Alert archive / Florida / Tornado Watches in 2004

Tornado Watch 73

April 13, 20046 counties in Florida

The Storm Prediction Center issued this tornado watch at Apr 13, 2004, 2:45 AM EDT for 6 counties in Florida. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Apr 13, 2004, 2:45 AM EDT (06:45 UTC)
Expired: Apr 13, 2004, 8:00 AM EDT
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Broward County, FL, Collier County, FL, Hendry County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL

The radar

The Miami radar (KAMX), 85 km from the middle of the area, began a volume at 06:49 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

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

Issued	Product	Office	Counties	Lasted
Apr 13, 3:05 AM EDT	Tornado Warning	MFL	Collier	25 min
Apr 13, 4:15 AM EDT	Tornado Warning	MFL	Broward	60 min
Apr 13, 4:35 AM EDT	Tornado Warning	MFL	Collier	55 min
Apr 13, 5:20 AM EDT	Severe Thunderstorm Warning	EYW	Monroe	55 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

Mesoscale Discussion 347Apr 13, 2:35 AM EDT

The nearest sounding before it

Miami, FL (KMFL), launched 00:00Z, 6.8 hours before the alert went out and 95 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: 262 J/kg
Mixed-layer CIN: -94 J/kg
Mixed-layer LCL: 1327 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 145 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.2

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 130649
SEL3  
SPC WW 130645
FLZ000-CWZ000-131200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 73
NWS STORM PREDICTION CENTER NORMAN OK
245 AM EDT TUE APR 13 2004

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

       SOUTH FLORIDA
       COASTAL WATERS

EFFECTIVE THIS TUESDAY MORNING FROM 245 AM UNTIL 800 AM EDT.

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 65 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 55 MILES NORTH NORTHWEST OF KEY WEST FLORIDA
TO 30 MILES NORTHEAST OF MIAMI 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...EMBEDDED SUPERCELLS EXPECTED TO PERSIST INVOF WEAK
OUTFLOW BOUNDARY STALLED WSW/ESE ACROSS COLLIER/BROWARD COUNTIES. 
ABUNDANT /60+ KT/ LOW LEVEL SHEAR  AND RICH /MID 70S SURFACE
DEWPOINTS/ BOUNDARY LAYER MOISTURE INFLOW SUGGEST GOOD LIKELIHOOD
FOR LOW LEVEL STORM ROTATION.  OTHER STORMS NOW OVER THE FAR ERN
GULF MAY MOVE E/ENE ALONG BOUNDARY LATER THIS MORNING AS IMPULSE
ROTATING AROUND SE QUADRANT OF LWR MS VLY UPPER LOW MAKES CONDITIONS
LESS FAVORABLE FOR BACK-BUILDING.

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 550.
MEAN STORM MOTION VECTOR 25030.


...CORFIDI

261,0820 270,0795 251,0795 242,0820

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 12, 10:25 PM EDT	Mesoscale Discussion	SPC	Collier, Hendry, Monroe	3 hr
Apr 13, 2:35 AM EDT	Mesoscale Discussion	SPC	Miami-Dade, Monroe	115 min

Nearby

Tornado Watches in Florida, 2004 Every tornado watch in 2004

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.