167 

FGUS76 KSGX 220907

ESFSGX



Hydrologic Forecast for Extreme Southwestern California

National Weather Service San Diego CA

207 AM PDT Sat Aug 22 2026



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



.SYNOPSIS...

Monsoonal moisture will decrease this weekend, with a slight chance

of showers and thunderstorms in the mountains and low desert

returning Monday afternoon. No flash flooding is expected 

today and Sunday.



$$



CAZ058-230145-

San Diego County Mountains-

Including the cities of Julian and Pine Valley

207 AM PDT Sat Aug 22 2026



.TODAY...None...no flash flooding is expected. 

.SUNDAY...None...no flash flooding is expected. 



$$



CAZ043-048-050-055>057-060>062-065-552-554-230145-

San Diego County Coastal Areas-

San Bernardino and Riverside County Valleys-The Inland Empire-

San Diego County Valleys-San Bernardino County Mountains-

Riverside County Mountains-Santa Ana Mountains and Foothills-

Apple and Lucerne Valleys-Coachella Valley-

San Diego County Deserts-San Gorgonio Pass near Banning-

Orange County Coastal Areas-Orange County Inland Areas-

Including the cities of Oceanside, Vista, Carlsbad, Encinitas, 

Chula Vista, National City, San Diego, Riverside, San Bernardino, 

Ontario, Moreno Valley, Fontana, Rancho Cucamonga, Corona, 

Escondido, El Cajon, San Marcos, La Mesa, Santee, Poway, 

Crestline, Lake Arrowhead, Big Bear City, Big Bear Lake, 

Running Springs, Wrightwood, Idyllwild-Pine Cove, Victorville, 

Hesperia, Apple Valley, Lucerne Valley, Indio, Palm Springs, 

Cathedral City, Palm Desert, Palm Desert Country, La Quinta, 

Coachella, Borrego Springs, Huntington Beach, Costa Mesa, 

Newport Beach, Laguna Beach, San Clemente, Santa Ana, Anaheim, 

Garden Grove, Irvine, Orange, Fullerton, and Mission Viejo

207 AM PDT Sat Aug 22 2026



.TODAY...None...no flash flooding is expected. 

.SUNDAY...None...no flash flooding is expected. 



$$






902 

FGMY70 PGUM 220943

ESFGUM

GUC010-MPC100-110-120-230945-



Hydrologic Outlook

National Weather Service Tiyan GU

743 PM ChST Sat Aug 22 2026



...HEAVY RAINFALL, FLOODING, AND MUDSLIDE POTENTIAL FOR THE MARIANAS

BEGINNING TUESDAY...



This Hydrologic Outlook is for Guam, Rota, Tinian, and Saipan.



A potential tropical disturbance will likely develop in the area and

bring periods of heavy rainfall to the Marianas with rainfall totals

of 4 to 7 inches possible.



Heavy showers will moisten soils throughout the event and increase

potential for mudslides.



Residents on the Marianas need to closely monitor this developing

situation as flood watches, advisories and flash flood warnings could

be issued later.



If living near streams and rivers, prepare to move items away from

stream and river banks. Make sure storm drains nearby are not

clogged, especially If living at low-lying areas.



$$



JAW