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FGUS76 KSGX 212241
ESFSGX

Hydrologic Forecast for Extreme Southwestern California
National Weather Service San Diego CA
341 PM PDT Thu Aug 21 2025

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

.SYNOPSIS...
Monsoonal moisture will increase through the weekend with
increasing chances for showers and thunderstorms. Best chances are
currently Saturday afternoon and early evening in the mountains
and deserts, with lower chances of thunderstorms moving into the
valleys. Chances of showers and thunderstorms over the mountains
and deserts remain in the forecast through at least the middle of
next week.

$$

CAZ055-056-058-221315-
San Bernardino County Mountains-Riverside County Mountains-
San Diego County Mountains-
Including the cities of Crestline, Lake Arrowhead, Big Bear City,
Big Bear Lake, Running Springs, Wrightwood, Idyllwild-Pine Cove,
Julian, and Pine Valley
341 PM PDT Thu Aug 21 2025

.TONIGHT...None...no flash flooding is expected.
.FRIDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.
.SATURDAY...High...thunderstorms with areas of heavy rain are
expected and the threat of flash flooding is significant.

$$

CAZ060>062-065-221315-
Apple and Lucerne Valleys-Coachella Valley-
San Diego County Deserts-San Gorgonio Pass near Banning-
Including the cities of Victorville, Hesperia, Apple Valley,
Lucerne Valley, Indio, Palm Springs, Cathedral City, Palm Desert,
Palm Desert Country, La Quinta, Coachella, and Borrego Springs
341 PM PDT Thu Aug 21 2025

.TONIGHT...None...no flash flooding is expected.
.FRIDAY...Low...the risk of flash flooding is minimal.
.SATURDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.

$$

CAZ048-050-221315-
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
341 PM PDT Thu Aug 21 2025

.TONIGHT...None...no flash flooding is expected.
.FRIDAY...Low...the risk of flash flooding is minimal.
.SATURDAY...Low...the risk of flash flooding is minimal.

$$

CAZ043-057-552-554-221315-
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
341 PM PDT Thu Aug 21 2025

.TONIGHT...None...no flash flooding is expected.
.FRIDAY...None...no flash flooding is expected.
.SATURDAY...None...no flash flooding is expected.

$$

CO