225
FXUS61 KBOX 101821
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
221 PM EDT WED SEP 10 2025
SYNOPSIS
LOW PRESSURE MOVES OFFSHORE TONIGHT FOLLOWED BY HIGH PRESSURE
THURSDAY WHICH WILL BRING SUNSHINE AND SEASONABLY WARM
TEMPERATURES. DRY WEATHER WITH NEAR SEASONABLE TEMPERATURES
PREVAILS FOR THE REST OF THE WEEK AND INTO MUCH OF THE WEEKEND
AS HIGH PRESSURE REMAINS OVER NEW ENGLAND. WEATHER PATTERN
BECOMES UNSETTLED FOR THE SECOND HALF OF THE WEEKEND INTO EARLY
NEXT WEEK; HOWEVER, THERE IS UNCERTAINTY IN THE DETAILS (TIMING,
COVERAGE, AMOUNTS). THIS WILL EXTEND INTO MONDAY, POTENTIALLY
LINGERING AS LATE AS TUESDAY.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
* CLEARING SKIES FROM NW TO SE TONIGHT
COASTAL LOW WILL MOVE OFFSHORE TONIGHT TAKING THE DEEPER MOISTURE
PLUME WITH IT. STILL CAN'T RULE OUT A BRIEF PASSING SHOWER EARLY
THIS EVENING OVER THE CAPE AND ISLANDS WHERE BACK EDGE OF 1.5" PWAT
PLUME IS LOCATED, BUT TREND WILL BE FOR DRYING CONDITIONS FROM THE
NORTH TONIGHT. SKIES HAVE CLEARED ACROSS INTERIOR MA AND THIS
CLEARING WILL GRADUALLY OVERSPREAD THE REST OF SNE TONIGHT WITH CAPE
AND ISLANDS THE LAST TO CLEAR OUT LATE TONIGHT. N WINDS WILL
DIMINISH TONIGHT ESPECIALLY INTERIOR WHERE GOOD RADIATIONAL COOLING
WILL DEVELOP. LOWS WILL RANGE FROM THE MID-UPPER 40S INTERIOR TO LOW-
MID 50S COASTAL PLAIN, EXCEPT UPPER 50S CAPE/ISLANDS WHERE CLOUDS
AND STEADIER WIND WILL PERSIST THE LONGEST.
SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
KEY MESSAGES:
* SUNNY AND SEASONABLY WARM THU
* PARTLY CLOUDY AND COOL THU NIGHT
THE COASTAL LOW MOVES FURTHER OFFSHORE AS HIGH PRES BUILDS OVER
CANADA SETTING UP A DRY NORTHERLY FLOW. WEDGE OF DRY AIR WILL BRING
LOTS OF SUNSHINE THU WITH SEASONABLY WARM TEMPS EXPECTED. 925 MB
TEMPS 16-18C WILL SUPPORT HIGHS WELL INTO THE 70S AND CAN'T RULE OUT
A FEW PLACES REACHING 80F. MODEST NORTH BREEZE WITH LOCAL SEABREEZES
DEVELOPING ALONG THE EASTERN MA COAST.
WEAK MID LEVEL SHORTWAVE MOVES THROUGH THU NIGHT BUT HIGH PRES WILL
BE IN CONTROL TO THE NORTH. THE SHORTWAVE MAY BRING A PERIOD OF MID
CLOUDS, OTHERWISE A DRY AND COOL NIGHT WITH LOWS IN THE UPPER 40S
AND 50S.
LONG TERM /FRIDAY THROUGH TUESDAY/
KEY MESSAGES:
* DRY FRIDAY THROUGH THE FIRST HALF OF THE WEEKEND WITH BELOW NORMAL
TEMPERATURES.
* BECOMING MORE UNSETTLED FOR SECOND HALF OF WEEKEND INTO EARLY NEXT
WEEK.
FRIDAY AND SATURDAY:
MUCH OF THE EXTENDED PERIOD WILL BE DOMINATED BY GENERAL UPPER
TROUGHING ACROSS THE NORTHEAST. A COOLER AIRMASS SETTLES INTO
SOUTHERN NEW ENGLAND ON FRIDAY WITH NORTHEASTERLY SURFACE FLOW. THIS
WILL BRING SLIGHTLY BELOW NORMAL TEMPERATURES WITH HIGHS IN THE LOW
TO MID 70S FOR MOST AREAS. IMMEDIATE COASTAL AREAS IN THE EAST MAY
END UP STRUGGLING TO HIT 70 GIVEN THE ONSHORE FLOW. HIGH PRESSURE IS
EXPECTED TO BE IN PLACE SUPPORTING DRY CONDITIONS. SIMILAR
CONDITIONS ARE EXPECTED SATURDAY.
SATURDAY THROUGH EARLY NEXT WEEK:
THERE IS A GENERAL CONSENSUS AMONG ENSEMBLE GUIDANCE THAT A
SHORTWAVE TROUGH/UPPER LOW DROPS ACROSS THE NORTHEASTERN STATES
SUNDAY. CONFIDENCE BEGINS TO DROP OFF IN THE DETAILS SUCH AS TIMING
AND AMOUNTS. ENSEMBLE MEMBERS SHOW POTENTIAL FOR SHOWERS
ARRIVING SUNDAY LATER SUNDAY INTO MONDAY FROM WEST TO EAST. WPC
CLUSTER ANALYSIS DEPICTS GOOD AGREEMENT AMONG MODEL GUIDANCE FOR
A FAIRLY STAGNANT UPPER PATTERN IN PLACE WITH A STRONG/NARROW
RIDGE ACROSS THE LOWER GREAT LAKES. THIS WILL LIKELY FAVOR A
SLOW EXIT OF THE SYSTEM. SCATTERED SHOWERS WILL BE POSSIBLE
MONDAY, BUT MAY LINGER THROUGH LATE TUESDAY DEPENDING ON THE
PROGRESSION OF THE UPPER LEVEL PATTERN. ENSEMBLE MEANS HAVE RAIN
AMOUNTS ON THE LIGHTER END WITH TRACE-0.25", BUT THERE ARE SOME
INDIVIDUAL SOLUTIONS WITH HIGHER AMOUNTS IN SPOTS (0.50-1"+).
THEY ARE LIKELY PICKING UP ON SOME POTENTIAL MARGINAL
INSTABILITY IN PLACE (SCT THUNDERSTORMS) AND HIGHER AVAILABLE
MOISTURE. THIS WILL BE SOMETHING TO KEEP AN EYE ON IN THE COMING
DAYS TO ADJUST FORECAST RAIN AMOUNTS. TEMPERATURES WILL BE
SLIGHTLY BELOW NORMAL IN THE UPPER 60S TO MID 70S.
AVIATION /18Z WEDNESDAY THROUGH SUNDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE: HIGH CONFIDENCE IN TRENDS.
THROUGH TONIGHT...
MVFR-IFR CIGS OVER THE CAPE/ISLANDS EXPECTED TO BACK INTO SE MA
LATE AFTERNOON AND EVENING, BUT SHOULD REMAIN VFR TO THE WEST.
BOS-PVD CORRIDOR WILL BE ON THE EDGE OF THE LOWER CIGS WITH
SCT-BKN025 AT TIMES THIS AFTERNOON. CLEARING TREND TONIGHT BUT
MVFR CIGS LIKELY PERSISTING OVER CAPE/ISLANDS. NE WIND GUSTS UP
TO 20 KT ALONG THE SOUTH COAST AND CAPE/ISLANDS INTO THIS
EVENING.
THURSDAY AND THURSDAY NIGHT...
VFR. N WIND 5-10 KT. AFTERNOON SEA-BREEZES POSSIBLE ALONG
EASTERN MA COAST.
KBOS TERMINAL...MODERATE CONFIDENCE. SCT TO OCCASIONAL BKN MVFR
CIGS AROUND 2500 FT THIS AFTERNOON, BUT DRYING TREND BY LATE
AFTERNOON. VFR WITH CLEARING TONIGHT. SEA-BREEZE DEVELOPS BY 18Z
THU.
KBDL TERMINAL...HIGH CONFIDENCE.
OUTLOOK /FRIDAY THROUGH SUNDAY/...
THURSDAY NIGHT THROUGH FRIDAY: VFR. BREEZY.
FRIDAY NIGHT THROUGH SATURDAY NIGHT: VFR.
SUNDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SLIGHT CHANCE
SHRA, SLIGHT CHANCE TSRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
SCAS FOR THE SOUTH COASTAL WATERS INTO THIS EVENING FOR A
COMBINATION OF MARGINAL SCA WINDS AND SEAS, BUT GRADUALLY IMPROVING
CONDITIONS TONIGHT INTO THU AND WINDS AND SEAS SUBSIDE. ANOTHER
PERIOD OF 25 KT NE GUSTS POSSIBLE THU NIGHT OVER NE MA WATERS.
OUTLOOK /FRIDAY THROUGH SUNDAY/...
THURSDAY NIGHT THROUGH FRIDAY: WINDS LESS THAN 25 KT. AREAS OF
SEAS APPROACHING 5 FT.
FRIDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
SATURDAY THROUGH SATURDAY NIGHT: WINDS LESS THAN 25 KT.
SUNDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
SLIGHT CHANCE OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR ANZ232.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ233>235.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THURSDAY FOR ANZ254-255.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR ANZ256.
SYNOPSIS...KJC/MENSCH
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...MENSCH
AVIATION...KJC/MENSCH
MARINE...KJC/MENSCH
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