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049 FXUS62 KMFL 190655 AFDMFL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 255 AM EDT SUN MAY 19 2013 .SHORT TERM (TODAY-TUESDAY)... RECENTLY ANIMATED WATER VAPOR LOOP WAS CHARACTERIZED WITH AN UPPER RIDGE EXTENDING NORTH OVER THE MS VALLEY GRADUALLY BUILDING EASTWARD WITH NORTHWEST FLOW STREAMING OVER THE STATE OUT AHEAD OF IT. A FEW WEAK IMPULSES EMBEDDED WITHIN THIS NORTHWEST FLOW WILL CONTINUE TO INFLUENCE THE LOCAL WEATHER THROUGH THE SHORT-TERM PERIOD. THE MORNING SURFACE ANALYSIS DEPICTED THE SUBTROPICAL RIDGE AXIS EXTENDING WEST ACROSS CENTRAL FLORIDA WITH LIGHT SOUTHEAST WINDS OVER SOUTH FLORIDA. THE LATEST NUMERICAL GUIDANCE HAS INITIALIZED WELL WITH THESE SYNOPTIC FEATURES AND GENERALLY INDICATES INCREASING DEEP LAYER MOISTURE ALONG WITH AN UPPER LOW CLOSING OFF OVERHEAD BY TUESDAY. MODEL SOUNDINGS REFLECT THIS AND GENERALLY INDICATE SLIGHTLY COOLER H5 TEMPS AND DECENT MID-LEVEL LAPSE RATES EACH DAY. THE MID-LEVEL CAP THAT WAS EVIDENT YESTERDAY FROM 650-700MB IS FORECAST TO DIMINISH TODAY. THESE FACTORS COMBINED WITH LIGHT SOUTHEAST LOW-LEVEL FLOW...INCREASING MOISTURE AND DAYTIME HEATING WILL ONLY ENHANCE THE DIURNALLY INDUCED CONVECTION EACH DAY THROUGH THE AFTERNOON AND EARLY EVENING PERIODS. SEA BREEZE AND MESOSCALE BOUNDARIES WILL SERVE AS THE FOCUS FOR SHOWER/TSTM INITIATION EACH DAY...ESPECIALLY ACROSS THE INTERIOR WHERE THE GULF AND ATLANTIC BREEZES CONVERGE. ALTHOUGH THE SEVERE THUNDERSTORM THREAT REMAINS LOW...A FEW STRONG STORMS WILL CERTAINLY REMAIN POSSIBLE WITH THE MAIN IMPACTS BEING HAIL AND DAMAGING STRAIGHT-LINE WINDS (40-55 MPH). THE BEST CHANCE FOR EAST COAST/METRO SHOWERS WILL BE THROUGH THE LATE NIGHT AND EARLY MORNING HOURS AS SHOWERS DEVELOP OVER THE ATLANTIC AND SPREAD ASHORE. MODEL SOUNDINGS DO INDICATE MORE OF A NORTHERLY UPPER FLOW TODAY...SO CIRRUS BLOW-OFF SHOULDN`T IMPACT THE EAST COAST TEMPERATURES AS MUCH AS YESTERDAY AFTERNOON. TEMPERATURES WILL REMAIN AROUND OR SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. .LONG TERM (WEDNESDAY-SUNDAY)... THE GFS/GFS ENSEMBLE MEAN AND ECMWF GENERALLY REMAIN IN GOOD AGREEMENT THROUGH THE EXTENDED PERIOD AND INDICATE A PERSISTENT UPPER TROUGH/LOW CONTINUING TO INFLUENCE THE LOCAL AREA THROUGH THE MID-WEEK PERIOD. 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 LOW COULD LEAD TO MORE WIDESPREAD RAINFALL ACTIVITY WEDNESDAY THROUGH THURSDAY. THE GFS AND ECMWF BOTH INDICATE THIS WEAK SURFACE REFLECTION FURTHER DEVELOPING AS A SURFACE LOW LIFTING NORTH OVER THE STATE ON THURSDAY. DESPITE THE CONSISTENCY FROM RUN TO RUN OVER THE PAST 24 HRS...WE WILL REMAIN STEADY WITH THE RAINFALL CHANCES SINCE THIS IS STILL BEYOND THE 72 HR TIME FRAME. ANY SHIFT TO THE EAST AS THIS SURFACE FEATURE LIFTS NORTH COULD KEEP THE BULK OF THE RAINFALL EAST OF THE AREA. DRIER AIR WILL OVERSPREAD THE AREA AS THIS FEATURE LIFTS NORTH FRIDAY THROUGH THE WEEKEND. && .AVIATION... VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE PERIOD. EASTERLY FLOW WILL PERSIST ACROSS THE AREA WITH HIGH PRESSURE SITUATED ACROSS THE WESTERN ATLANTIC. SHORT RANGE MODELS DEPICT A GULF BREEZE DEVELOPING AROUND 17Z WHICH SHOULD PROVIDE ENOUGH OF A FOCUS FOR SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT. BELIEVE MOST OF THE ACTIVITY SHOULD REMAIN CONFINED ACROSS THE WESTERN INTERIOR BUT COULD BUILD BACK WEST TOWARD KAPF. KEPT OUT ANY THUNDER MENTION FOR NOW AND COVERED WITH VCSH. KEPT EAST COAST TERMINALS DRY ATTM. && .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. A WEAK SURFACE TROUGH WILL LIFT NORTH OVER THE STATE THROUGH THE MID-WEEK PERIOD AND WILL LEAD TO INCREASING RAINFALL CHANCES AND POSSIBLY A PERIOD OR TWO WITH NEAR ADVISORY LEVEL WINDS AND SEAS OVER THE ATLANTIC WATERS. && .FIRE WEATHER... SOUTHEAST LOW-LEVEL WINDS ALONG WITH INCREASING MOISTURE AND RAIN CHANCES WILL BE EXPECTED THROUGH THE WEEK. 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. MORE WIDESPREAD RAINFALL ACTIVITY WILL BE POSSIBLE THROUGH THE MID-WEEK TIME FRAME. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 86 74 84 72 / 20 20 20 20 FORT LAUDERDALE 84 75 85 74 / 20 20 20 20 MIAMI 85 75 85 74 / 20 20 20 20 NAPLES 89 71 88 70 / 30 30 30 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...10/CD