Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 27, NWS Phoenix, AZ

July 31, 2012Imperial County, California

NWS Phoenix, AZ issued this flash flood warning at Jul 31, 2012, 4:58 AM PDT for Imperial County, California. It was in force for 3 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
Jul 31, 2012, 4:58 AM PDT (11:58 UTC)
Expired
Jul 31, 2012, 8:00 AM PDT
In force
3 hr
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Flood severity
None

County Imperial County, CA

The radar

The Yuma radar (KYUX), 114 km from the middle of the area, began a volume at 11:58 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 00:00Z, 12.0 hours before the alert went out and 155 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 00:00Z on 2012-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2012-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1963 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
57 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.

861 
WGUS55 KPSR 311158
FFWPSR
CAC025-311500-
/O.NEW.KPSR.FF.W.0027.120731T1158Z-120731T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
458 AM PDT TUE JUL 31 2012

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL IMPERIAL COUNTY IN SOUTHEAST CALIFORNIA...
  THIS INCLUDES BRAWLEY...

* UNTIL 800 AM PDT

* AT 454 AM PDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED   
  VERY HEAVY RAIN THAT WILL CAUSE FLASH FLOODING. A STATIONARY BAND  
  OF HEAVY RAIN WITH HOURLY RAINFALL RATES OF 1 TO 2 INCHES PER HOUR 
  IS AFFECTING THE AREA. RADAR ESTIMATES OF 1 TO 1.5 INCHES OF RAIN  
  HAS ALREADY FALLEN IN PARTS OF THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO CALIPATRIA 
  AND WESTMORLAND.

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...STREETS AND UNDERPASSES...AND DETENTION
BASINS AFFECTING SOME COMMUNITY PARKS. UNBRIDGED CROSSINGS WILL BE
ESPECIALLY DANGEROUS.

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 3329 11563 3310 11539 3294 11552 3313 11579

$$

KUHLMAN
1 follow-up statement
757 
WGUS75 KPSR 311327
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
627 AM PDT TUE JUL 31 2012

CAC025-311500-
/O.CON.KPSR.FF.W.0027.000000T0000Z-120731T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
IMPERIAL CA-
627 AM PDT TUE JUL 31 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 800 AM PDT FOR
CENTRAL IMPERIAL COUNTY...

AT 624 AM PDT...NATIONAL WEATHER SERVICE RADAR ESTIMATES OF 2 TO 3 
INCHES OF RAIN HAS FALLEN SINCE 4 AM...POTENTIALLY CAUSING FLASH 
FLOODING. THE RAINFALL HAS DIMINISHED CONSIDERABLY...BUT LIGHT RAIN 
CONTINUES TO FALL IN THE WARNED AREA. ADDITIONAL RAINFALL AMOUNTS OF 
A QUARTER TO ONE HALF INCH WILL BE POSSIBLE THROUGH 8 AM.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO CALIPATRIA.

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...STREETS AND UNDERPASSES...AND DETENTION
BASINS AFFECTING SOME COMMUNITY PARKS. UNBRIDGED CROSSINGS WILL BE
ESPECIALLY DANGEROUS.

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 3329 11563 3310 11539 3294 11552 3313 11579

$$

KUHLMAN

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 6:15 PM PDTAreal Flood AdvisoryPSRImperial2 hr
Jul 30, 7:31 PM PDTAreal Flood WarningPSRImperial15 hr
Jul 31, 3:42 AM PDTFlash Flood WatchPSR15 hr
Jul 31, 4:49 AM PDTAreal Flood AdvisoryPSRImperial116 min
Jul 31, 9:02 AM PDTAreal Flood AdvisoryPSRRiverside, San Bernardino3 hr
Jul 31, 10:16 AM PDTFlash Flood WarningPSRImperial, Riverside, San Bernardino3 hr
Jul 31, 12:12 PM PDTSevere Thunderstorm WarningPSRRiverside, San Bernardino49 min
Jul 31, 1:28 PM PDTAreal Flood AdvisoryPSRImperial, Riverside3 hr
Jul 31, 1:31 PM PDTFlash Flood WarningPSRSan Bernardino119 min
Jul 31, 3:40 PM PDTAreal Flood AdvisoryPSRRiverside, San Bernardino2 hr

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.