Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 28, NWS San Diego, CA

August 21, 2012San Diego County, California

NWS San Diego, CA issued this flash flood warning at Aug 21, 2012, 2:08 PM PDT for San Diego County, California. It was in force for 112 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 21, 2012, 2:08 PM PDT (21:08 UTC)
Expired
Aug 21, 2012, 4:00 PM PDT
In force
112 min
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

County San Diego County, CA

The radar

The San Diego radar (KNKX), 64 km from the middle of the area, began a volume at 21:10 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.

What was reported inside it

TimeReportWhereRemark
Aug 21, 2:15 PM PDTFLASH FLOOD4 Se Ranchita, CAAT 215 PM PDT BORREGO COUNTY ROAD MAINTENENCE CREW REPORTED WATER AND DEBREE FLOWING ACROSS SAN FELIPE ROAD JUST NORTH OF HIGHWAY 78 BETWEEN MILE MARKER 12 AND 14.
Aug 21, 2:50 PM PDTFLOOD9 Ese Ranchita, CA2 TO 3 INCHES OF WATER FLOWING ALONG PART OF ROUTE 78 AND S3.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 9.1 hours before the alert went out and 83 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 2012-08-21Temperature 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 2012-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 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
899 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
20 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

865 
WGUS56 KSGX 212108
FFWSGX
CAC073-212300-
/O.NEW.KSGX.FF.W.0028.120821T2108Z-120821T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
208 PM PDT TUE AUG 21 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL SAN DIEGO COUNTY IN SOUTHWEST CALIFORNIA...

* UNTIL 400 PM PDT.

* AT 200 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THUNDERSTORMS PRODUCING HEAVY RAIN WHICH WILL LIKELY PRODUCE 
  FLASH FLOODING FROM A STORM OVER SHELTER VALLEY...HIGHWAY 78 
  AND THE SAN FELIPE CREEK BASIN. THE STORMS WERE NEARLY STATIONARY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

&&

LAT...LON 3324 11651 3323 11631 3314 11629 3301 11632
      3302 11655

$$

HARRISON
2 follow-up statements
440 
WGUS76 KSGX 212202
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
302 PM PDT TUE AUG 21 2012

CAC073-212300-
/O.CON.KSGX.FF.W.0028.000000T0000Z-120821T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-
302 PM PDT TUE AUG 21 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR EAST
CENTRAL SAN DIEGO COUNTY...

SAN DIEGO COUNTY OFFICIALS REPORTED WATER AND DEBRIS FLOWING ACROSS  
THE ROAD ON SAN FELIPE ROAD JUST NORTH OF HIGHWAY 78. ALTHOUGH 
NATIONAL  WEATHER SERVICE DOPPLER RADAR INDICATED THAT  THE 
THUNDERSTORMS AND SHOWERS HAVE WEAKENED IN AND AROUND THE SHELTER  
VALLEY AREA...RUN-OFF IS LIKELY TO CONTINUE OVER THE NEXT  
HOUR...AND SO THE FLASH FLOOD WARNING CONTINUES.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...
DIPS...OR LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...
EVEN A SMALL ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER
GROUND.

&&

LAT...LON 3324 11651 3323 11631 3314 11629 3301 11632
      3302 11655

$$

HARRISON
913 
WGUS76 KSGX 212255
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
355 PM PDT TUE AUG 21 2012

CAC073-212302-
/O.EXP.KSGX.FF.W.0028.000000T0000Z-120821T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-
355 PM PDT TUE AUG 21 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 400 PM PDT FOR EAST CENTRAL
SAN DIEGO COUNTY...

HEAVY RAINFALL FROM SHOWERS AND THUNDERSTORMS OVER AND AROUND THE 
SHELTER  VALLEY AREA HAS DISSIPATED...SO THE FLASH FLOOD WARNING 
WILL BE  ALLOWED TO EXPIRE AT 4 PM. SOME RUN-OFF MAY CONTINUE THROUGH 
THE SAN FELIPE CREEK BASIN OVER THE NEXT COUPLE HOURS. 

LAT...LON 3324 11651 3323 11631 3314 11629 3301 11632
      3302 11655

$$

HARRISON

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 7:39 AM PDTFlood WatchSGXRiverside, San Bernardino, San Diego88 min
Aug 21, 9:07 AM PDTFlash Flood WatchSGXRiverside, San Bernardino, San Diego11 hr
Aug 21, 1:50 PM PDTSevere Thunderstorm WarningSGXSan Diego40 min
Aug 21, 2:47 PM PDTSevere Thunderstorm WarningSGXSan Diego28 min
Aug 21, 3:10 PM PDTAreal Flood AdvisorySGXRiverside, San Diego2 hr
Aug 21, 3:12 PM PDTAreal Flood AdvisorySGXSan Diego2 hr
Aug 21, 3:15 PM PDTSevere Thunderstorm WarningSGXSan Diego35 min

Nearby

Flash Flood Warnings in California, 2012Every flash flood warning in 2012

Sources

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