Special Marine Warning 231, NWS Miami, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
152 AM EDT WED JUL 11 2012

.AVIATION...

FOR THE VERY SHORT TERM...TERMINALS KPBI...KFXE AND KFLL COULD
HAVE BRIEF PERIODS OF SUB-VFR CONDITIONS. TERMINAL KPBI HAS BEEN
ASSIGNED VCTS FOR THE SHORT TERM AND TERMINAL KFXE HAS A BRIEF
HEAVY SHOWER WITH VISIBILITY REPORTED DOWN TO NEAR 2 MILES BUT THE
CELL CONTINUES TO MOVE WESTWARD WITH VISIBILITY AND CEILINGS
CLEARING QUICKLY AFTER 06Z. THE REMAINING TERMINALS HAVE BEEN
ASSIGNED VCSH DURING THE EARLY MORNING HOURS WITH MAINLY VFR
CONDITIONS EXPECTED EXCEPT FOR BRIEF SUB-VFR CONDITIONS WITH A
BRIEF PASSING SHOWER. FOR WEDNESDAY...ALL TERMINALS ASSIGNED VCTS
AT 14Z WITH SCATTERED THUNDERSTORMS POSSIBLE IN THE LATE MORNING
AND AFTERNOON HOURS ACROSS THE PENINSULA.

60

&&

.PREV DISCUSSION... /ISSUED 1035 PM EDT TUE JUL 10 2012/

UPDATE...SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER
THE ATLANTIC...ESPECIALLY OFF THE PALM BEACH COAST. HAVE TRENDED
POPS SCATTERED ALONG THE PALM BEACHES TO ISOLATED ELSEWHERE. THE
HRRR DOES SHOW THE CURRENT TREND WELL AND CONTINUES TO PUSH
ACTIVITY ONSHORE ACROSS PALM BEACH COUNTY...SO HAVE HIGHEST POPS
THERE. THE MIAMI SOUNDING SHOWS THAT THE FLOW BELOW 700 MB HAS
GONE FROM EASTERLY THIS MORNING TO NOW SOUTHEASTERLY...WITH
SLIGHTLY HIGHER INSTABILITY IN THE 6-15K FT LAYER/STEEPER LAPSE
RATES. STILL...LIGHTNING AND HEAVY DOWNPOURS ARE EXPECTED TO BE
THE MAIN IMPACTS FROM THE STORMS OVERNIGHT. /GREGORIA

PREV DISCUSSION... /ISSUED 735 PM EDT TUE JUL 10 2012/

AVIATION...EXPECT SHOWERS TO CONTINUE MOVING ACROSS THE TERMINALS
OVERNIGHT...WITH WINDS BECOMING LIGHT BY 11/01Z. ONCE
AGAIN...EASTERLY FLOW WILL PICK UP SPEED AND SHOWERS AND
THUNDERSTORMS WILL DEVELOP BY 11/14Z...BUT NOT CONFIDENT AT THIS
MOMENT OF THEIR LOCATION RELATED TO THE TERMINALS.
THEREFORE...KEPT VCTS EVERYWHERE AND WILL AMEND IF NECESSARY.

PREV DISCUSSION... /ISSUED 216 PM EDT TUE JUL 10 2012/

DISCUSSION...DEEP LAYER RIDGE HAS BECOME ESTABLISHED ACROSS THE
ATLANTIC AND EXTENDING ACROSS N FL WITH A WEAK TROUGH OVER THE
WESTERN GULF. THIS SYNOPTIC PATTERN WILL PERSIST THROUGH THE SHORT
TERM FCST MAINTAINING A DEEP EASTERLY FLOW ACROSS THE REGION WITH
SLIGHTLY ABOVE AVERAGE PWAT VALUES FOR MID JULY. EMBEDDED IN THE
EAST FLOW WILL BE A SERIES OF WEAK LOW-MID LEVEL TROUGHS
INTERACTING WITH THE ABUNDANT TROPICAL MOISTURE. THE TIMING OF
EACH INDIVIDUAL TROUGH IS UNCERTAIN BUT THIS TYPE OF PATTERN
SUGGESTS NOCTURNAL SHRA/ISOLD TSRA OVER THE ATLANTIC AND GULF
WATERS WITH AFTERNOON AND EARLY EVENING ENHANCED CONVECTION OVER
THE MAINLAND WITH THE INTERIOR AND WEST COAST BEING THE MAIN
FOCUS. THE PRIMARY THREAT WILL BE LOCALLY HEAVY RAINFALL WITH
FREQUENT TO EXCESSIVE LIGHTNING ALTHOUGH A FEW STORMS COULD BECOME
STRONG WITH GUSTY WINDS.

THIS PATTERN WILL CHANGE LITTLE THROUGH THE END OF THE WEEK INTO THE
UPCOMING WEEKEND AS A LARGE MID LEVEL RIDGE WILL BUILD OFF THE
CAROLINA CST AND HEIGHTS SLOWLY RISE OVER THE SOUTHEAST STATES. A
TUTT LIKE FEATURE WILL ALSO TRACK WEST ACROSS CUBA AND THE GULF THIS
WEEKEND. AS THE SFC RIDGE AXIS REMAINS TO THE NORTHEAST OF S FL WILL
MAINTAIN AN EASTERLY FLOW. THIS WILL CONTINUE A TRANSPORT OF
MOIST FLOW ACROSS S FL WITH SCT DIURNAL CONVECTION EXPECTED AND
TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL.

MARINE...WINDS WILL GENERALLY BE 15 KNOTS OR LESS THROUGH AT LEAST
THE END OF THIS WEEK AND POSSIBLY A SLIGHT INCREASE TOWARDS THE
WEEKEND. SEAS WILL BE AT 4 FT OR LESS FOR THE MOST PART WITH SCT
SHRA/TSRA THROUGH THE PERIOD.

FIRE WEATHER...AMPLE LOW LEVEL TROPICAL MOISTURE TO REMAIN IN
PLACE SO NO MAJOR CONCERNS AT THIS TIME.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  89  76  89  76 / 50 30 40 30
FORT LAUDERDALE  89  77  90  78 / 50 30 40 30
MIAMI            89  78  90  77 / 50 30 50 30
NAPLES           89  75  90  76 / 60 30 50 30

&&

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

DISCUSSION/MARINE/FIRE...14/MJB
AVIATION/RADAR...60/BD

HAZARDOUS WEATHER OUTLOOK FOR SOUTH FLORIDA
NATIONAL WEATHER SERVICE MIAMI FL
707 PM EDT TUE JUL 10 2012

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
111600-
LAKE OKEECHOBEE-BISCAYNE BAY-
COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM
20 NM TO 60 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM
TO THE TERRITORIAL WATERS OF THE BAHAMAS-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-
COASTAL WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING FROM
20 TO 60 NM-
707 PM EDT TUE JUL 10 2012

...SCATTERED THUNDERSTORMS POSSIBLE ATLANTIC WATERS...
...SLIGHT RISK OF WATERSPOUTS GULF AND ATLANTIC WATERS...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.

.DAY ONE...TONIGHT

THUNDERSTORMS: THERE IS A CHANCE OF THUNDERSTORMS ACROSS THE
ADJACENT COASTAL WATERS OVERNIGHT. THE PRIMARY IMPACTS WILL BE
OCCASIONAL TO FREQUENT LIGHTNING STRIKES AND HEAVY RAINFALL. A FEW
THUNDERSTORMS MAY ALSO PRODUCE GUSTY WINDS.

WATERSPOUTS: THERE IS A SLIGHT RISK OF WATERSPOUTS OVER THE
GULF WATERS AND THE ATLANTIC WATERS, INCLUDING BISCAYNE BAY.

RIP CURRENTS: LIGHT ONSHORE FLOW WILL RESULT IN A SLIGHT RISK OF
RIP CURRENTS AT THE EAST COAST BEACHES.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THERE IS A CHANCE OF THUNDERSTORMS EACH DAY, ESPECIALLY DURING
THE AFTERNOON AND EVENING HOURS. LOCALLY HEAVY RAINFALL,
OCCASIONAL TO FREQUENT LIGHTNING STRIKES, AND GUSTY WINDS ARE
POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED, HOWEVER INDIVIDUAL SPOTTERS
ARE ENCOURAGED TO REPORT ANY STRONG THUNDERSTORMS TO THE NATIONAL
WEATHER SERVICE IN MIAMI.

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