FXUS62 KMLB 071852
AFDMLB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
152 PM EST MON DEC 7 2009
.DISCUSSION...
...WARMING TREND INTO MIDWEEK WITH OVERNIGHT FOG...
...COOLING ON THURSDAY BEHIND NEXT FRONT...
TONIGHT/TUE...A TROUGH OF LOW PRESSURE LYING ACROSS THE SOUTHERN
HALF OF THE PENINSULA IS EXPECTED TO SLOWLY WEAKEN OVER LAND WITH
THE EASTERN PORTION LIFTING NORTH ALONG THE EAST FL MARINE AREA INTO
TUE. ISOLATED RAIN SHOWERS ARE FORECAST TO LIFT NORTHWARD IN
CONJUNCTION WITH THE SFC TROUGH AND MENTIONABLE SHOWERS SHOULD
REMAIN CONFINED TO NORTH OF THE METRO ORLANDO AREA AND THE COASTAL
WATERS TONIGHT. WINDS WILL DIMINISH SHORTLY AFTER DARK AND AREAS
OF FOG WILL BE PREVALENT ALONG WITH DEVELOPING LOW CLOUD
CEILINGS...ESPECIALLY OVER THE INTERIOR BY DAYBREAK TUE.
THE COMBINATION OF HIGH PRESSURE BUILDING OVER THE WESTERN
ATLC BASIN AND THE APCH OF A MID LATITUDE SYSTEM WILL ACT TO VEER
WINDS TO SOUTHERLY TUE WITH WARMER AFTERNOON TEMPS INTO THE 80S.
ADDED A LOW CONFIDENCE POP FOR THE ORANGE COUNTY AREA NWD TO
ACCOUNT FOR AFTN INSTABILITY AND SUITABLE MOISTURE.
WED-FRI...(FEW ADJUSTMENTS FROM PREVIOUS DISCUSSION)...STRONG MID
LATITUDE SFC LOW MOVES EAST FROM THE MIDWEST ON WEDNESDAY WITH THE
MAIN SYSTEM OVER THE LOWER GREAT LAKES AND A SECONDARY LOW FORMING
OFF OF NORTH CAROLINA. THE POLAR AND SUBTROPICAL JETS ARE EXPECTED
TO BE PHASED ACROSS THE MID CONTINENT AT THIS TIME...AS 500 MB FLOW
REMAINS RELATIVELY ZONAL ACROSS THE COUNTRY.
WITH THE MAIN SFC LOW OVER EASTERN CANADA BY THURS MORNING...AND
LITTLE UPPER DYNAMICS...THE COLD FRONT ASSOCIATED WITH THE LOW WILL
LIMP ACROSS THE PENINSULA THURS. FOR NOW CAPPED POPS AROUND 30%
FOR THAT TIME FRAME AS PINPOINTING AN EXACT PERIOD FOR THE BEST
RAIN CHANCES IS STILL A LITTLE UNCERTAIN. TEMPERATURES WILL REMAIN
WARM AND MUGGY INTO WEDNESDAY AS THE REGION REMAINS IN S-SW FLOW.
THE 07/00Z ECMWF IS MORE ROBUST WITH THE SFC LOW BUILDING INTO THE
SOUTHEAST ON FRIDAY...WHICH IN TURN PUSHES THE SFC FRONT FAR ENOUGH
SOUTH TO CLEAR CENTRAL FLORIDA THURS NIGHT. THE ECMWF IS ALSO ABOUT
12 HOURS SLOWER WITH THE NEXT SHORTWAVE SWINGING THROUGH THE
SOUTHERN TIER AS THE FLOW SPLITS AND THE SOUTHERN JET BECOME MORE
ACTIVE. THIS RESULTS IN TIMING DIFFERENCE BETWEEN THE GFS AND
ECMWF IN HOW QUICKLY THE NEXT SFC LOW LIFTS OUT OF THE WESTERN
GULF INTO THE SOUTHEAST. HAVE SPLIT THE DIFFERENCE FOR THE MOMENT
AND INTRODUCED A SLIGHT CHANCE OF POPS FOR FRI AND FRI NIGHT AS
THE AREA IS PLACED ONCE AGAIN INTO THE WARM SECTOR OF AN
APPROACHING SYSTEM.
SAT-SUN...(PREVIOUS DISCUSSION)...THE TIMING OF MID LEVEL INDIVIDUAL
DISTURBANCES IN THE SOUTHERN STREAM INTO NEXT WEEKEND ARE EVEN
HARDER TO PIN DOWN...RESULTING IN NOTABLE MODEL DIFFERENCES IN THE
DEVELOPMENT AND POSITION OF SFC LOWS. THE TAKE AWAY STORY WILL BE
THAT THE WEATHER WILL REMAIN ACTIVE INTO THE LATTER PART OF THE
WEEKEND.
&&
.AVIATION...
VARIOUS CLOUD BASES FLIRTING WITH MVFR CONDITIONS WL CONTINUE OVER
SITES FROM VRB-ISM NWD THROUGH THE EVENING. DEVELOPMENT OF BR AND
BKN/OVC BLO 020 AFT 08Z WITH LOCALIZED IFR CONDITIONS OVER
INTERIOR SITES AFT 06Z. AREAS OF MVFR CONDS IN BR AND CIGS
EXPECTED AFT 08Z.
&&
.MARINE...
SEA HEIGHTS FORECAST TO GRADUALLY DIMINISH INTO TUE WITH WEAKENING OF
LOCAL WINDS. TRIMMED BACK WAVE WATCH INDICATED SEA HEIGHTS
SLIGHTLY OVER THE OUTER WATERS THIS EVENING WHERE 4 TO 5 FT SHOULD
PREVAIL WITH 3 TO 4 FT SEAS CLOSER TO THE COAST. LOWERING BL
STABILITY FACTOR IN SE WINDS TUE SHOULD ALLOW FOR FURTHER
DIMINISHMENT OF SEAS.
TUE NIGHT-WED NIGHT...THE PRESSURE GRADIENT WILL TIGHTEN IN ADVANCE
OF A COLD FRONTAL BOUNDARY DURING THIS PERIOD. A CHANCE OF SHOWERS
WILL ACCOMPANY THE BOUNDARY WED/WED NIGHT. SSE WINDS ARE FORECAST TO
VEER SLIGHTLY TO SSW BY WED MORNING WHILE INCREASING TO NEAR 20 KTS
WELL OFFSHORE. SSW WINDS ARE FORECAST TO REMAIN IN THE 15-20 KT
RANGE DURING THE DAY ON WED/WED NIGHT WHILE FINALLY VEERING TO MORE
SOUTHWESTERLY WED EVENING AND OVERNIGHT. CAUTIONARY STATEMENTS WILL
BE NEEDED AND FUTURE SHIFTS WILL NEED TO MONITOR IN CASE A SCA IS
NEEDED OFFSHORE. SEAS MAINLY 2-4 FT NEAR SHORE AND 3-5 FT OFFSHORE.
THU-SAT...(PREVIOUS)...COLD FRONTAL PASSAGE WILL BRING GUSTY NW-NE
WINDS THURS AFTERNOON INTO EARLY FRIDAY. WINDS QUICKLY FLOP AROUND
TO THE EAST AND EVENTUALLY TO THE SOUTH-SOUTHEAST BY SATURDAY AS
ANOTHER SYSTEM PULLS NE OUT OF THE WESTERN GULF INTO THE DEEP SOUTH
AND THE FL PENINSULA IS BACK IN THE WARM SECTOR. SOME MODEL
DIFFERENCES IN THE TIMING OF THE SYSTEMS DEVELOPMENT...SO NOT AS
CONFIDENT ON THE TIMING OF THE WINDS COMING AROUND TO THE S-SW BY
SAT EVE. SEAS 2-4FT NEARSHORE/3-5FT OFFSHORE...WITH THE POSSIBILITY
OF LOCALLY HIGHER SEAS IN THE GULF STREAM LATE THURS AND FRI AS
WINDS COME AROUND TO THE NE AND EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 62 81 69 84 / 20 20 20 30
MCO 61 82 67 83 / 10 20 10 30
MLB 66 83 71 83 / 10 10 10 20
VRB 67 84 69 85 / 10 10 10 20
LEE 59 82 66 82 / 10 20 10 30
SFB 61 84 68 83 / 20 20 10 30
ORL 62 83 68 83 / 10 20 10 30
FPR 67 84 69 85 / 10 10 10 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...PENDERGRAST
LONG TERM....SEDLOCK
