Tornado Warning 12, NWS Tampa Bay, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY-RUSKIN FL
225 PM EDT FRI JUN 4 1999

IMPRESSIVE INSTABILITY ACROSS THE REGION CONTINUES THIS AFTERNOON.
BOTH LAPS DATA AND MODEL SOUNDINGS SHOW LIFTED INDICES AROUND -6.
THERE REMAINS A CONSIDERABLE AMOUNT OF DRY AIR AT THE MID LEVELS...
KEEPING THE THREAT OF WIND DAMAGE AND HAIL OVER THE NORTHERN TWO-THIRDS
OF THE AREA IN ANY STORMS THAT DEVELOP.

MOST NOTABLE CONVECTION IS CURRENTLY ALONG THE EAST COAST SEA BREEZE
BOUNDARY (WHICH IS A BIT FARTHER EAST AT 2PM THAN I THOUGHT IT WOULD
BE AT THIS TIME).  ONE CELL IS ALSO FIRING IN EASTERN HERNANDO COUNTY.

SEVERAL ELEMENTS ARE COMING INTO PLAY FOR THE SHORT-TERM. FIRST...WE
HAVE THE NEARLY INEVITABLE SEA BREEZE COLLISION WHICH WILL TAKE PLACE
LATE THIS AFTERNOON OVER THE WESTERN HALF OF THE PENINSULA.  SECOND...
THE DRY AIR ALOFT IS THERE...ESPECIALLY ACROSS THE NORTH.  THIRD...THE
SEA BREEZE COLLISION TODAY SHOULD COINCIDE WITH THE MAXIMUM HEATING.
ALL OF THESE THINGS KEEP THE POSSIBILITY OF SEVERE STORMS ACROSS THE
AREA THROUGH THIS EVENING...WITH THE GREATEST RISK BEING ACROSS THE
NORTH...MAINLY LEVY...CITRUS...AND SUMTER COUNTIES. WITH THE NORTHERLY
STEERING FLOW PRESENT...WILL HAVE TO WATCH FOR THESE CELLS FIRING OVER
THE NORTHERN COUNTIES AND PROPAGATING SOUTHWARD AS WE WORK TOWARD
EVENING. THE SOUTHERN COUNTIES MAY NOT BE TOTALLY OUT OF THE WOODS AS
THE RISK IS ALWAYS THERE WITH THE SEA BREEZE COLLISIONS THAT A STRONG
STORM OR TWO COULD SPIN-UP THERE AS WELL.

AS THE WEEKEND EVOLVES WE WILL HAVE TO WATCH A NUMBER OF FEATURES
AFFECTING OUR WEATHER.  THE MODELS HINT AT DROPING A WEAK SHORTWAVE
DOWN THE SIDE OF THE RIDGE ON SATURDAY. THIS WILL HELP TO GIVE US A
LITTLE DYNAMICAL FORCING SATURDAY AND ADD TO THE CHANCE OF POPS
FOR ALL AREAS.

ON SUNDAY...A BROAD HIGH BUILDS OFF OF THE MID-ATLANTIC AND PRESSURES
LOWER TO OUR SOUTH COURTESY OF A TROPICAL WAVE.  THIS WILL PICK UP
OUR EASTERLY FLOW QUITE A BIT. IT LOOKS AS IF THIS HIGH WILL ALSO
TRY TO SHOVE SOME DRIER AIR OVER FLORIDA ON SUNDAY. THE HIGH'S EFFORTS
MAY BE FOR NAUGHT HOWEVER...AS THE AVN WANTS TO DEVELOP A LOW OVER THE
BAHAMAS AND SPREAD PLENTY OF MOISTURE OVER FLORIDA ON SUNDAY. AT THIS
EARLY STAGE WILL ADOPT A WAIT AND SEE ATTITUDE AND SUGGEST KEEPING
30% POPS ACROSS THE SOUTH AND 20% ACROSS THE CENTRAL SECTIONS FOR
SUNDAY...BUT FIND IT HARD TO GET TOO EXCITED ABOUT THE TROPICAL
SYSTEM THIS EARLY IN THE GAME.

TPA  71/91/70/91  1412  (RECOMMEND MENTIONING EVEN POPS IN ZONES TNGT)
LAL  69/93/69/92  1412
FMY  73/92/74/93  1513

PAYLOR