Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 42, NWS San Diego, CA

September 10, 2012San Diego County, California

NWS San Diego, CA issued this flash flood warning at Sep 10, 2012, 2:42 PM PDT for San Diego County, California. It was in force for 93 min. 3 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
Sep 10, 2012, 2:42 PM PDT (21:42 UTC)
Expired
Sep 10, 2012, 4:15 PM PDT
In force
93 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), 40 km from the middle of the area, began a volume at 21:45 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
Sep 10, 3:00 PM PDTHEAVY RAIN 1.465 Ssw Palomar Mountain, CAEASTERN TANKS AT LA JOLLA AMAGO...BETWEEN 1411-1500 PDT...REPORTED 1.46 INCHES OF RAIN.
Sep 10, 3:05 PM PDTHEAVY RAIN 1.546 Ssw Palomar Mountain, CALA JOLLA INDIAN RESERVATION...BETWEEN 1417-1505 PDT... MEASURED 1.54 INCHES OF RAIN.
Sep 10, 3:09 PM PDTHEAVY RAIN 0.996 Wnw Lake Henshaw, CAVALLECITOS REPEATER...BETWEEN 1422-1509 PDT...MEASURED 0.99 INCHES OF RAIN.

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, 9.7 hours before the alert went out and 58 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 2012-09-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 642 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 2012-09-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -37 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
642 J/kg
Mixed-layer CIN
-197 J/kg
Mixed-layer LCL
930 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
-37 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.

452 
WGUS56 KSGX 102142
FFWSGX
CAC073-102315-
/O.NEW.KSGX.FF.W.0042.120910T2142Z-120910T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
242 PM PDT MON SEP 10 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

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

* UNTIL 415 PM PDT

* AT 236 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  FLASH FLOODING FROM A STORM OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PAUMA
  VALLEY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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.

&&

LAT...LON 3336 11703 3336 11666 3309 11667 3309 11703

$$

SMALL
2 follow-up statements
201 
WGUS76 KSGX 102219
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
319 PM PDT MON SEP 10 2012

CAC073-102315-
/O.CON.KSGX.FF.W.0042.000000T0000Z-120910T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-
319 PM PDT MON SEP 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM PDT FOR
CENTRAL SAN DIEGO COUNTY...

AT 306 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 PAUMA VALLEY
AND LAKE HENSHAW.

TWO RAIN GAGES IN THE WARNING AREA HAVE REPORTED AROUND 1.50 INCHES 
IN THE PAST HOUR. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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.

&&

LAT...LON 3336 11703 3336 11666 3309 11667 3309 11703

$$

SMALL
511 
WGUS76 KSGX 102311
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
411 PM PDT MON SEP 10 2012

CAC073-102318-
/O.EXP.KSGX.FF.W.0042.000000T0000Z-120910T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN DIEGO CA-
411 PM PDT MON SEP 10 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 415 PM PDT FOR CENTRAL SAN
DIEGO COUNTY...

THE THUNDERSTORM HAS WEAKENED...SO THE FLASH FLOOD WARNING WILL BE 
ALLOWED TO EXPIRE. 

LAT...LON 3336 11703 3336 11666 3309 11667 3309 11703

$$

SMALL

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 9, 5:23 PM PDTSevere Thunderstorm WarningSGXSan Diego45 min
Sep 9, 5:30 PM PDTFlash Flood WarningSGXSan Diego104 min
Sep 9, 7:01 PM PDTFlash Flood WatchSGXRiverside, San Bernardino, San Diego23 hr
Sep 9, 7:26 PM PDTBlowing Dust AdvisorySGXRiverside, San Diego3 hr
Sep 10, 12:21 PM PDTAreal Flood AdvisorySGXRiverside, San Bernardino119 min
Sep 10, 1:17 PM PDTSevere Thunderstorm WarningSGXRiverside49 min
Sep 10, 1:29 PM PDTFlash Flood WarningSGXSan Bernardino3 hr
Sep 10, 2:00 PM PDTAreal Flood AdvisorySGXSan Bernardino3 hr
Sep 10, 2:33 PM PDTSevere Thunderstorm WarningSGXOrange, Riverside50 min
Sep 10, 2:59 PM PDTFlash Flood WarningSGXSan Bernardino2 hr
Sep 10, 3:07 PM PDTSpecial Weather StatementSGXOrange53 min
Sep 10, 4:34 PM PDTAreal Flood AdvisorySGXSan Bernardino116 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.