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000
FXUS62 KMFL 181305
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
905 AM EDT SAT MAY 18 2013

.UPDATE...
MORNING SOUNDING DATA INDICATES A MOISTENING TREND OF THE LOCAL
AIR MASS. THIS IS CONFIRMED BY RADAR THIS MORNING SHOWING
SCATTERED SHOWERS ALONG THE EAST COAST AND ATLANTIC, WITH EARLIER
SHOWERS OVER THE GULF OF MEXICO AS WELL. THIS ALL POINTS TO A
GENERAL INCREASE IN SHOWERS AND THUNDERSTORMS THIS AFTERNOON,
ESPECIALLY INTERIOR AND LAKE OKEECHOBEE AREAS WHERE SOUTHEAST TO
SOUTH LOW-LEVEL FLOW WILL FOCUS CONVERGENCE. MINOR MID-LEVEL SHORTWAVE
MOVING ACROSS SOUTH FLORIDA FROM THE GULF THIS AFTERNOON WILL COOL
THE MID-LEVELS A BIT THIS AFTERNOON, ACTING TO ERODE MID-LEVEL
CAPPING AND HELPING IN THE DEVELOPMENT OF A FEW STRONG STORMS
ACROSS THE INTERIOR/LAKE AREAS. LIGHTNING, GUSTY WINDS AND SMALL
HAIL ARE THE PRIMARY IMPACTS.

SHOWERS/STORMS THIS AFTERNOON WILL LIKELY MOVE LITTLE OR DRIFT
EAST, WHICH SHOULD RESULT IN METRO/COASTAL AREAS ALONG BOTH COASTS
REMAINING MOSTLY DRY THIS AFTERNOON. IN ALL, NO CHANGES OF NOTE TO
THE PREVIOUS FORECAST PACKAGE.

MOLLEDA

&&

.PREV DISCUSSION... /ISSUED 740 AM EDT SAT MAY 18 2013/

AVIATION...
ISOLATED LIGHT TO MODERATE SHOWERS AND POSSIBLY A THUNDERSTORM OR
TWO WILL CONTINUE ACROSS THE COASTAL ATLANTIC WATERS THROUGH THE
MORNING HOURS. STILL EXPECT A FEW OF THESE SHOWERS TO PUSH INLAND
THROUGH THE LATE MORNING HOURS. THEREFORE...KEPT VCSH MENTION AT ALL
EAST COAST SITES. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH
THE PEAK HEATING HOURS OF THE DAY WILL BE ACROSS INTERIOR AND
WESTERN AREAS WITH A DEVELOPED GULF BREEZE. HOWEVER...CANNOT RULE
OUT AN ISOLATED THUNDERSTORM TO AFFECT THE EAST COAST TERMINALS THIS
AFTERNOON...BUT LEFT ANY THUNDER MENTION OUT OF TAFS FOR NOW.

PREV DISCUSSION... /ISSUED 300 AM EDT SAT MAY 18 2013/

SHORT TERM (TODAY-MONDAY)...
ANOTHER WARM AND PLEASANT WEEKEND IS ANTICIPATED ACROSS SOUTH
FLORIDA WITH TEMPERATURES REMAINING AROUND TO SLIGHTLY ABOVE NORMAL
EACH DAY. THE LATEST NUMERICAL GUIDANCE REMAINS PERSISTENT AND IN
GOOD AGREEMENT DEPICTING AN UPPER RIDGE BUILDING EASTWARD OVER THE
MS VALLEY TRAILING A SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST
FLOW ALOFT. AS THIS SHORTWAVE ADVANCES E-SEWD OVER THE
STATE...UPPER HEIGHTS WILL SLIGHTLY FALL OVER THE STATE BY THE END
OF THE DAY. MODEL SOUNDINGS ACROSS THE NORTHERN AND INTERIOR
LOCATIONS OF THE LOCAL AREA REFLECT THIS AND INDICATE SOME MID-
LEVEL COOLING BY 00Z (H5 TEMPS AROUND -11C) WITH MID-LEVEL LAPSE
RATES STEEPENING (-6 TO -7 C/KM). THIS COMBINED WITH LIGHT
SOUTHEAST LOW-LEVEL FLOW...A SUFFICIENT AMOUNT OF LOW-LEVEL
MOISTURE AND DAYTIME HEATING WILL SUPPORT A FEW STORMS LATER TODAY
THROUGH THE LATE AFTERNOON/EARLY EVENING TIME FRAME. THE BEST
CHANCE FOR THIS ACTIVITY WILL BE ACROSS THE INTERIOR AND NORTHERN
LOCATIONS. THE FSU GRIDDED LIGHTNING PROBABILITY DATABASE AND THE
LATEST GRIDDED MOS THUNDERSTORM PROBABILITIES ARE GENERALLY
OUTPUTTING 20-40 PERCENT CHANCES OVER THESE INTERIOR LOCATIONS
THROUGH THIS TIME. THE MAIN LIMITING FACTORS FOR WIDESPREAD DEEP
MOIST CONVECTION WILL BE A PERSISTENT MID-LEVEL CAP BETWEEN 650 MB
AND 700 MB ALONG WITH PLENTY OF MID-LEVEL DRY AIR EN-TRAINING INTO
ANY DEVELOPING CELLS. ANY STORM THAT DOES DEVELOP COULD BECOME
STRONG WITH THE MAIN IMPACTS BEING SMALL HAIL AND DAMAGING
STRAIGHT-LINE WINDS (40-55 MPH). THE LATEST HI-RES MODEL
REFLECTIVITIES BETWEEN THE WRF AND NAM GENERALLY LINE UP WELL AND
DEPICT SOME ACTIVITY INITIATING INLAND AND TOWARD THE NORTH AROUND
LAKE OKEECHOBEE THROUGH THE LATE AFTERNOON AND EARLY EVENING
PERIODS. SIMILAR CONDITIONS WILL PERSIST WITH THE EASTERLY LOW-
LEVEL FAVORING INTERIOR AFTERNOON ACTIVITY AGAIN ON SUNDAY AND
MONDAY. OVERNIGHT AND THROUGH THE EARLY MORNING HOURS EACH
DAY...SHOWERS AND A FEW STORMS ACROSS THE ATLANTIC WATERS AND THE
EAST COAST LOCATIONS WILL REMAIN POSSIBLE DUE TO THE CONFLUENT
BOUNDARIES SETTING UP DOWNSTREAM OF THE BAHAMAS AND RADIATIONAL
CLOUD-TOP COOLING.

LONG TERM (MONDAY NIGHT-FRIDAY)...
THE GFS/ENSEMBLE MEAN AND ECMWF GENERALLY REMAIN IN GOOD AGREEMENT
THROUGH THE EXTENDED PERIOD AND INDICATE A PERSISTENT UPPER TROUGH
CONTINUING TO INFLUENCE THE LOCAL AREA. ADDITIONALLY...A SURGE OF
DEEP LAYER MOISTURE LATER IN THE WEEK ASSOCIATED WITH A WEAK SURFACE
TROUGH EMBEDDED IN THE EASTERLY FLOW COMBINED WITH THE UPPER TROUGH
COULD LEAD TO MORE WIDESPREAD RAINFALL ACTIVITY EACH DAY WEDNESDAY
THROUGH FRIDAY. HOWEVER...WE WILL CONTINUE TO MONITOR LATER MODEL
TRENDS FOR CONSISTENCY OVER THE WEEKEND BEFORE INCREASING THE
RAINFALL CHANCES. TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL EACH DAY.

AVIATION...
ISOLATED LIGHT TO MODERATE SHOWERS WILL CONTINUE ACROSS THE COASTAL
ATLANTIC WATERS THROUGH THE EARLY MORNING HOURS. LATEST HRRR AND
LOCAL MODELS INCREASE COVERAGE OF SHOWERS THROUGH THE MORNING AND
PUSH THEM INLAND ACROSS THE EAST COAST METRO AREAS UNDER WEAK
EASTERLY FLOW. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH
THE PEAK HEATING HOURS OF THE DAY WILL BE ACROSS INTERIOR AND
WESTERN AREAS WITH A DEVELOPED GULF BREEZE. HOWEVER...CANNOT RULE
OUT AN ISOLATED THUNDERSTORM TO AFFECT THE EAST COAST TERMINALS THIS
AFTERNOON...BUT LEFT ANY THUNDER MENTION OUT OF TAFS FOR NOW.

MARINE...
LIGHT TO MODERATE EAST AND SOUTHEAST WINDS WILL CONTINUE THROUGH
MUCH OF THE FORECAST PERIOD AS HIGH PRESSURE REMAINS IN CONTROL
NORTHEAST OF THE MARINE AREA. ISOLATED OVERNIGHT AND EARLY MORNING
SHOWERS WILL REMAIN POSSIBLE EACH DAY ACROSS THE ATLANTIC WATERS.

FIRE WEATHER...
SOUTHEAST LOW-LEVEL WINDS ALONG WITH PLENTY OF LOW-LEVEL MOISTURE
WILL PERSIST THROUGH THE WEEKEND. MOST OF THE SHOWERS AND STORMS
THAT DEVELOP WILL BE FOCUSED ALONG THE EAST COAST THROUGH THE EARLY
MORNING HOURS AND ACROSS THE INTERIOR LOCATIONS THROUGH THE
AFTERNOON/EVENING PERIODS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  86  74  85  74 / 20 20 20 20
FORT LAUDERDALE  85  76  86  76 / 20 20 20 20
MIAMI            87  75  87  75 / 20 20 20 20
NAPLES           89  71  89  71 / 20 20 30 10

&&

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

$$

PUBLIC/MARINE...59/MOLLEDA
AVIATION/RADAR/FIRE...84/AK