FXUS62 KMLB 131904 AFDMLB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 304 PM EDT THU MAR 13 2014 .DISCUSSION... ...MUCH COOLER TONIGHT BEHIND THE RECENT COLD FRONT... ...HAZARDOUS MARINE CONDITIONS CONTINUE INTO TONIGHT... CURRENT-TONIGHT...AFTERNOON HIGHS STRUGGLING TO MEET FORECAST HIGHS THUS FAR. WITH CLEAR SKIES AND DEWPOINT READINGS IN THE 30S WOULD NOT BE SURPRISED TO SEE TEMPERATURES BEGIN TO DROP LIKE A ROCK AFTER SUNSET...ESPECIALLY WHERE WINDS DIE DOWN QUICKEST. SURFACE HIGH PRESSURE CONTINUES TO BUILD OVER THE DEEP SOUTH AND SOUTHEAST U.S. OVERNIGHT. NORTHERLY WINDS HAVE BEEN DECREASING THIS AFTERNOON AND WILL BE ABLE TO GET RID OF THE LAKE WIND ADVISORY BY THE AFTERNOON FORECAST PACKAGE ISSUANCE TIME. WINDS WILL CONTINUE TO DECREASE AFTER SUNSET BECOMING LIGHT NORTHERLY WITH MODEL GUIDANCE SUGGESTING A NORTH-NORTHEAST DIRECTIONAL COMPONENT BY SUNRISE FRI MORNING. SKIES SHOULD REMAIN MOSTLY CLEAR WITH CONDITIONS DRY. UNSEASONABLY COLD TONIGHT. OVERNIGHT LOWS WILL RANGE FROM THE LOWER 40S TO AROUND 40 DEGREES ACROSS INLAND VOLUSIA AND LAKE COUNTIES TO THE UPPER 40S ALONG THE BREVARD AND INDIAN RIVER COASTS...EXCEPT LOWER TO MIDDLE 50S ALONG THE IMMEDIATE BEACHSIDE AREAS OF SAINT LUCIE AND MARTIN COUNTIES...ALSO TO INCLUDE THE BARRIER ISLANDS. FRI...HIGH PRESSURE WILL MOVE OFF OF THE SOUTHEAST U.S. COAST WITH RIDGING REMAINING NORTH OF THE AREA. THIS WILL ALLOW WINDS TO VEER TO OUT OF THE EAST OR EAST-SOUTHEAST WITH SPEEDS 7-12 MPH...EXCEPT 10-15 MPH ALONG THE SPACE AND TREASURE COASTS. WILL GRADUALLY SEE A FEW MORE CLOUDS DEVELOPING OVER EAST CENTRAL FLORIDA AS LOW-LEVEL MOISTURE SLOWLY INCREASES...THOUGH CONDITIONS WILL REMAIN DRY. AFTER A COOL START TO THE DAY ON FRI MORNING...WE WILL BEGIN TO SEE A GRADUAL WARM-UP WITH TEMPERATURES RECOVERING INTO THE UPPER 60S TO LOWER 70S ALONG THE COAST AND LOWER 70S TO POSSIBLY A FEW MIDDLE 70S INTO THE INTERIOR. THIS WILL STILL BE ON THE ORDER OF A FEW TO SEVERAL DEGREES BELOW CLIMO. FRI NIGHT-SAT NIGHT...HIGH PRESSURE CENTER WILL SHIFT FARTHER SEAWARD WITH AN AXIS EXTENDING BACK INTO CENTRAL FLORIDA. THIS WILL CAUSE A SOUTHEAST/SOUTH RETURN FLOW AND GRADUALLY MODIFY THE AIR MASS...WITH MAX TEMPS GETTING BACK CLOSE TO AVERAGE ON SAT. THE ONLY WEATHER HAZARD POSSIBLE IN THIS PATTERN WOULD BE EARLY MORNING FOG BUT WILL NOT BE ADDING THAT TO THE FORECAST YET. SUN-WED... NOTE...THE WEATHER PREDICTION CENTER HAS LEANED MORE TO THE ECMWF MODEL WITH RESPECT TO THE NEXT LOW PRESSURE SYSTEM MOVING ACROSS THE SOUTHEAST STATES AND THE ASSOCIATED COLD FRONT THAT IS PROGGED TO APPROACH THE AREA EARLY IN THE WEEK. THE 12Z GFS SHOWED A STRONG LOW DEVELOPING IN THE DEEP SOUTH ON MON...BUT THIS LOOKS WAY OVERDONE AND HAS NOT BEEN SHOWN BY PREVIOUS ECMWF RUNS NOR THE 12Z UKMET. SO LEANING TOWARDS A WEAKER/SLOWER SLOWER COLD FRONT PROGRESSING DOWN THE PENINSULA LOOKS BEST RIGHT NOW. PREVIOUS DISCUSSION... H30-H20 JET PATTERN ACRS THE SRN CONUS WILL SHIFT FROM A ZONAL TO A A LIFTING ORIENTATION OVER THE WEEKEND IN RESPONSE TO A MID/UPR LVL SHORT WAVE TROF OVER THE EAST PAC DIGS ITS WAY ACRS THE DESERT SW. THE LIFTING NATURE OF THE JET WILL NOT BE ABLE TO DISLODGE THE ATLC RIDGE AXIS ON ITS OWN. HOWEVER...ITS ASCENDING RIGHT REAR QUAD SHOULD BE CAPABLE OF INDUCING A SECONDARY SFC LOW ALONG THE FRONTAL BNDRY LATE SUN NIGHT THAT WOULD DRIVE THE FRONT INTO THE S PENINSULA A LITTLE FASTER THAN PREVIOUSLY FCST...PERHAPS AS EARLY AS MON NIGHT INTO TUE. THIS PARTICULAR WX PATTERN USUALLY DOES NOT GENERATE LARGE OUTBREAKS OF STRONG/SVR WX. EVEN SO...WITH H50 TEMPS ARND -12C AND THE PROSPECT FOR FURTHER COLD AIR ADVECTION ALOFT...CANNOT RULE TSRAS OUT OF THE FCST SUN/MON ESP S OF THE I-4 CORRIDOR WHERE TEMPS WILL WARM INTO THE L/M80S DURING THE HEAT OF THE DAY. WILL GO WITH CHC SHRAS/SLGT CHC SHRAS TO START THE WEEK...CAPPING POPS AT 40/50PCT SUN NIGHT INTO MON TO COINCIDE WITH THE FROPA. WILL CARRY SMALL POPS INTO TUE SHOULD THE FRONT BECOME HUNG UP ON THE RIDGE...BUT THESE SHOULD HAVE MINIMAL IMPACT. POPS BLO MENTIONABLE LVLS ON WED. WINDS WILL VEER TO THE SW ON SUN AS THE FRONT INITIALLY STALLS OVER N FL...BUT WILL SHIFT TO THE W/NW ON MON AS THE FRONT ADVANCES THRU THE STATE. LIMITED COLD AIR ADVECTION WITH THIS FRONT AS HIGH PRES BUILDS ACRS THE REGION AND FORCES WINDS TO VEER TO THE NE BY DAYBREAK TUE. WARM AIR ADVECTION ON SUN WILL PUSH MAX TEMPS INTO THE L/M80S. AS THE FRONT SLIDES THROUGH CENTRAL FL ON MON...CLOUDS AND PERIODIC SHRAS WILL KEEP MAX TEMPS IN THE M/U70S N OF I-4...WHILE PREFRONTAL TEMPS OVER THE SRN CWA REMAIN IN THE L/M80S. MIN TEMPS GENERALLY IN THE L/M60S TO START THE WEEK...COOLING INTO THE M50S/L60S TUE MRNG BEHIND THE FRONT. && .AVIATION...VFR THE NEXT 24 HOURS. WINDS HAVE BEEN DECREASING THIS AFTERNOON AS MODEL GUIDANCE HAS SUGGESTED. THE PRESSURE GRADIENT CONTINUES TO RELAX OVERNIGHT WITH MAINLY LIGHT NORTHERLY WINDS. WINDS WILL VEER EASTERLY DURING THE DAY ON FRI. REMAINING MOSTLY CLEAR TO CLEAR OVERNIGHT WITH A FEW MORE CLOUDS DEVELOPING DURING THE DAY ON FRI. WILL NEED TO MONITOR COASTAL TAF SITES ON FRI IF MARINE STRATOCU GETS DRAGGED ASHORE WITH THE DEVELOPING ONSHORE FLOW. && .MARINE... AFTERNOON-TONIGHT...NORTHERLY WIND SPEEDS AWAY FROM THE COAST REMAIN A HEALTHY 20-25 KTS AND GUSTY EARLY THIS AFTERNOON. WINDS WILL SLOWLY VEER TO NORTHEAST OVERNIGHT. SEA HEIGHTS AT BUOY 41009 REMAIN ABOVE 8 FT. THE PRESSURE GRADIENT IS STILL FORECAST TO GRADUALLY DECREASE TONIGHT FALLING TO AROUND 15 KTS OFFSHORE BY DAYBREAK FRI MORNING...THOUGH MAY REMAIN BETWEEN 15-20 KTS OFFSHORE/SOUTH OF SEBASTIAN INLET. INITIAL SEA HEIGHTS OF 7-10 FT OFFSHORE/GULF STREAM WILL DECREASE TO 5-7 FT BY DAYBREAK FRI MORNING. NEAR SHORE SEAS OF 5-7 FT WILL FALL BACK TO 3-5 FT CAPE-NORTHWARD AND 4-6 FT SOUTHWARD FROM CAPE TO JUPITER INLET BY DAYBREAK FRI MORNING. WITH ALL OF THAT SAID WILL CONTINUE CURRENT SMALL CRAFT ADVISORY CONFIGURATION UNTIL 10PM NEAR SHORE AND 4AM OFFSHORE. EVEN AFTER ADVISORIES EXPIRE EXPECT CAUTIONARY STATEMENTS FOR AT LEAST ANOTHER PERIOD MOST LEGS. LATER FORECAST SHIFTS WILL NEED TO MONITOR IF EXTENSION OF THE SCA OFFSHORE/GULF STREAM IS WARRANTED. FRI...HIGH PRESSURE OVER THE DEEP SOUTH WILL MOVE OFFSHORE THE SOUTHEAST COAST AND INTO THE WESTERN ATLANTIC. THIS WILL ALLOW FOR NORTHEAST EARLY MORNING WINDS TO CONTINUE TO VEER TO EAST AND THEN SOUTHEAST DURING THE DAY. SPEEDS WILL FALL TO 10-15 KTS OVER THE COASTAL WATERS INTO THE AFTERNOON. SEAS WILL ALSO CONTINUE TO SLOWLY SUBSIDE FALLING TO 3-4 FT NEAR SHORE AND 4-5 FT OFFSHORE BY LATE IN THE DAY. WEEKEND...HIGH PRESSURE CENTER WILL SHIFT FARTHER SEAWARD AND A RIDGE AXIS WILL EXTEND BACK TO FLORIDA. SOUTHEAST/SOUTH WINDS SAT SHOULD BE 10 KNOTS OR LESS. ON SUNDAY THE GFS SHOWS SOUTHERLY FLOW INCREASING TO 15-20 KNOTS AS LOW PRESSURE STARTS TO DEVELOP OVER THE SOUTHEAST STATES. THE TIMING OF THIS LOW PRESSURE DEVELOPMENT AND HOW MUCH IT WILL STRENGTHEN IS NOT AGREED UPON BY THE MODELS... BUT IN GENERAL...SAT LOOKS LIKE A MORE FAVORABLE BOATING DAY RIGHT NOW. MON-TUE...THE FORECAST IS NOT CERTAIN BUT THE PREFERRED SCENARIO IS FOR A COLD FRONT TO MOVE ONLY SLOWLY DOWN THE PENINSULA. SOUTHWEST FLOW SHOULD CONTINUE MON AND MAYBE EVEN INTO TUE IF THE FRONT DOES NOT PROGRESS VERY FAST LIKE THE ECMWF MODEL SUGGESTS. SPEEDS COULD STILL BE 15-20 KNOTS OFFSHORE. && .FIRE WEATHER... REMAINDER OF AFTERNOON...WINDS ARE SLOWLY DECREASING OVER THE AREA WITH ONLY OCCASIONAL HIGHER GUSTS INSTEAD OF FREQUENT AS WE SAW EARLIER. TEMPERATURES HAVE BEEN STRUGGLING TO MAKE FORECAST HIGHS THOUGH STILL DRIER CONDITIONS EXIST POSING A FIRE WEATHER CONCERN. A RED FLAG WARNING REMAINS IN EFFECT FOR BREVARD AND OSCEOLA COUNTIES UNTIL 6PM THIS EVENING. THIS FOR WINDS/LOW RH AND ERC NUMBERS AROUND 27. FRI-SAT...A WEAKER PRESSURE GRADIENT OVER THE AREA AND WINDS WILL VEER TO EASTERLY FRI THEN SOUTHEAST SAT. AS SUCH LOW-LEVEL MOISTURE VALUES WILL BEGIN TO MODERATE...FASTER NEAR THE COAST. WE STILL MAY SEE A FEW HOURS OF LOW RH VALUES BETWEEN 30 AND 35 PERCENT WELL INTO THE INTERIOR EACH AFTERNOON. WIND SPEEDS WILL REMAIN BELOW CRITICAL THRESHOLDS. && .PRELIMINARY POINT TEMPS/POPS... DAB 44 70 52 76 / 0 0 0 10 MCO 45 74 53 80 / 0 0 0 0 MLB 48 71 55 77 / 0 0 0 0 VRB 48 72 55 77 / 0 0 0 0 LEE 42 73 52 78 / 0 0 0 0 SFB 45 74 53 79 / 0 0 0 0 ORL 48 74 55 79 / 0 0 0 0 FPR 48 73 54 77 / 0 0 0 0 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING UNTIL 6 PM EDT THIS EVENING FOR NORTHERN BREVARD-OSCEOLA-SOUTHERN BREVARD. AM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 4 AM EDT FRIDAY FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. && $$ SHORT TERM...SEDLOCK LONG TERM....LASCODY PALMBAYWEATHER.info
Posted on: Thu, 13 Mar 2014 19:04:32 +0000