FXUS61 KBOX 021837
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
137 PM 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 CLOUDS ALREADY STREAMING INTO THE REGION LATE THIS MORNING
AHEAD OF STRENGTHENING LOW PRES ACROSS THE LOWER MISSISSIPPI VALLEY.
NOTING A HUGE AMOUNT OF C/G LIGHTNING ASSOCIATED WITH THIS LOW...
ALONG WITH A TORNADO WATCH ACROSS THE SOUTH CENTRAL COAST OF THE
GULF. THIS IS INDICATIVE OF VERY STRONG DYNAMICS ALREADY IN PLACE
WITH THIS LOW. WV SATELLITE SHOWING STRONG SHORT WAVE WITH JET
WRAPPING AROUND THE LOW...HELPING FUEL THE CONVECTION AHEAD OF THE
DRY TONGUE. WITH THIS LOW/S HISTORY...THIS LENDS MORE CREDENCE FOR
A LOT OF QUICK HITTING ACTION LATER TONIGHT.
AS FOR THIS AFTERNOON...EXPECT CLOUDS TO QUICKLY INCREASE BUT PRECIP
TO HOLD OFF UNTIL TONIGHT. NORTHERN EDGE OF PRECIP SEEN ON NE
REGIONAL RADAR UP TO CHESAPEAKE BAY/S DELAWARE AT 16Z.
TEMPS ARE RUNNING A BIT COOLER THAN FORECAST...BUT FEEL THEY WILL
RECOVER TO PREVIOUSLY FORECASTED HIGHS. UPDATED THE GRIDS AND ZONES
TO REFLECT THIS THINKING...AS WELL AS BRINGING OTHER PARAMETERS
CURRENT.
&&
.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 WEDNESDAY/...
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 /19Z WEDNESDAY THROUGH MONDAY/...
REMAINDER OF THIS AFTERNOON...
VFR WITH LIGHT SOUTHERLY WINDS.
THIS EVENING...
VFR TO START WITH CEILINGS QUICKLY LOWERING TO MVFR TOWARD MIDNIGHT
WITH A LOW PROBABILITY OF IFR BY THEN AT BDL/BAF. RAIN WILL BEGIN TO
OVERSPREAD TERMINALS 03Z BDL/BAF TO 06Z MHT/BOS/HYA/ACK.
OVERNIGHT...
MARGINAL MVFR/IFR CONDITIONS ESPECIALLY AFTER 09Z. THINK CIGS WILL
HOVER AROUND 008-012 THEREAFTER DESPITE MUCH OF THE MODEL GUIDANCE
SUGGESTING WIDESPREAD LIFR. RAIN WILL BE HEAVY AT TIMES ALONG WITH A
LOW PROBABILITY OF THUNDER 09Z- 12Z PVD/HYA/FMH AND ACK. LLWS LIKELY
ALL TERMINALS ESPECIALLY PVD/HYA/FMH AND ACK WITH STRONG LOW LEVEL
SOUTHERLY JET OF 80 KT WITH 60 KT DOWN TO 1KFT ACROSS TERIMALS
MENTIONED ABOVE.
THURSDAY...
AS MENTIONED ABOVE MUCH OF THE MODEL GUIDANCE SUGGEST WIDESPREAD LIFR
BUT PATTERN RECOGNITION SUGGEST MARGINAL IFR/MVFR THROUGH 13Z- 15Z.
LLWS AND ISOLATED THUNDER POSSIBLE THROUGH 13Z-15Z FROM SOUTHWEST TO
NORTHEAST. CONDITIONS RAPIDLY IMPROVE THEREAFTER TO VFR. ANY CIGS
DURING THE AFTERNOON WILL BE AROUND 4KFT.
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...
THROUGH THIS AFTERNOON...W-SW WINDS LESS THAN 10 KTS EARLY WILL PICK
UP TO 10-15 KT ON THE SOUTHERN WATERS LATE IN THE DAY. SEAS 3 FEET
OR LESS.
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. THE LOW THIS MORNING AT
LOGAN WAS 35 DEGREES...THUS AS OF THIS MORNING THE RECORD HAS BEEN
TIED. THE OVERNIGHT LOW TONIGHT IS FORECASTED TO REMAIN ABOVE
FREEZING...THUS THE RECORD WILL LIKELY BE BROKEN. AVERAGE FIRST DATE
OF 32 IN BOSTON IS AROUND NOVEMBER 4TH.
RECORDS AT OUR 4 CLIMATE SITES FOR THURSDAY...DECEMBER 3 ARE AS FOLLOWS:
MAX T HIGH MIN PCPN
BOS...65 IN 1932 48 IN 1932 1.82 IN 1986
PVD...63 IN 1932 46 IN 1998* 3.38 IN 1986
BDL...64 IN 1932 43 IN 1932 1.60 IN 1967
ORH...61 IN 1932 47 IN 1998 1.69 IN 1986
*MEANS RECORD NOTED ALSO SET IN PREVIOUS YEARS.
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...EVT
SHORT TERM...EKSTER
LONG TERM...FRANK
AVIATION...NOCERA/FRANK
MARINE...EKSTER/FRANK/EVT
TIDES/COASTAL FLOODING...
CLIMATE...KAB
