Severe Thunderstorm Warning 102, NWS Miami, FL

SOUTH FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
251 PM EDT WED OCT 20 2004

.DISCUSSION...LATEST SURFACE ANALYSIS SHOWS SURFACE RIDGE JUST TO THE
SOUTH OF THE CWA WITH WEAK FRONTAL TROUGH ACROSS NORTH CNTRL FL. 12Z
UPR AIR ANALYSIS SHOWS TROUGH ACROSS EAST COAST DIGGING SOUTH WITH
S/W ROTATING ALONG THE BASE OF THE TROUGH AS IT APPROACHES THE CWA
FROM THE NW. ALONG WITH THESE FEATURES UPR LVL JET IS ALSO DIGGING
INTO THE EASTERN GULF OF MEXICO BETWEEN RIDGE TO THE WEST AND THE
TROUGH TO THE EAST. UPR LVL STREAM LINE ANALYSIS SHOWS GOOD UPR LVL
DIVERGENCE ASSOCIATED WITH THIS FEATURES RIGHT OVER THE CWA. 12Z
SNDG ALSO SHOWED PLENTY OF INSTABILITY WITH LI OF -8 AND MODIFIED
CAPES OF AROUND 4200 THIS AFTERNOON. PWAT WAS AROUND 1.7 IN AND
THESE LEVELS HAVE RAISED A LITTLE SINCE THEN PER LATEST GPSMET WATER
VAPOR RETRIEVALS. SO THE ONLY THING MISSING FOR THIS AFTERNOON SO
FAR IS A LOW LEVEL FORCING MECHANISM TO START THE CONVECTION ACROSS
THE MAINLAND. LOOKS LIKE C-BREEZES WILL DO THE TRICK AND WITH WHAT
IN MIND WILL KEEP LKLY POPS FOR EASTERN HALF AND HIGH END SCT
ELSEWHERE FOR THE LATE AFTERNOON. PLAN OF LOWERING THEM FOR THE
EVENING PERIOD AND THEN LEAVE AT LEAST A SLIGHT CHC OVERNIGHT AS THE
S/W CLEARS THE AREA. WILL MENTION A FEW STORM COULD BE STRONG FOR
THE LATE AFTERNOON AND EARLY EVENING PERIOD IF CONVECTION BEGINS THE
MATERIALIZE.

AFTER TONIGHT...FRONTAL TROUGH MOVES OFFSHORE WITH CYCLOGENESIS
TAKING PLACE OFFSHORE THE MID ATLANTIC STATES THROUGH THE END OF THE
WEEK AND RIDGE BUILDING FROM THE NORTH ACROSS THE CWA. WITH
THAT...EXPECT SLIGHT CHC POPS ACROSS ATL WATERS AND EAST COAST
THROUGH THE PERIOD.

FOR THE EXTENDED PERIOD...RIDGE MOVES SOUTH ACROSS CWA OVER THE
WEEKEND BRINGING DRY WEATHER WITH IT. NO COLD WEATHER IN SIGHT AT
THIS TIME ONLY DRIER AND WITH TEMPS CLOSE TO NORMAL. ANOTHER BADGE
OF MOISTURE IS EXPECTED TO AFFECT THE AREA EARLY NEXT WEEK AS A WEAK
FRONTAL SYSTEM MOVES INTO THE NORTHERN PART OF THE STATE. EXPECT
SLIGHT CHC POPS AGAIN FOR THAT TIME PERIOD.
&&

.MARINE...WITH STORM SYSTEM DEVELOPING OFF THE MID ATLANTIC STATES
LATE IN THE WEEK...WINDS WILL PICK UP ACROSS THE AREA BUT NOT AS
HIGH AS GFS SUGGEST. IN ANYCASE SCA CONDITIONS EXPECTED TO DEVELOP
ACROSS THE ATLANTIC WATERS BY FRIDAY WITH SWELLS BEGINNING TO AFFECT
THE PALM BEACH WATERS LATE FRIDAY REACHING MODERATE LEVELS BY
SATURDAY (3 TO 4 FEET) ALONG WITH WIND WAVES AS HIGH AS 8 FEET OR
SO. THESE CONDITIONS SHOULD GRADUALLY IMPROVE THEN THROUGH THE REST
OF THE WEEKEND AS SYSTEM MOVES AWAY FROM THE COAST.
&&

.FIRE WEATHER...NO CONCERNS HERE SINCE RHS WILL REMAIN ABOVE
CRITICAL NUMBERS THROUGH THE FORECAST PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 85 70 83 / 40 20 20 20
FORT LAUDERDALE 73 86 71 84 / 50 20 20 20
MIAMI           74 86 73 85 / 50 20 20 20
NAPLES          73 85 69 85 / 20 00 00 00
&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATE
NATIONAL WEATHER SERVICE MIAMI FL
1041 AM EDT WED OCT 20 2004

FLZ063-066>075-201800-
BROWARD METROPOLITAN-EASTERN COLLIER-GLADES-HENDRY-MAINLAND MONROE-
MIAMI-DADE METROPOLITAN-PALM BEACH EASTERN-PALM BEACH WESTERN-
WESTERN BROWARD-WESTERN COLLIER-WESTERN MIAMI DADE-
1041 AM EDT WED OCT 20 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.

.DAY ONE...TODAY

...STRONG THUNDERSTORMS POSSIBLE THIS AFTERNOON...

A TROUGH WILL MOVE ACROSS SOUTH FLORIDA THROUGH THIS EVENING.
SUFFICIENT MOISTURE AND INSTABILITY AHEAD OF THE TROUGH WILL ALLOW
FOR THUNDERSTORMS TO DEVELOP THIS AFTERNOON. SOME OF THE
THUNDERSTORMS COULD BECOME STRONG WITH LOCALLY HEAVY RAIN, GUSTY
WINDS AND SMALL HAIL. FREQUENT LIGHTNING WILL ALSO ACCOMPANY SOME OF
THE STORMS.

ADDITIONAL INFORMATION AND DETAILED GRAPHICS CAN BE FOUND ON THE
NATIONAL WEATHER SERVICE WEB SITE AT MIAMIWEATHER.INFO. FOR
INFORMATION IN SPANISH, VISIT OUR WEB SITE AT ELTIEMPOENMIAMI.INFO.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

SEAS ACROSS THE ATLANTIC WATERS WILL RAPIDLY BUILD LATE FRIDAY...AS
SURFACE WINDS AROUND LOW PRESSURE OFF THE MID ATLANTIC STATES SENDS
A NORTHEAST SWELL INTO THE AREA. SEAS MAY REACH 8 FEET THIS
WEEKEND ACROSS THE WATERS OFF OF PALM BEACH COUNTY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MIAMI FL
445 PM EDT WED OCT 20 2004

FLZ068-072-202115-
BROWARD METROPOLITAN-PALM BEACH EASTERN-
445 PM EDT WED OCT 20 2004

...STRONG THUNDERSTORMS IN SOUTHEAST PALM BEACH COUNTY MOVING TOWARD
NORTHEAST BROWARD...

AT 444 PM EDT NATIONAL WEATHER SERVICE DOPPER RADAR SHOWED STRONG
THUNDERSTORMS OVER SOUTHEAST PALM BEACH COUNTY FROM ABOUT 4 MILES
WEST OF DELRAY BEACH WEST TO ABOUT 6 MILES NORTH OF PARKLAND. THESE
STORMS WILL BE MOVING SOUTH ACROSS DELRAY BEACH AND BOCA RATON AND
INTO EXTREME NORTHEAST BROWARD COUNTY AROUND DEERFIELD
BEACH...PARKLAND...CORAL SPRINGS...AND POMPANO BEACH THROUGH 530 PM
EDT.

EXPECT FREQUENT LIGHTNING...GUSTY WINDS TO 50 MPH...PEA-SIZED HAIL...
AND TORRENTIAL DOWNPOURS. A WARNING WILL BE ISSUED IF THIS
THUNDERSTORM ACTIVITY STRENGTHENS.

THE PRIMARY IMPACTS WILL BE FREQUENT LIGHTNING AND GUSTY WINDS OF 40
TO 50 MPH...WHICH CAN DOWN SMALL TREE LIMBS AND BRANCHES...AND BLOW
AROUND UNSECURED SMALL OBJECTS. SEEK SHELTER IN A SAFE BUILDING UNTIL
THE STORM PASSES.

REPORT SIGNIFICANT WEATHER OR DAMAGE TO THE NEAREST LAW ENFORCEMENT
AGENCY OR YOUR COUNTY EMERGENCY MANAGEMENT. THEY WILL RELAY YOUR
REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN MIAMI. OR
YOU CAN ALSO CALL THE NATIONAL WEATHER SERVICE IN MIAMI DIRECTLY AT
305.229.4522 TO REPORT SIGNIFICANT WEATHER.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MIAMI FL
513 PM EDT WED OCT 20 2004

FLZ067-202145-
PALM BEACH WESTERN-
513 PM EDT WED OCT 20 2004

AT 511 PM...NATIONAL WEATHER SERVICE RADAR INDICATED A STRONG STORM
ALONG US HIGHWAY 27 NEAR OKEELANTA...MOVING TO THE SOUTHEAST AT 15
MPH.

MOTORISTS ALONG HIGHWAY 27 CAN EXPECT FREQUENT LIGHTNING...GUSTY
WINDS TO 50 MPH...PEA-SIZED HAIL...AND TORRENTIAL DOWNPOURS. A
WARNING WILL BE ISSUED IF THIS THUNDERSTORM ACTIVITY STRENGTHENS.