Flash Flood Warning 8, NWS San Diego, CA

692 
WGUS76 KSGX 242303
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
403 PM PDT Thu Sep 24 2026

CAC065-242313-
/O.CAN.KSGX.FF.W.0008.000000T0000Z-260924T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-
403 PM PDT Thu Sep 24 2026

...FLASH FLOOD WARNING IS CANCELLED FOR RIVERSIDE COUNTY...

The heavy rain has ended. The Flash Flood Warning has been cancelled
but a Flood Advisory remains in effect for this area through 315 PM
PDT. Please continue to heed remaining road closures.

&&

LAT...LON 3365 11660 3367 11651 3361 11642 3350 11647
      3355 11661

$$

Area Forecast Discussion
National Weather Service San Diego CA
1241 PM PDT Thu Sep 24 2026

.SYNOPSIS...
Warmer through Saturday with moderate HeatRisk for the coast and
western valleys Friday and Saturday. Night and morning low clouds
and fog will stay confined to the coastal areas for the next few
nights. There is a slight chance of showers and thunderstorms over
the mountains this afternoon. Tropical mid and high level
moisture will bring more clouds and cooler temperatures late
weekend early next week. Warming trend after Monday.

&&

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

...UPDATED AVIATION, MARINE, AND BEACHES DISCUSSIONS...

Ample cloud cover this morning from a very robust and shallower
marine layer, with satellite still showing some inland coverage as
of 11am. Areas of patchy fog were reported, mostly in part thanks to
increasing heights as a weak ridge attempts to take hold of SoCal
and a shortwave trough moves eastward today. The morning sounding
already shows drier air in the mid and upper levels with the
departure of the trough, also evident on mid-level water vapor
satellite with additional subsidence 150 miles southwest of San
Diego. This lack of moisture will be a main limiting factor for
storms in the mountains this afternoon, although a few thunderstorms
remain possible for primarily the San Diego and Riverside County
Mountains. Anything that develops will be diurnally driven and
unlikely to produce flash flooding, with storms ending by sunset.

Southern California will be in a push-and-pull for the remainder of
the week between a deepening low over the PacNW, high pressure over
Texas, and two tropical cyclones in the eastern Pacific. The
aforementioned weak ridge will hold through at least Friday and keep
temperatures well above normal with highs in the 90s for inland and
High Desert, 80s for the coast and mountains, and 100-103 for the
low deserts. Things start to change this weekend as the ridge is
compressed and the high over Texas shifts southward, allowing for
tropical moisture to shift up Baja and into Southern California and
western Arizona. This could mean some very warm morning temperatures
both Saturday and Sunday as the moisture reduces radiational cooling,
and temperatures in the afternoon remain elevated as heights will be
slow to fall. This is likely to bring about some Moderate HeatRisk
for the coastal areas on Saturday with temperatures around 10-12
degrees above normal and warm overnight lows above 71 degrees. A lot
of this will depend heavily on cloud cover associated with the
tropical cyclones well to our south, which could impact peak heating
on Saturday, limiting our warming.

By late weekend, a trough off the aforementioned larger low in the
PacNW will swing down and become a closed low by Monday. This could
help initiate some convection while mixing with the influx of
moisture. For now, much of any precipitation looks to stay east of
the region, as drier air on the backside of the trough looks to push
in as tropical moisture is shunted east of the mountains. Should
SoCal get dry slotted (80-90% confidence), Sunday and Monday would at
least feature cooler weather thanks to the deepening low as it
meanders into Arizona and Utah. Meanwhile, other states in the
Desert SW may experience multiple rounds of precipitation and some
heavy rainfall. At this point, the tracks of Polo and Odalys and
where the larger upper level pattern will be are not conducive to
precipitation for SoCal.

With building high pressure to the west and drier air filter in, the
region will return to a warming trend after Monday along with
quieter weather.

A few impacts that may be observed early next week due to the
tropical cyclones:
-higher humidity for the deserts, especially the low deserts, late
weekend into early next week.
-coastal flooding and coastal erosion, especially for south-facing
beaches, Sunday through Tuesday. Additional details on this can be
found in the Beaches discussion below.

&&

.AVIATION...
241800Z...Coast/Valleys...Low clouds from last night's marine layer
intrusion have lifted (with bases now around 1500-1700ft MSL) and
been scattering out this morning. While CIG scattering is expected
at the coastal TAF sites (KSAN, KCRQ, KSNA) by 19z Thurs, SCT-BKN
clouds may linger along the beaches/immediate coasts through the
afternoon. Low clouds begin to fill back in as early as 02z Friday,
but could be somewhat limited in pushing ashore until around 06-07z.
Afterwards, clouds will fill back in with similar areal coverage and
bases compared to this morning. Clouds clear back to the coast by 17-
19z Friday.

Otherwise...Mostly clear today and tonight. Except for SCT cumulus
based near 10 kft over mountains and isolated SHRA/TSRA 20-01z. Any
storm that develops will be capable of producing gusty, erratic
winds, lightning, and vis reductions in SHRA/BLDU.

&&

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

&&

.BEACHES...
Southwesterly swell (3-4 ft at 12 seconds from ~210 degrees) from
Hurricane Odalys begins to increase on Friday, bringing surf up to 3-
5 feet with sets up to 6 feet to most beaches. This swell from
Odalys is expected to persist into this weekend. Given tides are
already observed over 6 feet and are expected to gradually increase
into this weekend, a Beach Hazard Statement has been issued for
Friday morning through Sunday evening. Minor tidal overflow and
minor coastal erosion are the primary impacts during this period.

The swell associated with Hurricane Polo (4-5 ft at 14 seconds from
~160 degrees) increases on Monday. However, given this direction,
most of San Diego County beaches will be largely sheltered from this
swell, but Orange County beaches still look to be impacted by this
swell. Meanwhile, a northwesterly swell (3-4 ft at 8 seconds from
~290 degrees) from an incoming storm system will also be building
Sunday into Monday. Between these two swells, surf of 4-6 feet look
to remain possible along all beaches into Tuesday. Tides see their
bi-monthly astronomical peak Monday-Wednesday morning, with peak
tides near 7.0 ft Between the combination of higher tides and the
expected surf, there is a risk for minor-moderate coastal flooding
during the late morning/early afternoon high tides. Stay tuned as
details continue to become more clear in the coming days.

Please note - listed tide predictions have been adjusted to reflect
actual measured tide observations.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from late tonight through Sunday
     afternoon for Orange County Coastal Areas-San Diego County
     Coastal Areas.

PZ...None.

&&

PUBLIC...Zuber
AVIATION/MARINE/BEACHES...Munyan

Special Weather Statement
National Weather Service San Diego CA
218 PM PDT Thu Sep 24 2026

CAZ048-056-242200-
Riverside County Mountains CA-
San Bernardino and Riverside County Valleys-The Inland Empire CA-
218 PM PDT Thu Sep 24 2026

...A STRONG THUNDERSTORM WILL IMPACT RIVERSIDE COUNTY THROUGH 300 PM
PDT...

At 217 PM PDT, Doppler radar was tracking a strong thunderstorm near
Hwy 74 Between Mountain Center And Anza, or near Anza, moving east at
10 mph.

HAZARD...Wind gusts up to 50 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...
Anza, Hwy 74 Between Mountain Center And Anza, Mountain Center, Hwy
74 Between Anza And Palm Desert, Cahuilla Indian Reservation, Lake
Hemet, 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 3350 11674 3362 11681 3374 11661 3353 11646
TIME...MOT...LOC 2117Z 248DEG 8KT 3360 11669

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

KW