Tropical Storm Warning 2, NWS Miami, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
742 AM EDT TUE SEP 28 2010

.AVIATION...
INCRG CLOUDINESS CAN BE XPCTD THRU THE PD AS A LOW PRES
SYS IN THE W CARIB MOVS NE TWD CUBA. ATTM ISOLD-WDLY SCT SHRA MOVG
NW OVR ATLC WTRS AND OCNLLY ONSHORE. VCSH IN E COAST TAFS ATTM AND
AFT 14 CB RMKS THEN AFT 16Z TSRA XPCTD TO DVLP. SPEED OF TSRA MVMNT
MAY LIMIT MVFR CIG/VSBY DURATION. MVFR CIG/VSBY PSBL AS WELL BUT AFT
00Z WHEN SYSTEM GETS CLOSER BUT NO TEMPO ATTM INDICATING IN TAFS
ATTM. SFC WNDS SE 10-14KTS WITH OCNL GUSTS 20 KTS.

60

&&

.PREV DISCUSSION... /ISSUED 504 AM EDT TUE SEP 28 2010/

..FLOOD WATCH ISSUED FOR MUCH OF SOUTH FLORIDA...
..POTENTIAL FOR A WIDESPREAD HEAVY RAINFALL EVENT INCREASING...

DISCUSSION...
CURRENT WATER VAPOR IMAGERY DEPICTS TROPICAL MOISTURE STREAMING
UP THE FLORIDA PENINSULA AND OFF THE SOUTHEAST U.S. COAST. A
PESKY UPPER LOW IS CENTERED OVER THE OHIO VALLEY...WITH A COLD
FRONT TRAILING INTO NORTH FLORIDA. MEANWHILE...AN AREA OF LOW
PRESSURE CONTINUES TO FORM SOUTH OF CUBA AND WILL ALLOW
CONSIDERABLE DEEP MOISTURE TO CONTINUE PUSHING NORTH...WITH FIRST
SIGNIFICANT IMPACTS ON SOUTH FLORIDA THIS AFTERNOON.

MODEL GUIDANCE SUGGESTS SCATTERED SHOWERS AND THUNDERSTORMS WILL
BECOME WIDESPREAD AND LOCALLY HEAVY BY LATE IN THE DAY. IT IS
INTERESTING TO NOTE THAT THE GFS AND ECMWF HAVE SHIFTED EVEN A
BIT FARTHER EAST WITH THE AXIS OF HEAVIEST RAINFALL...WHICH WOULD
IMPACT ONLY THE IMMEDIATE EAST COAST. MEANWHILE...THE NAM HAS
BECOME WETTER AND ALSO KEEPS THE HEAVIEST PRECIPITATION FARTHER
WEST...WHERE IT IMPACTS MUCH OF THE PENINSULA INCLUDING AT LEAST
THE WEST COAST FOR SEVERAL HOURS. NAM12 FORECAST SOUNDINGS FOR
MIAMI INDICATE PRECIPITABLE WATERS APPROACHING 2.5 INCHES BY 21Z
TODAY...RISING TO 2.75 INCHES BY 08Z TONIGHT. WHILE THESE AMOUNTS
ARE EXTREMELY IMPRESSIVE...THEY ARE A BIT LOWER THAN THOSE
FORECAST 24 HOURS AGO. SHOWER COVERAGE AND INTENSITY WILL
CERTAINLY BE ON THE INCREASE BY EVENING AS LOW LEVEL
SOUTHEASTERLY FLOW RESULTS IN STRONG CONVERGENCE ALONG AND TO THE
SOUTH OF THE STALLED FRONTAL BOUNDARY OVER CENTRAL FLORIDA. GIVEN
THE COPIOUS AMOUNT OF MOISTURE...DEEP SATURATION THROUGH H4...AND
THE POTENTIAL FOR LINEAR BANDS OF VERY HEAVY RAINFALL...FLOODING
IS A CONCERN. THE HEAVIER BANDS OF RAINFALL MAY BECOME TRAINED
OVER THE SAME LOCALES...WITH RAINFALL RATES IN EXCESS OF 2 INCHES
PER HOUR QUITE POSSIBLE.

THE MOST WIDESPREAD AND HEAVIEST RAINFALL IS ANTICIPATED LATE
THIS EVENING THROUGH WEDNESDAY MORNING...WITH THE AXIS OF DEEP
MOISTURE THEN PUSHING OFF THE EAST COAST BY 18Z WEDNESDAY.
RAINFALL AMOUNTS OF 3 TO 5 INCHES ARE POSSIBLE ALONG THE EAST
COAST INCLUDING THE METRO AREAS...WITH LOCALLY HIGHER AMOUNTS. 2
TO 4 INCHES OF RAINFALL IS EXPECTED ELSEWHERE IN THE WATCH AREA.
GLADES AND HENDRY COUNTIES MAY SEE 1 TO 3 INCHES - A HYDROLOGIC
OUTLOOK (ESF) WAS CONTINUED FOR THIS AREA.

IT SHOULD BE NOTED THAT THE TRACK AND FORWARD SPEED OF THE MID-
UPPER LEVEL LOW ACROSS THE OHIO VALLEY...ALONG WITH ITS DIGGING
TROUGH...WILL BE CRITICAL IN DETERMINING IF THE AXIS OF HEAVIEST
RAINFALL TRAVELS ACROSS SOUTH FLORIDA...OR TO THE EAST OVER THE
ATLANTIC. ADDITIONALLY...IF THE FRONTAL BOUNDARY STALLS FARTHER
TO THE EAST...MUCH OF THE HEAVIEST RAINFALL WILL CERTAINLY BE
PUSHED OFF THE MAINLAND.

CONDITIONS WILL BEGIN TO IMPROVE BY LATE WEDNESDAY AFTERNOON AS
THE LOW BEGINS TO PULL NORTHEAST AND PRECIPITABLE WATERS QUICKLY
FALL AS DRIER ALOFT ARRIVES FROM THE NORTH.

FORECAST REMAINS HIGHLY UNCERTAIN FOR THE END OF THE WEEK AS
ANOTHER TROPICAL CYCLONE MAY TRY TO FORM IN THE NORTHWEST
CARIBBEAN AND LIFT NORTH TOWARD SOUTH FLORIDA SATURDAY OR SUNDAY.
AT THIS TIME...WE OPTED TO MAKE FEW CHANGES TO THE EXTENDED
FORECAST AND AWAIT BETTER MODEL CONTINUITY AND AGREEMENT.

MARINE...WINDS WILL GRADUALLY INCREASE TODAY AND TONIGHT...WITH
SMALL CRAFT CONDITIONS POSSIBLE ACROSS THE ATLANTIC WATERS BY
DAYBREAK WEDNESDAY. THE WIND FORECAST REMAINS SOMEWHAT
UNCERTAIN...AND WILL BE DEPENDENT ON THE TRACK OF A DEVELOPING
LOW TO THE SOUTH OF CUBA.

FIRE WEATHER...NO CONCERNS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  87  76  87  75 / 80 80 80 50
FORT LAUDERDALE  87  78  86  78 / 80 80 80 50
MIAMI            87  76  86  78 / 80 80 80 50
NAPLES           86  75  86  78 / 70 70 60 30

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
     AFTERNOON FOR COASTAL BROWARD-COASTAL COLLIER-COASTAL MIAMI
     DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND BROWARD-
     INLAND COLLIER-INLAND MIAMI DADE-INLAND PALM BEACH-MAINLAND
     MONROE-METRO BROWARD-METRO MIAMI DADE-METRO PALM BEACH.

AM...NONE.
GM...NONE.
&&

DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...60/BD

HAZARDOUS WEATHER OUTLOOK FOR SOUTH FLORIDA...UPDATED
NATIONAL WEATHER SERVICE MIAMI FL
927 AM EDT TUE SEP 28 2010

FLZ063-066>075-168-172>174-282200-
GLADES-HENDRY-INLAND PALM BEACH-METRO PALM BEACH-COASTAL COLLIER-
INLAND COLLIER-INLAND BROWARD-METRO BROWARD-INLAND MIAMI DADE-
METRO MIAMI DADE-MAINLAND MONROE-COASTAL PALM BEACH-COASTAL
BROWARD-COASTAL MIAMI DADE-FAR SOUTH MIAMI DADE-
927 AM EDT TUE SEP 28 2010

...FLOOD WATCH FOR MOST OF SOUTH FLORIDA LATE THIS AFTERNOON THROUGH WEDNESDAY AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.

.DAY ONE...TODAY AND TONIGHT

FLOODING: INCREASING SHOWERS AND SOME THUNDERSTORM ACTIVITY THROUGH
THE AFTERNOON WILL LEAD TO LOCALLY HEAVY RAINFALL THAT COULD
FLOOD LOW LYING AND FLOOD PRONE AREAS. BY LATE THIS AFTERNOON INTO
TONIGHT...RAINFALL COULD SIGNIFICANTLY INCREASE AND FLOODING MAY
OCCUR...ESPECIALLY IN THE EAST COAST METROPOLITAN AREAS. A FLOOD
WATCH IS IN EFFECT FOR ALL OF MAINLAND SOUTH FLORIDA WITH THE
EXCEPTION OF GLADES AND HENDRY COUNTIES...IN EFFECT UNTIL WEDNESDAY
AFTERNOON.

THUNDERSTORMS: ISOLATED THUNDERSTORMS CAN BE EXPECTED WITH LIGHTNING
STRIKES...TORRENTIAL RAIN AND WIND GUSTS TO 30 MPH POSSIBLE.

TORNADO: THERE IS A MINIMAL RISK OF A WEAK TORNADO FROM LATE THIS
AFTERNOON THROUGH MIDDAY WEDNESDAY.

WIND: GUSTY WINDS TO AROUND 40 MPH ARE POSSIBLE IN FAST MOVING SHOWERS
AND THUNDERSTORMS, ESPECIALLY ACROSS THE ATLANTIC WATERS AND EAST
COAST METRO AREAS LATE TONIGHT.

RIP CURRENTS: A SOUTHEAST WIND OF 10 TO 15 MPH WILL LEAD TO A SLIGHT
RISK OF RIP CURRENTS ALONG THE ATLANTIC BEACHES TODAY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

LOW PRESSURE WILL MOVE OFF CUBA EARLY WEDNESDAY AND PUSH NORTHEAST
ALONG THE SOUTHEAST FLORIDA COAST THROUGH THE DAY. WIDESPREAD HEAVY
RAINFALL WILL BE POSSIBLE WITH A POTENTIAL FOR SOME
FLOODING...ESPECIALLY IN THE EAST COAST METROPOLITAN AREAS...THOUGH
ALL OF SOUTH FLORIDA HAS SOME VULNERABILITY.

AN INCREASE IN WINDS OVER THE LOCAL WATERS WEDNESDAY WILL LEAD TO AN
INCREASED THREAT OF RIP CURRENTS ALONG COASTAL AREAS. CONDITIONS FOR
MARINERS COULD DETERIORATE AS WELL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT, BUT SPOTTERS
ARE ENCOURAGED TO REPORT ANY FLOODING TO THE NATIONAL WEATHER
SERVICE FORECAST OFFICE IN MIAMI.

FOR MORE INFORMATION...VISIT THE NATIONAL WEATHER SERVICE IN
MIAMI WEBSITE AT WWW.WEATHER.GOV/MIAMI.