Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 27, NWS San Diego, CA

August 19, 2012Riverside County, California

NWS San Diego, CA issued this flash flood warning at Aug 19, 2012, 3:52 PM PDT for Riverside 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 19, 2012, 3:52 PM PDT (22:52 UTC)
Expired
Aug 19, 2012, 6:20 PM PDT
In force
2 hr
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

County Riverside County, CA

The radar

The San Diego radar (KNKX), 98 km from the middle of the area, began a volume at 22:54 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, 10.9 hours before the alert went out and 117 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 2012-08-19Temperature 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 2012-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 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
1473 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
-18 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.

285 
WGUS56 KSGX 192252
FFWSGX
CAC065-200145-
/O.NEW.KSGX.FF.W.0027.120819T2252Z-120820T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
352 PM PDT SUN AUG 19 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

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

* UNTIL 645 PM PDT

* AT 342 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  FLASH FLOODING FROM A STORM NEAR SANTA ROSA MOUNTAIN.

* AREAS IMPACTED INCLUDE THE SANTA ROSA INDIAN RESERVATION...        
  NIGHTINGALE...PALM CANYON CREEK...DEEP CREEK...AND STATE ROUTE 74.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLASH FLOODING OF 
SMALL CREEKS...STREAMS...AND RURAL ROADS.

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.

&&

LAT...LON 3370 11640 3363 11631 3353 11646 3354 11662
      3372 11663 3383 11655

$$

JAD
3 follow-up statements
111 
WGUS76 KSGX 192321
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
421 PM PDT SUN AUG 19 2012

CAC065-200145-
/O.CON.KSGX.FF.W.0027.000000T0000Z-120820T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-
421 PM PDT SUN AUG 19 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM PDT FOR
CENTRAL RIVERSIDE COUNTY...

AT 406 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A STRONG THUNDERSTORM WITH HEAVY RAIN CAPABLE OF PRODUCING 
FLASH FLOODING JUST NORTH OF SANTA ROSA MOUNTAIN.

THIS STORM WAS OVER THE HEADWATERS OF PALM CANYON CREEK AND DEEP 
CREEK AND WAS MOVING VERY SLOWLY. 

CAMPERS AND HIKERS IN THESE AREAS SHOULD MOVE TO HIGHER GROUND 
IMMEDIATELY. RUNOFF FROM THIS STORM IS EXPECTED RUN THROUGH PALM 
CANYON CREEK...DEEP CREEK...AND ASSOCIATED TRIBUTARIES AND WASHES 
THROUGH THE FOOTHILLS WEST OF PALM SPRINGS...AND PALM DESERT. 


PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

IN HILLY TERRAIN THERE ARE LOW WATER CROSSINGS WHICH ARE POTENTIALLY 
DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS FLOODED 
ROADS. FIND ALTERNATE ROUTES. IT TAKES ONLY A FEW INCHES OF SWIFTLY 
FLOWING WATER TO CARRY VEHICLES AWAY.

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.

&&

LAT...LON 3370 11640 3363 11631 3353 11646 3354 11662
      3372 11663 3383 11655

$$

JAD
234 
WGUS76 KSGX 200046
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
546 PM PDT SUN AUG 19 2012

CAC065-200145-
/O.CON.KSGX.FF.W.0027.000000T0000Z-120820T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-
546 PM PDT SUN AUG 19 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM PDT FOR
CENTRAL RIVERSIDE COUNTY...

THE THUNDERSTORM RESPONSIBLE FOR HEAVY RAINFALL IN THE SANTA ROSA 
MOUNTAINS HAS DISSIPATED. HOWEVER WATER IS LIKELY STILL FLOWING 
THROUGH THE PALM CANYON CREEK AND DEEP CANYON WASHES. 

A REMOTE RAIN GAGE NEAR THE STORM REPORTED JUST OVER THREE QUARTERS 
OF AN INCH BY 5 PM THIS EVENING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...RURAL ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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 3370 11640 3363 11631 3353 11646 3354 11662
      3372 11663 3383 11655

$$

JAD
715 
WGUS76 KSGX 200120
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
620 PM PDT SUN AUG 19 2012

CAC065-200122-
/O.CAN.KSGX.FF.W.0027.000000T0000Z-120820T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
RIVERSIDE CA-
620 PM PDT SUN AUG 19 2012

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

RAINFALL ENDED AROUND 445 PM THIS AFTERNOON AND NO FURTHER 
THUNDERSTORM ACTIVITY IS EXPECTED. 

SOME RUNOFF AMY CONTINUE THROUGH THE LOWER REACHES OF PALM CREEK 
CANYON AND DEEP CANYON CREEKS FOR SEVERAL HOURS...BUT THE THREAT OF 
A DAMAGING FLASH FLOOD HAS DIMINISHED.

BASED ON LIMITED RAINFALL REPORTS...A LARGE PORTION OF THE UPPER 
WATERSHEDS OF THESE CREEKS BETWEEN MOUNTAIN CENTER AND SANTA ROSA 
PEAK RECEIVED BETWEEN ONE-HALF AND ON-INCH OF RAIN BETWEEN 3 AND 5 
PM THIS AFTERNOON.


LAT...LON 3370 11640 3363 11631 3353 11646 3354 11662
      3372 11663 3383 11655

$$

JAD

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 3:14 PM PDTAreal Flood AdvisorySGXRiverside, San Bernardino91 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.