Alert archive / California / Flash Flood Warnings in 2020

Flash Flood Warning 13, NWS San Diego, CA

August 22, 2020San Diego County, California

NWS San Diego, CA issued this flash flood warning at Aug 22, 2020, 2:34 PM PDT for San Diego County, California. It was in force for 76 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
Aug 22, 2020, 2:34 PM PDT (21:34 UTC)
Expired
Aug 22, 2020, 3:50 PM PDT
In force
76 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), 65 km from the middle of the area, began a volume at 21:38 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, 9.6 hours before the alert went out and 78 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 2020-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 29 joules per kilogram.LCLLFCEL10008507005003002001001 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 2020-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 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
29 J/kg
Mixed-layer CIN
-704 J/kg
Mixed-layer LCL
1990 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
81 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

086 
WGUS56 KSGX 222134
FFWSGX
CAC073-230030-
/O.NEW.KSGX.FF.W.0013.200822T2134Z-200823T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
234 PM PDT Sat Aug 22 2020

The National Weather Service in San Diego has issued a

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

* Until 530 PM PDT.

* At 232 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Storms were becoming nearly 
  stationary in the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Life threatening flash flooding. Heavy rain producing 
           flash flooding.

  SOURCE...Radar indicated.

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

* Some locations that will experience flooding include...
  Mount Laguna, I-8 Between Pine Valley And Boulevard, I-8 Between
  Boulevard And Imperial County Line, Cuyamaca Rancho State Park,
  Pine Valley, Hwy S2 Between Canebrake And Imperial County Line,
  Boulevard, Lake Morena, Potrero and Campo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 3290 11623 3263 11623 3263 11657 3291 11657

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

$$

JMB
2 follow-up statements
767 
WGUS76 KSGX 222157
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
257 PM PDT Sat Aug 22 2020

CAC073-230030-
/O.CON.KSGX.FF.W.0013.000000T0000Z-200823T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Diego CA-
257 PM PDT Sat Aug 22 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM PDT FOR
SOUTHEASTERN SAN DIEGO COUNTY...

At 256 PM PDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area.  Flash flooding is ongoing or expected 
to begin shortly. Storms are nearly stationary or moving slowly to 
the north.

HAZARD...Life threatening flash flooding. Heavy rain producing flash 
         flooding.

SOURCE...Radar indicated.

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

Some locations that will experience flooding include...
Mount Laguna, I-8 Between Pine Valley And Boulevard, I-8 Between
Boulevard And Imperial County Line, Cuyamaca Rancho State Park, Pine
Valley, Hwy S2 Between Canebrake And Imperial County Line, Boulevard,
Lake Morena, Potrero and Campo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

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 3290 11623 3263 11623 3263 11657 3291 11657

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

$$

JMB
433 
WGUS76 KSGX 222250
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
350 PM PDT Sat Aug 22 2020

CAC073-222259-
/O.CAN.KSGX.FF.W.0013.000000T0000Z-200823T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Diego CA-
350 PM PDT Sat Aug 22 2020

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SAN DIEGO COUNTY IS
CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed any remaining road closures. 
Flooding was reported on Sunrise Highway just north of Interstate 8. 

LAT...LON 3290 11623 3263 11623 3263 11657 3291 11657

$$

JMB

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 22, 1:55 PM PDTSpecial Weather StatementSGX50 min
Aug 22, 2:21 PM PDTSevere Thunderstorm WarningSGXSan Diego54 min
Aug 22, 3:11 PM PDTSpecial Weather StatementSGX64 min
Aug 22, 4:13 PM PDTSevere Thunderstorm WarningSGXSan Bernardino47 min
Aug 22, 4:55 PM PDTAreal Flood AdvisorySGXSan Bernardino2 hr

Nearby

Flash Flood Warnings in California, 2020Every flash flood warning in 2020

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.