876
FXUS61 KBOX 161050
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
550 AM EST TUE DEC 16 2025
WHAT HAS CHANGED
CONFIDENCE CONTINUES TO INCREASE FOR POTENTIAL WIND AND MINOR
COASTAL FLOOD IMPACTS THURSDAY NIGHT INTO FRIDAY.
KEY MESSAGES
- STRONG AND POSSIBLY DAMAGING WINDS POSSIBLE LATE THURSDAY
NIGHT INTO FRIDAY WITH GALE FORCE WINDS ON MA/RI WATERS.
- MINOR COASTAL FLOODING POSSIBLE ALONG SOUTH FACING SHORES
AROUND HIGH TIDE FRIDAY MORNING.
DISCUSSION
KEY MESSAGE 1...STRONG AND POSSIBLY DAMAGING WINDS.
MAIN CONCERN FOR THIS FORECAST IS A "WARMER" STORM SYSTEM THAT
IS EXPECTED TO TRACK THROUGH THE GREAT LAKES AND SWING A STRONG
COLD FRONT THROUGH SOUTHERN NEW ENGLAND FRIDAY MORNING. MODELS
ARE IN GOOD AGREEMENT IN SHOWING A 500 MB TROUGH BECOMING
NEGATIVELY TILTED AS IT ROTATES THROUGH NEW ENGLAND, WITH DECENT
MOISTURE TRANSPORT AND A FAIRLY ROBUST WIND FIELD ALOFT WITH
60-80KT LOW LEVEL JET AT 925 AND 850 MB, THOUGH WE'RE SEEING A
TREND THAT THESE STRONGER LOWER LEVEL WINDS WILL MATERIALIZE AS
SYSTEM REACHES GULF OF MAINE, AND AS A RESULT, NBMV4.3
PROBABILITIES FOR 50+ MPH WINDS HAVE COME DOWN A BIT SINCE
YESTERDAY, ALTHOUGH NBMV5.0 SHOWS BETTER POTENTIAL ESPECIALLY
ACROSS RI AND SE MA AS WELL AS COASTAL WATERS.
TAKING A LOOK AT ENSEMBLE WIND PROBABILITIES AND A CURSORY LOOK
AT NAM/GFS FORECAST SOUNDINGS GIVES HIGHER CONFIDENCE FOR
SOUTHERLY GUSTS IN 40-50 MPH RANGE LATE THURSDAY NIGHT INTO
FRIDAY, BUT IF WE CAN WARM INTO UPPER 50S FRIDAY MORNING, WE
WOULD BE ABLE TO MORE EASILY MIX DOWN 50-60 MPH WINDS WHICH
WOULD INCREASE THE POTENTIAL FOR WIND DAMAGE. ADDITIONALLY, WE
WILL NEED TO KEEP AN EYE ON POSSIBILITY OF A FINE LINE OF
CONVECTION DEVELOPING ALONG COLD FRONT AS IT CROSSES SNE FRIDAY
MORNING WHICH COULD BRING BRIEF DOWNPOURS AND STRONGER WIND
GUSTS BUT THAT IS HIGHLY DEPENDENT UPON HAVING SOME INSTABILITY,
SOMETHING THAT CAN BE SEEN ON 00Z RRFS WHICH HAS 100-200 J/KG
OF MUCAPE.
BEHIND FRONT, COLD ADVECTION TAKES HOLD WITH W/NW WINDS
POTENTIALLY GUSTING TO 40-50 MPH, ESPECIALLY ACROSS HIGHER
TERRAIN AND NEAR COAST (AND ON COASTAL WATERS) DUE TO DEEPENING
MIXED LAYER AND STRONG PRESSURE RISES. ANOTHER SHOT OF COLD
ARRIVES FRIDAY AFTERNOON INTO SATURDAY, ALBEIT NOT AS COLD AS
WHAT WE JUST EXPERIENCED.
KEY MESSAGE 2...MINOR COASTAL FLOODING.
CONFIDENCE IS LOWER THAN WITH WIND IMPACTS DESCRIBED ABOVE DUE
TO TIMING OF WHEN HIGHEST SURGE WILL ARRIVE AND IF IT WILL
COINCIDE WITH HIGH TIDE ALONG SOUTH COAST FRIDAY MORNING,
ROUGHLY BETWEEN 6 AND 8 AM. THIS IS TIED TO HOW QUICKLY STRONGER
WINDS CAN RAMP UP AND TO SOME EXTENT OFFSHORE SEAS AS WELL.
IF EVERYTHING COMES TOGETHER, THE WORST CASE SCENARIO WOULD BE
FOR MINOR COASTAL FLOODING ALONG SOUTH COAST (LESS THAN 1 FOOT
DEEP ON VULNERABLE SHORE ROADS) SINCE WE WOULD NEED A SURGE
CLOSE TO 3 FT. STEVENS INSTITUTE ENSEMBLE GUIDANCE SHOWS A
POTENTIAL 1-2 FT SURGE WHILE P-ETSS IS UNDER 1 FT AND PROBABLY
UNDERDONE. EROSION SHOULD NOT BE MUCH OF A FACTOR GIVEN OFFSHORE
SEAS OF 10-15 FT AND ONLY THIS HIGH TIDE CYCLE BEING AFFECTED.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE: HIGH CONFIDENCE.
VFR THROUGH THE PERIOD. W WINDS AROUND 10KT BACK TO SW THIS
AFTERNOON, THEN INCREASE OVERNIGHT AND WED WITH GUSTS OF
20-30KT.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /THURSDAY THROUGH SATURDAY/...
THURSDAY: VFR. BREEZY.
THURSDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE. STRONG WINDS WITH
GUSTS UP TO 45 KT. CHANCE RA.
FRIDAY: MAINLY MVFR, WITH LOCAL IFR POSSIBLE. STRONG WINDS WITH
GUSTS UP TO 45 KT. CHANCE RA.
FRIDAY NIGHT: VFR. WINDY WITH GUSTS UP TO 35 KT.
SATURDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY THROUGH WEDNESDAY NIGHT...HIGH CONFIDENCE.
CALM WINDS AND SEAS UNDER A RIDGE, WITH A HIGH PRESSURE SYSTEM
SITTING SOUTH OF OUR WATERS. WINDS AND SEAS BEGIN TO BUILD LATE
TONIGHT THROUGH WEDNESDAY MORNING INTO SCA LEVELS. WIND GUSTS
OVER THE FAR SOUTHERN AND FAR NORTHERN WATERS LOOK TO BE ON THE
HIGHER END OF SCA AND MAY REACH MARGINAL GALES BUT NOT CONFIDENT
ENOUGH TO RAISE GALE WARNINGS AT THIS TIME.
OUTLOOK /THURSDAY THROUGH SATURDAY/...
THURSDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT.
THURSDAY NIGHT: MODERATE RISK FOR GALE FORCE WINDS WITH GUSTS
UP TO 45 KT. ROUGH SEAS UP TO 14 FT. CHANCE OF RAIN.
FRIDAY: GALE FORCE WINDS WITH GUSTS UP TO 45 KT. ROUGH SEAS UP
TO 16 FT. RAIN.
FRIDAY NIGHT: STRONG WINDS WITH AREAS OF GUSTS UP TO 45 KT.
ROUGH SEAS UP TO 13 FT. SLIGHT CHANCE OF RAIN.
SATURDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 3 AM TO 4 PM EST WEDNESDAY FOR
ANZ230.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM EST
WEDNESDAY FOR ANZ231-251.
SMALL CRAFT ADVISORY FROM 1 AM TO 10 PM EST WEDNESDAY FOR
ANZ232>235-237.
SMALL CRAFT ADVISORY FROM 3 AM TO 6 PM EST WEDNESDAY FOR
ANZ236.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
THURSDAY FOR ANZ250-254>256.
DISCUSSION...JWD
AVIATION...MCMINN/JWD
MARINE...MCMINN
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