359
FGUS76 KSGX 222259
ESFSGX

Hydrologic Forecast for Extreme Southwestern California
National Weather Service San Diego CA
359 PM PDT Fri Aug 22 2025

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

.SYNOPSIS...
Monsoonal moisture will increase into Saturday, decrease slightly
for Sunday and Monday, with a more significant surge of lower
level moisture into the lower deserts possible on Tuesday.

There will be chances for afternoon and early evening showers and
thunderstorms, mostly for the mountains and deserts each day
through much of next week. Daily chances for Big Bear to receive
one-half inch or more of rainfall are 16 percent or less through
Monday, then increase to 25 percent on Tuesday.

Any rainfall through Saturday morning is expected to be
insufficient for flash flooding. For Saturday afternoon and early
evening, thunderstorms could cause isolated flash flooding, mainly
for the San Bernardino Mountains, the Riverside County mountains,
and the Lucerne Valley.

$$

CAZ055-056-060-231315-
San Bernardino County Mountains-Riverside County Mountains-
Apple and Lucerne Valleys-
Including the cities of Crestline, Lake Arrowhead, Big Bear City,
Big Bear Lake, Running Springs, Wrightwood, Idyllwild-Pine Cove,
Victorville, Hesperia, Apple Valley, and Lucerne Valley
359 PM PDT Fri Aug 22 2025

.TONIGHT...Low...the risk of flash flooding is minimal.
.SATURDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.
.SUNDAY...Moderate...thunderstorms are expected to develop and
isolated flash flooding is possible.

$$

CAZ058-061-062-065-231315-
San Diego County Mountains-Coachella Valley-
San Diego County Deserts-San Gorgonio Pass near Banning-
Including the cities of Julian, Pine Valley, Indio, Palm Springs,
Cathedral City, Palm Desert, Palm Desert Country, La Quinta,
Coachella, and Borrego Springs
359 PM PDT Fri Aug 22 2025

.TONIGHT...Low...the risk of flash flooding is minimal.
.SATURDAY...Low...the risk of flash flooding is minimal.
.SUNDAY...Low...the risk of flash flooding is minimal.

$$

CAZ048-231315-
San Bernardino and Riverside County Valleys-The Inland Empire-
Including the cities of Riverside, San Bernardino, Ontario,
Moreno Valley, Fontana, Rancho Cucamonga, and Corona
359 PM PDT Fri Aug 22 2025

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

$$

CAZ043-050-057-552-554-231315-
San Diego County Coastal Areas-San Diego County Valleys-
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, Escondido, El Cajon,
San Marcos, La Mesa, Santee, Poway, Huntington Beach, Costa Mesa,
Newport Beach, Laguna Beach, San Clemente, Santa Ana, Anaheim,
Garden Grove, Irvine, Orange, Fullerton, and Mission Viejo
359 PM PDT Fri Aug 22 2025

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

$$