flooding potential. Check the Coastal Flood Advisory
for details.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 11 PM PDT Wednesday for Orange
     County Coastal Areas-San Diego County Coastal Areas.

PZ...None.

&&

PUBLIC...Stewey
AVIATION/MARINE/BEACHES...SZ

Special Weather Statement
National Weather Service San Diego CA
Issued by National Weather Service OXNARD CA
1154 AM PDT Tue Aug 11 2026

CAZ056-061-111930-
Riverside County Mountains CA-Coachella Valley CA-
1154 AM PDT Tue Aug 11 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL RIVERSIDE COUNTY
THROUGH 1230 PM PDT...

At 1153 AM PDT, Doppler radar was tracking a strong thunderstorm over
Hwy 74 Between Anza And Palm Desert, or 13 miles southwest of Indio,
moving north at 15 mph.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Hwy 74 Between Anza And Palm Desert...
Indian Wells...
and Santa Rosa Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3352 11645 3358 11649 3366 11646 3368 11637
      3360 11634
TIME...MOT...LOC 1853Z 188DEG 13KT 3362 11642

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

Cohen/Stewey

Special Weather Statement
National Weather Service San Diego CA
Issued by National Weather Service OXNARD CA
112 PM PDT Tue Aug 11 2026

CAZ056-058-061-062-112045-
San Diego County Mountains CA-San Diego County Deserts CA-
Riverside County Mountains CA-Coachella Valley CA-
112 PM PDT Tue Aug 11 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN RIVERSIDE AND
NORTHEASTERN SAN DIEGO COUNTIES THROUGH 145 PM PDT...

At 112 PM PDT, Doppler radar was tracking a strong thunderstorm 9
miles southwest of Thermal, or 13 miles northeast of Borrego Springs.
This storm was nearly stationary.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Santa Rosa Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3345 11633 3352 11621 3347 11616 3344 11614
      3338 11618 3337 11629
TIME...MOT...LOC 2012Z 335DEG 4KT 3344 11622

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

Black/Cohen

Special Weather Statement
National Weather Service San Diego CA
Issued by National Weather Service OXNARD CA
138 PM PDT Tue Aug 11 2026

CAZ058-062-112115-
San Diego County Mountains CA-San Diego County Deserts CA-
138 PM PDT Tue Aug 11 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL SAN DIEGO COUNTY
THROUGH 215 PM PDT...

At 138 PM PDT, Doppler radar was tracking a strong thunderstorm near
Warner Springs, or 14 miles west of Borrego Springs, moving south at
5 mph.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Los Coyotes Indian Reservation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3339 11666 3341 11651 3333 11649 3330 11651
      3329 11651 3327 11661
TIME...MOT...LOC 2038Z 348DEG 5KT 3333 11656

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

Black/Cohen

Special Weather Statement
National Weather Service San Diego CA
Issued by National Weather Service OXNARD CA
142 PM PDT Tue Aug 11 2026

CAZ056-061-112115-
Riverside County Mountains CA-Coachella Valley CA-
142 PM PDT Tue Aug 11 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL RIVERSIDE COUNTY
THROUGH 215 PM PDT...

At 142 PM PDT, Doppler radar was tracking a strong thunderstorm over
Hwy 74 Between Anza And Palm Desert, or 11 miles east of Anza. This
storm was nearly stationary.

HAZARD...Wind gusts of 50 to 55 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Hwy 74 Between Anza And Palm Desert...
and Santa Rosa Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3362 11651 3362 11640 3350 11642 3352 11654
TIME...MOT...LOC 2042Z 014DEG 1KT 3358 11647

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH

Cohen

Special Weather Statement
National Weather Service San Diego CA
Issued by National Weather Service OXNARD CA
146 PM PDT Tue Aug 11 2026

CAZ056-058-061-062-112115-
San Diego County Mountains CA-San Diego County Deserts CA-
Riverside County Mountains CA-Coachella Valley CA-
146 PM PDT Tue Aug 11 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN RIVERSIDE AND
NORTHEASTERN SAN DIEGO COUNTIES THROUGH 215 PM PDT...

At 145 PM PDT, Doppler radar was tracking a strong thunderstorm 8
miles north of Hwy S22 Between Borrego Springs And Imperial County
Line, or 12 miles northeast of Borrego Springs. This storm was nearly
stationary, but drifting slowly to the south and southeast.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Santa Rosa Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3345 11627 3350 11619 3344 11612 3337 11616
      3337 11626
TIME...MOT...LOC 2045Z 332DEG 4KT 3341 11620

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

Black/Cohen