Alert archive / California / Flash Flood Warnings in 2011

Flash Flood Warning 20, NWS San Diego, CA

August 27, 2011San Bernardino County, California

NWS San Diego, CA issued this flash flood warning at Aug 27, 2011, 2:24 PM PDT for San Bernardino 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 27, 2011, 2:24 PM PDT (21:24 UTC)
Expired
Aug 27, 2011, 4:30 PM PDT
In force
2 hr
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 9.4 hours before the alert went out and 198 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 2011-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 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 2011-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 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
46 J/kg
Mixed-layer CIN
-838 J/kg
Mixed-layer LCL
2203 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

713 
WGUS56 KSGX 272124
FFWSGX
CAC071-272330-
/O.NEW.KSGX.FF.W.0020.110827T2124Z-110827T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
224 PM PDT SAT AUG 27 2011

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WEST CENTRAL SAN BERNARDINO COUNTY IN SOUTHERN CALIFORNIA...
  THIS INCLUDES THE CITIES OF...VICTORVILLE...HESPERIA...APPLE
  VALLEY...

* UNTIL 430 PM PDT

* AT 218 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
SEVERAL STRONG THUNDERSTORMS PRODUCING HEAVY RAIN. THESE STORMS WERE 
DEVELOPING IN ALL AREAS OF THE UPPER DESERTS.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO GEORGE AFB
  AND ADELANTO

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.

&&

LAT...LON 3473 11646 3470 11646 3467 11651 3461 11651
      3460 11647 3456 11646 3433 11645 3431 11648
      3422 11645 3444 11712 3439 11730 3449 11764
      3482 11763

$$

WHITLOW
2 follow-up statements
155 
WGUS76 KSGX 272224
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
324 PM PDT SAT AUG 27 2011

CAC071-272330-
/O.CON.KSGX.FF.W.0020.000000T0000Z-110827T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
324 PM PDT SAT AUG 27 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM PDT FOR WEST
CENTRAL SAN BERNARDINO COUNTY...

AT 312 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE HEAVY RAIN PRODUCING FLASH FLOODING OVER THE WARNED AREA. 
MOST OF THE THUNDERSTORMS HAVE MOVED NORTH EXCEPT A FEW STRONG 
STORMS CONTINUE IN THE WEST AND EAST PARTS WITH HEAVY RAIN. DUE TO 
STRONG THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP AND RUNOFF 
FROM THE PREVIOUS THUNDERSTORMS MAY AFFECT ROADS THAT CROSS WASHES 
AND GULLIES FOR ANOTHER HOUR...THE FLASH FLOOD WARNING CONTINUES.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO GEORGE AFB...
APPLE VALLEY AND ADELANTO

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.

&&

LAT...LON 3473 11646 3470 11646 3467 11651 3461 11651
      3460 11647 3456 11646 3433 11645 3431 11648
      3422 11645 3444 11712 3439 11730 3449 11764
      3482 11763

$$

WHITLOW
437 
WGUS76 KSGX 272325
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
425 PM PDT SAT AUG 27 2011

CAC071-272333-
/O.EXP.KSGX.FF.W.0020.000000T0000Z-110827T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
425 PM PDT SAT AUG 27 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 430 PM PDT FOR WEST CENTRAL
SAN BERNARDINO COUNTY...

THUNDERSTORMS HAVE DISSIPATED. A FEW THUNDERSTORMS WERE STILL 
DEVELOPING IN THE WEST PART. ANY MORE THUNDERSTORMS MAY HAVE BRIEF 
HEAVY RAIN...BUT FLASH FLOODING IS NO LONGER EXPECTED.

LAT...LON 3473 11646 3470 11646 3467 11651 3461 11651
      3460 11647 3456 11646 3433 11645 3431 11648
      3422 11645 3444 11712 3439 11730 3449 11764
      3482 11763

$$

SGX

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 12:30 PM PDTSpecial Weather StatementSGX60 min
Aug 27, 12:49 PM PDTFlash Flood WarningSGXSan Bernardino86 min
Aug 27, 1:37 PM PDTSevere Thunderstorm WarningSGXSan Diego30 min
Aug 27, 2:28 PM PDTFlash Flood WarningSGXRiverside, San Diego92 min

Nearby

Flash Flood Warnings in California, 2011Every flash flood warning in 2011

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.