Severe Thunderstorm Warning 5, NWS Tampa Bay, FL

WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
236 AM EST THU MAR 29 2001

CURRENTLY...LARGE CANOPY OF MID AND HIGH LEVEL CLOUDS COVERS ALL OF
THE FORECAST AREAS EARLY THIS MORNING. 88D RETURNS INDICATE A LARGE
AREA OF CONVECTION OVER THE ADJACENT GULF WATERS SPREADING EAST AHEAD
OF SHORT WAVE TROUGH OVER THE CENTRAL GULF. MUCH MILDER THIS MORNING
COMPARED TO PREVIOUS MORNINGS WITH TEMPERATURES MAINLY IN THE 60S.

SHORT TERM...AFTER REVIEWING MODELS IT APPEARS THAT THE MESO-ETA/AVN
SEEM TO HAVE INITIALIZED FEATURES THE BEST THIS MORNING...SO WILL
USE IN THIS PACKAGE. ACTIVE PERIOD OF WET WEATHER AND POSSIBLE SEVERE
THUNDERSTORMS IS ON TAP FOR THE ENTIRE CWA TODAY THROUGH FRIDAY AS
SERIES OF SHORT WAVE TROUGHS/VORT MAXS AND WEAK SURFACE LOWS MOVE
ACROSS THE GULF AND NEWD THROUGH THE SERN GULF STATES THROUGH THE
PERIOD.

FIRST SHORT WAVE WILL INDUCE WEAK SURFACE LOW DEVELOPMENT OFF THE LA
COAST THIS MORNING WITH THE LOW TRACKING NEWD ACROSS AL/GA THIS
AFTERNOON. A SECOND STRONGER SHORT WAVE AND MID LEVEL JET STREAK
WILL APPROACH THE FLORIDA WEST COAST BY LATER TONIGHT AND EARLY
FRIDAY MORNING. INCREASING DEEP LAYERED MOISTURE...INSTABILITY AND
FAVORABLE JET POSITION ALOFT ENHANCING DIVERGENCE WILL RESULT IN
STRONG UVV FIELDS THROUGH THE PERIOD WHICH WILL RESULT IN HIGH POP
REGIME FOR SHOWERS AND THUNDERSTORMS. WITH THIS IN MIND PLAN TO
ADVERTISE CATEGORICAL POPS NORTH...AND LIKELY CATEGORY CENTRAL AND
SOUTH. IN ADDITION MODEL SOUNDINGS PROG INCREASING AND VEERING LOW
AND MID LEVEL WIND FIELDS WHICH WILL SUPPORT THE POSSIBILITY OF
STRONG TO SEVERE THUNDERSTORMS AS WELL AND WILL WORD FOR IN 5 AM
PACKAGE...AND HIT ON IN HWO LATER THIS MORNING. TIGHTENING GRADIENT
WILL SUPPORT WINDY WORDING FOR MOST ZONES. CLOUDS AND EXPECTED PRECIP
SHOULD KEEP TEMPS SOMEWHAT COOLER THAN YESTERDAYS READINGS. GUIDANCE
NUMBERS ARE CLOSE AND BLEND SHOULD SUFFICE ACROSS THE BOARD.

BY FRIDAY NIGHT MAIN UPPER SUPPORT FOR PRECIP BEGINS TO SHIFT EAST
SO PLAN TO TAPER POPS BACK TO HIGH CHANCE CATEGORY (50%) ACROSS THE
BOARD. AMPLE MOISTURE WILL CONTINUE TO SUPPORT MOSTLY CLOUDY SKIES
AND TEMPERATURES WILL CONTINUE NEAR OR SLIGHTLY ABOVE SEASONAL
LEVELS.

EXTENDED...FRONTAL BOUNDARY ACROSS THE NORTHERN PENINSULA ALONG WITH
AMPLE MOISTURE WILL CONTINUE THE THREAT OF SHOWERS AND STORMS ON
SATURDAY AND SATURDAY NIGHT. THEN NEXT STRONG SHORT WAVE TROUGH AND
ATTENDANT COLD FRONT WILL BEGIN TO AFFECT THE CWA ON SUNDAY WITH THE
POSSIBILITY OF YET ANOTHER SQUALL LINE DURING THE LATE AFTERNOON AND
EVENING HOURS...WITH PRECIP FINALLY ENDING FROM NORTH TO SOUTH BY
EARLY MONDAY MORNING. COOLER AND DRIER WEATHER IS EXPECTED FOR
TUESDAY AND WEDNESDAY AS HIGH PRESSURE BUILDS IN OVER THE GULF. THE
ONGOING EXTENDED LOOKS GOOD...BUT WILL REVIEW MRF LATER THIS MORNING
AND MAKE ANY ADJUSTMENTS IF NEEDED.

MARINE...TIGHTENING GRADIENT WILL RESULT IN INCREASING WIND AND SEA
STATES TODAY THROUGH FRIDAY AND WILL HIGHLIGHT SMALL CRAFT ADVISORY
IN THE 430 AM PACKAGE. WIND/SEAS WILL WEAKEN ON SATURDAY...THEN
INCREASE AGAIN ON SUNDAY AND MONDAY AS THE NEXT COLD FRONT
APPROACHES.

FIRE WEATHER...NO PROBLEMS EXPECTED TODAY OR FRIDAY.

PRELIMINARY NUMBERS
TPA TT 078/069 078/068 7865
FMY TT 081/069 082/070 6865

.TBW...SMALL CRAFT ADVISORY TODAY BONITA BEACH TO SUWANNEE RIVER OUT
       60NM INCLUDING TAMPA BAY.

MCMICHAEL

FLZ039-042-043-048>052-055>057-060>062-065-291630-

WEST CENTRAL AND SOUTHWEST FLORIDA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
541 AM EST THU MAR 29 2001

...SCATTERED THUNDERSTORMS TODAY AND TONIGHT SOME POSSIBLY SEVERE...

...SMALL CRAFT ADVISORY IN EFFECT TODAY FROM BONITA BEACH TO THE
   SUWANNEE RIVER OUT 60 NM INCLUDING TAMPA BAY...

ABUNDANT LOW LEVEL MOISTURE...ADEQUATE INSTABILITY...AND AN UPPER
LEVEL TROUGH OF LOW PRESSURE MOVING EAST FROM THE GULF OF MEXICO WILL
RESULT IN NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS ACROSS WEST
CENTRAL AND SOUTHWEST FLORIDA TODAY...SOME OF WHICH COULD BECOME
SEVERE.

A LARGE AREA OF RAIN WITH EMBEDDED THUNDERSTORMS OVER THE ADJACENT
GULF WATERS EARLY THIS MORNING WILL BEGIN TO MOVE INTO WEST CENTRAL
AND SOUTHWEST FLORIDA BY LATER THIS MORNING...WITH ADDITIONAL SHOWERS
AND THUNDERSTORMS DEVELOPING ACROSS THE REGION DURING THE AFTERNOON
HOURS. BY TONIGHT ANOTHER UPPER LEVEL DISTURBANCE ALONG WITH THE
APPROACH OF A MID LEVEL JET WILL HELP TO INCREASE THE COVERAGE AND
INTENSITY OF SHOWERS AND THUNDERSTORM ACROSS THE REGION ESPECIALLY
DURING THE LATE EVENING AND OVERNIGHT HOURS.

AT THE PRESENT TIME THE PRIMARY THREAT FROM THUNDERSTORMS WILL BE
STRONG GUSTY WINDS IN EXCESS OF 45 MPH...FREQUENT DEADLY LIGHTNING...
VERY HEAVY RAINS...AND POSSIBLY SOME SMALL HAIL. IN ADDITION STRONG
WINDS IN THE LOWER AND MID LEVEL OF THE ATMOSPHERE WILL PROVIDE AN
ENVIRONMENT THAT WILL BECOME INCREASINGLY FAVORABLE FOR ISOLATED
TORNADOES...DAMAGING WIND GUSTS AND MARINE WATERSPOUTS ESPECIALLY BY
LATE THIS MORNING AND CONTINUING INTO TONIGHT.

IN ADDITION TO THE THUNDERSTORMS INCREASING SOUTH WINDS OF 20 TO 25
KNOTS WITH HIGHER GUSTS CAN BE EXPECTED OVER THE ADJACENT GULF WATER
THROUGH TONIGHT. THESE STRONG WINDS WILL TO BUILD SEAS OVER THE GULF
AND MAKE BAY AND INLAND WATERWAYS VERY ROUGH. MARINERS SHOULD BE ON
THE LOOKOUT FOR THUNDERSTORMS AND SHOULD SEEK A SAFE HARBOR
IMMEDIATELY IF THREATENING WEATHER APPROACHES. SMALL CRAFT OPERATORS
SHOULD NOT VENTURE FAR FROM PORT TODAY.

ALL RESIDENTS OF WEST CENTRAL AND SOUTHWEST FLORIDA SHOULD REMAIN
ALERT TO RAPIDLY CHANGING WEATHER CONDITIONS TODAY. IF THREATENING
WEATHER APPROACHES YOUR LOCATION MOVE INDOORS IMMEDIATELY. SKYWARN
SPOTTERS ARE ASKED TO RELAY ANY REPORTS OF SEVERE WEATHER TO THE
NATIONAL WEATHER SERVICE OFFICE HERE IN RUSKIN.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR LOCAL MEDIA OUTLETS FOR
ADDITIONAL STATEMENTS AND OR WARNINGS SHOULD THEY BECOME NECESSARY.
ANOTHER HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED BY THIS OFFICE LATER
THIS MORNING.

MCMICHAEL