Alert archive / Florida / Tornado Watches in 2002
Tornado Watch 777
The Storm Prediction Center issued this tornado watch at Dec 13, 2002, 11:55 AM EST for 6 counties in Florida. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 13, 2002, 11:55 AM EST (16:55 UTC)
- Expired
- Dec 13, 2002, 4:00 PM EST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
Counties Broward County, FL, Collier County, FL, Hendry County, FL, Martin County, FL, Palm Beach County, FL, Saint Lucie County, FL
The radar
The Miami radar (KAMX), 126 km from the middle of the area, began a volume at 16:55 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
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 13, 12:19 PM EST | Severe Thunderstorm Warning | MLB | Okeechobee, Saint Lucie | 7 days |
The nearest sounding before it
Miami, FL (KMFL), launched 12:00Z, 4.9 hours before the alert went out and 108 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.
- Mixed-layer CAPE
- 396 J/kg
- Mixed-layer CIN
- -37 J/kg
- Mixed-layer LCL
- 947 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 218 m²/s²
- 0-3 km storm-relative helicity
- 241 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 9.8
The text
As transmitted, in the capitals the NWS used until 2016.
000 WWUS20 KWNS 131655 SEL7 SPC WW 131655 FLZ000-CWZ000-132100- URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 777 STORM PREDICTION CENTER NORMAN OK 1155 AM EST FRI DEC 13 2002 THE STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF EAST CENTRAL AND SOUTH FLORIDA ADJACENT COASTAL WATERS EFFECTIVE THIS FRIDAY MORNING AND AFTERNOON FROM 1155 AM UNTIL 400 PM EST. 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 40 STATUTE MILES EAST AND WEST OF A LINE FROM 125 MILES SOUTH SOUTHWEST OF VERO BEACH FLORIDA TO 40 MILES EAST NORTHEAST OF VERO 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. OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO WATCH NUMBER 776. WATCH NUMBER 776 WILL NOT BE IN EFFECT AFTER 1155 AM EST. DISCUSSION...PRE-FRONTAL SQUALL LINE WITH EMBEDDED BOW STRUCTURES WILL CONTINUE EWD ACROSS S FL THIS AFTERNOON...WHILE ADDITIONAL STORMS FORM IN THE WARM SECTOR E OF THE LINE. THOUGH LOW-LEVEL WINDS AND SHEAR ARE GRADUALLY WEAKENING OVER FL...INSTABILITY AND SHEAR SHOULD REMAIN SUFFICIENT FOR STORMS WITH DAMAGING GUSTS AND A TORNADO OR TWO THROUGH MID AFTERNOON. THE MOST LIKELY THREAT AREA FOR TORNADOES WILL BE ALONG THE IMMEDIATE E COAST WHERE STORMS INTERACT WITH A WEAK SEA BREEZE. 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 450. MEAN STORM MOTION VECTOR 24035. ...THOMPSON 255,0814 275,0802 275,0790 255,0803
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 13, 6:45 AM EST | Tornado Watch | SPC | Brevard, Charlotte, DeSoto, Glades, Hardee, Hendry and 11 more | 5 hr |
Nearby
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.