Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 5, NWS San Diego, CA

July 25, 2021San Diego County, California

NWS San Diego, CA issued this flash flood warning at Jul 25, 2021, 3:23 PM PDT for San Diego County, California. It was in force for 112 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 25, 2021, 3:23 PM PDT (22:23 UTC)
Expired
Jul 25, 2021, 5:15 PM PDT
In force
112 min
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County San Diego County, CA

The radar

The San Diego radar (KNKX), 39 km from the middle of the area, began a volume at 22:27 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, 10.4 hours before the alert went out and 57 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 2021-07-25Temperature 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 2021-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 square meters per square second.1939Sfc1 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
1039 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

035 
WGUS56 KSGX 252223
FFWSGX
CAC073-260015-
/O.NEW.KSGX.FF.W.0005.210725T2223Z-210726T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
323 PM PDT Sun Jul 25 2021

The National Weather Service in San Diego has issued a

* Flash Flood Warning for...
  Central San Diego County in southwestern California...

* Until 515 PM PDT.

* At 323 PM PDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.5 and 1 inch of rain has fallen. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar and automated gauges.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Cuyamaca Rancho State Park, Lake Cuyamaca, Hwy 79 Between Julian 
  And Lake Cuyamaca, Descanso, Hwy S1 Between Lake Cuyamaca And 
  Mount Laguna, Boulder Creek and Captain Grande Indian Reservation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

Remain alert for flooding even in locations not receiving rain. 
Arroyos, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3304 11658 3297 11652 3292 11669 3299 11674
      3301 11670

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CO
3 follow-up statements
283 
WGUS76 KSGX 252255
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
355 PM PDT Sun Jul 25 2021

CAC073-260015-
/O.CON.KSGX.FF.W.0005.000000T0000Z-210726T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Diego CA-
355 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM PDT THIS 
AFTERNOON FOR CENTRAL SAN DIEGO COUNTY...

At 355 PM PDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 1 
and 2 inches of rain have fallen. Additional rainfall amounts of 
0.25 to 0.5 inches are possible in the warned area. Flash flooding 
is ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Cuyamaca Rancho State Park, Lake Cuyamaca, Hwy 79 Between Julian 
  And Lake Cuyamaca, Descanso, Hwy S1 Between Lake Cuyamaca And 
  Mount Laguna, Boulder Creek and Captain Grande Indian Reservation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

Remain alert for flooding even in locations not receiving rain. 
Arroyos, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3304 11658 3297 11652 3292 11669 3299 11674
      3301 11670

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CO
255 
WGUS76 KSGX 252323
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
423 PM PDT Sun Jul 25 2021

CAC073-260015-
/O.CON.KSGX.FF.W.0005.000000T0000Z-210726T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Diego CA-
423 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM PDT THIS 
AFTERNOON FOR CENTRAL SAN DIEGO COUNTY...

At 423 PM PDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 1 
to 3 inches of rain have fallen. Additional rainfall amounts of 0.25 
to 0.5 inches are likely in the warned area. Flash flooding is 
ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Cuyamaca Rancho State Park, Lake Cuyamaca, Hwy 79 Between Julian 
  And Lake Cuyamaca, Descanso, Hwy S1 Between Lake Cuyamaca And 
  Mount Laguna, Boulder Creek and Captain Grande Indian Reservation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

Remain alert for flooding even in locations not receiving rain. 
Arroyos, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3304 11658 3297 11652 3292 11669 3299 11674
      3301 11670

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Brotherton
835 
WGUS76 KSGX 260014
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
514 PM PDT Sun Jul 25 2021

CAC073-260024-
/O.EXP.KSGX.FF.W.0005.000000T0000Z-210726T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Diego CA-
514 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 515 PM PDT THIS AFTERNOON FOR 
CENTRAL SAN DIEGO COUNTY...

The heavy rain has ended. Additional heavy rain could move into the 
area in the next hour so remain alert to evolving weather conditions.

LAT...LON 3304 11658 3297 11652 3292 11669 3299 11674
      3301 11670

$$

Brotherton

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 3:08 PM PDTAreal Flood AdvisorySGXSan Diego15 min
Jul 25, 4:14 PM PDTSevere Thunderstorm WarningSGXRiverside36 min
Jul 25, 4:32 PM PDTAreal Flood AdvisorySGXSan Diego77 min

Nearby

Flash Flood Warnings in California, 2021Every flash flood warning 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.