Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 57, NWS Phoenix, AZ

August 30, 2012Imperial County, California

NWS Phoenix, AZ issued this flash flood warning at Aug 30, 2012, 11:25 AM PDT for Imperial County, California. It was in force for 2 hr. 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 30, 2012, 11:25 AM PDT (18:25 UTC)
Expired
Aug 30, 2012, 1:30 PM PDT
In force
2 hr
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Flood severity
None

County Imperial County, CA

The radar

The San Diego radar (KNKX), 108 km from the middle of the area, began a volume at 18:28 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 30, 11:46 AM PDTFLASH FLOOD2 W Mt. Signal, CAROAD CLOSURE AT SR 98 AND DREW RD. WATER RUNNING OVER ROADWAY

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, 6.4 hours before the alert went out and 122 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 2012-08-30Temperature 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 12:00Z on 2012-08-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
2209 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
73 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.

418 
WGUS55 KPSR 301825
FFWPSR
CAC025-302030-
/O.NEW.KPSR.FF.W.0057.120830T1825Z-120830T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
1125 AM PDT THU AUG 30 2012

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN IMPERIAL COUNTY IN SOUTHEAST CALIFORNIA...
  THIS INCLUDES PLASTER CITY...

* UNTIL 130 PM PDT

* AT 1116 AM PDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
  VERY HEAVY RAIN THAT WILL CAUSE FLASH FLOODING.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
DIXIELAND...THE OLD OVERLAND STAGE ROUTE...THE EVANS HEWES 
HIGHWAY...STATE ROUTE 98 WEST OF MOUNT SIGNAL...AND INTERSTATE 8.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN MOTORIZED VEHICLES. WHEN ENCOUNTERING
FLOODED ROADS...MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

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.

TO REPORT FLOODING...PLEASE RELAY YOUR REPORT TO LOCAL LAW
ENFORCEMENT WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 3290 11604 3295 11581 3264 11562 3263 11588
      3273 11598

$$

MEYERS
3 follow-up statements
140 
WGUS75 KPSR 301856
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1156 AM PDT THU AUG 30 2012

CAC025-302030-
/O.CON.KPSR.FF.W.0057.000000T0000Z-120830T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
IMPERIAL CA-
1156 AM PDT THU AUG 30 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 PM PDT FOR
SOUTHWESTERN IMPERIAL COUNTY...

AT 1144 AM PDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUE TO 
DETECT THUNDERSTORMS PRODUCING VERY HEAVY RAIN THAT WILL CAUSE FLASH 
FLOODING. RADAR PRECIPITATION ESTIMATES INDICATE THAT APPROXIMATELY 
TWO INCHES OF RAIN HAS FALLEN WITHIN THE LAST HOUR IN SOME 
AREAS...MAINLY NEAR PLASTER CITY. 

LOCATIONS IN THE WARNING INCLUDE INTERSTATE 8...DIXIELAND...THE OLD 
OVERLAND STAGE ROUTE...THE EVANS HEWES HIGHWAY...AND STATE ROUTE 98 
WEST OF MOUNT SIGNAL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN MOTORIZED VEHICLES. WHEN ENCOUNTERING
FLOODED ROADS...MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

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.

TO REPORT FLOODING...PLEASE RELAY YOUR REPORT TO LOCAL LAW
ENFORCEMENT WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 3290 11604 3295 11581 3264 11562 3263 11588
      3273 11598

$$

MEYERS
452 
WGUS75 KPSR 301947
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1247 PM PDT THU AUG 30 2012

CAC025-302030-
/O.CON.KPSR.FF.W.0057.000000T0000Z-120830T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
IMPERIAL CA-
1247 PM PDT THU AUG 30 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 PM PDT FOR
SOUTHWESTERN IMPERIAL COUNTY...

AT 1231 PM PDT...SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED. 
HOWEVER...LIGHT TO MODERATE RAINFALL WILL PERSIST OVER THE AREA NEAR 
PLASTER CITY AND OCOTILLO FOR THE NEXT HOUR OR SO. RUNOFF FROM THESE 
STORMS WILL CONTINUE TO RAPIDLY FLOW INTO WASHES...CANALS AND LOW 
LYING AREAS AND LEAD TO FLASH FLOODING.

LOCATIONS IN THE WARNING INCLUDE INTERSTATE 8 EAST OF OCOTILLO... 
DIXIELAND...THE OLD OVERLAND STAGE ROUTE...THE EVANS HEWES 
HIGHWAY...AND STATE ROUTE 98 WEST OF MOUNT SIGNAL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN MOTORIZED VEHICLES. WHEN ENCOUNTERING
FLOODED ROADS...MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

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.

TO REPORT FLOODING...PLEASE RELAY YOUR REPORT TO LOCAL LAW
ENFORCEMENT WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 3290 11604 3295 11581 3264 11562 3263 11588
      3273 11598

$$

MEYERS
822 
WGUS75 KPSR 302028
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
128 PM PDT THU AUG 30 2012

CAC025-302035-
/O.EXP.KPSR.FF.W.0057.000000T0000Z-120830T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
IMPERIAL CA-
128 PM PDT THU AUG 30 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 130 PM PDT FOR SOUTHWESTERN
IMPERIAL COUNTY...

RUNOFF FROM EARLIER STORMS WILL CONTINUE TO FLOW INTO WASHES... 
CANALS AND LOW LYING AREAS OVER THE NEXT SEVERAL HOURS.

LOCATIONS THAT MAY CONTINUE TO BE IMPACTED BY VARYING DEGREES OF 
INUNDATION INCLUDE INTERSTATE 8 EAST OF OCOTILLO...DIXIELAND...THE 
OLD OVERLAND STAGE ROUTE...THE EVANS HEWES HIGHWAY...AND STATE ROUTE 
98 WEST OF MOUNT SIGNAL.

LAT...LON 3290 11604 3295 11581 3264 11562 3263 11588
      3273 11598

$$

MEYERS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 29, 6:43 PM PDTSevere Thunderstorm WarningPSRRiverside, San Bernardino62 min
Aug 29, 7:49 PM PDTAreal Flood AdvisoryPSRRiverside, San Bernardino3 hr
Aug 29, 9:09 PM PDTFlash Flood WarningPSRRiverside105 min
Aug 30, 6:24 AM PDTAreal Flood AdvisoryPSRImperial111 min
Aug 30, 11:05 AM PDTSpecial Weather StatementPSRImperial40 min
Aug 30, 1:44 PM PDTAreal Flood WarningPSRImperial4 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.