Alert archive / California / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 2, NWS San Francisco Bay Area, CA

October 10, 2012Santa Clara County, Santa Cruz County, California

NWS San Francisco Bay Area, CA issued this severe thunderstorm warning at Oct 10, 2012, 4:05 PM PDT for Santa Clara County, Santa Cruz County, California. It was in force for 25 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
Oct 10, 2012, 4:05 PM PDT (23:05 UTC)
Expired
Oct 10, 2012, 4:30 PM PDT
In force
25 min
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon

Counties Santa Clara County, CA, Santa Cruz County, CA

The radar

The San Francisco radar (KMUX), 15 km from the middle of the area, began a volume at 23:06 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 12:00Z, 11.1 hours before the alert went out and 83 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 12:00Z on 2012-10-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Oakland, CA at 12:00Z on 2012-10-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 square meters per square second.193958Sfc1 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
1 J/kg
Mixed-layer CIN
-332 J/kg
Mixed-layer LCL
936 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

280 
WUUS56 KMTR 102305
SVRMTR
CAC085-087-102330-
/O.NEW.KMTR.SV.W.0002.121010T2305Z-121010T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
405 PM PDT WED OCT 10 2012

THE NATIONAL WEATHER SERVICE IN THE SAN FRANCISCO BAY AREA HAS ISSUED
A

* SEVERE THUNDERSTORM WARNING FOR...
  SANTA CLARA COUNTY IN WESTERN CALIFORNIA...
  THIS INCLUDES THE CITY OF MORGAN HILL...
  SANTA CRUZ COUNTY IN WESTERN CALIFORNIA...

* UNTIL 430 PM PDT

* AT 401 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  MORGAN HILL...AND MOVING NORTHWEST AT 20 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BROWN
  VALLEY ROAD...UVAS CANYON PARK AND EUREKA CANYON ROAD

LAT...LON 3704 12188 3721 12178 3710 12159 3698 12166
TIME...MOT...LOC 2304Z 113DEG 17KT 3707 12171

$$

RILEY
1 follow-up statement
397 
WWUS56 KMTR 102318
SVSMTR

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
418 PM PDT WED OCT 10 2012

CAC085-087-102330-
/O.CON.KMTR.SV.W.0002.000000T0000Z-121010T2330Z/
SANTA CRUZ CA-SANTA CLARA CA-
418 PM PDT WED OCT 10 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM PDT
FOR SANTA CLARA AND SANTA CRUZ COUNTIES...

AT 414 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE 
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  STORM SPOTTER 
REPORTED QUARTER SIZE HAIL WITH THIS STORM.  THIS STORM WAS LOCATED 
7 MILES NORTH OF CORRALITOS...MOVING NORTHWEST AT 20 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO EUREKA
CANYON ROAD

LAT...LON 3714 12170 3702 12174 3706 12187 3719 12179
TIME...MOT...LOC 2317Z 113DEG 17KT 3709 12178

$$

RILEY

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 10, 3:41 PM PDTSpecial Weather StatementMTRSanta Clara34 min
Oct 10, 4:28 PM PDTSevere Thunderstorm WarningMTRSanta Clara, Santa Cruz32 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.