The 2nd Severe Thunderstorm Watch of the day has been issued for the southern 2/3rds of the Florida Peninsula including all of Tampa Bay. A substantially elevated risk for severe storm persists through the day with extreme instability, very high moisture and unusually high temperatures. CAPE values are currently sitting around 4000 J/KG which indicates an extremely unstable airmass, even by Florida standards. An isolated tornado or waterspout is possible as well with low level boundary collisions such as outflow boundaries or sea breezes.
Currently storm development is occurring along a residual boundary stretching from Citrus county through Lakeland, and down towards Sebring. The overall movement of these storms is to the SSE, but these storms do have the potential to propogate away if a strong outflow boundary develops from these.
Additionally another heat advisory has been issued since afternoon temps are sitting in the mid to upper 90s inland, near 90 at the coast. This is creating heat index values of 105-110F, extremely hot conditions for Florida.
URGENT – IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 499
NWS STORM PREDICTION CENTER NORMAN OK
235 PM EDT TUE JUN 23 2009THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OFFLORIDA
COASTAL WATERSEFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 235 PM UNTIL
900 PM EDT.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 60
STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTHEAST OF
OCALA FLORIDA TO 55 MILES SOUTH OF MIAMI FLORIDA. FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU9).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…THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 495. WATCH NUMBER 495 WILL NOT
BE IN EFFECT AFTER 235 PM EDT. CONTINUE…WW 496…WW 497…WW
498…DISCUSSION…SEASONABLY STRONG NLY FLOW ALOFT WILL CONTINUE ACROSS
FL THIS AFTERNOON/EVENING AS DEEP MID LEVEL TROUGH DIGS OFF THE NERN
FL COAST. AIR MASS REMAINS VERY UNSTABLE…DESPITE EARLIER LINEAR
MCS…WITH SUFFICIENT SHEAR FOR ORGANIZATION INTO LINES/CLUSTERS AND
PERHAPS A BRIEF SUPERCELL OR TWO. DAMAGING WINDS AND ISOLATED LARGE
HAIL WILL REMAIN PRIMARY THREATS…ALTHOUGH A BRIEF
WATERSPOUT/TORNADO COULD ACCOMPANY STORMS ALONG RESIDUAL SURFACE
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 500. MEAN STORM
MOTION VECTOR 33030.
