FXUS62 KMLB 210859 AFDMLB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 359 AM EST THU NOV 21 2013 .DISCUSSION... CURRENTLY... EVENING SOUNDINGS CAME IN QUITE MOIST WITH BOTH KTBW/KMFL PWAT VALUES NEARING 2.0. EVEN SO...LATEST RUC ANALYSIS SHOWS A POCKET OF RELATIVELY DRY AIR IMMEDIATELY UPSTREAM WITH H100-H70 MEAN RH VALUES DROPPING FROM AOA 90PCT OVER THE PENINSULA TO BLO 75PCT N OF THE BAHAMAS. WEAK UPR LVL SUPPORT AS THE H30-H20 WINDS OVERHEAD ARE ARE AOB 50KTS. HOWEVER...LCL H85-H50 VORT MAXES ALONG THE WEAKENING BOUNDARY OVER S FL HAVE BEEN PROVIDING SUFFICIENT MID LVL SUPPORT TO MAINTAIN SCT SHRA ACTIVITY OVER THE ATLC. DESPITE FAIRLY COOL TEMPS ALOFT (H70 ARND 6C...H50 BTWN -8C AND -9C) LAPSE RATES ACRS THE REGION ARE QUITE WEAK...GENERALLY AOB 5.5C/KM. TODAY-TONIGHT... THE CENTER OF THE LARGE H100-H70 RIDGE AXIS BLANKETING THE ERN CONUS WILL PUSH OFF THE NEW ENGLAND COAST AND STEADILY WEAKEN. AS IT DOES...ITS SRN EXTENSION TO BECOME DOMINANT OVER THE MID ATLC. THE STATIONARY FRONTAL BOUNDARY OVER S FL WILL WASH OUT...ALLOWING THE RELATIVELY TIGHT PGRAD TO THE N TO EXPAND SWD...RESULTING IN A DEEP AND STEADY ERLY BREEZE ACRS CENTRAL FL. DESPITE DECREASING MOISTURE UPSTREAM AND A WEAK THERMODYNAMIC PROFILE...SHRA ACTIVITY OVER THE ATLC HAS PERSISTED FOR SVRL HRS. DEPTH AND STRENGTH OF THE ONSHORE FLOW WILL CONTINUE TO PUSH POCKETS OF ENHANCED MOISTURE ONSHORE...WILL STICK CLOSE TO MOS GUIDANCE FOR PRECIP AND WORD FOR COVERAGE...NO THUNDER AS THE SUPPORT AND INSTABILITY OVERHEAD AND UPSTREAM ARE TOO WEAK. WILL GO WITH 50-60PCT ALONG THE TREASURE COAST...40-50PCT SPACE COAST... DECREASING TO 30-40PCT OVER THE INTERIOR FOR TODAY...DECREASING TO 20-30PCT S OF I-4...LESS THAN 20PCT N OF I-4. DEEP ONSHORE FLOW AND MID/UPR LVL CLDS WILL RESULT IN FAIRLY UNIFORM MAX TEMPS IN THE U70S ALONG THE COAST...L80S INTERIOR. MIN TEMPS WILL BE QUITE MILD FOR LATE FALL...U60S/M70S ALONG THE COAST... M/U60S INTERIOR...A SOLID 10-15F ABV AVG. FRI... HIGH PRESSURE RIDGE VICINITY OF THE CAROLINAS EARLY WILL WEAKEN AND SHIFT SOUTHEAST AS A COLD FRONT PUSHES TOWARDS THE SOUTHEAST STATES. THIS WILL CAUSE ONSHORE FLOW TO WEAKEN. THE GFS HAS GONE BACK TO A LITTLE MORE DRYING WITH THIS RUN AND WITH THE WEAKENING LOW LEVEL FLOW...THE MODEL FOCUSES POPS IN SOUTHERN SECTIONS...WITH VALUES LESS THAN 10 PERCENT IN THE NORTH. WITH SOME WEAK RIDGING ALOFT AND SUBSIDENCE WILL FOLLOW CLOSE TO THE MOS NUMBERS. WEEKEND... WEAK HIGH PRESSURE RIDGE WILL EXTEND OVER THE AREA ON SAT THEN A COLD FRONT IS SHOWN ON OUR DOORSTEP FIRST THING SUNDAY MORNING. PRE FRONTAL CONVERGENCE WILL BE WEAK SO WILL JUST MAINTAIN A SLIGHT CHANCE FOR SHOWERS AS PER MOS GUIDANCE...EVEN THOUGH MOS IS ALREADY SHOWING DRYING OCCURRING IN THE NORTH BY EARLY SUNDAY. THE MAIN STORY SUNDAY WILL BE GUSTY NORTHERLY WINDS WHICH SHOULD REQUIRE AT LEAST A LAKE WIND ADVISORY AND MAYBE EVEN A STRAIGHT WIND ADVISORY AS 925 MB WINDS ARE FORECAST 25-30 KNOTS IN THE AFTERNOON. TEMPS WILL CONTINUE ABOVE NORMAL SAT AND SAT NIGHT THEN ON SUNDAY MAX TEMPS MAY STRUGGLE TO REACH 70 IN THE NORTH AND MID 70S CENTRAL. SOUTHERN SECTIONS MIGHT REACH THE UPPER 70S BEFORE COLD ADVECTION KICKS IN. MON-THU... EARLY TO MID WEEK LOOKS LIKE A QUITE DYNAMIC PERIOD AS THE MODELS ARE STILL DEVELOPING A LOW IN THE NORTHWEST GULF OF MEXICO ON MON AND MOVING IT EAST/NORTHEAST THROUGH WED. THE GFS IS A TAD SLOWER AND FARTHER SOUTH THAN THE ECMWF BUT OVERALL THE MODELS ARE IN DECENT AGREEMENT. ON MON...THE COOL/DRY AIR MASS WILL MODIFY AS LOW LEVEL FLOW BECOMES EASTERLY. MOS HAS SLIGHT CHANCE POPS ACROSS THE SOUTH AS SURFACE DEW POINTS ARE FORECAST TO MODIFY INTO THE UPPER 50S BUT THE NORTH LOOKS TOO DRY FOR MENTIONABLE POPS WITH DEW POINTS IN THE LOWER 50S. MON NIGHT THE GFS SHOWS INCREASING EAST/SOUTHEAST LOW LEVEL FLOW AND SOME ISENTROPIC LIFT DEVELOPING. EXPECT SOME ONSHORE MOVING SHOWERS ALONG THE COAST AND THERE MAY ALSO BE SOME AREAS OF RAIN BREAKING OUT. MOS POPS ARE AROUND 25 PERCENT AND WILL GO WITH THAT ACROSS THE AREA. FOR TUE AND WED...THE GFS SHOWS A BAND OF HIGHER MOISTURE LIFTING NORTH ACROSS THE AREA TUE ALONG PSEUDO WARM FRONT. WITH INCREASING LOW LEVEL WINDS IN RESPONSE TO LOW CENTER WHICH IS FORECAST TO BE VICINITY MISSISSIPPI DELTA REGION...WILL INTRODUCE A SLIGHT CHANCE FOR STORMS IN ADDITION TO BUMPING POPS TO 40 PERCENT THROUGH THE PERIOD. THE GENERAL SYNOPTIC PATTERN IS SUGGESTIVE OF A THREAT FOR STRONG- SEVERE STORMS DUE TO DEEPENING LOW PRESSURE CLOSE TO THE STATE. THE GFS SHOWED THE ASSOCIATED MID LEVEL SHORTWAVE TROUGH TAKING ON A SLIGHT NEGATIVE TILT...HOWEVER QUITE STRONGLY DIFFLUENT FLOW ALOFT SUGGESTS CONSIDERABLE DEBRIS CLOUDINESS OVERSPREADING THE WARM SECTOR...LIMITING INSTABILITY. TIMING IS FAR FROM CERTAIN AT THIS POINT AND THERE IS PLENTY OF TIME TO REFINE THE FORECAST. SNEAK PEAK FOR THANKSGIVING DAY...THE MODELS SHOW COLD FRONT EAST OF THE AREA EARLY SO EXPECT A DRIER AIR MASS AND COOLER TEMPS. && .AVIATION... THRU 21/15Z...ERLY LLWS FL015 INTERIOR SITES...OCNL SFC WND G22KTS ALONG THE COAST S OF KTIX...W OF KMLB-KOBE PREVAILING CIGS BTWN FL060-080 WITH ISOLD MVFR COASTAL SHRAS N OF KTIX...E OF KMLB-KOBE PREVAILING CIGS BTWN FL040-060 WITH SCT MVFR SHRAS. BTWN 21/15Z-21/23Z...OCNL SFC WND G18-22KTS N OF KVRB-KISM... PREVAILING CIGS BTWN FL040-060 WITH SCT MVFR SHRAS...BRIEF IFR VSBYS IN +SHRAS. AFT 21/23Z...PREVAILING CIGS BTWN FL080-100...CHC MVFR SHRAS S OF KMLB-KOBE...SLGT CHC N OF KMLB-KOBE. && .MARINE... TODAY-TONIGHT...LCL DATA BUOY/C-MAN NETWORK SHOWING A CONSISTENT 15-20KTS OF ERLY FLOW WITH 5-7FT SEAS NEARSHORE AND 8-9FT OFFSHORE. HOWEVER...BUOY012 IS STARTING TO PICK UP A NEW SWELL TRAIN...ONE WITH DOMINANT PDS BTWN 11-12SEC AS OPPOSED TO BUOY008/009 WHOSE DOMINANT PDS ARE BTWN 8-9SEC. WHILE THE LONGER SWELL PD WILL HELP DAMPEN THE ROUGH SEAS... CONDITIONS WILL REMAIN HAZARDOUS FOR SMALL CRAFT. THE CENTER OF A LARGE HIGH PRES RIDGE OVER THE ERN CONUS WILL PUSH OFF THE NEW ENGLAND COAST AND WEAKEN. THIS WILL ALLOW THE SRN EXTENSION OF THE RIDGE TO BECOME DOMINANT AND BUILD OVER THE MID ATLC. LCL SFC/BNDRY LYR WINDS WILL WEAKEN...ALBEIT SLOWLY..AS THE REDEVELOPING RIDGE KEEPS A FAIRLY TIGHT PGRAD ACRS THE REGION...ONE CAPABLE OF MAINTAINING A MODERATE TO FRESH ERLY BREEZE ACRS THE LCL ATLC. WILL NEED TO ADJUST THE TIMING OF THE CURRENT SCA...AT MINIMUM PLANS ARE TO EXTEND IT FOR THE OFFSHORE LEG THRU 22/09Z. FRI-SAT...HIGH PRESSURE RIDGE NORTH OF THE AREA FRI WILL WEAKEN AND SHIFT SOUTHEAST AHEAD OF A COLD FRONT. EASTERLY FLOW WILL GRADUALLY WEAKEN FRI BUT THE COMBINATION OF WINDS AND SEAS SHOULD PRODUCE POOR-HAZARDOUS CONDITIONS FOR SMALL CRAFT. WILL GO WITH AN ADVISORY FOR SEAS THROUGH FRI AFTERNOON AS WINDS WILL BE CLOSE TO 15 KNOTS THEN AND SEAS STILL 5-8 FEET. THE GOOD NEWS LOOKS TO BE THAT ON SAT THE WINDS WILL DIMINISH TO 5-10 KNOTS. CONDITIONS TRAVERSING THE INLETS MAY STILL BE HAZARDOUS THOUGH AS SWELLS 4-5 FEET CONTINUE IN THE ATLANTIC. SUN-MON...STRONG COLD FRONT IS STILL PROGGED TO SWEEP FROM THE NORTHERN WATERS EARLY IN THE DAY TO SOUTH OF THE WATERS BY AFTERNOON. MODEL LOW LEVEL WINDS STILL SUGGEST THAT NORTHERLY WINDS GUSTING TO 30 KNOTS WILL BE POSSIBLE. THE FLOW WILL SWING AROUND TO THE NORTHEAST/EAST ON MON AND STILL LOOK QUITE GUSTY 20-25 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... DAB 78 68 80 63 / 40 20 10 10 MCO 82 67 82 63 / 30 20 10 10 MLB 80 73 81 66 / 50 30 20 10 VRB 80 73 81 66 / 50 30 30 10 LEE 81 65 82 62 / 30 20 10 10 SFB 82 67 82 63 / 30 20 10 10 ORL 82 67 82 64 / 30 20 10 10 FPR 81 73 81 66 / 60 30 30 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY 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-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. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM TO 4 PM EST FRIDAY 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- 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...BRAGAW LONG TERM....LASCODY PALMBAYWEATHER.info
Posted on: Thu, 21 Nov 2013 08:59:14 +0000
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