394
FXUS61 KBOX 110457
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1257 AM EDT THU SEP 11 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 TODAY/
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 /TONIGHT THROUGH 6 PM FRIDAY/
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 NIGHT THROUGH WEDNESDAY/
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 /06Z THURSDAY THROUGH MONDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE:
THROUGH 12Z...HIGH CONFIDENCE.
MVFR-IFR CIGS OVER THE CAPE/ISLANDS EARLY THIS MORNING, BUT
REMAIN VFR TO THE WEST. NE WINDS LIGHT N. NNE WINDS WITH GUSTS
UP TO 20 KTS FOR CAPE/ISLANDS.
TODAY...HIGH CONFIDENCE IN TRENDS.
CEILINGS IMPROVE TO VFR FOR CAPE/ISLANDS BETWEEN 09-12Z. VFR. N
WINDS 5-10 KT. WINDS STRONGER FOR ACK WITH GUSTS AROUND 20 KTS,
BUT TRENDING DOWNWARD THROUGH THE AFTERNOON. AFTERNOON SEA-
BREEZES FOR PARTS OF EASTERN MA COAST (AT LEAST FOR BOS). FEW-
SCT CLOUDS AT 040-060 DEVELOPING FOR AFTERNOON.
TONIGHT...HIGH CONFIDENCE.
VFR. LIGHT AND VARIABLE TO START, BECOMING N AFTER 04Z.
FRIDAY...HIGH CONFIDENCE.
VFR. WINDS LIGHT AND VARIABLE INLAND, NE 10-15 KTS OVER THE
CAPE AND ISLANDS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...
FRIDAY: VFR. BREEZY.
FRIDAY NIGHT THROUGH SATURDAY NIGHT: VFR.
SUNDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SLIGHT CHANCE
SHRA, SLIGHT CHANCE TSRA.
SUNDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. CHANCE
SHRA, SLIGHT CHANCE TSRA.
MONDAY: VFR. CHANCE SHRA.
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 NIGHT THROUGH MONDAY/...
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.
SUNDAY NIGHT THROUGH MONDAY: WINDS LESS THAN 25 KT. AREAS OF
SEAS 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 THIS MORNING FOR ANZ232.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ254-
255.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ256.
SYNOPSIS...KJC/MENSCH
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...MENSCH
AVIATION...BW
MARINE...KJC/MENSCH
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