738
FGUS76 KSGX 021127
ESFSGX

Hydrologic Forecast for Extreme Southwestern California
National Weather Service San Diego CA
427 AM PDT Tue Sep 2 2025

...Flash Flood Potential Index for Extreme Southwestern California...

.SYNOPSIS...
Monsoonal moisture will increase from the southeast this morning
as upper level low pressure moves northward across the area today.
This will bring widespread showers and a 15 to 30 percent chance
of thunderstorms, with the greatest chances this afternoon over
the mountains and deserts. Rainfall rates will generally be 0.50
inch per hour or less, with the potential for isolated rates up to
around 1.00 or more inch per hour in stronger thunderstorms
should sufficient daytime heating occur.

Moisture will gradually decrease for Wednesday through Friday with
the more typical afternoon showers and thunderstorms, primarily
across the mountains and deserts.

$$

CAZ055-030345-
San Bernardino County Mountains-
Including the cities of Crestline, Lake Arrowhead, Big Bear City,
Big Bear Lake, Running Springs, and Wrightwood
427 AM PDT Tue Sep 2 2025

.TODAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.
.WEDNESDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.

$$

CAZ056-058-030345-
Riverside County Mountains-San Diego County Mountains-
Including the cities of Idyllwild-Pine Cove, Julian,
and Pine Valley
427 AM PDT Tue Sep 2 2025

.TODAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.
.WEDNESDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.

$$

CAZ060-030345-
Apple and Lucerne Valleys-
Including the cities of Victorville, Hesperia, Apple Valley,
and Lucerne Valley
427 AM PDT Tue Sep 2 2025

.TODAY...Low...the risk of flash flooding is minimal.
.WEDNESDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.

$$

CAZ061-062-065-030345-
Coachella Valley-San Diego County Deserts-
San Gorgonio Pass near Banning-
Including the cities of Indio, Palm Springs, Cathedral City,
Palm Desert, Palm Desert Country, La Quinta, Coachella,
and Borrego Springs
427 AM PDT Tue Sep 2 2025

.TODAY...Low...the risk of flash flooding is minimal.
.WEDNESDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.

$$

CAZ048-050-030345-
San Bernardino and Riverside County Valleys-The Inland Empire-
San Diego County Valleys-
Including the cities of Riverside, San Bernardino, Ontario,
Moreno Valley, Fontana, Rancho Cucamonga, Corona, Escondido,
El Cajon, San Marcos, La Mesa, Santee, and Poway
427 AM PDT Tue Sep 2 2025

.TODAY...Low...the risk of flash flooding is minimal.
.WEDNESDAY...Low...the risk of flash flooding is minimal.

$$

CAZ043-057-552-554-030345-
San Diego County Coastal Areas-Santa Ana Mountains and Foothills-
Orange County Coastal Areas-Orange County Inland Areas-
Including the cities of Oceanside, Vista, Carlsbad, Encinitas,
Chula Vista, National City, San Diego, Huntington Beach,
Costa Mesa, Newport Beach, Laguna Beach, San Clemente, Santa Ana,
Anaheim, Garden Grove, Irvine, Orange, Fullerton,
and Mission Viejo
427 AM PDT Tue Sep 2 2025

.TODAY...Low...the risk of flash flooding is minimal.
.WEDNESDAY...None...no flash flooding is expected.

$$

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