277
FXUS61 KBOX 092001
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
401 PM EDT THU OCT 9 2025
SYNOPSIS
HIGH PRESSURE BUILDS IN FROM THE WEST, BRING DRIER AND COLDER
CONDITIONS INTO SATURDAY. A COASTAL STORM BRINGS RAIN AND GUSTY
WINDS TO START NEXT WEEK, ALONG WITH THE RISK FOR SOME COASTAL
FLOODING AND EROSION.
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
KEY MESSAGES...
* BECOMING MUCH COLDER TONIGHT WITH FREEZING TEMPERATURES AND FROST.
HIGH PRESSURE OVERHEAD CONTINUES TO DOMINATE THE WEATHER PATTERN FOR
SNE THIS EVENING AND OVERNIGHT RESULTING IN LITTLE TO NO WIND
BENEATH CLEAR SKIES. THIS SETUP IS IDEAL FOR RADIATIONAL COOLING AND
SO THE FORECAST HAS BEEN TRENDED TOWARD MOS GUIDANCE WHICH HANDLES
THESE SITUATIONS BETTER. IT IS LIKELY THAT MANY LOCATIONS AWAY FROM
THE IMMEDIATE COASTS REACH FREEZING OR SUB-FREEZING TEMPERATURES
OVERNIGHT WHICH HAS PROMPTED A FREEZE WARNING FOR MANY LOCATIONS.
FOR MANY OF THOSE CLOSER TO THE WATER, FROST ADVISORIES ARE IN
EFFECT AS IT WILL BE QUITE COLD REGARDLESS.
SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/
KEY MESSAGES...
* DRY AND A FEW DEGREES WARMER ON FRIDAY.
FRIDAY HIGH PRESSURE REMAINS IN CONTROL, SHIFTING EAST WHICH MEANS
WE'LL SEE WINDS BACK TO THE SOUTHEAST. THIS ADVECTS WARMER AIR
OVERHEAD IN THE LOW/MID LEVELS WITH 925 MB TEMPS RISING FROM 3C
TODAY TO 5-6C FRIDAY AFTERNOON. THE RESULTANT HIGH TEMPS AT THE
SURFACE WILL BE BELOW NORMAL BUT A BIT WARMER THAN THURSDAY, IN THE
LOW 60S. THAT MODERATING AIRMASS AS WELL AS INCREASING CLOUDCOVER
FRIDAY NIGHT WILL KEEP LOWS IN CHECK, IN THE UPPER 30S AND LOW 40S.
LONG TERM /SATURDAY THROUGH THURSDAY/
KEY MESSAGES:
* BRIEF WARM-UP SATURDAY BEFORE HIGHS RETURN TO THE LOWER 60S/UPPER
50S THROUGH THE REST OF THE WEEKEND AND NEXT WEEK
* COASTAL STORM MAY BRING MORE RAIN AND GUSTY WINDS SUNDAY THROUGH
MONDAY, ALONG WITH THE RISK FOR SOME COASTAL FLOODING AND BEACH
EROSION
* PATTERN REMAINS UNSETTLED THROUGH MIDWEEK
HIGH PRESSURE BEGINS TO MOVE OFFSHORE SATURDAY, THOUGH WINDS ARE
EXPECTED TO REMAIN LIGHT AND CONDITIONS WILL CONTINUE TO BE DRY.
HIGH LEVEL CLOUDS WILL BE ABLE TO CREEP IN FROM THE SOUTH ASSOCIATED
WITH THE BUILDING COASTAL STORM. SATURDAY REMAINS ON TRACK TO BE THE
WARMEST DAY IN THIS PERIOD (AND WEEKEND), WITH 925 MB TEMPERATURES
AT AND ABOVE 10C ACROSS SOUTHERN NEW ENGLAND IN THE AFTERNOON. LIGHT
SOUTHERLY WINDS WILL PREVAIL THROUGH THE DAY BEFORE SHIFTING EAST
OVERNIGHT. HIGHS IN THE MID 60S WITH LOCALLY HIGHER TEMPERATURES IN
THE UPPER 60S WILL BE SUPPORTED IN THIS ENVIRONMENT.
CONFIDENCE IS CONTINUING TO INCREASE REGARDING THE COASTAL STORM
TRACKING FROM THE SOUTH TOWARDS SOUTHERN NEW ENGLAND, THOUGH SOME
DETAILS REMAIN UNCERTAIN AT THIS TIME. THE GENERAL TRENDS REMAIN
CONSISTENT ACROSS MODEL SUITES: A STRONG SURFACE HIGH PRESSURE
SETTLED OVER QUEBEC, MAINE AND PARTS OF THE CANADIAN MARITIMES, AND
AS THE HYBRID COASTAL STORM FROM THE SOUTH APPROACHES OUR SOUTHERN
WATERS LATE SUNDAY, THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS
WILL TIGHTEN. THIS WILL LEAD TO STRONG NE WINDS FROM LATE SUNDAY
THROUGH MONDAY EVENING, WITH GUSTS UP TO 55 KNOTS POSSIBLE OVER THE
WATERS, THOUGH THEY WILL BE ELEVATED OVER LAND AS WELL. ROUGHER SEAS
ARE ALSO EXPECTED IN THIS TIME PERIOD. CONFIDENCE IS INCREASING
REGARDING RAINFALL ASSOCIATED WITH THIS STORM REACHING SOUTHERN NEW
ENGLAND AS WELL; ENSEMBLES ARE INDICATING MODERATE PROBABILITIES FOR
24 HOUR TOTALS THROUGH MONDAY MORNING REACHING AND EXCEEDING 1"
ACROSS THE REGION. NAEFS GUIDANCE HAS PWAT VALUES OVER THE REGION
MONDAY INTO TUESDAY JUST UNDER 2 STANDARD DEVIATIONS ABOVE NORMAL.
CANADIAN ENSEMBLE GUIDANCE IS WETTER THAN THE OTHER ENSEMBLES, WITH
THE ECMWF ENSEMBLE BEING THE DRIEST. HOWEVER, ACROSS THESE TWO AND
THE GFS ENSEMBLE, TOTALS OVER EASTERN MA ARE TRENDING AS THE HIGHEST.
SOME SPREAD STILL REMAINS REGARDING THIS SYSTEM'S EXIT FROM THE
REGION. CANADIAN ENSEMBLE AND DETERMINISTIC GUIDANCE KEEPS THE
SYSTEM ON A SLOWER TRACK EAST (AND ALSO EXPANDS THE SURFACE LOW AS
IT MOVES EAST) WHILE THE GFS AND ECMWF GUIDANCE REMAIN MORE
PROGRESSIVE, WITH THE ECMWF GUIDANCE STARTING TO TREND MORE IN LINE
WITH THE GFS. ONCE THIS SYSTEM MOVES OUT SOMETIME MIDWEEK, THE
PATTERN IS STILL EXPECTED TO REMAIN UNSETTLED AS MORE TROUGHING FROM
CANADA WILL IMPACT THE REGION. HIGHS THROUGH THE WEEK REMAIN
CONSISTENTLY IN THE LOW 60S AS 925 MB TEMPERATURES REMAIN AT OR JUST
BELOW 10C THROUGH THE AFTERNOONS.
AVIATION /19Z THURSDAY THROUGH TUESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z UPDATE...
THIS AFTERNOON...HIGH CONFIDENCE.
VFR. NW WINDS 8-12 KTS WITH GUSTS 20 KNOTS. GUSTS OF 20 TO
30 KNOTS TOWARD THE CAPE AND NANTUCKET.
TONIGHT AND FRIDAY...HIGH CONFIDENCE.
VFR. WINDS DIMINISH QUICKLY WITH GUSTS FALLING OFF A LITTLE
BEFORE 00Z AND SUSTAINED WINDS BECOMING LIGHT TO CALM. LIGHT SW
WINDS DEVELOP FRIDAY AFTERNOON AND BECOMING LIGHT TO CALM
OVERNIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY: VFR.
SATURDAY NIGHT: VFR. BREEZY. SLIGHT CHANCE SHRA.
SUNDAY: MAINLY VFR, WITH AREAS MVFR POSSIBLE. STRONG WINDS WITH
LOCAL GUSTS UP TO 40 KT. CHANCE SHRA.
SUNDAY NIGHT: MAINLY MVFR, WITH LOCAL IFR POSSIBLE. STRONG
WINDS WITH GUSTS UP TO 45 KT. SHRA.
COLUMBUS DAY: MAINLY MVFR, WITH AREAS IFR POSSIBLE. STRONG
WINDS WITH GUSTS UP TO 45 KT. SHRA.
MONDAY NIGHT: MAINLY MVFR, WITH AREAS IFR POSSIBLE. WINDY WITH
GUSTS UP TO 35 KT. SHRA LIKELY.
TUESDAY: MVFR/IFR CONDITIONS POSSIBLE. WINDY WITH LOCAL GUSTS
UP TO 30 KT. CHANCE SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH FRIDAY NIGHT... HIGH CONFIDENCE.
IMPROVING CONDITIONS THIS EVENING WITH EASING WINDS AND
SUBSIDING SEAS. HIGH PRESSURE SETTLES OVER THE WATERS TONIGHT
INTO FRIDAY NIGHT. A STORM WATCH HAS BEEN ISSUED TO ADDRESS
POTENTIAL FOR STRONG WINDS OVER THE WATERS LATE SUNDAY AND
MONDAY.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY: WINDS LESS THAN 25 KT.
SATURDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
LOCAL GUSTS UP TO 30 KT. SEAS LOCALLY APPROACHING 5 FT. CHANCE
OF RAIN SHOWERS.
SUNDAY: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO 45 KT.
AREAS OF ROUGH SEAS. RAIN SHOWERS LIKELY. LOCAL VISIBILITY 1 TO
3 NM.
SUNDAY NIGHT THROUGH COLUMBUS DAY: STORM FORCE WINDS POSSIBLE WITH
GUSTS UP TO 50 KT. ROUGH SEAS UP TO 20 FT. RAIN SHOWERS, SLIGHT
CHANCE OF THUNDERSTORMS. LOCAL VISIBILITY 1 TO 3 NM.
MONDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS
UP TO 19 FT. RAIN SHOWERS, SLIGHT CHANCE OF THUNDERSTORMS.
TUESDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
AREAS OF GUSTS UP TO 30 KT. ROUGH SEAS UP TO 15 FT. RAIN
SHOWERS LIKELY.
BOX WATCHES/WARNINGS/ADVISORIES
CT...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM EDT FRIDAY FOR
CTZ002>004.
MA...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM EDT FRIDAY FOR
MAZ005-006-009>014-017-018-020-021.
FROST ADVISORY FROM 11 PM THIS EVENING TO 9 AM EDT FRIDAY FOR
MAZ007-015-016-019-023.
COASTAL FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE MONDAY
NIGHT FOR MAZ007-015-016-019>024.
RI...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM EDT FRIDAY FOR
RIZ001-003-006.
FROST ADVISORY FROM 11 PM THIS EVENING TO 9 AM EDT FRIDAY FOR
RIZ002-004-005-007.
COASTAL FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE MONDAY
NIGHT FOR RIZ004>008.
MARINE...STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY EVENING FOR
ANZ231>235-237-250-251-254>256.
SYNOPSIS...BW/HRENCECIN
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...HRENCECIN
AVIATION...BW/HRENCECIN
MARINE...BW/HRENCECIN
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