Alert archive / California / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 2, NWS Sacramento, CA

April 12, 2012Calaveras County, San Joaquin County, Stanislaus County, California

NWS Sacramento, CA issued this severe thunderstorm warning at Apr 12, 2012, 5:53 PM PDT for Calaveras County, San Joaquin County, Stanislaus County, California. It was in force for 34 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
Apr 12, 2012, 5:53 PM PDT (00:53 UTC)
Expired
Apr 12, 2012, 6:27 PM PDT
In force
34 min
Issued by
NWS Sacramento, CA
Area
Storm-based polygon

Counties Calaveras County, CA, San Joaquin County, CA, Stanislaus County, CA

The radar

The Sacramento radar (KDAX), 90 km from the middle of the area, began a volume at 00:55 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

Oakland, CA (KOAK), launched 00:00Z, 0.9 hours before the alert went out and 126 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, Oakland, CA at 00:00Z on 2012-04-13Temperature 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, Oakland, CA at 00:00Z on 2012-04-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 square meters per square second.1939587897Sfc1 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
1716 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
37 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.

400 
WUUS56 KSTO 130053
SVRSTO
CAC009-077-099-130130-
/O.NEW.KSTO.SV.W.0002.120413T0053Z-120413T0130Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SACRAMENTO CA
553 PM PDT THU APR 12 2012

THE NATIONAL WEATHER SERVICE IN SACRAMENTO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN CALAVERAS COUNTY IN CENTRAL CALIFORNIA...
  EXTREME EAST CENTRAL SAN JOAQUIN COUNTY IN CENTRAL CALIFORNIA...
  NORTH CENTRAL STANISLAUS COUNTY IN CENTRAL CALIFORNIA...

* UNTIL 630 PM PDT

* AT 548 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  
  THIS STORM WAS LOCATED NEAR MILTON...OR 5 MILES NORTH OF 
  EUGENE...AND MOVING NORTHEAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HODSON BY 600 PM PDT...
  COPPEROPOLIS BY 605 PM PDT...

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.

&&

LAT...LON 3821 12094 3804 12053 3787 12078 3793 12092
TIME...MOT...LOC 0051Z 223DEG 18KT 3799 12077

$$

PCH
2 follow-up statements
006 
WWUS56 KSTO 130118
SVSSTO

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SACRAMENTO CA
618 PM PDT THU APR 12 2012

CAC077-099-130128-
/O.CAN.KSTO.SV.W.0002.000000T0000Z-120413T0130Z/
STANISLAUS CA-SAN JOAQUIN CA-
618 PM PDT THU APR 12 2012

...THE SEVERE THUNDERSTORM WARNING FOR EXTREME EAST CENTRAL SAN
JOAQUIN AND NORTH CENTRAL STANISLAUS COUNTIES IS CANCELLED...

LAT...LON 3797 12068 3804 12084 3817 12085 3804 12054
TIME...MOT...LOC 0118Z 223DEG 18KT 3809 12065

$$

CAC009-130130-
/O.CON.KSTO.SV.W.0002.000000T0000Z-120413T0130Z/
CALAVERAS CA-
618 PM PDT THU APR 12 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM PDT
FOR CENTRAL CALAVERAS COUNTY...

AT 612 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE
HAIL.  THIS STORM WAS LOCATED NEAR HODSON...OR 8 MILES SOUTH OF SAN
ANDREAS...MOVING NORTHEAST AT 20 MPH.

LAT...LON 3797 12068 3804 12084 3817 12085 3804 12054
TIME...MOT...LOC 0118Z 223DEG 18KT 3809 12065

$$

PCH
919 
WWUS56 KSTO 130127
SVSSTO

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SACRAMENTO CA
627 PM PDT THU APR 12 2012

CAC009-130131-
/O.CAN.KSTO.SV.W.0002.000000T0000Z-120413T0130Z/
CALAVERAS CA-
627 PM PDT THU APR 12 2012

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CALAVERAS COUNTY IS
CANCELLED...

THE STORM HAS WEAKENED AND THUS THE SEVERE THUNDERSTORM WARNING IS 
NO LONGER IN EFFECT. THIS STORM IS STILL CAPABLE OF PRODUCING 
SIGNIFICANT AMOUNTS OF PEA SIZED HAIL...HEAVY RAIN...AND GUSTY WINDS 
THROUGH 7 PM. THE STORM IS CURRENTLY NEAR SAN ANDREAS AND MOVING 
NORTHEAST AT AROUND 20 MPH.



LAT...LON 3797 12068 3804 12084 3817 12085 3804 12054
TIME...MOT...LOC 0121Z 223DEG 18KT 3810 12064

$$

PCH

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 12, 5:18 PM PDTSpecial Weather StatementSTOSan Joaquin42 min
Apr 12, 5:31 PM PDTSevere Thunderstorm WarningSTOAmador, Calaveras, Sacramento, San Joaquin43 min
Apr 12, 5:42 PM PDTSpecial Weather StatementSTOSacramento48 min
Apr 13, 9:11 AM PDTAreal Flood AdvisorySTOAmador, Butte, Calaveras, El Dorado, Nevada, Placer and 7 more4 hr
Apr 13, 2:08 PM PDTSpecial Weather StatementSTOSan Joaquin42 min
Apr 13, 2:26 PM PDTSpecial Weather StatementSTOSan Joaquin49 min
Apr 13, 3:19 PM PDTSpecial Weather StatementSTOSacramento41 min

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.