Special Weather Statement, NWS Miami, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
227 PM EDT THU JUN 30 2011

.AVIATION...THRU. 00Z SAT.
SCATTERED SHOWERS AND STORMS WILL REMAIN IN THE FORECAST THROUGH
THE AFTERNOON AND EVENING HOURS...WHICH MAY RESULT IN BRIEF MVFR
PERIODS WHILE OVER OR AROUND THE TERMINALS. THIS ACTIVITY WILL
LINGER WELL INTO THE EVENING BEFORE DYING DOWN AS AN UPPER TROUGH
NORTH OF THE AREA AND WEAK SURFACE REFLECTION CONTINUE TO
INFLUENCE THE LOCAL WEATHER CONDITIONS. VERY SIMILAR CONDITIONS
WILL BE PRESENT THROUGH THE DAY FRIDAY AS THIS WEAK SURFACE
BOUNDARY CONTINUES TO DROP SOUTH ACROSS THE FLORIDA PENINSULA.
85/AG

&&

.PREV DISCUSSION... /ISSUED 1013 AM EDT THU JUN 30 2011/

DISCUSSION...

THE SHORT TERM FORECAST WAS UPDATED FOR THE REST OF TODAY...MAINLY
TO UPDATE CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE REGION.
THE 12Z SOUNDING INDICATED LOW LEVEL EASTERLY FLOW IN THE LOWEST
LEVELS AND THEN SOUTHWESTERLY FLOW AROUND 5 TO 15 KFT...A CHANGE
FROM PREVIOUS DAYS. THE PWAT IS AROUND 2 INCHES...A DECREASE OF
ABOUT 0.2 TO 0.3 INCHES FROM THE LAST COUPLE OF DAYS. THE UPDATED
FORECAST INCLUDED A SLIGHT INCREASE IN THE POPS ACROSS THE REGION.
THE 12Z SOUNDING INDICATED A COOLING TREND IN THE MID LEVELS AND
THE LAPSE RATES IN THE LOWER LEVELS INDICATES SOME INCREASE IN
INSTABILITY FROM PREVIOUS DAYS. ALTHOUGH CONSIDERABLE CLOUD
COVERAGE ACROSS THE REGION WILL DECREASE MAX TEMPERATURES
TODAY...ANY LOCAL BREAKS IN THE CLOUDINESS COULD ALLOW FOR CONVECTION TO BE
INITIATED...SIMILAR TO EARLY YESTERDAY AFTERNOON. IN ADDITION
THERE ARE STILL SOME LINGERING BOUNDARIES ACROSS THE REGION.
LASTLY...GIVEN THE PRESENCE OF LOW LEVEL CLOUD CONVERGENCE BANDS
ACROSS THE LOCAL GULF AND ATLANTIC WATERS AND THE WEAK LOW LEVEL
WESTERLY SHEAR THERE IS A CHANCE OF WATERSPOUTS ACROSS THE
REGIONAL WATERS.

60

PREV DISCUSSION... /ISSUED 733 AM EDT THU JUN 30 2011/

AVIATION...
THE REGION IS MUCH MORE STABLE THAN THIS TIME YESTERDAY DUE TO
THE RAINFALL ON WEDNESDAY. THE DEEP TROPICAL MOISTURE WILL ALSO
GET PUSHED TO THE NORTH OF THE REGION AND SLIGHTLY DRIER AIR IN
THE LOW/MID LEVELS IS EXPECTED TO MOVE IN FROM THE SOUTHEAST. WILL
LEAVE VCSH FOR KPBI THIS MORNING AS THERE ARE LIGHT SHOWERS
AROUND. THE MORE STABLE CONDITIONS...MID/HIGH CLOUDS OVER THE
REGION AND DRIER AIR WILL LIKELY DELAY TSTORM DEVELOPMENT UNTIL
THIS AFTERNOON WITH LESS COVERAGE OF TSTORMS ACROSS THE REGION.
THEREFORE...PUSHED BACK THE VCTS TO AFTER 18Z FOR THE TAF
SITES...AND ONLY HAVE VCSH WITH CB FOR KAPF. CONVECTION IS
EXPECTED TO WIND DOWN AFTER 00Z WITH LIGHT WINDS EXPECTED
OVERNIGHT.

PREV DISCUSSION... /ISSUED 325 AM EDT THU JUN 30 2011/

DISCUSSION...WATER VAPOR IMAGERY SHOWS A TROUGH ALONG THE EASTERN
SEABOARD OF THE UNITED STATES...EXTENDING ALL THE WAY DOWN INTO
NORTH FLORIDA. THE WEAK ATLANTIC RIDGE LIES ACROSS THE
KEYS/STRAITS. THE PATTERN OVER THE NEXT FEW DAYS WILL CONTINUE
WITH THIS MID/UPPER LEVEL TROUGH MOVING INTO CENTRAL FL WITH THE
WEAK ATLANTIC RIDGE NEAR OR JUST SOUTH OF THE AREA. MOISTURE LOOKS
TO DECREASE IN THE LOWER LEVELS THIS AFTERNOON...AND THIS SHOULD
RESULT IN MORE SCATTERED ACTIVITY AS OPPOSED TO THE WIDESPREAD
ACTIVITY SEEN YESTERDAY. STEERING FLOW IS SW...SO HAVE HIGHEST
POPS INTERIOR AND EAST COAST TODAY.

MODEL CONSENSUS IS FOR CENTRAL FLORIDA TO SEE THE MOST NUMEROUS
ACTIVITY THIS AFTERNOON...WITH SOUTH FL SEEING LESS DUE TO THE
POCKET OF LOW LEVEL DRY AIR. ALSO...SHOULD MENTION THAT WE HAVE
STABILIZED FROM YESTERDAY'S CONVECTION...WITH TEMPS AND DEWPOINTS
SOME 5F LOWER FROM THIS TIME YESTERDAY. IT WILL TAKE SOME TIME TO
RECOVER...SO NOT EXPECTING MUCH ACTIVITY UNTIL THE
AFTERNOON...UNLIKE PREVIOUS DAYS.

THE TREND FOR THE UPCOMING WEEKEND IN THE LAST FEW RUNS OF THE GFS
AND ECMWF ARE NOT GOOD...IF YOU WANT IT DRIER WITH MORE SUN THIS
HOLIDAY WEEKEND. BECAUSE BOTH MODELS LAG THE AFOREMENTIONED
TROUGH ACROSS SOUTH FLORIDA WITH A CONTINUED BAND OF MID LEVEL
CLOUDINESS AS WELL AS SUFFICIENT MOISTURE IN THE LOWER LEVELS
TO RESULT IN AT LEAST SCATTERED CONVECTION EACH DAY. HAVE TRENDED
THE FORECAST FOR THE HOLIDAY WEEKEND TOWARDS THIS SCENARIO...BUT
NOT AS PESSIMISTIC AS THE MODELS SHOW. THE FORECAST SKY COVER AND
POPS MAY NEED FURTHER INCREASING IF THESE CLOUDIER AND WETTER
TRENDS CONTINUE.

FOR EARLY NEXT WEEK THE QUESTION IS HOW MUCH MOISTURE WILL MOVE
INTO SOUTH FL ASSOCIATED WITH A TROPICAL WAVE. THE LATEST ECMWF
RUN IS VERY WET TUE-THU OF NEXT WEEK...BRINGING A SLUG OF DEEP
TROPICAL MOISTURE NORTHWARD FROM THE CARIB...WITH PWATS INCREASING
TO ABOUT 1.4 INCHES AND NO DOUBT A MORE WIDESPREAD HEAVY RAIN
POTENTIAL. HOWEVER...THE GFS IS NOT NEARLY AS AGGRESSIVE. SO NEAR
CLIMO POPS LOOKS GOOD FOR NOW GIVEN THIS UNCERTAINTY.

MARINE...SSE WINDS 10-15 KT TODAY WILL SUBSIDE OVER THE UPCOMING
WEEKEND. SEAS WILL CONTINUE LOW THROUGHOUT THE PERIOD.

FIRE WEATHER...NO CONCERNS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  75  88  75  87 / 40 50 30 40
FORT LAUDERDALE  78  89  78  87 / 30 40 30 40
MIAMI            77  89  76  88 / 30 40 30 40
NAPLES           75  87  75  89 / 30 50 30 40

&&

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

DISCUSSION/MARINE...60/BD
AVIATION/RADAR/FIRE...85/AG

HAZARDOUS WEATHER OUTLOOK FOR SOUTH FLORIDA
NATIONAL WEATHER SERVICE MIAMI FL
333 AM EDT THU JUN 30 2011

FLZ063-066>075-168-172>174-302245-
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-
333 AM EDT THU JUN 30 2011

...A FEW STRONG THUNDERSTORMS POSSIBLE TODAY...
...LOCALLY HEAVY RAINFALL POSSIBLE...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH FLORIDA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS: SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON
THROUGH THE EARLY EVENING. A FEW OF THE THUNDERSTORMS COULD BECOME
STRONG, CONTAINING FREQUENT LIGHTING STRIKES AND STRONG GUSTY
WINDS. HEAVY RAINS WILL ACCOMPANY THE STORMS AS WELL.

WIND: THE STRONGEST THUNDERSTORMS TODAY WILL BE CAPABLE OF
PRODUCING WIND GUSTS TO AROUND 50 MPH.

FLOODING: LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IN SOME SHOWERS
AND THUNDERSTORMS THROUGH THIS EVENING. SLOW STORM MOVEMENT MAY
RESULT IN MINOR STREET FLOODING IN SOME LOCALES.

RIP CURRENTS: THERE IS A SLIGHT RISK OF RIP CURRENTS AT THE LOCAL
ATLANTIC BEACHES DUE TO A SOUTHEAST WIND NEAR 10 MPH.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS ARE EXPECTED TO DEVELOP EACH DAY...WITH THE PRIMARY
RISK BEING LIGHTNING STRIKES...GUSTY WINDS AND HEAVY DOWNPOURS.

.SPOTTER INFORMATION STATEMENT...

WIDESPREAD SPOTTER ACTIVATION IS NOT ANTICIPATED, HOWEVER
INDIVIDUAL SPOTTERS ARE ENCOURAGED TO REPORT HIGH WIND, HAIL AND
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.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MIAMI FL
234 PM EDT THU JUN 30 2011

FLZ071>074-301900-
INLAND BROWARD COUNTY FL INLAND MIAMI-DADE COUNTY FL METRO BROWARD
COUNTY FL METROPOLITAN MIAMI DADE FL
234 PM EDT THU JUN 30 2011

THE NATIONAL WEATHER SERVICE IN MIAMI HAS ISSUED A

* SIGNIFICANT WEATHER ADVISORY FOR...
  SOUTH CENTRAL BROWARD COUNTY
  NORTHEASTERN MIAMI-DADE COUNTY

* UNTIL 300 PM EDT

* AT 230 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
  A STRONG THUNDERSTORM NEAR CORAL GABLES. THIS STORM WAS MOVING
  NORTHEAST AROUND 5 MPH.

FREQUENT LIGHTNING...GUSTY WINDS FROM 45 T0 55 MPH...UP TO
NICKEL-SIZED HAIL...TORRENTIAL DOWNPOURS...OR A COMBINATION OF THESE
ARE POSSIBLE. LIGHTNING IS THE NUMBER ONE WEATHER RELATED KILLER IN
FLORIDA. TREES AND OPEN SHELTERS OFFER NO PROTECTION. THESE WINDS
CAN DOWN SMALL TREE LIMBS AND BRANCHES...AND BLOW AROUND UNSECURED
SMALL OBJECTS. SEEK SHELTER IN A SAFE BUILDING UNTIL THE STORM
PASSES.

LAT...LON 2612 8053 2610 8019 2575 8025 2577 8044
TIME...MOT...LOC 1833Z 180DEG 0KT 2572 8026

85-GIBBS