Alert archive / California / Flash Flood Watches in 2021

Flash Flood Watch 2, NWS San Diego, CA

January 27, 20214 counties in California

NWS San Diego, CA issued this flash flood watch at Jan 27, 2021, 10:58 AM PST for 4 counties in California. It took effect at Jan 28, 2021, 7:00 PM PST. It was in force for 21 hr.

The area

The counties it named.

The facts

Issued
Jan 27, 2021, 10:58 AM PST (18:58 UTC)
In effect from
Jan 28, 2021, 7:00 PM PST
Expired
Jan 29, 2021, 4:00 PM PST
In force
21 hr
Issued by
NWS San Diego, CA
Flood severity
None

Counties Orange County, CA, Riverside County, CA, San Bernardino County, CA, San Diego County, CA

The radar

The Santa Ana Mts radar (KSOX), 88 km from the middle of the area, began a volume at 18:57 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 7.0 hours before the alert went out and 124 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, San Diego, CA at 12:00Z on 2021-01-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 12:00Z on 2021-01-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 88 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1202 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
216 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

134 
WGUS66 KSGX 271858
FFASGX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service San Diego CA
1058 AM PST Wed Jan 27 2021

CAZ043-048-050-055>058-552-554-280615-
/O.NEW.KSGX.FF.A.0002.210129T0300Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-San Diego County Mountains-Orange County Coastal Areas-
Orange County Inland Areas-
Including the cities of Vista, Ontario, Santee, Idyllwild-Pine Cove, 
Fontana, Garden Grove, Fullerton, Orange, Santa Ana, National City, 
Riverside, Poway, Big Bear Lake, Oceanside, Big Bear City, San 
Diego, Lake Arrowhead, Irvine, El Cajon, Newport Beach, Escondido, 
Chula Vista, Crestline, San Clemente, Wrightwood, Corona, Anaheim, 
Huntington Beach, San Bernardino, Moreno Valley, Mission Viejo, 
Laguna Beach, Julian, Pine Valley, Costa Mesa, La Mesa, Encinitas, 
Running Springs, San Marcos, Carlsbad, and Rancho Cucamonga
1058 AM PST Wed Jan 27 2021

...FLASH FLOOD WATCH IN EFFECT FROM THURSDAY EVENING THROUGH FRIDAY 
AFTERNOON...

The National Weather Service in San Diego has issued a

* Flash Flood Watch for a portion of southwest California, including 
  the following areas, the Apple burn scar, El Dorado burn scar, 
  Bond burn scar, Silverado burn scar, Blue Ridge burn scar, and 
  Valley burn scar, Orange County Coastal Areas, Orange County 
  Inland Areas, Riverside County Mountains below 5500 ft, San 
  Bernardino County Mountains below 5500 ft, San Bernardino and 
  Riverside County Valleys-The Inland Empire, San Diego County 
  Coastal Areas, San Diego County Mountains below 5500 ft, San Diego 
  County Valleys and Santa Ana Mountains and Foothills.

* From Thursday evening through Friday afternoon

* Moderate to heavy rain showers will impact areas west of the 
  mountains below 5500 ft, including the Apple, El Dorado, Bond, 
  Silverado, Blueridge, and Valley burn scars. Showers will develop 
  Thursday evening, becoming more widespread late Thursday into 
  Friday. The heaviest rain is expected to begin before midnight on 
  Thursday, lasting through Friday morning in Orange County and the 
  Inland Empire. Periods of heavy rain are expected early Friday 
  morning through Friday afternoon in San Diego County. Rain rates 
  of 0.50 inch to 0.60 inch an hour are expected. There is a slight 
  chance of thunderstorms Thursday night and Friday. Rain totals of 
  1.25-1.50 inches, locally up to 1.70 expected for the coast, 
  valleys, and Inland Empire with totals 2-3 inches on the coastal 
  slopes of the mountains below 5500 ft.

* Heavy rainfall can lead to areas of flash flooding, as well as mud 
  and debris flows near burn scars, especially the Apple, El Dorado, 
  and Bond burn scars.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away or be swept away. Know your escape routes. Be ready to act 
immediately and heed all evacuation orders. Keep updated on the 
latest weather forecasts.

&&

$$

CO
7 follow-up statements
561 
WGUS66 KSGX 280510
FFASGX

FLOOD WATCH
NATIONAL WEATHER SERVICE San Diego CA
910 PM PST Wed Jan 27 2021


CAZ043-048-050-055>058-552-554-281400-
/O.CON.KSGX.FF.A.0002.210129T0300Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-
San Diego County Mountains-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, Julian, 
Pine Valley, Huntington Beach, Costa Mesa, Newport Beach, 
Laguna Beach, San Clemente, Santa Ana, Anaheim, Garden Grove, 
Irvine, Orange, Fullerton, and Mission Viejo
910 PM PST Wed Jan 27 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM THURSDAY EVENING
THROUGH FRIDAY AFTERNOON...

The Flash Flood Watch continues for

* A portion of southwest California...including the following
  areas - Orange County...Coastal Areas and Inland Areas... 
  Riverside County Mountains...San Bernardino County Mountains... 
  San Bernardino and Riverside County Valleys-The Inland 
  Empire...San Diego County Coastal Areas...San Diego County 
  Mountains...San Diego County Valleys and Santa Ana Mountains and
  Foothills. 

* from Thursday evening through Friday afternoon

* Moderate to heavy rain showers will impact areas west of the
  mountains below 5500 ft, including the Apple, El Dorado, Bond,
  Silverado, Blue Ridge, and Valley burn scars. Showers will 
  develop Thursday evening, becoming more widespread late Thursday
  into Friday. The heaviest rain is expected to begin before 
  midnight on Thursday, lasting through Friday morning in Orange 
  County and the Inland Empire. Periods of heavy rain are expected
  early Friday morning through Friday afternoon in San Diego 
  County. Rain rates of 0.50 inch to 0.60 inch an hour are 
  expected. There is a slight chance of thunderstorms Thursday 
  night and Friday. Rain totals of 1.25-1.50 inches, locally up to
  1.70 expected for the coast, valleys, and Inland Empire with 
  totals 2-3 inches on the coastal slopes of the mountains below 
  5500 ft. 

* Heavy rainfall can lead to areas of flash flooding, as well as 
  mud and debris flows near burn scars, especially the Apple, El 
  Dorado, and Bond burn scars. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away or be swept away. Know your escape routes. Be ready to
act immediately and heed all evacuation orders. Keep updated on
the latest weather forecasts.

&&

$$

APR
012 
WGUS66 KSGX 281132
FFASGX

Flood Watch
National Weather Service San Diego CA
332 AM PST Thu Jan 28 2021

CAZ043-048-050-055>058-552-554-281945-
/O.CON.KSGX.FF.A.0002.210129T0300Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-San Diego County Mountains-Orange County Coastal Areas-
Orange County Inland Areas-
Including the cities of Vista, Ontario, Santee, Idyllwild-Pine Cove, 
Fontana, Garden Grove, Fullerton, Orange, Santa Ana, National City, 
Riverside, Poway, Big Bear Lake, Oceanside, Big Bear City, San 
Diego, Lake Arrowhead, Irvine, El Cajon, Newport Beach, Escondido, 
Chula Vista, Crestline, San Clemente, Wrightwood, Corona, Anaheim, 
Huntington Beach, San Bernardino, Moreno Valley, Mission Viejo, 
Laguna Beach, Julian, Pine Valley, Costa Mesa, La Mesa, Encinitas, 
Running Springs, San Marcos, Carlsbad, and Rancho Cucamonga
332 AM PST Thu Jan 28 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM THIS EVENING THROUGH 
FRIDAY AFTERNOON...

The Flash Flood Watch continues for

* Coast, valleys, and mountains below 5500 feet in southwestern 
  California.

* From this evening through Friday afternoon

* Showers with moderate to locally heavy rainfall will impact areas 
  west of the mountains below 5500 feet, including the Apple, El 
  Dorado, Bond, Silverado, Blueridge, and Valley burn scars. Showers 
  will develop this evening, becoming more widespread tonight into 
  Friday. The heaviest rain is expected to begin before midnight, 
  lasting through 6 AM Friday with periods of showers continuing 
  through Friday afternoon. Rainfall rates of 0.50 inch to 0.60 inch 
  per hour are expected. There is a slight chance of thunderstorms 
  tonight and Friday. Rainfall is expected to range from around 1.5 
  inch near the coast to 2 inches near the lower coastal slopes of 
  the mountains, with 2 to 3 inches of rainfall on coastal slopes of 
  the mountains below 5500 feet.

* Heavy rainfall can lead to areas of flash flooding, as well as mud 
  and debris flows near burn scars, especially the Apple, El Dorado, 
  and Bond burn scars.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away or be swept away. Know your escape routes. Be ready to act 
immediately and heed all evacuation orders. Keep updated on the 
latest weather forecasts.

&&

$$

17
566 
WGUS66 KSGX 282057
FFASGX

Flood Watch
National Weather Service San Diego CA
1257 PM PST Thu Jan 28 2021

CAZ043-048-050-055>058-552-554-290615-
/O.CON.KSGX.FF.A.0002.210129T0300Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-San Diego County Mountains-Orange County Coastal Areas-
Orange County Inland Areas-
Including the cities of Vista, Ontario, Santee, Idyllwild-Pine Cove, 
Fontana, Garden Grove, Fullerton, Orange, Santa Ana, National City, 
Riverside, Poway, Big Bear Lake, Oceanside, Big Bear City, San 
Diego, Lake Arrowhead, Irvine, El Cajon, Newport Beach, Escondido, 
Chula Vista, Crestline, San Clemente, Wrightwood, Corona, Anaheim, 
Huntington Beach, San Bernardino, Moreno Valley, Mission Viejo, 
Laguna Beach, Julian, Pine Valley, Costa Mesa, La Mesa, Encinitas, 
Running Springs, San Marcos, Carlsbad, and Rancho Cucamonga
1257 PM PST Thu Jan 28 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 7 PM PST THIS EVENING 
THROUGH FRIDAY AFTERNOON...

The Flash Flood Watch continues for

* Coast, valleys, and mountains below 5500 feet in southwestern 
  California. Including the Apple, El Dorado, Bond, Blue Ridge, 
  Silverado, and Valley burn scars.

* From 7 PM PST this evening through Friday afternoon

* Showers with moderate to locally heavy rainfall will impact areas 
  west of the mountains below 5500 feet, including the Apple, El 
  Dorado, Bond, Silverado, Blueridge, and Valley burn scars. Showers 
  will develop this evening, becoming more widespread tonight into 
  Friday. The heaviest rain is expected to begin before midnight, 
  lasting through 6 AM Friday with periods of showers continuing 
  through Friday afternoon. Rainfall rates of 0.50 inch to 0.60 inch 
  per hour are expected. There is a slight chance of thunderstorms 
  tonight and Friday. Rainfall is expected to range from around 1.5 
  inches near the coast to 2 inches near the lower coastal slopes of 
  the mountains, with 2 to 3 inches of rainfall on coastal slopes of 
  the mountains below 5500 feet.

* Heavy rainfall can lead to areas of flash flooding, as well as mud 
  and debris flows near burn scars, especially the Apple, El Dorado, 
  and Bond burn scars.

PRECAUTIONARY/PREPAREDNESS ACTIONS...


Stay away or be swept away. Know your escape routes. Be ready to
act immediately and heed all evacuation orders. Keep updated on
the latest weather forecasts.

&&

$$

CO
128 
WGUS66 KSGX 290521
FFASGX

FLOOD WATCH
NATIONAL WEATHER SERVICE San Diego CA
921 PM PST Thu Jan 28 2021

CAZ043-048-050-055>058-552-554-291400-
/O.CON.KSGX.FF.A.0002.000000T0000Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-
San Diego County Mountains-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, Julian, 
Pine Valley, Huntington Beach, Costa Mesa, Newport Beach, 
Laguna Beach, San Clemente, Santa Ana, Anaheim, Garden Grove, 
Irvine, Orange, Fullerton, and Mission Viejo
921 PM PST Thu Jan 28 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY AFTERNOON...

The Flash Flood Watch continues for

* Coast, valleys, and mountains below 5500 feet in southwestern
  California. Including the Apple, El Dorado, Bond, Blue Ridge,
  Silverado, and Valley burn scars.

* Showers with moderate to locally heavy rainfall will continue to
  impact areas west of the mountains below 5500 feet, including
  the Apple, El Dorado, Bond, Silverado, Blue Ridge, and Valley 
  burn scars. The heaviest rain will slowly progress to the east 
  over the region tonight into Friday morning, with periods of 
  showers continuing through Friday afternoon and early evening. 
  Rainfall rates of 0.50 inch to 0.60 inch per hour are expected. 
  There is a slight chance of thunderstorms tonight and Friday. 
  Rainfall is expected to range from around 1.5 inches near the 
  coast to 2 inches near the lower coastal slopes of the 
  mountains, with 2 to 3 inches of rainfall on coastal slopes of 
  the mountains below 5500 feet. 

* Heavy rainfall can lead to areas of flash flooding, as well as 
  mud and debris flows near burn scars, especially the Apple, El 
  Dorado, and Bond burn scars. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND, DON'T DROWN. Know your escape routes, and be ready 
to act immediately and heed all evacuation orders. Keep updated on
the latest weather forecasts on our website and social media.

&&

$$

APR
021 
WGUS66 KSGX 291156
FFASGX

FLOOD WATCH
NATIONAL WEATHER SERVICE San Diego CA
356 AM PST Fri Jan 29 2021

CAZ043-048-050-055>058-552-554-292000-
/O.CON.KSGX.FF.A.0002.000000T0000Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-
San Diego County Mountains-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, Julian, 
Pine Valley, Huntington Beach, Costa Mesa, Newport Beach, 
Laguna Beach, San Clemente, Santa Ana, Anaheim, Garden Grove, 
Irvine, Orange, Fullerton, and Mission Viejo
356 AM PST Fri Jan 29 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS AFTERNOON...

The Flash Flood Watch continues for

* Orange County...the Inland Empire...San Diego County Coastal,
  Valley and Mountains...and Santa Ana Mountains and Foothills.

* through this afternoon

* Heavy rainfall can lead to areas of flash flooding. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Know your escape routes, and be ready to act immediately and heed
all evacuation orders. Keep updated on the latest weather 
forecasts on our website and social media.

&&

$$

Moede
451 
WGUS66 KSGX 292054
FFASGX

Flood Watch
National Weather Service San Diego CA
1254 PM PST Fri Jan 29 2021

CAZ043-048-050-055>058-552-554-300000-
/O.CON.KSGX.FF.A.0002.000000T0000Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-San Diego County Mountains-Orange County Coastal Areas-
Orange County Inland Areas-
Including the cities of Vista, Ontario, Santee, Idyllwild-Pine Cove, 
Fontana, Garden Grove, Fullerton, Orange, Santa Ana, National City, 
Riverside, Poway, Big Bear Lake, Oceanside, Big Bear City, San 
Diego, Lake Arrowhead, Irvine, El Cajon, Newport Beach, Escondido, 
Chula Vista, Crestline, San Clemente, Wrightwood, Corona, Anaheim, 
Huntington Beach, San Bernardino, Moreno Valley, Mission Viejo, 
Laguna Beach, Julian, Pine Valley, Costa Mesa, La Mesa, Encinitas, 
Running Springs, San Marcos, Carlsbad, and Rancho Cucamonga
1254 PM PST Fri Jan 29 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 4 PM PST THIS 
AFTERNOON...

The Flash Flood Watch continues for

* Coast, valleys, and mountains below 5500 feet in southwestern 
  California. Including the Apple, El Dorado, Bond, Blue Ridge, 
  Silverado, and Valley burn scars.

* Until 4 PM PST this afternoon

* Areas of moderate to locally heavy showers will continue through 
  the afternoon. Rain rates 0.20 inch to 0.30 inch are expected. 
  There is a chance of thunderstorms. Rain will end from the 
  northwest to southeast later this afternoon into tonight.

* Heavy rainfall can lead to areas of flash flooding, as well as mud 
  and debris flows near burn scars, especially the Apple, El Dorado, 
  and Bond burn scars.

PRECAUTIONARY/PREPAREDNESS ACTIONS...


Stay away or be swept away. Know your escape routes. Be ready to
act immediately and heed all evacuation orders. Keep updated on
the latest weather forecasts.

&&

$$

CO
510 
WGUS66 KSGX 300007
FFASGX

FLOOD WATCH
NATIONAL WEATHER SERVICE San Diego CA
407 PM PST Fri Jan 29 2021

CAZ043-048-050-055>058-552-554-300115-
/O.EXP.KSGX.FF.A.0002.000000T0000Z-210130T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
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-
San Diego County Mountains-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, Julian, 
Pine Valley, Huntington Beach, Costa Mesa, Newport Beach, 
Laguna Beach, San Clemente, Santa Ana, Anaheim, Garden Grove, 
Irvine, Orange, Fullerton, and Mission Viejo
407 PM PST Fri Jan 29 2021

...FLASH FLOOD WATCH HAS EXPIRED...

The Flash Flood Watch for A portion of southwest California has
expired. 

While a final band of heavy showers moves through San Diego 
County, the threat of flash flooding has diminished and will
continue to diminish through 5 pm. 

$$

The office that day

Everything else NWS San Diego, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 27, 12:58 PM PSTWinter Storm WarningSGXRiverside, San Bernardino50 hr

Nearby

Flash Flood Watches in California, 2021Every flash flood watch in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.