Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 3, NWS San Diego, CA

July 22, 2021San Diego County, California

NWS San Diego, CA issued this flash flood warning at Jul 22, 2021, 4:18 PM PDT for San Diego County, California. It was in force for 117 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 22, 2021, 4:18 PM PDT (23:18 UTC)
Expired: Jul 22, 2021, 6:15 PM PDT
In force: 117 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), 75 km from the middle of the area, began a volume at 23:22 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, 11.3 hours before the alert went out and 92 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1541 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -16 m²/s²
0-3 km storm-relative helicity: -8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

651 
WGUS56 KSGX 222318
FFWSGX
CAC073-230115-
/O.NEW.KSGX.FF.W.0003.210722T2318Z-210723T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
418 PM PDT Thu Jul 22 2021

The National Weather Service in San Diego has issued a

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

* Until 615 PM PDT.

* At 418 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. The expected rainfall rate is 
  0.5 to 1.25 inches in 1 hour. Flash flooding is ongoing or 
  expected to begin shortly.

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

  SOURCE...Radar.

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

* Some locations that will experience flash flooding include...
  Hwy 78 Between S2 And Borrego Springs Rd, Hwy 78 Between Borrego 
  Springs Rd And Ocotillo Wells, Borrego Springs, Hwy 78 Between 
  Banner And S2, eastern Mount Laguna, Hwy S2 Between Shelter Valley 
  And Agua Caliente, Fish Creek Wash, Hwy S2 Between Agua Caliente 
  And Canebrake, Ocotillo Wells, Hwy S22 Between Ranchita And 
  Borrego Springs, Hwy S2 Vallecito Creek Rd, Ranchita, Hwy S22 
  Between Borrego Springs And Imperial County Line, Hwy S2 Between 
  Canebrake And Imperial County Line, Borrego Palm Canyon, Hwy S2 
  Between Hwy 79 And Hwy 78, Agua Caliente, Shelter Valley, 
  Canebrake and Ocotillo Wells Vehicular Rec Area.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3274 11638 3331 11663 3333 11608 3307 11608
      3307 11610 3280 11610

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.5-1.25 INCHES IN 1 HOUR

$$

SS

2 follow-up statements

182 
WGUS76 KSGX 230004
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
504 PM PDT Thu Jul 22 2021

CAC073-230115-
/O.CON.KSGX.FF.W.0003.000000T0000Z-210723T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Diego CA-
504 PM PDT Thu Jul 22 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM PDT THIS 
EVENING FOR NORTHEASTERN SAN DIEGO COUNTY...

At 504 PM PDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. The expected rainfall rate is 0.5 to 1 
inch in 1 hour. Flash flooding is ongoing or expected to begin 
shortly.

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

SOURCE...Radar.

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

Some locations that will experience flash flooding include...
  Hwy 78 Between S2 And Borrego Springs Rd, Hwy 78 Between Borrego 
  Springs Rd And Ocotillo Wells, Borrego Springs, Hwy 78 Between 
  Banner And S2, eastern Mount Laguna, Hwy S2 Between Shelter Valley 
  And Agua Caliente, Fish Creek Wash, Hwy S2 Between Agua Caliente 
  And Canebrake, Ocotillo Wells, Hwy S22 Between Ranchita And 
  Borrego Springs, Hwy S2 Vallecito Creek Rd, Ranchita, Hwy S22 
  Between Borrego Springs And Imperial County Line, Hwy S2 Between 
  Canebrake And Imperial County Line, Borrego Palm Canyon, Hwy S2 
  Between Hwy 79 And Hwy 78, Agua Caliente, Shelter Valley, 
  Canebrake and Ocotillo Wells Vehicular Rec Area.

Heaviest rainfall is occurring along Highway 78 near Ocotillo Wells. 
While storms over most of the warned area have weakened, flooding 
will still pose a threat as runoff continues.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3274 11638 3331 11663 3333 11608 3307 11608
      3307 11610 3280 11610

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.5-1 INCH IN 1 HOUR

$$

SS

550 
WGUS76 KSGX 230107
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
607 PM PDT Thu Jul 22 2021

CAC073-230117-
/O.EXP.KSGX.FF.W.0003.000000T0000Z-210723T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Diego CA-
607 PM PDT Thu Jul 22 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 615 PM PDT THIS EVENING FOR 
NORTHEASTERN SAN DIEGO COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3274 11638 3331 11663 3333 11608 3307 11608
      3307 11610 3280 11610

$$

SS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 3:45 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	2 hr
Jul 22, 4:22 PM PDT	Severe Thunderstorm Warning	SGX	San Diego	53 min
Jul 22, 4:23 PM PDT	Flash Flood Warning Considerable damage threat	SGX	Riverside	2 hr

Nearby

Flash Flood Warnings in California, 2021 Every 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.