048
FGUS76 KSGX 272303
ESFSGX

Hydrologic Forecast for Extreme Southwestern California
National Weather Service San Diego CA
403 PM PDT Wed Aug 27 2025

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

.SYNOPSIS...
Isolated thunderstorms will continue this afternoon along the
desert slopes of the mountains in Riverside and San Diego Counties
into the adjacent deserts. Peak hourly rainfall will most be one-
quarter inch or less.

For late tonight into Thursday evening, there will be increasing
moisture from the remnants of Tropical Storm Juliette with
scattered showers spreading northeastward across portions of
southwestern California. The most likely locations for
thunderstorms on Thursday should be toward the northern edge of
the moisture where cloud cover is less and daytime heating
greater, though the trend has been for the moisture/thick cloud
cover to move further north, decreasing thunderstorm chances with
only a low risk of flash flooding. There is a 10% chance of
showers over San Bernardino Mountains on Friday afternoon with
rainfall rates below 0.25 inch per hour.

$$

CAZ055-056-281330-
San Bernardino County Mountains-Riverside County Mountains-
Including the cities of Crestline, Lake Arrowhead, Big Bear City,
Big Bear Lake, Running Springs, Wrightwood,
and Idyllwild-Pine Cove
403 PM PDT Wed Aug 27 2025

.TONIGHT...Low...the risk of flash flooding is minimal.
.THURSDAY...Low...the risk of flash flooding is minimal.
.FRIDAY...Low...the risk of flash flooding is minimal.

$$

CAZ060-281330-
Apple and Lucerne Valleys-
Including the cities of Victorville, Hesperia, Apple Valley,
and Lucerne Valley
403 PM PDT Wed Aug 27 2025

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

$$

CAZ061-062-065-281330-
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
403 PM PDT Wed Aug 27 2025

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

$$

CAZ058-281330-
San Diego County Mountains-
Including the cities of Julian and Pine Valley
403 PM PDT Wed Aug 27 2025

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

$$

CAZ048-050-281330-
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
403 PM PDT Wed Aug 27 2025

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

$$

CAZ043-057-552-554-281330-
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
403 PM PDT Wed Aug 27 2025

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

$$