Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 37, NWS Phoenix, AZ

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

NWS Phoenix, AZ issued this flash flood warning at Aug 17, 2012, 2:32 PM PDT for Riverside County, San Bernardino County, California. It was in force for 118 min. 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, 2:32 PM PDT (21:32 UTC)
Expired
Aug 17, 2012, 4:30 PM PDT
In force
118 min
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Flood severity
None

Counties Riverside County, CA, San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 137 km from the middle of the area, began a volume at 21:34 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, 9.5 hours before the alert went out and 170 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.

759 
WGUS55 KPSR 172132
FFWPSR
CAC065-071-172330-
/O.NEW.KPSR.FF.W.0037.120817T2132Z-120817T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
232 PM PDT FRI AUG 17 2012

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTH CENTRAL RIVERSIDE COUNTY IN SOUTHERN CALIFORNIA...
  SOUTH CENTRAL SAN BERNARDINO COUNTY IN SOUTHERN CALIFORNIA...

* UNTIL 430 PM PDT

* AT 221 PM PDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
  VERY HEAVY RAIN THAT WILL CAUSE FLASH FLOODING.

* THE STORM PRODUCING VERY HEAVY RAIN THAT WILL CAUSE FLASH          
  FLOODING IN INDIAN COVE AND BLACK ROCK CANYON IN JOSHUA TREE       
  NATIONAL PARK. FLASH FLOODING WILL OTHERWISE REMAIN OVER MAINLY    
  RURAL AREAS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT PEOPLE ALONG THE BANKS OF WASHES AND
CREEKS SHOULD MOVE TO HIGHER GROUND IMMEDIATELY. NORMALLY DRY WASHES
AND STREAMS WILL SUDDENLY HAVE RUNNING WATER AND MAKE UNBRIDGED
CROSSINGS IMPASSABLE. STREETS...UNDERPASSES...AND LOW SPOTS WILL
BECOME INUNDATED MAKING DRIVING HAZARDOUS IN THE WARNED AREA.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF NORMALLY
DRY WASHES AND CREEKS...ROADS...AND LOW LYING SPOTS. UNBRIDGED
CROSSINGS WILL BE ESPECIALLY DANGEROUS.

&&

LAT...LON 3408 11628 3408 11626 3412 11626 3412 11606
      3411 11605 3411 11604 3397 11608 3399 11629

$$

MCLANE
2 follow-up statements
002 
WGUS75 KPSR 172303
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
403 PM PDT FRI AUG 17 2012

CAC065-071-172330-
/O.CON.KPSR.FF.W.0037.000000T0000Z-120817T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-SAN BERNARDINO CA-
403 PM PDT FRI AUG 17 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO AND NORTH CENTRAL RIVERSIDE COUNTIES...

AT 356 PM PDT...THUNDERSTORMS WERE CONTINUING TO MOVE THROUGH 
PORTIONS OF JOSHUA TREE NATIONAL PARK PRODUCING HEAVY RAINFALL. 
FLASH FLOODING REMAINS LIKELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT PEOPLE ALONG THE BANKS OF WASHES AND
CREEKS SHOULD MOVE TO HIGHER GROUND IMMEDIATELY. NORMALLY DRY WASHES
AND STREAMS WILL SUDDENLY HAVE RUNNING WATER AND MAKE UNBRIDGED
CROSSINGS IMPASSABLE. STREETS...UNDERPASSES...AND LOW SPOTS WILL
BECOME INUNDATED MAKING DRIVING HAZARDOUS IN THE WARNED AREA.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF NORMALLY
DRY WASHES AND CREEKS...ROADS...AND LOW LYING SPOTS. UNBRIDGED
CROSSINGS WILL BE ESPECIALLY DANGEROUS.

&&

LAT...LON 3408 11628 3408 11626 3412 11626 3412 11606
      3411 11605 3411 11604 3397 11608 3399 11629

$$

MCLANE
823 
WGUS75 KPSR 172330
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
430 PM PDT FRI AUG 17 2012

CAC065-071-172337-
/O.EXP.KPSR.FF.W.0037.000000T0000Z-120817T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-SAN BERNARDINO CA-
430 PM PDT FRI AUG 17 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 430 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO AND NORTH CENTRAL RIVERSIDE COUNTIES...

HEAVY RAIN HAS ENDED ACROSS THE REGION. THE FLASH FLOOD WARNING HAS 
THEREFORE BEEN ALLOWED TO EXPIRE FOR SOUTH CENTRAL SAN BERNARDINO 
AND NORTH CENTRAL RIVERSIDE COUNTIES.

INDIVIDUALS IN THE AREA SHOULD CONTINUE TO REMAIN ALERT...AS HIGH 
WATER WILL CONTINUE TO FLOW IN MANY DRAINAGE BASINS FOR THE NEXT FEW 
HOURS.

LAT...LON 3408 11628 3408 11626 3412 11626 3412 11606
      3411 11605 3411 11604 3397 11608 3399 11629

$$

MCLANE

The office that day

Everything else NWS Phoenix, AZ issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 16, 11:29 PM PDTAreal Flood AdvisoryPSRRiverside2 hr
Aug 17, 12:54 AM PDTAreal Flood AdvisoryPSRImperial111 min
Aug 17, 11:59 AM PDTBlowing Dust AdvisoryPSR2 hr
Aug 17, 2:25 PM PDTSpecial Weather StatementPSRRiverside50 min
Aug 17, 2:57 PM PDTAreal Flood AdvisoryPSRRiverside2 hr
Aug 17, 3:28 PM PDTSpecial Weather StatementPSRRiverside47 min
Aug 17, 3:44 PM PDTSpecial Weather StatementPSRRiverside31 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.