Alert archive / California / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 7, NWS San Diego, CA

August 11, 2012Riverside County, California

NWS San Diego, CA issued this severe thunderstorm warning at Aug 11, 2012, 2:23 PM PDT for Riverside County, California. It was in force for 22 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 11, 2012, 2:23 PM PDT (21:23 UTC)
Expired
Aug 11, 2012, 2:45 PM PDT
In force
22 min
Issued by
NWS San Diego, CA
Area
Storm-based polygon

County Riverside County, CA

The radar

The Santa Ana Mts radar (KSOX), 43 km from the middle of the area, began a volume at 21:24 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, 9.4 hours before the alert went out and 115 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 2012-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 268 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 2012-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 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
268 J/kg
Mixed-layer CIN
-713 J/kg
Mixed-layer LCL
1560 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
30 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.

066 
WUUS56 KSGX 112123
SVRSGX
CAC065-112145-
/O.NEW.KSGX.SV.W.0007.120811T2123Z-120811T2145Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
223 PM PDT SAT AUG 11 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WEST CENTRAL RIVERSIDE COUNTY IN SOUTHERN CALIFORNIA...
  THIS INCLUDES THE CITIES OF...MORENO VALLEY...HEMET...

* UNTIL 245 PM PDT

* AT 218 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED   
  TO INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER     
  SIZE   HAIL AND DAMAGING WINDS. THIS STORM WAS LOCATED 7 MILES     
  EAST OF PERRIS...OR 8 MILES NORTHWEST OF HEMET...AND WAS NEARLY    
  STATIONARY. 

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MARCH
  AFB AND MARCH FIELD

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

&&

LAT...LON 3381 11734 3400 11723 3388 11695 3369 11699
TIME...MOT...LOC 2121Z 124DEG 5KT 3381 11710

$$

JT/PG
1 follow-up statement
403 
WWUS56 KSGX 112136
SVSSGX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
236 PM PDT SAT AUG 11 2012

CAC065-112145-
/O.CON.KSGX.SV.W.0007.000000T0000Z-120811T2145Z/
RIVERSIDE CA-
236 PM PDT SAT AUG 11 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM PDT
FOR WEST CENTRAL RIVERSIDE COUNTY...

AT 235 PM PDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER 
SIZE HAIL AND DAMAGING WINDS WAS LOCATED NEAR PERRIS. THIS STORM WAS 
NEARLY STATIONARY.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
NUEVO...LAKEVIEW...PERRIS...MORENO VALLEY...MARCH AFB AND MARCH FIELD

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

&&

LAT...LON 3381 11734 3400 11723 3388 11695 3369 11699
TIME...MOT...LOC 2134Z 124DEG 5KT 3382 11712

$$

JT/PG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 5:20 PM PDTAreal Flood AdvisorySGXRiverside115 min
Aug 11, 12:00 PM PDTAreal Flood AdvisorySGXSan Bernardino92 min
Aug 11, 12:58 PM PDTAreal Flood AdvisorySGXSan Bernardino2 hr
Aug 11, 1:23 PM PDTFlash Flood WarningSGXSan Bernardino3 hr
Aug 11, 1:58 PM PDTAreal Flood AdvisorySGXRiverside, San Bernardino3 hr
Aug 11, 2:03 PM PDTSevere Thunderstorm WarningSGXRiverside27 min
Aug 11, 2:46 PM PDTSevere Thunderstorm WarningSGXRiverside44 min
Aug 11, 3:05 PM PDTSevere Thunderstorm WarningSGXRiverside, San Diego40 min
Aug 11, 3:22 PM PDTAreal Flood AdvisorySGXSan Bernardino113 min
Aug 11, 3:33 PM PDTSevere Thunderstorm WarningSGXOrange, Riverside42 min
Aug 11, 4:40 PM PDTAreal Flood AdvisorySGXSan Diego3 hr

Nearby

Severe Thunderstorm Warnings in California, 2012Every severe thunderstorm 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.