Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 26, NWS San Diego, CA

August 17, 2012Riverside County, California

NWS San Diego, CA issued this flash flood warning at Aug 17, 2012, 2:19 PM PDT for Riverside County, California. It was in force for 46 min. 1 report 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 17, 2012, 2:19 PM PDT (21:19 UTC)
Expired
Aug 17, 2012, 3:05 PM PDT
In force
46 min
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

County Riverside County, CA

The radar

The Santa Ana Mts radar (KSOX), 31 km from the middle of the area, began a volume at 21:21 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 17, 2:45 PM PDTFLOOD4 W Perris, CACHP REPORTS FLOODED ROAD ON ELLIS AV.

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, 9.3 hours before the alert went out and 112 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.

977 
WGUS56 KSGX 172119
FFWSGX
CAC065-172315-
/O.NEW.KSGX.FF.W.0026.120817T2119Z-120817T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WEST CENTRAL RIVERSIDE COUNTY IN SOUTHERN CALIFORNIA...

* UNTIL 415 PM PDT

* AT 212 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   
WOODCREST...PERRIS...MARCH FIELD...AND SUN CITY

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

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.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

&&

LAT...LON 3381 11740 3390 11739 3390 11720 3372 11710
      3366 11729

$$

MM
1 follow-up statement
831 
WGUS76 KSGX 172205
FFSSGX

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

CAC065-172214-
/O.CAN.KSGX.FF.W.0026.000000T0000Z-120817T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-
305 PM PDT FRI AUG 17 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR WEST CENTRAL
RIVERSIDE COUNTY...

THE HEAVY THUNDERSTORM OVER THE AREA HAS WEAKENED AND NO ADDITIONAL 
FLASH FLOODING IS EXPECTED.

LAT...LON 3381 11740 3390 11739 3390 11720 3372 11710
      3366 11729

$$
MM

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, 12:28 PM PDTFlash Flood WarningSGXRiverside, San Diego2 hr
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, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.