000 FXUS62 KMLB 100810 AFDMLB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 310 AM EST FRI FEB 10 2012 .DISCUSSION... ...BEST SHOT AT RAIN IN A LONG TIME TODAY AND TONIGHT... ...TURNING SHARPLY COLDER THIS WEEKEND... TODAY...SURFACE TROUGHING DEVELOPS OVER FLORIDA IN RESPONSE TO MID LEVEL IMPULSES MOVING SOUTHWEST TO NORTHEAST IN THE SOUTHWEST FLOW ALOFT. VEERING LOW LEVEL WIND FLOW AHEAD OF THE TROUGH AXIS PULLS A VERY MOIST AIR MASS NORTHWARD UP THE FLORIDA PENINSULA WITH PRECIPITABLE WATER VALUE AROUND AN INCH AND A HALF. COOLER TEMPERATURES ALOFT...-12C TO -14C...ADVECTING IN AHEAD OF THE MAIN UPPER TROUGH STEEPING MID LEVEL LAPSE RATES AND ALONG WITH MORNING SUN THROUGH BREAKS IN THE CIRRUS FURTHER DESTABILIZING THE ATMOSPHERE THERE WILL BE A POTENTIAL FOR ISOLATED AFTERNOON THUNDERSTORMS AHEAD OF THE FRONT. IF STORMS DO DEVELOP THERE COULD BE SOME QUARTER INCH OR MORE RAINFALL AMOUNTS ESPECIALLY ALONG THE COAST FROM CAPE CANAVERAL SOUTH WHERE CONVERGENCE WOULD BE BETTER DUE TO LOW LEVEL ONSHORE WIND AND SOUTHERLY WIND ALOFT. FRI NIGHT...RAIN CHANCES REMAIN HIGH...LIKELY/60 POP THROUGH AROUND MIDNIGHT OR UNTIL THE FRONT PUSHES ACROSS NORTH TO SOUTH ACROSS CENTRAL FLORIDA. HELD ON TO CHANCE POP FOR THE REST OF THE NIGHT AS LINGERING MOISTURE AND THE WESTERLY WIND RIGHT BEHIND THE FRONT WILL BE ENOUGH FORCING TO PRODUCE LOW CLOUDS AND LIGHT RAIN. SAT-SUN...10/00Z RUNS HAVE COME IN FASTER WITH THE FRONTAL PASSAGE ON SATURDAY...NOW TAKING ALL THE PRECIP OUT OF THE AREA BY MID MORNING. CLOUD COVER WILL DIMINISH FROM NW TO SE AS WELL WITH SKIES CLEARING N OF I-4 BY SUNSET AND AREAWIDE OVERNIGHT. LOW LEVEL WINDS WILL PICK UP FAIRLY QUICKLY OUT OF THE NW BEHIND THE FRONT WITH BREEZY CONDITIONS FOR THE AFTERNOON AND EVENING...ESPECIALLY ALONG THE COAST. THE COLDER AIRMASS FILTERING INTO THE AREA WILL LIMIT MAX TEMPS TO THE LOW-MID 70S. THE REAL BRUNT OF THE COLD WEATHER WILL IMPACT CENTRAL FL AFTER SUNSET ON SATURDAY AS A 1040MB ARCTIC SFC HIGH BUILDS OUT OF THE CENTRAL PLAINS AND INTO THE SOUTHEAST. TIGHT GRADIENT WILL MAINTAIN A STEADY 10-15 MPH NW SFC WIND THAT WILL SEND MIN TEMPS INTO THE M/U30S N OF I-4 AND INTO THE L/M40S ALONG THE COAST...A 30-35F DROP FROM SAT MAX READINGS AND A DROP OF 15-20F FROM THE FRI NIGHT MINS. RELATIVE HUMIDITIES LOOK TO LOW AND WINDS REMAIN TO HIGH FOR FROST TO BE A MAJOR CONCERN...BUT IF CURRENT GUIDANCE HOLDS LOCALIZED FREEZING TEMPERATURES WILL BE POSSIBLE. WIND CHILLS WILL BE A FACTOR AS WELL WITH READINGS FALLING INTO THE M/U20S N OF I-4 AND INTO THE M/U30S ALONG THE COAST. SUNDAY WILL BE A RAW DAY ACROSS THE REGION ESPECIALLY CONSIDERING THE RECENT ABOVE NORMAL TEMPERATURES. HIGHS ARE NOT EXPECTED TO GET OUT OF THE 50S ALONG AND NORTH OF THE I-4 CORRIDOR WITH LOW 60S FOR AREAS SOUTH. THIS WILL BE IN COMBINATION WITH BREEZY NORTHERLY WINDS WHICH WILL KEEP WIND CHILLS IN THE 40S THROUGH MID MORNING FOR MANY AREAS. NORTHERLY WINDS WILL BECOME MORE ONSHORE BY LATE SUNDAY BUT ALSO DROP TO 5 MPH OR LESS OVERNIGHT WHICH WILL ALLOW FOR BETTER RADIATIONAL COOLING IF NO MARINE STRATOCU IS ADVECTED ONSHORE. TEMPERATURES DIPPING INTO THE LOW-MID 30S ACROSS THE INTERIOR SUN NIGHT WITH FREEZING TEMPS ACROSS LAKE AND INTERIOR VOLUSIA COUNTIES...AND LOW 40S ALONG THE COAST AND METRO AREAS. MON-THU...THE SURFACE HIGH OVER THE SOUTHEAST WILL SLIDE INTO THE WESTERN ATLANTIC EARLY IN THE WEEK...BRINGING WINDS OUT OF THE EAST AND SOUTHEAST AND ENDING THE BRIEF PERIOD OF COLD AIR ADVECTION ACROSS THE STATE. TEMPERATURES ON MONDAY WILL REMAIN A FEW DEGREES BELOW NORMAL IN THE UPPER 60S TO AROUND 70 WITH OVERNIGHT LOWS IN THE MID-UPPER 40S. FORECAST UNCERTAINTIES CREEP IN ONCE AGAIN FOR TUESDAY ONWARDS AS MODEL SOLUTIONS ARE NOW LEANING TOWARDS A SHORTWAVE MOVING ACROSS THE TN VALLEY LEADING TO A WEAK SFC LOW DEVELOPING ACROSS THE DEEP SOUTH AND BOUNDARY DROPPING INTO N FL. THE ECMWF BRINGS THIS BOUNDARY THROUGH THE PENINSULA LATE WEDNESDAY WHILE THE GFS WASHES IT OUT TO OUR NORTH. HAVE LEFT MENTIONABLE POPS OUT OF THE FORECAST FOR THE MOMENT. WITH FLOW EXPECTED TO BE GENERALLY E-SE...TEMPERATURES WILL CLIMB TO ABOVE NORMAL BY MID WEEK IN THE UPPER 70S AND LOW 80S. && .AVIATION... MVFR CEILINGS LATE OVERNIGHT AND FIRST COUPLE OF HOURS OF DAYLIGHT. DAYTIME HEATING SHOULD MIX OUT THE MVFR CEILING MID LATE MORNING THEN VFR THROUGH MID AFTERNOON WHEN MVFR SHOWERS DEVELOP AS THE LOW LEVEL FLOW BECOMES MORE SOUTHEAST TO SOUTH. TEMPO MVFR CONDITIONS DURING THE EVENING AND OVERNIGHT AHEAD OF A COLD FRONT. VFR SUNRISE SATURDAY MORNING. && .MARINE... TODAY...EASTERLY WIND AROUND 15 KNOTS VEERING TO THE SOUTHEAST THEN TO THE SOUTH DURING THE DAY AS SURFACE TROUGHING OVER THE MAINLAND SHIFTS EAST INTO THE ATLANTIC. WINDS SHIFT TO THE SOUTHWEST DURING THE EVENING AS A COLD FRONT IS FORECAST TO BE APPROACHING EAST CENTRAL FLORIDA AND ITS ADJACENT COASTAL WATERS. FRONT PASSAGE BETWEEN MIDNIGHT NORTHERN AREAS AND SUNRISE SOUTHERN WATERS. SOUTHWEST WIND SHIFTS TO THE WEST AFTER MIDNIGHT AND INCREASES NORTH TO SOUTH AS COLDER AIR ADVECTS IN BEHIND THE FRONT. SEAS 3 TO 4 FEET NEARSHORE AND 4 TO 5 FEET OFFSHORE UNTIL AFTER THE FRONT MOVES THROUGH AND THE WIND PICKS UP FIRST OVER THE NORTHERN OFFSHORE WATERS AND BUILDS SEAS TO 6 FEET WELL OFFSHORE...BEYOND 40 MILES OF SHORE TOWARD SUNRISE SATURDAY. SAT-SUN...TREACHEROUS BOATING CONDITIONS FOR THE WEEKEND AS SFC WINDS VEER FROM W TO NW ON SATURDAY BEHIND A COLD FRONT PUSHING THROUGH THE STATE. STRONG ARCTIC SFC HIGH WILL DROP INTO THE CENTRAL PLAINS AND INTO THE SOUTHEAST BY SUNDAY...KEEPING A TIGHT GRADIENT OVER THE WATERS. NW WINDS 15-20KTS ON SATURDAY BEHIND THE FRONT BECOMING N 20-25KT SAT NIGHT WITH A WIND SURGE AND SLOWLY DIMINISHING LATE SUNDAY. SEAS WILL BUILD OFFSHORE INITIALLY ON SATURDAY UNDER OFFSHORE FLOW WITH 4-6FT NEARSHORE/6-8FT OFFSHORE. NORTH FLOW ON SUNDAY WILL BUILD SEAS MORE QUICKLY AND CLOSER TO THE COAST...7-8 FT NEARSHORE AND 9-12 FT OFFSHORE. CAUTIONARY STATEMENTS WILL LIKELY BE NEEDED ON SATURDAY...WITH ADVISORY CONDITIONS STARTING SATURDAY EVENING THROUGH AT LEAST LATE SUN. MON-TUE...WINDS WILL VEER TO THE NE/E AND DIMINISH TO AROUND 10KTS EARLY MON MORNING...AND THEN VEER TO THE SE/S 10-15KTS ON TUE AS THE SFC HIGH BUILDS OFF THE SOUTHEASTERN SEABOARD AND WEAKENS OVER THE WESTERN ATLC. SEAS WILL BE A LITTLE SLOWER TO SUBSIDE...THOUGH ARE EXPECTED TO DROP BELOW 6FT OFFSHORE BY MONDAY NIGHT WITH 2-3FT NEARSHORE/4-5FT OFFSHORE ON TUESDAY. && .PRELIMINARY POINT TEMPS/POPS... DAB 75 53 71 37 / 70 60 20 10 MCO 78 57 72 39 / 70 60 20 10 MLB 77 60 74 41 / 80 60 30 10 VRB 78 58 74 41 / 80 60 30 10 LEE 77 54 70 35 / 60 60 20 0 SFB 78 57 72 37 / 70 60 20 10 ORL 77 57 71 42 / 70 60 20 10 FPR 79 58 75 42 / 80 60 30 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...WIMMER LONG TERM....MOSES