FXUS62 KMLB 021444
AFDMLB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
945 AM EST WED DEC 2 2009
.DISCUSSION...
...WINDY TODAY AHEAD OF THE APPROACHING LOW PRESSURE...
...STRONG/SVR STORMS POSSIBLE ALONG A SQUALL LINE TONIGHT...
...SIGNIFICANT RAINFALL POSSIBLE FRIDAY AND FRIDAY NIGHT...
MORNING UPDATE...SQUALL LINE EXTENDS FROM NEAR APPALACHICOLA BAY SW
OVER THE GULF AT MID MORNING. MODELS STILL HAVE DISCREPENCIES ON
TIMING. AGREE WITH PREV SHIFT THAT A BLEND LOOKS MOST REALISTIC AT
THIS POINT...WITH MAIN LINE APPROACHING NW SECTIONS OF EC FL HEADING
TOWARD SUNSET THAN CONTINUING ACROSS THE AREA DURING THE EVENING
HOURS. CURRENT FORECAST AND HAZARDS ON TRACK AND ONLY MINOR TWEAKS
MAINLY FOR TIMING ARE ANTICIPATED. FOR THE DAYTIME HOURS...WARM AND
WINDY WITH ONLY ISOLATED SHRA/TSRA AHEAD OF THE MAIN LINE OF STORMS.
(PREVIOUS DISCUSSION)
CURRENT/TODAY...A WARM FRONT HAS PASSED NORTH OF CENTRAL FLORIDA
EARLY THIS MORNING. BEHIND IT MILD TEMPERATURES AND INCREASING LOW
LEVEL MOISTURE VALUES. THIS PUTS ALL OF EAST CENTRAL FLORIDA IN A
WARM SECTOR AHEAD OF THE APPROACHING LOW PRESSURE SYSTEM. EARLY THIS
MORNING THE LOW PRESSURE WAS LOCATED ALG THE LOUISIANA GULF COAST. A
COLD FRONT EXTENDED FROM THE LOW PRESSURE IN THE WEST CENTRAL
GOMEX. THE LOW PRESSURE WILL RACE NORTHEASTWARD FROM THE GULF
COAST STATES THROUGH THE DAY TOWARDS THE TENNESSEE AND OHIO
VALLEYS. AS IT DOES THE COLD FRONT WILL BE DRAGGED INTO THE
FLORIDA PANHANDLE AND TOWARDS THE WEST COAST OF FLORIDA BY LATE IN
THE DAY. AHEAD OF THE FRONT AN ORGANIZED LINE OF STRONG TO SEVERE
STORMS WILL ALSO MOVE TOWARD THE PENINSULA.
SOUTH/SOUTHEAST WINDS WILL PICK UP AFTER SUNRISE AS THE PRESSURE
GRADIENT TIGHTENS AND INCREASE TO 15-20 MPH WITH FREQUENT GUSTS TO
BETWEEN 25-30 MPH. WINDS ABOVE THE SURFACE ARE HOWLING AND EXPECT
THEM TO MIX DOWN TO THE SURFACE THROUGHOUT THE DAY AS THE WIND
FIELDS ALOFT INTENSIFY AHEAD OF THE APPROACHING SYSTEM. WILL GO
AHEAD AND HOIST A LAKE WIND ADVISORY BEGINNING AT 10AM THRU 7PM THIS
EVENING. THE WINDS WILL VEER SLIGHTLY TO THE SOUTHWEST BY LATE IN
THE AFTERNOON.
THROUGH THERE WILL BE INCREASING CLOUD COVER FROM THE NORTH AND WEST
DURING THE DAY MAX AFTERNOON TEMPERATURES WILL STILL HAVE NO TROUBLE
SOARING SEVERAL DEGREES ABOVE CLIMO INTO THE LOWER 80S. A FEW MIDDLE
80S ACROSS THE AREA ARE NOT OUT OF THE QUESTION.
WILL STAY BELOW MOS GUIDANCE FOR POPS TODAY...THOUGH NUMBERS MAY
STILL BE HIGHER THAN ACTUALLY WILL WARRANT. THE BIG SHOW FOR
PRECIPITATION CHANCES START LATER THIS EVENING. FOR NOW WILL HANG
ONTO SLIGHT CHANCE FOR SHOWERS THROUGH THE EARLY AFTERNOON PERIOD
AND INCREASE COVERAGE TO CHANCE FOR LATER IN THE DAY. MODEL
SOUNDINGS SHOW ONLY MARGINAL INSTABILITY THROUGH THE AFTERNOON
HOURS...THOUGH WIND FIELDS ABOVE THE SURFACE WILL CONTINUE TO
STRENGTHEN AND VEER WITH HEIGHT.
TONIGHT...THE GFS REMAINS THE FASTER SOLUTION COMPARED WITH THE
NAM/ECMWF AND THINK IT BEST TO GO WITH A BLEND IN TERMS OF TIMING.
THE LOW PRESSURE WILL CONTINUE TO RACE NORTHEASTWARD FROM THE GULF
COAST STATES THIS EVENING AND OVERNIGHT TOWARDS THE EASTERN GREAT
LAKES AND NEW YORK STATE. THE ORGANIZED SQUALL LINE OF HEAVY SHOWERS
AND STRONG/SEVERE STORMS WILL MOVE ONTO THE WEST COAST ROUGHLY
AROUND 00Z (7PM) AND MOVE EAST WHILE INDIVIDUAL STORMS EMBEDDED IN
THE LINE WILL PRESS NORTHEAST. TIMING FOR ACTIVITY TO APPROACH LAKE
COUNTY WILL BE 02Z-03Z (9PM-10PM). ANY STRONGER STORMS WITHIN THIS
LINE OR ANY STORMS THAT FORM AHEAD OF THE SQUALL LINE WILL NEED TO
BE WATCHED FOR ROTATION. THE MAIN THREATS THIS EVENING & OVERNIGHT
ACROSS EAST CENTRAL FLORIDA WILL BE DAMAGING WIND GUSTS...ISOLATED
TORNADOES...FREQUENT LIGHTNING...SMALL HAIL AND TORRENTIAL DOWNPOURS
WITH MINOR FLOODING POSSIBLE IN LOW LYING AREAS. THE CURRENT
THINKING FOR GREATEST LIKELIHOOD OF SEVERE WEATHER LIES FROM NORTH
OSCEOLA COUNTY TO NORTH BREVARD COUNTY AND FURTHER NORTHWARD. FOR
POPS HAVE GONE 70%-80% AREAWIDE WITH MENTION OF GUSTY THUNDERSTORM
WINDS AND HEAVY DOWNPOURS IN THE ZONE WORDING.
THE SEVERE WEATHER THREAT SHOULD DIMINISH IN THE PREDAWN HOURS THU
MORNING AS BEST DYNAMICS WITH THIS SYSTEM RACE UP THE EASTERN
SEABOARD. LOWS WILL REMAIN MILD OVERNIGHT AND MAINLY IN THE 60S.
THERE MAY BE A FEW LOWER 70S ALONG THE EAST COAST ALONG THE TREASURE
COAST.
THU...FRONTAL BOUNDARY WILL PUSH INTO CENTRAL FL DURING THE DAY
KEEPING A CHANCE FOR SHOWERS ACROSS THE AREA...LIKELY ACROSS THE
SOUTH. RAIN CHANCES WILL END FROM NORTH TO SOUTH BEHIND NORTHERLY
WIND SHIFT. SUFFICIENT FRONTAL CONVERGENCE AND BUOYANCY SHOULD
SUPPORT A CHANCE FOR THUNDER ACROSS SOUTHERN AREAS BUT SEVERE
THREAT LOOKS VERY LOW AS FORCING AND SHEAR ARE WEAK.
THU NIGHT...FRONT IS FORECAST TO STALL ACROSS SOUTH FLORIDA BUT
EXPECT RAIN SHOWERS TO SPREAD BACK NORTHWARD OVERNIGHT AS WARM
ADVECTION DEVELOPS ABOVE COOL BOUNDARY LAYER.
FRI/FRI NIGHT...UPPER IMPULSES EMBEDDED IN THE SUBTROPICAL JET
WILL PROMOTE WAVES OF LOW PRESSURE MOVING NE ALNG THE STALLED
BOUNDARY WHICH WILL BECOME THE FOCUS FOR ADDITIONAL AND EXPANDED
AREA OF RAIN. THE FRONT WILL PROBABLY LIFT A LITTLE NORTHWARD BY
THIS TIME WHICH WOULD PLACE THE AXIS OF HIGHEST PRECIP ACROSS OUR
CENTRAL OR NORTHERN CWA (ROUGHLY OSCEOLA/BREVARD NORTHWARD). WHILE
MANY AREAS LOOK TO RECEIVE A BENEFICIAL SOAKING RAINFALL OF 1-2
INCHES THERE IS THE POTENTIAL FOR TRAINING CONVECTION AND A
SIGNIFICANT RAIN EVENT PRODUCING 3 INCHES OR MORE. BOTH GFS AND
ECMWF ARE SHOWING THIS BUT WITH SOME DIFFERENCES IN PLACEMENT OF
HIGHEST RAINFALL.
ONE SIGNIFICANT DIFF BETWEEN THE 2 MODELS IS THE 00Z GFS IS MORE
AGGRESSIVE SHOWING A CLOSED 1009 MB LOW OVER THE EASTERN GULF AND
STRONG (50-55KT) 850 MB WINDS WHICH WOULD PRODUCE SUFFICIENT SHEAR
FOR SEVERE STORMS. HOWEVER...THE ECMWF IS MUCH WEAKER AND KEEPS
THE LOWS AS OPEN WAVES RIDING ALG THE BOUNDARY. THIS SOLN IS
PREFERRED FOR NOW AS IT HAS CONTINUITY.
SAT-TUE...LOW PRESSURE IS FORECAST TO DEVELOP OFF THE EASTERN
SEABOARD AND SWEEP THE STALLED FRONT WELL EAST OF THE AREA AND
BRING COOLER DRIER CONDS TO CENTR FL.
&&
.AVIATION...INSERTED SOME LOW LEVEL WIND SHEAR ACROSS NORTHERN TAFS
UNTIL ~15Z WHEN SURFACE WINDS INCREASE...GIVEN FLOW MUCH STRONGER
JUST ABOVE SURFACE THIS MORNING. MAIN CONCERN THROUGH THE DAYTIME
WILL BE THE STRENGTHENING WINDS WITH ONLY ISOLATED STORMS THROUGH
THE LATE AFTERNOON. SQUALL LINE TO PUSH ACROSS THE AREA THIS EVENING
WITH POTENTIAL STRONG/SVR STORMS...WITH WIDESPREAD IFR/LIFR WITH
SQUALL LINE PASSAGE.
&&
.MARINE...CURRENT FORECAST/HEADLINES ON TRACK...NO SIG CHANGES.
(PREVIOUS) TODAY/TONIGHT...SOUTHEAST WINDS 20-25 KTS OFFSHORE WITH
GUSTS TO 30 KTS. S/SE WINDS WILL VEER TO THE SOUTHWEST OVERNIGHT. A
SMALL CRAFT ADVISORY FOR WINDS/SEAS REMAINS IN EFFECT THRU 09Z (4AM)
THU MORNING FOR ALL OFFSHORE LEGS. WILL GO AHEAD AND UPGRADE NEAR
SHORE LEGS TO A SMALL CRAFT ADVISORY FOR WINDS THRU 09Z AS WELL.
WILL CAP WINDS AT 20 KTS NEAR SHORE. SEAS WILL BE SLOWER TO RESPOND
BUT WILL BUILD TO 5-7 FT OFFSHORE AND 4-5 FT NEAR SHORE.
LATER TONIGHT AS A STRONG WEATHER SYSTEM APPROACHES FROM THE WEST A
SQUALL LINE IS EXPECTED TO MOVE ONSHORE ALONG THE WEST COAST OF
FLORIDA AND ADVANCE QUICKLY INLAND ACROSS THE PENINSULA AND
EVENTUALLY OUT OVER THE COASTAL WATERS OF THE WESTERN ATLC DURING
THE MID/LATE EVENING AND OVERNIGHT HOURS. COASTAL WATERS ACROSS THE
NORTH WILL BE FIRST TO EXPERIENCE THIS LINE. FOR NOW ONLY A SCHC/CHC
OF SHRA/TSRA EXIST THROUGH THE DAY PERIOD BUT WILL SEE CHANCES
INCREASE TO WIDESPREAD/LIKELY SHRA'S/TSRA'S AFTER DARK. DAMAGING
WIND GUSTS AND EVEN ISOLD WATERSPOUTS...DANGEROUS LIGHTNING AND
HEAVY DOWNPOURS WILL ACCOMPANY THIS LINE.
THU-SUN...PGRAD WILL WEAKEN CONSIDERABLY THU AS LOW PRESSURE
LIFTS WELL NORTH OF THE AREA AND WINDS TURN NORTH BEHIND FRONT.
PGRAD WILL SUPPORT MAINLY 10 KNOTS. FRONT IS FORECAST TO STALL
JUST SOUTH OF THE WATERS THU NIGHT AND MAY LIFT BACK NORTHWARD A
BIT FRI AS WAVES OF LOW PRESSURE MOVE ALONG IT. LARGE AREA OF RAIN
MAY AFFECT THE WATERS ALONG AND NORTH OF THE FRONT FRI-FRI NIGHT.
DEEPENING LOW PRESSURE OFF THE EASTERN SEABOARD SAT WILL PUSH THE
FRONT WELL EAST OF THE AREA AND MAY PRODUCE A PERIOD OF STRONG
N/NW WINDS THIS WEEKEND.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR COASTAL VOLUSIA-INDIAN RIVER-INLAND VOLUSIA-
MARTIN-NORTHERN BREVARD-NORTHERN LAKE-OKEECHOBEE-ORANGE-
OSCEOLA-SEMINOLE-SOUTHERN BREVARD-SOUTHERN LAKE-ST. LUCIE.
AM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM EST THURSDAY 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 EST THURSDAY 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.
&&
$$
UPDATE...GLITTO/BRAGAW
