Severe Thunderstorm Watch 21

Issued

Feb 13, 2007, 12:54 PM EST (17:54 UTC)

Expired

Feb 13, 2007, 6:05 PM EST

In force

5 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Tampa radar (KTBW), 74 km from the middle of the area, began a volume at 17:56 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.

Two or more tornadoes

20%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

80%

• Mesoscale Discussion 149Feb 13, 11:17 AM EST
• Mesoscale Discussion 155Feb 13, 3:15 PM EST

000
WWUS20 KWNS 131758
SEL1  
SPC WW 131758
FLZ000-CWZ000-140000-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 21
NWS STORM PREDICTION CENTER NORMAN OK
1255 PM EST TUE FEB 13 2007

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

       CENTRAL FLORIDA
       COASTAL WATERS

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 1255 PM UNTIL
700 PM EST.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
STATUTE MILES EITHER SIDE OF A LINE FROM 20 MILES NORTH OF OCALA
FLORIDA TO 50 MILES EAST OF FORT MEYERS FLORIDA.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU1).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 20...

DISCUSSION...TSTM CLUSTER OFF THE W CST OF FL...AND ADDITIONAL
STORMS LIKELY TO FROM IN HEATED ENVIRONMENT OVER THE INTERIOR...MAY
POSE A THREAT FOR HIGH WIND AND HAIL AS REGION CONTINUES TO
DESTABLIZE DOWNSTREAM FROM 50 KT WLY MID LEVEL JET STREAK.  WHILE
LOW LEVEL SHEAR IS WEAK OVER MOST OF WW AREA...LOW LEVEL DIRECTIONAL
SHEAR WILL BE ENHANCED INVOF E CST SEA BREEZE BOUNDARY AND OUTFLOWS
FROM EARLIER STORMS.  PART OF WATCH NUMBER 21 ALONG THE IMMEDIATE E
CST MAY REQUIRE UPGRADE TO TORNADO IF IT APPEARS THAT DISCRETE
STORMS WILL INDEED INTERACT WITH THOSE BOUNDARIES.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 26035.


...CORFIDI

Severe Thunderstorm Watches in Florida, 2007Every severe thunderstorm watch in 2007

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.