Alert archive / California / Tornado Warnings in 2010

Tornado Warning 2, NWS San Francisco Bay Area, CA

January 23, 2010Contra Costa County, California

NWS San Francisco Bay Area, CA issued this tornado warning at Jan 23, 2010, 1:05 PM PST for Contra Costa County, California. It was in force for 25 min. 3 reports 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
Jan 23, 2010, 1:05 PM PST (21:05 UTC)
Expired
Jan 23, 2010, 1:30 PM PST
In force
25 min
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon

County Contra Costa County, CA

The radar

The Sacramento radar (KDAX), 71 km from the middle of the area, began a volume at 21:08 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
Jan 23, 1:05 PM PSTFUNNEL CLOUDBrentwood, CAPOSSIBLE FUNNEL SPOTTED BY BRENTWOOD PD. POWER LINES DOWN
Jan 23, 1:37 PM PSTHAIL 0.882 S Brentwood, CATWO VEHICLES SLID OF ROAD DUE TO HEAVY HAIL AS REPORTED BY CHP
Jan 23, 1:40 PM PSTFUNNEL CLOUD5 Ese Brentwood, CAFUNNEL CLOUD NEAR DISCOVERY BAY MOVING EAST AS REPORTED BY SHERIFFS DEPT TO CALWAS

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 9.1 hours before the alert went out and 53 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 2010-01-23Temperature 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 2010-01-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 96 square meters per square second.1939587897117136156175Sfc1 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
-8 J/kg
Mixed-layer LCL
530 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
96 m²/s²
0-3 km storm-relative helicity
149 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.

888 
WFUS56 KMTR 232105
TORMTR
CAC013-232130-
/O.NEW.KMTR.TO.W.0002.100123T2105Z-100123T2130Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
105 PM PST SAT JAN 23 2010

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

* TORNADO WARNING FOR...
  CONTRA COSTA COUNTY IN NORTHERN CALIFORNIA...

* UNTIL 130 PM PST

* AT 103 PM PST...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD
  NEAR BRENTWOOD...OR 7 MILES SOUTH OF OAKLEY...MOVING SOUTHEAST AT 5
  MPH.

* THE TORNADO WILL BE NEAR...
  6 MILES SOUTHWEST OF DISCOVERY BAY BY 120 PM PST...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WHEN A TORNADO WARNING IS ISSUED BASED ON DOPPLER RADAR...IT MEANS
THAT STRONG ROTATION HAS BEEN DETECTED IN THE STORM. A TORNADO MAY
ALREADY BE ON THE GROUND...OR IS EXPECTED TO DEVELOP SHORTLY. IF YOU
ARE IN THE PATH OF THIS DANGEROUS STORM...MOVE INDOORS AND TO THE
LOWEST LEVEL OF THE BUILDING. STAY AWAY FROM WINDOWS. IF DRIVING...DO
NOT SEEK SHELTER UNDER A HIGHWAY OVERPASS.

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 3789 12155 3787 12156 3783 12152 3781 12154
      3780 12157 3776 12177 3792 12185 3801 12166
TIME...MOT...LOC 2105Z 331DEG 5KT 3788 12170

$$

STROBIN
1 follow-up statement
050 
WWUS56 KMTR 232115
SVSMTR

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
115 PM PST SAT JAN 23 2010

CAC013-232130-
/O.CON.KMTR.TO.W.0002.000000T0000Z-100123T2130Z/
CONTRA COSTA CA-
115 PM PST SAT JAN 23 2010

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 130 PM PST FOR CONTRA
COSTA COUNTY...

AT 111 PM PST...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD. 
THIS TORNADO WAS LOCATED NEAR BRENTWOOD...OR 8 MILES SOUTH OF
OAKLEY...MOVING SOUTHEAST AT 5 MPH.

THE TORNADO WILL BE NEAR...
  MAINLY RURAL AREAS...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 3789 12155 3787 12156 3783 12152 3781 12154
      3780 12157 3776 12177 3792 12185 3801 12166
TIME...MOT...LOC 2114Z 331DEG 5KT 3787 12169

$$

STROBIN

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 23, 3:34 AM PSTSmall Craft Advisory for Hazardous SeasMTR17 hr
Jan 23, 6:40 AM PSTHigh Surf AdvisoryMTRMonterey8 hr
Jan 23, 1:32 PM PSTTornado WarningMTRContra Costa28 min

Nearby

Tornado Warnings in California, 2010Every tornado warning in 2010Tornadoes in 2010

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.