Alert archive / California / Tornado Watches in 2001

Tornado Watch 842

December 2, 200113 counties in California

The Storm Prediction Center issued this tornado watch at Dec 2, 2001, 1:00 PM PST for 13 counties in California. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Dec 2, 2001, 1:00 PM PST (21:00 UTC)
Expired: Dec 2, 2001, 6:00 PM PST
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Amador County, CA, Butte County, CA, Colusa County, CA, El Dorado County, CA, Glenn County, CA, Nevada County, CA, Placer County, CA, Sacramento County, CA, Shasta County, CA, Sutter County, CA, Tehama County, CA, Yolo County, CA, Yuba County, CA

Warnings issued inside it

2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Dec 2, 2:00 PM PST	Severe Thunderstorm Warning	STO	Nevada	40 min
Dec 2, 2:40 PM PST	Severe Thunderstorm Warning	STO	Nevada	35 min

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 9.0 hours before the alert went out and 248 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 742 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 528 m²/s²
0-3 km storm-relative helicity: 663 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.

000 
WWUS20 KWNS 022102
SEL2  
SPC WW 022053
CAZ000-030200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 842
STORM PREDICTION CENTER NORMAN OK
1253 PM PST SUN DEC 2 2001

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   NORTHERN CALIFORNIA                         

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 100 PM UNTIL 600
PM PST.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS TO
60 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 45 STATUTE MILES EITHER SIDE OF
A LINE FROM 50 MILES NORTH OF RED BLUFF CALIFORNIA TO 35 MILES EAST
SOUTHEAST OF SACRAMENTO CALIFORNIA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

DISCUSSION...DAYTIME HEATING/ARRIVAL OF COLDER AIR ALOFT HAVE
RESULTED IN SUFFICIENT DESTABILIZATION TO PRODUCE SCATTERED DEEP
CONVECTION OVER THE COASTAL RANGES AND PARTS OF THE SACRAMENTO
VALLEY IN THE LAST 1-2 HOURS.  STRENGTHENING TREND SHOULD CONTINUE
FOR THE NEXT SEVERAL HOURS...WITH A THREAT FOR SUPERCELLS/TORNADOES
GIVEN BACKED NEAR-SURFACE FLOW BENEATH 50+ KT SW JET AT 700 MB. 

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH...EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 50 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 300. 
MEAN STORM MOTION VECTOR 24035.

...CORFIDI

411,1212 383,1200 380,1213 403,1230

Nearby

Tornado Watches in California, 2001 Every tornado watch in 2001

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.