FXUS61 KBOX 022052
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
352 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. COASTAL LOW PRESSURE WILL MOST LIKELY
PASS FAR ENOUGH OFFSHORE SATURDAY/SATURDAY NIGHT TO PREVENT A
SIGNIFICANT WINTER STORM. ANOTHER LOW PRESSURE AREA MAY MOVE THROUGH
NEW ENGLAND NEXT WEDNESDAY OR WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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 AM THURSDAY MORNING 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/...
LONG TERM IS BASED ON A CONSENSUS OF MODELS...ESPECIALLY A BLEND OF
12Z GFS AND ECMWF.
THURSDAY NIGHT AND FRIDAY...
SURFACE LOW WILL HAVE MOVED OFF THROUGH THE MARITIMES...BUT UPPER
LOW AND TROF LINGERS OVER THE MIDWEST. THIS KEEPS US IN A SOUTHWEST
FLOW ALOFT AND CHANNELS THE COLD CORE WITH THE TROF BACK NORTH INTO
CANADA. WHILE TEMPS WILL COOL OFF FROM THE RELATIVELY BALMY LEVELS OF
THURSDAY...READINGS SHOULD BE NEAR NORMAL LEVELS.
FRIDAY NIGHT-SATURDAY-SATURDAY NIGHT...
SHORTWAVE IN THE PACIFIC NORTHWEST DIVES AROUND THE MIDWEST UPPER
TROF AND MOVES UP THE SOUTHWEST UPPER FLOW SATURDAY. GENERAL MODEL
AGREEMENT THAT THIS GENERATES A COASTAL LOW OFF GEORGIA/FLORIDA
FRIDAY WHICH THEN MOVES UP THE COAST SATURDAY AND PASSES WELL
OFFSHORE OF NANTUCKET EARLY SATURDAY NIGHT. THE CLOUD SHIELD LEADING
THE LOW WILL MOVE INTO OUR AREA FRIDAY NIGHT. BUT THE ARRIVAL OF
PRECIPITATION IS STILL AN OPEN QUESTION. THE CONSENSUS TRACK WOULD
KEEP MOST PRECIPITATION OFFSHORE...BUT THE UPPER TROF MAY DRAW THIS
NORTHWARD. THE EURO AND NAM BRING .01 TO KEENE AND GREENFIELD /MA/ WITH
ALL MODELS BRINGING MEASUREABLE UP TO THE SOUTH COAST. WE WILL
CONTINUE WITH CHANCE POPS UP TO A MHT-BAF LINE AND GRADING TO HIGH-
END CHANCE VALUES ALONG THE SOUTH COAST. BASED ON 12Z INFORMATION IT
APPEARS THAT A SIGNIFICANT PRECIPITATION EVENT WILL STAY OFFSHORE OF
NEW ENGLAND.
TEMPERATURE PROFILES OVER NEW ENGLAND ARE COLD ENOUGH TO SUPPORT
SNOW...ESPECIALLY AT NIGHT...WITH 1000-500 MB THICKNESSES BELOW 5400
M. AND 1000-850 MB THICKNESSES BELOW 1300 M. EVERYWHERE BUT THE
CAPE/ISLANDS. HOWEVER SURFACE TEMPERATURES WILL BE WARM ENOUGH SO
THAT ANY SNOW WILL EITHER MELT ON CONTACT OR BE LIMITED TO LESS THAN
AN INCH. STAY TUNED.
SUNDAY THROUGH TUESDAY...
QUIET WEATHER AS HIGH PRESSURE BUILDS OVER THE REGION. UPPER FLOW
TURNS ZONAL...SO TEMPS SHOULD BE SEASONABLY COOL.
WEDNESDAY...
ANOTHER SHORTWAVE CARVES INTO THE MIDWEST TUESDAY AND GENERATES
SURFACE LOW PRESSURE WHICH THEN MOVES TOWARD THE EAST COAST
WEDNESDAY. THE 12Z EURO TRACKS THE LOW WELL SOUTH OF NEW ENGLAND
WHILE OTHER GUIDENCE BRINGS IT UP THROUGH THE NORTHEAST. EITHER WAY
AN UPPER TROF SWINGS THROUGH SOUTHERN NEW ENGLAND. IT IS ALSO A DAY 7
FORECAST. WE WILL GO WITH INCREASING CLOUDS WEDNESDAY AND CHANCE
POPS WEDNESDAY AFTERNOON/NIGHT.
&&
.AVIATION /20Z 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...VFR.
SATURDAY AND SATURDAY NIGHT...MVFR-IFR CONDITIONS POSSIBLE WITH BEST
CHANCE OVER THE CAPE AND ISLANDS...LEAST CHANCE OVER SOUTHERN NH.
SUNDAY-MONDAY...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...DIMINISHING WINDS. EXPECT SMALL CRAFT ADVISORY
CRITERIA WINDS AND SEAS THROUGH THE NIGHT.
FRIDAY AND FRIDAY NIGHT...WINDS WILL BE LESS THAN SMALL CRAFT
CRITERIA. SEAS WILL SUBSIDE...BUT LINGER ABOVE 5 FEET ON THE
SOUTHERN OUTER WATERS.
SATURDAY AND SATURDAY NIGHT...COASTAL LOW PRESSURE WILL PASS WELL
SOUTHEAST OF NANTUCKET AND KEEP THE HEAVIEST WEATHER WELL OFFSHORE.
THE LOW WILL INTENSIFY ENOUGH TO SPEAD SMALL CRAFT WINDS AND SEAS
INTO THE SOUTHERN AND SOUTHEAST WATERS.
SUNDAY...WINDS AND SEAS DIMINISH BELOW SMALL CRAFT LEVELS.
MONDAY...WINDS AND SEAS REMAIN BELOW SMALL CRAFT LEVELS.
&&
.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 2 AM EST THURSDAY THROUGH THURSDAY
AFTERNOON FOR CTZ002>004.
MA...COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING
FOR MAZ020>024.
HIGH WIND WATCH FROM 2 AM EST THURSDAY 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 2 AM EST THURSDAY 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...WTB
NEAR TERM...EVT
SHORT TERM...EKSTER
LONG TERM...WTB
AVIATION...WTB/NOCERA
MARINE...WTB/EKSTER/EVT
TIDES/COASTAL FLOODING...
CLIMATE...KAB
