FXUS61 KBOX 020855
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
355 AM EST WED DEC 2 2009
.SYNOPSIS...
STRONG LOW PRESSURE PASSING WELL TO OUR WEST WILL BRING A PERIOD OF
STRONG WINDS...HEAVY RAIN AND UNSEASONABLY MILD TEMPERATURES LATE
TONIGHT AND THURSDAY MORNING. SEASONABLY CHILLY WEATHER WILL ARRIVE
FRIDAY INTO EARLY NEXT WEEK. LOW PRESSURE WILL MOST LIKELY PASS FAR
ENOUGH EAST OF OUR REGION SATURDAY/SATURDAY NIGHT TO PREVENT A
SIGNIFICANT WINTER STORM.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE RIDGING THROUGHOUT THE COLUMN WILL PROVIDE US WITH A
FAIR WEATHER DAY TODAY. WE WILL START OUT SUNNY...BUT HIGH CLOUDS
WILL ADVANCE FROM THE SOUTH RATHER QUICKLY LATER THIS MORNING AND
ESPECIALLY THIS AFTERNOON AS A LOW PRESSURE SYSTEM GATHERS STRENGTH
ACROSS THE SOUTHEASTERN STATES. AT THIS TIME...WE THINK ANY
PRECIPITATION IN ASSOCIATION WITH THIS DEVELOPING LOW PRESSURE
SYSTEM WILL REMAIN TO OUR SOUTH DURING THE DAYLIGHT HOURS. WINDS WILL
BE FAIRLY LIGHT AND HIGH TEMPERATURES WILL TOP OUT AROUND 10 DEGREES
ABOVE NORMAL AFTER A CHILLY EARLY MORNING START. OVERALL...A NICE DAY
WEATHERWISE DESPITE THE THICKENING CLOUDINESS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
MAIN FORECAST CONCERNS DURING THIS PERIOD REVOLVE AROUND THE CHANCES
FOR HIGH WIND...CONVECTION...HEAVY RAIN...AND COASTAL FLOODING.
A VIGOROUS LOW PRESSURE WILL CONTINUE TO DEVELOP TODAY ACROSS THE
LOWER MISSISSIPPI VALLEY WHILE MOVING NORTHEASTWARD. THIS LOW WILL
GRADUALLY GATHER STRENGTH AS IT MOVES NORTHEASTWARD...LIKELY TO
UPSTATE NEW YORK BY EARLY THURSDAY MORNING.
AS FAR AS WIND GOES...THIS SYSTEM WILL BE ACCOMPANIED BY A VERY
STRONG SOUTHERLY LOW LEVEL JET...WITH WINDS UPWARDS OF 80 KTS IN THE
900-850MB LAYER. AS IS USUALLY THE QUESTION WITH SOUTHERLY LOW LEVEL
JET EVENTS IN SOUTHERN NEW ENGLAND...HOW MUCH WIND WILL BE ABLE TO
MIX DOWN? A LOW LEVEL INVERSION ALMOST ALWAYS KEEPS THE HIGHEST WINDS
OF THE JET CORE AT BAY...BUT OCCASIONALLY POCKETS OF DAMAGING WIND
WILL DEVELOP AS THE SURFACE WARMS OR IS BROUGHT DOWN IN CONVECTION.
AS THE LOW LEVEL JET TRANSPORTS RICH THETA-E AIR NORTHWARD...A WARM
FRONT WILL PROGRESS NORTHWARD AND PROBABLY BE ON THE SOUTH COAST/S
DOORSTEP BETWEEN 6Z AND 9Z TONIGHT. THIS FRONT WILL PROBABLY BE FOUND
ALONG A KBAF-KBOS LINE BY 12Z...THEN LIFT NORTHEAST FROM THERE. THE
BEST CHANCE OF POCKETS OF DAMAGING WIND SHOULD OCCUR ALONG AND SOUTH
OF THE WARM FRONT LATE TONIGHT...ESPECIALLY SINCE IT LOOKS LIKE
CONVECTION WILL OCCUR...AND QUITE POSSIBLY THUNDER. I WOULDN/T BE
SURPRISED IF MUCH OF RHODE ISLAND AND EASTERN MASS IS IN THE MID 60S
AT 12Z THURSDAY MORNING IN THE WAKE OF THE SFC WARM FRONT. WE HAVE
THEREFORE ISSUED A HIGH WIND WATCH FOR THE AREA THAT LOOKS TO HAVE
THE BEST SHOT TO TRULY GET INTO THE WARM SECTOR LATER TONIGHT INTO
THURSDAY MORNING...WHICH IS ROUGHLY AN AREA ALONG AND SOUTH OF A
KBDL-KLWM LINE. DAMAGING WINDS ARE NOT A LOCK...BUT THE POTENTIAL IS
THERE...SO HENCE THE WATCH ISSUANCE.
A COLD FRONT WILL THEN SWEEP ACROSS SOUTHERN NEW ENGLAND FROM WEST TO
EAST DURING THE MORNING TO EARLY AFTERNOON HOURS. THIS WILL ALLOW THE
BOUNDARY LAYER TO BECOME MIXED AS THE INVERSION GETS SCOURED OUT.
THIS MAY ALLOW FOR A RELATIVELY BRIEF WINDOW FOR STRONG SOUTHWESTERLY
WINDS THROUGH EARLY THURSDAY AFTERNOON.
AS FAR AS POPS GO...THEY ARE PRETTY STRAIGHTFORWARD...THEY RAPIDLY
BECOME CATEGORICAL THIS EVENING FROM SOUTH TO NORTH. DRY SLOT QUICKLY
ADVECTS IN FROM SOUTHWEST TO NORTHEAST THURSDAY MORNING AND THIS WILL
RAPIDLY SHUT THE PRECIP OFF. SUNSHINE IS PROBABLE BY LATE THURS
AFTERNOON MOST LOCATIONS.
LOW PROB THAT A SVR TSTM WARNING MAY BE ISSUED FOR WIND LATE TONIGHT
OR EARLY THURSDAY MORNING IF CONVECTION CAN BECOME ROBUST. RAIN MAY
BE HEAVY AT TIMES LATER TONIGHT THROUGH EARLY MORNING THURSDAY WITH 1
TO 2 INCHES POSSIBLE...AND THIS MAY CAUSE URBAN AND POOR DRAINAGE
FLOODING FOR THE THURSDAY MORNING COMMUTE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THURSDAY NIGHT AND FRIDAY...
DRY AND SOMEWHAT COOLER AIR WILL WORK BACK INTO THE REGION. THE
AIRMASS WILL BE OF PACIFIC ORIGIN AND TEMPERATURES SHOULD STILL
AVERAGE A FEW DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR.
LOWS SHOULD MAINLY BE IN THE 30S...WITH LOWER 40S IN DOWNTOWN
BOSTON. HIGHS ON FRIDAY SHOULD GENERALLY BE IN THE UPPER 40S TO
AROUND 50. SKIES SHOULD GENERALLY BE MOSTLY CLEAR OVER THIS
PERIOD...WITH THE EXCEPTION OF THE DISTANT INTERIOR WHERE SOME
STRATO-CUMULUS MAY SLIP OVER THE BERKSHIRES AT TIMES.
FRIDAY NIGHT...
LOW PRESSURE DEVELOPING OVER THE GULF COAST WILL RESULT IN AN
INCREASE IN MID/HIGH LEVEL CLOUDINESS. HOWEVER...HIGH PRESSURE
OVERHEAD SHOULD KEEP OUR WEATHER DRY. LOWS SHOULD MAINLY BE IN THE
20S...TO BETWEEN 30 AND 35 IN DOWNTOWN BOSTON/PROVIDENCE.
SATURDAY AND SATURDAY NIGHT...
LOW PRESSURE WILL LIFT NORTHEAST FROM THE SOUTHEAST COAST AND LIKELY
PASS WELL EAST OF SOUTHERN NEW ENGLAND. THE 00Z MODELS/ENSEMBLES
ARE IN GOOD AGREEMENT THAT THE LOW SHOULD PASS FAR ENOUGH EAST TO
PERHAPS JUST BRING US A GLANCING BLOW. THIS IS PROBABLY THE BEST
WAY TO GO WITH THE FORECAST AT THIS POINT...AS NONE OF THE MODELS
ARE SHOWING THE LOW TRACKING CLOSE TO ENOUGH TO THE COAST FOR A
MAJOR STORM HERE. WE ARE STILL ABOUT 3 AND A HALF DAYS FROM THE
POTENTIAL EVENT...SO WILL DEFINITELY KEEP OPTIONS OPEN FOR A TRACK
CLOSER TO THE COAST WITH A BIGGER IMPACT. AT THIS POINT THOUGH IT
APPEARS TO BE A LOW PROBABILITY FOR A SIGNIFICANT STORM ACROSS
SOUTHERN NEW ENGLAND.
EVEN WITH THE EASTWARD TRACK...SOME LIGHT PRECIPITATION MAY GET
THROWN BACK WELL WEST OF THE SURFACE LOW. THEREFORE...WILL CONTINUE
WITH CHANCE POPS MAINLY FOR THE SOUTHERN AND EASTERN SECTIONS.
BASED ON THE CURRENT TRACK WHAT EVER REACHES THE INTERIOR SHOULD BE
IN THE FORM OF LIGHT SNOW. HOWEVER...ON THE COASTAL PLAIN INCLUDING
THE BOSTON TO PROVIDENCE CORRIDOR POINTS SOUTH AND EAST THERE COULD
BE BOUNDARY LAYER ISSUES FOR A TIME. ESPECIALLY IF THE HEAVIER
PRECIPITATION REMAINS OVER THE OCEAN AS CURRENTLY EXPECTED. JUST
BECAUSE YOUR -4C OR -5C AT 850 MB DOES NOT MEAN IT WILL BE ALL
SNOW...ESPECIALLY THIS TIME OF YEAR WITH NOT MUCH COLD AIR IN
PLACE. WILL MENTION A CHANCE OF RAIN OR SNOW SHOWERS IN THIS REGION
WITH THE RELATIVELY MILD BOUNDARY LAYER.
SUNDAY THROUGH TUESDAY...
OVERALL IT LOOKS TO BE A QUIET WITH GENERALLY DRY WEATHER EXPECTED
AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. GENERALLY
EXPECT TEMPERATURES AT OR JUST BELOW NORMAL...BUT A STRONG WESTERLY
FLOW SHOULD KEEP THE COLDEST AIR BOTTLED UP WELL TO OUR NORTH.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
TODAY...VFR.
TONIGHT AND THURSDAY...VFR CONDITIONS EARLY TONIGHT WILL DETERIORATE
RAPIDLY TO IFR ALL TERMINALS AND LAST THROUGH AROUND 12Z THURSDAY.
WINDS WILL INCREASE OVERNIGHT AS WELL...AND PERHAPS GUST 40 TO 45 KT
FROM THE SOUTH TOWARD DAWN THURSDAY...ESPECIALLY SOUTHEAST MASS AND
RHODE ISLAND. WINDS SWITCH TO SW WITH FROPA THURSDAY MORNING AND
POTENTIALLY GUST AROUND 40 KT THROUGH EARLY AFTERNOON. CONDITIONS
BECOME VFR FROM SW TO NE DURING THE MORNING AS COLD FRONT SWEEPS
ACROSS. LLWS WILL PROBABLY BE AN ISSUE TONIGHT INTO EARLY THURSDAY
MORNING. LOW PROB THUNDER LATE TONIGHT.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY NIGHT AND FRIDAY...MAINLY VFR CONDITIONS EXPECTED.
SATURDAY AND SATURDAY NIGHT...LOW CONFIDENCE FORECAST BUT A PERIOD OF
MVFR-IFR CONDITIONS ARE STILL POSSIBLE IF LOW PRESSURE TRACKS CLOSE
ENOUGH TO THE COAST.
SUNDAY...MAINLY VFR.
&&
.MARINE...
TODAY...TRANQUIL WINDS AND SEAS.
TONIGHT...HAVE ISSUED A GALE WARNING FOR ALL WATERS FOR RAPIDLY
INCREASING SE WINDS...GUSTING UP TO 40-45 KTS LATE. SEAS QUICKLY
BUILD AND BECOME VERY ROUGH.
THURSDAY...SE/S WINDS FLIP TO SOUTHWEST AS COLD FRONT SWEEPS ACROSS
THURSDAY MORNING AND GUST UP TO 45 KT.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY NIGHT...ANY LEFT OVER WESTERLY GALE FORCE WIND GUSTS EARLY
IN THE EVENING SHOULD QUICKLY DIMINISH TO SCA LEVELS. SEAS WILL
REMAIN WELL ABOVE SCA THRESHOLDS ACROSS THE OUTER-WATERS AND WESTERN
SOUNDS.
FRIDAY AND FRIDAY NIGHT...WINDS SHOULD DIMINISH BELOW SCA CRITERIA BUT
SEAS WILL REMAIN ABOVE SCA THRESHOLDS ACROSS THE SOUTHERN
OUTER-WATERS THROUGH THE AFTERNOON.
SATURDAY AND SATURDAY NIGHT...LOW PRESSURE EXPECTED TO PASS WELL
EAST OF SOUTHERN NEW ENGLAND SHOULD STILL INTENSIFY ENOUGH TO ALLOW
SCA WIND GUSTS AND SEAS TO DEVELOP ACROSS AT LEAST OUR SOUTHERN AND
EASTERN WATERS. THE THREAT FOR GALE FORCE WIND GUSTS APPEARS TO BE A LOW
PROBABILITY AT THIS POINT.
SUNDAY...SCA WIND GUSTS AND ROUGH SEAS MAY CONTINUE IN THE COLD AIR
ADVECTION PATTERN.
&&
.TIDES/COASTAL FLOODING...
THE MONTHLY ASTRONOMICAL TIDE CYCLE PEAKS ON THURSDAY MORNING. THE
STRONGEST WINDS WITH THIS STORM WILL OCCUR ABOUT THE SAME TIME. WITH
WINDS EXPECTED FROM THE SOUTH AND SOUTHWEST...THIS WOULD PUSH THE
COASTAL WATERS UP AGAINST THE RI AND SOUTH MASSACHUSETTS COASTS.
NARRAGANSETT BAY AND BUZZARDS BAY WOULD...BY THEIR SHAPE...BE
ESPECIALLY AT RISK. THE POTENTIAL EXISTS FOR A 2 FOOT OR HIGHER STORM
SURGE ALONG THE SOUTH COAST. THIS SURGE...IF REALIZED...WOULD BRING A
RISK OF MODERATE COASTAL FLOODING TO THE SOUTH COAST AND ITS BAYS.
MODERATE COASTAL FLOODING MEANS THAT THERE IS THE POTENTIAL FOR
STRUCTURAL DAMAGE TO VULNERABLE AREAS. A COASTAL FLOOD HAS BEEN
ISSUED.
&&
.CLIMATE...
BOSTON/S LOGAN AIRPORT HAS NOT FALLEN TO THE FREEZING MARK SO FAR
THIS SEASON. THE RECORD LATEST IN THE SEASON THAT BOSTON HAS
RECORDED ITS FIRST 32F WAS DEC 2ND 1975. AVERAGE FIRST DATE OF 32 IN
BOSTON IS AROUND NOVEMBER 4TH. OVERNIGHT LOWS TONIGHT AND WEDNESDAY
NIGHT FORECASTED TO REMAIN ABOVE FREEZING.
NOVEMBER 2009 WAS TOP 10 WARMEST AT OUR 4 CLIMATE SITES. BELOW ARE
PRELIMINARY NOVEMBER TEMPERATURE AVERAGES AND DEPARTURES FOR THE
MONTH.
BOS 48.8...PLUS 3.9...RANKED NUMBER 6.
BDL 46.4...PLUS 4.6...RANKED NUMBER 6.
PVD 48.9...PLUS 5.1...RANKED NUMBER 3.
ORH 44.5...PLUS 4.9...RANKED NUMBER 5.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HIGH WIND WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON
FOR CTZ002>004.
MA...COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING
FOR MAZ020>024.
HIGH WIND WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON
FOR MAZ005>007-012>024.
NH...NONE.
RI...COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING
FOR RIZ002-004>008.
HIGH WIND WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON
FOR RIZ001>008.
MARINE...GALE WARNING FROM MIDNIGHT TONIGHT TO 7 PM EST THURSDAY FOR
ANZ230>237-250-251-254>256.
&&
$$
SYNOPSIS...FRANK
NEAR TERM...EKSTER
SHORT TERM...EKSTER
LONG TERM...FRANK
AVIATION...EKSTER/FRANK
MARINE...EKSTER/FRANK
