Severe Thunderstorm Warning 67, NWS Tampa Bay, FL

WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
247 PM EDT TUE AUG 8 2000

TRICKY FORECAST THIS PACKAGE WITH REGARD TO DETAILS...BUT IN GENERAL
EXPECT A BIT MORE CONVECTION (AS WE HAVE SEEN TODAY) THAN IN RECENT
DAYS...WITH PERHAPS MORE WIDESPREAD ACTIVITY BY THE WEEKEND.
CONSIDERING THAT WE STILL NEED MORE RAIN...THIS WOULD BE WELCOME
INDEED.

ALL MODELS ARE SIMILAR IN HOLDING A WEAK SHEAR AXIS ACROSS THE
STATE THROUGH THE PERIOD.  HOWEVER...DIFFERENCES ARISE...ESP BETWEEN
THE NGM AND ETA CONCERNING THE BACKSIDE OF THE TUTT CIRCULATION NOW
MOVING THROUGH.  THE NGM COMPLETELY KILLS THE SW FLOW BEHIND IT...
LEAVING A WEAK NE FLOW OVER THE AREA BY 48H.  THE ETA TURNS OUR
CURRENT ENE FLOW ALOFT TO A SW FLOW...CONTINUING THROUGH 60H.  THE
AVN MERGES WHAT'S LEFT OF THE TUTT FLOW WITH INCREASING SW FLOW
AHEAD OF DIGGING TROUGH IN EASTERN NOAM.

THE DIFFERENCES ARE IMPORTANT CONCERNING THE FUTURE MOVEMENT OF
T.D. 4 (OR "GYRE") SPINNING 200 MILES E OF VRB.  SHOULD THE ETA
VERIFY...THIS SYSTEM WILL BE WELL AWAY FROM FL BY FRIDAY.
OTHERWISE...IT WILL LIKELY TAKE ANOTHER DAY TO GET RID OF IT.  IN
ANY CASE...CURRENT FCSTS TAKE IT NOWHERE NEAR OUR CWFA.

THE FCST:  TONIGHT...PLENTY OF CONVECTION ACROSS THE NW CWFA ATTM.
EXPECT THIS TO CONTINUE INTO THE EVENING.  AC SHIELD FROM OLD
CONVECTION OFF THE ATLC COAST HAS DISRUPTED THE ECSB AND WILL HOLD
DEVELOPMENT DOWN OVER THE INTERIOR.  SW PORTION REMAINS AWAY FROM
THE BEST FORCING (SHEAR AXIS...OLD BOUNDARIES)...SO WILL KEEP
MINIMAL POPS THERE.

THURS...SFC FLOW GOES SLACK...SO SEA BREEZE COLLISIONS WILL BE
PRIMARY MECHANISM FOR MAINLY AFTN ACTIVITY.  BEST CHC WILL BE ACROSS
THE N 1/2...AND EXPECT INTERIOR CENTRAL COS TO GET IN ON THE ACT AS
MID AND UPPER ENE FLOW WEAKENS.

THURS NIGHT...TAKING THE ETA/AVN SOLN AT FACE VALUE GIVES AN
INCREASED CHC OF COASTAL ACTIVITY IN DEEPENING SW FLOW...ESP OVER
THE N PORTION.  HOWEVER...IT'S A BIT TOO EARLY TO GO ALL OUT...SO
WILL RETAIN LOW CHC POPS (NO TIMING) N...AND THE MORE USUAL SCT EVE
POPS ELSW.

FRI...SW FLOW SHOULD INCREASE A BIT MORE AND SHEAR AXIS STRENGTHENS
A BIT IN ADVANCE OF UPPER TROF'S APPROACH.  THIS COULD PUSH
ACTIVITY INLAND EARLY...BUT AGAIN TOO RISKY TO TRY TO TIME...EVEN FOR
THE COAST.  WILL BROAD BRUSH "SCT" 40 POP...NO TIMING NEAR SHORE
AND AFTN TIMING INLAND.

EXTENDED...AVN MAY BE A BIT OVERDONE WITH DEPTH OF TROF (TAKES IT
DOWN TO CUBA) BUT THE IDEA OF AN OLD SHEAR AXIS ENHANCING PCPN
CHANCES IS A GOOD ONE.  WILL GO WITH VRBL CLDS/SCT POPS SAT-MON
WITH SEASONABLE TEMPS.

MARINE:  LIGHT NW FLOW BECOMING SW WITH SOME INCREASE BY SAT.  FLOW
SHOULD RETURN TO S THEN SE LATER IN THE WEEKEND.  HIGHEST WINDS
(OUTSIDE OF CONVECTION) 15 KT...BUT MOST WILL BE 10 KT OR LESS.

FIRE WX:  NO FLAGS EXPECTED.

PRELIM NUMBERS:
TPA BB 074/091/076/090 2434
FMY BB 073/093/074/091 1324 88

.TBW...NONE.

GOLDSMITH