Area Forecast Discussion
Issued by NWS Miami, FL

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000
FXUS62 KMFL 050818
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
418 AM EDT TUE MAY 5 2015

.DISCUSSION...

A LOW LEVEL TROUGH CONTINUES TO LIFT NORTHWARD INTO THE CENTRAL
AND NORTHWEST BAHAMAS WITH DEEP TROPICAL MOISTURE SLOWLY LIFTING
NORTHWARD AS WELL. THE LATEST WATER VAPOR IMAGERY AND GUIDANCE
CONTINUE TO INDICATE A MID TO UPPER LEVEL TROUGH BUILDING INTO THE
EASTERN GULF WITH SOUTH FLORIDA TO THE EAST OF THE TROUGH AXIS.

LATEST SATELLITE DERIVED MOISTURE ESTIMATES INDICATE THE DEEP
LAYER MOISTURE IS STILL MOVING NORTHWARD WITH THE LEADING EDGE
ACROSS THE FLORIDA KEYS.

FOR TODAY...LATEST GUIDANCE CONSENSUS INDICATES MOISTURE WILL
CONTINUE TO MOVE NORTHWARD AS THE LOW LEVEL TROUGH LIFTS
NORTHWARD INTO THE NORTHERN BAHAMAS AND DEEPENS. FORECAST
SOUNDINGS INDICATE THE REGIONAL PWAT TODAY AT ABOUT 1.5 INCHES
WITH SOME DRYING IN THE LOWER LEVELS BUT NEARLY SATURATED AT THE
MID TO UPPER LEVELS. THE GUIDANCE INDICATES THAT AS THE TROUGH
LIFTS NORTHWARD THE LOW LEVEL MOISTURE CONVERGENCE WILL REMAIN
ACROSS THE BAHAMAS WITH LOW LEVEL DIVERGENCE ACROSS SOUTH
FLORIDA...HENCE THE LOW LEVEL DRIER LAYER. HOWEVER...THE PRESENCE
OF THE MID TO UPPER LEVEL TROUGH WILL PROMOTE THE POTENTIAL FOR
CONVECTION ACROSS THE REGION TODAY. FORECAST SOUNDINGS INDICATE
STEEP MID LEVEL LAPSE RATES AND MID LEVEL TEMPERATURES ABOUT 3
DEGREES COLDER THAN THE SEASONAL NORM WHICH IS CONSIDERABLE.
THEREFORE WILL MAINTAIN WIDESPREAD SHOWERS/THUNDERSTORMS TODAY
ACROSS THE REGION WITH THE GREATEST COVERAGE ACROSS THE ATLANTIC
WATERS AND THE EASTERN HALF OF THE PENINSULA. LOCALLY HEAVY
RAINFALL IN ISOLATED AREAS IS A POSSIBILITY WITH A CHANCE OF LOCAL
URBAN TYPE FLOODING. THERE MAY BE A CHANCE OF WATERSPOUTS WITH
THE ACTIVE CONVECTION TODAY AS WELL.

THE THREAT OF RIP CURRENTS WILL REMAIN HIGH TODAY ACROSS THE
ATLANTIC COAST BEACHES WITH A LINGERING LONG PERIOD SWELL AND
ELEVATED SEAS. REGIONAL WINDS...THE SWELL AND SEAS ARE EXPECTED TO
SLOWLY SUBSIDE TODAY INTO TONIGHT. THE HIGH THREAT WILL REMAIN
THROUGH 00Z TONIGHT AND MIGHT BE EXTENDED BEYOND THAT WITH
ADDITIONAL GUIDANCE TODAY.

FOR WEDNESDAY AND THURSDAY...THERE IS GENERAL AGREEMENT AMONGST
THE SUITE OF GUIDANCE THAT THE LOW LEVEL TROUGH WILL LIFT NORTH
OF THE BAHAMAS TONIGHT INTO WEDNESDAY AND CONTINUE TO DEEPEN INTO
A WEAK CLOSED SURFACE LOW. FURTHER DEEPENING OF THE LOW AND A
GENERALLY NORTHEASTWARD DRIFT IS FORECAST FOR THURSDAY. THE UPPER
LEVEL TROUGH AXIS COULD SHIFT A BIT EASTWARD DURING THIS PERIOD.
THIS SCENARIO WILL CONTINUE TO MAINTAIN AVAILABLE
MOISTURE...COOLER MID LEVEL TEMPS AND POTENTIAL FOR ACTIVE
CONVECTION WITH SCATTERED SHOWERS AND A CHANCE OF THUNDERSTORMS
FORECAST FOR WEDNESDAY AND THURSDAY.

FOR THE EXTENDED FORECAST...THERE IS BROAD GENERAL AGREEMENT IN
THE GLOBAL MODELS THAT THE SURFACE LOW WILL START A WESTWARD
DRIFT THURSDAY NIGHT INTO FRIDAY AND COULD BE OFF THE GEORGIA
COAST ON SATURDAY. THE GUIDANCE SUGGESTS THAT THE WESTWARD MOTION
WILL BE INITIATED BY A LARGE AMPLITUDE UPPER RIDGE FORECAST TO
BUILD ACROSS THE EASTERN CONUS AND A SURFACE RIDGE BUILDING
NORTHWARD OF THE LOW. IF THIS SCENARIO PANS OUT A GENERAL DRYING
TREND IS FORECAST FOR FRIDAY INTO THE WEEKEND...BUT LOTS OF
UNCERTAINTY IN THE EXTENDED FORECAST WITH THIS SCENARIO.


&&

.MARINE...

THE ELEVATED SEAS...REGIONAL WINDS AND LINGERING LONG PERIOD SWELL
ACROSS THE ATLANTIC WATERS ARE ALL EXPECTED TO SLOWLY SUBSIDE
TODAY THROUGH THIS EVENING. THE SMALL CRAFT ADVISORY FOR THE
ATLANTIC WATERS WILL CONTINUE THROUGH 15Z AND THEN FROM 15Z
THROUGH 00Z ONLY THE ATLANTIC WATERS TO THE EAST OF PALM BEACH
COUNTY WILL BE UNDER AN ADVISORY WITH LINGERING SEAS TO NEAR 7
FEET POSSIBLE. FOR THE GULF WATERS...WINDS IN THE 15 T0 20 KNOT
RANGE LIKELY CONTINUE WITH A PRE-CAUTIONARY STATEMENT IN EFFECT
WITH WINDS AND SEAS EXPECTED TO SLOWLY SUBSIDE TODAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  81  73  83  71 /  60  50  40  20
FORT LAUDERDALE  84  74  84  72 /  70  50  50  30
MIAMI            81  73  85  71 /  70  50  50  30
NAPLES           84  68  87  68 /  50  20  30  20

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK THROUGH THIS EVENING FOR FLZ168-172-173.

AM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ650-651-
     670-671.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 AM THIS MORNING
     TO 8 PM EDT THIS EVENING FOR AMZ650-670.

GM...NONE.
&&

$$

SHORT TERM...60/BD
LONG TERM....60/BD



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