Alert archive / Florida / Tornado Watches in 2002

Tornado Watch 776

December 13, 200217 counties in Florida

The Storm Prediction Center issued this tornado watch at Dec 13, 2002, 6:45 AM EST for 17 counties in Florida. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Dec 13, 2002, 6:45 AM EST (11:45 UTC)
Expired: Dec 13, 2002, 12:00 PM EST
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Brevard County, FL, Charlotte County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Highlands County, FL, Indian River County, FL, Lake County, FL, Lee County, FL, Okeechobee County, FL, Orange County, FL, Osceola County, FL, Polk County, FL, Sarasota County, FL, Seminole County, FL, Volusia County, FL

The radar

The Tampa radar (KTBW), 77 km from the middle of the area, began a volume at 11:45 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.

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Dec 13, 8:26 AM EST	Tornado Warning	MLB	Volusia	34 min
Dec 13, 9:02 AM EST	Tornado Warning	MLB	Brevard, Volusia	28 min
Dec 13, 10:46 AM EST	Severe Thunderstorm Warning	MLB	Brevard	44 min
Dec 13, 11:32 AM EST	Severe Thunderstorm Warning	MFL	Glades	43 min
Dec 13, 11:35 AM EST	Severe Thunderstorm Warning	MLB	Brevard, Indian River	55 min

The nearest sounding before it

Tampa Bay, FL (KTBW), launched 00:00Z, 11.8 hours before the alert went out and 77 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: 431 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 298 m²/s²
0-3 km storm-relative helicity: 384 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 131147
SEL6  
SPC WW 131145
FLZ000-CWZ000-131700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 776
STORM PREDICTION CENTER NORMAN OK
645 AM EST FRI DEC 13 2002

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

   CENTRAL FLORIDA                            
   COASTAL WATERS                     

EFFECTIVE THIS FRIDAY MORNING FROM 645 AM UNTIL NOON EST.

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

THE TORNADO WATCH AREA IS ALONG AND 55 STATUTE MILES EAST AND WEST
OF A LINE FROM 15 MILES SOUTH SOUTHWEST OF FORT MEYERS FLORIDA TO
20 MILES EAST NORTHEAST OF DAYTONA BEACH FLORIDA.

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...CONVECTION ALONG BROKEN LINE NOW MOVING ACROSS CENTRAL
FL AND EXTENDING SWWD OFF THE SWRN FL COAST SHOULD INCREASE THROUGH
THE MORNING.  TEMPERATURES WILL INCREASE INTO THE MID 70S AHEAD OF
THIS ACTIVITY SUPPORTING MODEST INSTABILITY...AS SURFACE DEW POINTS
HOLD IN THE LOWER 70S.  LOW LEVEL WINDS WILL VEER TO SWLY THROUGH
THE MORNING...THOUGH STRONG SPEED SHEAR IN THE LOWEST 1-2 KM AND
LOW LCL HEIGHTS WILL MAINTAIN A THREAT OF ISOLATED TORNADOES ALONG
WITH DAMAGING WINDS.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH...EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. 
MEAN STORM MOTION VECTOR 23040.


...EVANS

262,0825 291,0813 291,0794 262,0810

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 13, 11:55 AM EST	Tornado Watch	SPC	Broward, Collier, Hendry, Martin, Palm Beach, Saint Lucie	4 hr

Nearby

Tornado Watches in Florida, 2002 Every tornado watch in 2002

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.