Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 23, NWS San Diego, CA

August 17, 2012Riverside County, San Diego County, California

NWS San Diego, CA issued this flash flood warning at Aug 17, 2012, 12:28 PM PDT for Riverside County, San Diego County, California. It was in force for 2 hr. 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 17, 2012, 12:28 PM PDT (19:28 UTC)
Expired
Aug 17, 2012, 2:30 PM PDT
In force
2 hr
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

Counties Riverside County, CA, San Diego County, CA

The radar

The San Diego radar (KNKX), 61 km from the middle of the area, began a volume at 19:28 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, 7.5 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 2012-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 139 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 2012-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 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
139 J/kg
Mixed-layer CIN
-312 J/kg
Mixed-layer LCL
1655 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
29 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.

238 
WGUS56 KSGX 171928
FFWSGX
CAC065-073-172130-
/O.NEW.KSGX.FF.W.0023.120817T1928Z-120817T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
1228 PM PDT FRI AUG 17 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN RIVERSIDE COUNTY IN SOUTHERN CALIFORNIA...
  NORTH CENTRAL SAN DIEGO COUNTY IN SOUTHWEST CALIFORNIA...

* UNTIL 230 PM PDT.

* AT 1218 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
  THUNDERSTORMS PRODUCING HEAVY RAIN AND POSSIBLE FLASH FLOODING
  OVER SAGE...SOUTH 79 FREEWAY...OAK GROVE...AND PALOMAR MOUNTAIN.

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.

&&

LAT...LON 3334 11688 3340 11704 3364 11702 3363 11687
      3336 11671

$$

HARRISON
2 follow-up statements
210 
WGUS76 KSGX 172025
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
125 PM PDT FRI AUG 17 2012

CAC065-073-172130-
/O.CON.KSGX.FF.W.0023.000000T0000Z-120817T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-RIVERSIDE CA-
125 PM PDT FRI AUG 17 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 PM PDT FOR
SOUTHWESTERN RIVERSIDE AND NORTH CENTRAL SAN DIEGO COUNTIES...

AT 117 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE HEAVY RAIN PRODUCING FLASH FLOODING OVER THE WARNED AREA.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
AGUANGA...PALOMAR MOUNTAIN AND OAK GROVE.

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.

&&

LAT...LON 3334 11688 3340 11704 3364 11702 3363 11687
      3336 11671

$$

MM
786 
WGUS76 KSGX 172124
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
224 PM PDT FRI AUG 17 2012

CAC065-073-172132-
/O.EXP.KSGX.FF.W.0023.000000T0000Z-120817T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-RIVERSIDE CA-
224 PM PDT FRI AUG 17 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 230 PM PDT FOR SOUTHWESTERN
RIVERSIDE AND NORTH CENTRAL SAN DIEGO COUNTIES...

THE STORM OVER THE AREA HAS DECREASED IN COVERAGE AND INTENSITY... 
THEREFORE THE FLASH FLOOD WARNING WILL BE ALLOWED TO EXPIRE AT 230 
PM. 

LAT...LON 3334 11688 3340 11704 3364 11702 3363 11687
      3336 11671

$$

SMALL

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 16, 7:07 PM PDTFlash Flood WatchSGXRiverside, San Bernardino, San Diego25 hr
Aug 17, 12:14 PM PDTFlash Flood WarningSGXRiverside61 min
Aug 17, 12:55 PM PDTSevere Thunderstorm WarningSGXRiverside50 min
Aug 17, 1:07 PM PDTFlash Flood WarningSGXRiverside, San Bernardino3 hr
Aug 17, 1:39 PM PDTSevere Thunderstorm WarningSGXSan Diego51 min
Aug 17, 1:40 PM PDTFlash Flood WarningSGXSan Diego95 min
Aug 17, 2:19 PM PDTFlash Flood WarningSGXRiverside46 min
Aug 17, 3:19 PM PDTAreal Flood AdvisorySGXSan Bernardino86 min
Aug 17, 4:47 PM PDTAreal Flood AdvisorySGXSan Bernardino75 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.