Alert archive / Florida / Tornado Watches in 2004

Tornado Watch 748

August 12, 200410 counties in Florida

The Storm Prediction Center issued this tornado watch at Aug 12, 2004, 9:35 PM EDT for 10 counties in Florida. It was in force for 10 hr.

The area

The outline as issued.

The facts

Issued
Aug 12, 2004, 9:35 PM EDT (01:35 UTC)
Expired
Aug 13, 2004, 8:00 AM EDT
In force
10 hr
Issued by
the Storm Prediction Center

Counties Broward County, FL, Charlotte County, FL, Collier County, FL, Glades County, FL, Hendry County, FL, Lee County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL

The radar

The Miami radar (KAMX), 60 km from the middle of the area, began a volume at 01:36 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

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

IssuedProductOfficeCountiesLasted
Aug 12, 9:43 PM EDTTornado WarningEYWMonroe62 min
Aug 12, 11:58 PM EDTSevere Thunderstorm WarningMFLMiami-Dade47 min
Aug 13, 1:27 AM EDTSevere Thunderstorm WarningMFLBroward, Miami-Dade63 min
Aug 13, 1:29 AM EDTSevere Thunderstorm WarningMFLCollier46 min
Aug 13, 2:54 AM EDTSevere Thunderstorm WarningMFLGlades21 min
Aug 13, 5:49 AM EDTTornado WarningEYWMonroe26 min

Discussions around it

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

The nearest sounding before it

Miami, FL (KMFL), launched 00:00Z, 1.6 hours before the alert went out and 62 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, Miami, FL at 00:00Z on 2004-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2493 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Miami, FL at 00:00Z on 2004-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.1939Sfc1 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
2493 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
1169 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
46 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 130134
SEL8  
SPC WW 130135
FLZ000-CWZ000-131200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 748
NWS STORM PREDICTION CENTER NORMAN OK
935 PM EDT THU AUG 12 2004

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

       SOUTH FLORIDA
       COASTAL WATERS

EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 935 PM UNTIL
800 AM EDT.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 75 STATUTE MILES EAST AND WEST
OF A LINE FROM 50 MILES NORTHEAST OF FORT MEYERS FLORIDA TO 60
MILES EAST SOUTHEAST OF KEY WEST 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.

OTHER WATCH INFORMATION...CONTINUE...WW 746...WW 747...

DISCUSSION...OUTER BANDS OF HURRICANE CHARLEY WILL BEGIN TO AFFECT
THE FL KEYS IN THE NEXT COUPLE OF HOURS...AND INTO SOUTH FL
OVERNIGHT.  VERTICAL SHEAR PROFILES WILL INCREASE RAPIDLY...WITH AN
INCREASING RISK OF ISOLATED TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550.
MEAN STORM MOTION VECTOR 16030.


...HART

270,0800 241,0794 241,0820 270,0823

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 12, 9:00 PM EDTMesoscale DiscussionSPCCharlotte, Collier, Hendry, Lee, Miami-Dade, Monroe3 hr
Aug 13, 2:21 AM EDTMesoscale DiscussionSPCBroward, Charlotte, Collier, Glades, Hendry, Lee and 4 more114 min
Aug 13, 6:46 AM EDTMesoscale DiscussionSPCBroward, Charlotte, Collier, DeSoto, Glades, Hardee and 15 more119 min
Aug 13, 7:30 AM EDTTornado WatchSPCBroward, Charlotte, Collier, DeSoto, Glades, Hardee and 15 more10 hr
Aug 13, 11:04 AM EDTMesoscale DiscussionSPCBroward, Charlotte, Collier, DeSoto, Glades, Hardee and 15 more86 min
Aug 13, 1:02 PM EDTMesoscale DiscussionSPCBrevard, Broward, Charlotte, Citrus, Collier, DeSoto and 26 more88 min
Aug 13, 1:45 PM EDTTornado WatchSPCAlachua, Brevard, Broward, Charlotte, Citrus, Collier and 29 more12 hr
Aug 13, 4:06 PM EDTMesoscale DiscussionSPCAlachua, Brevard, Broward, Charlotte, Citrus, Collier and 29 more84 min
Aug 13, 6:14 PM EDTMesoscale DiscussionSPCBroward, Citrus, Collier, Glades, Hardee, Hendry and 14 more61 min

Nearby

Tornado Watches in Florida, 2004Every 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.