789
FXUS61 KBOX 111831
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
231 PM EDT THU SEP 11 2025
SYNOPSIS
A DRY COLD FRONTAL PASSAGE FROM NORTH TO SOUTH TAKES PLACE
TONIGHT, ALLOWING FOR A RETURN TO COOLER ONSHORE FLOW. DRY
WEATHER WITH NEAR SEASONABLE TEMPS FOR FRIDAY AND SATURDAY.
RAIN CHANCES RETURN SUNDAY WITH HIGHS IN THE LOW TO MID 70S. WE
THEN RETURN TO DRY WEATHER AND TEMPERATURES AROUND SEASONABLE
FOR EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
200 PM UPDATE:
KEY MESSAGES:
* PARTLY CLOUDY SKIES WITH WINDS BECOMING NORTHEAST FOR THE
FIRST HALF OF THE NIGHT AS A DRY COLD FRONT MOVES THROUGH.
* LOWS IN THE 50S.
DETAILS:
AFTER A COUPLE DAYS OF COOLER THAN NORMAL TEMPS...FULL SUN AND
WARMER LOW-LEVEL TEMPS HAVE ALLOWED FOR TEMPERATURES TO REACH
INTO MORE SEASONABLE READINGS IN THE MID TO UPPER 70S AT THIS
HOUR. HIGH PRESSURE IS ESTABLISHED OVER SOUTHERN NEW ENGLAND,
ALLOWING FOR NORTH WINDS AROUND 5-10 MPH WITH OCCASIONAL GUSTS
TO AROUND 20 MPH.
A COLD FRONT IS WORKING ITS WAY THROUGH SOUTHERN QUEBEC AND
NORTHERN NEW ENGLAND. THIS IS ASSOCIATED WITH A REINFORCING
COOLER SHOT OF AIR TIED TO A SHORTWAVE TROUGH MOVING INTO
SOUTHEAST QUEBEC AND NORTHERN ME. THIS FRONT WILL BE GRADUALLY
MAKING ITS WAY SOUTHWARD THROUGH LATE EVENING AND MIDNIGHT;
HOWEVER THE DRIER AIR IN PLACE WILL ALLOW FOR A DRY FRONTAL
PASSAGE. A SHALLOW LAYER OF MOISTURE COULD ALLOW FOR SOME
INCREASED STRATOCUMULUS, BUT THE MAIN EFFECT OF ITS PASSAGE WILL
BE WINDS BECOMING NE AROUND 10-15 MPH NEAR THE COASTS AND AROUND
5-10 MPH INLAND. LOWS IN THE 50S.
SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
200 PM UPDATE:
KEY MESSAGES:
* CLEAR SKIES AND DRY WEATHER PREVAILS, WITH ONSHORE BREEZES
DURING THE DAY, EASING AT NIGHT.
* HIGHS UPPER 60S/NEAR 70 EASTERN COAST, AND MID 70S INLAND.
LOWS MID 40S TO MID 50S.
WE CLOSE OUT THE WORKWEEK ON A PLEASANT NOTE FROM A WEATHER
PERSPECTIVE, AS A SPRAWLING RIDGE OF HIGH PRESSURE BUILDS INTO
SOUTHERN NEW ENGLAND. WITH COOL AND DRY ADVECTION TAKING PLACE,
TEMPS WILL END UP BEING A FEW DEGREES COOLER THAN THURSDAY, WITH
A EASTERLY ONSHORE FLOW KEEPING THE EASTERN COASTAL AREAS QUITE
A BIT COOLER THAN FURTHER INLAND. FULL SUN WITH HIGHS INLAND IN
THE LOW TO MID 70S; BUT NEAR THE EASTERN COAST WHERE ONSHORE
FLOW WILL GOVERN, HIGHS UPPER 60S/SPOT 70 DEGREES. CLEAR SKIES
AND EASING EASTERLY WINDS WILL ALLOW FOR GOOD RADIATIONAL
COOLING, BUT IT IS MORE THAN LIKELY TOO DRY FOR PATCHY
NIGHTTIME FOG TO DEVELOP. LOWS MID 40S TO MID 50S.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
KEY MESSAGES...
* DRY SATURDAY THEN A CHANCE FOR RAIN RETURNS SUN INTO MON.
* TEMPERATURES JUST A BIT COOLER THAN AVERAGE IN THE LOW TO MID 70S.
THE PREVIOUSLY MENTIONED LARGE SURFACE HIGH REMAINS OVERHEAD ON
SATURDAY ONCE AGAIN BRINGING QUIET AND DRY WEATHER WITH A GOOD
AMOUNT OF SUN TO THE REGION. CHANGE WILL BE ON THE HORIZON, HOWEVER,
AS A CLEAR START TO THE DAY WILL LIKELY BECOME INCREASINGLY CLOUDY
FROM NW TO SE AS A WEAK TROUGH APPROACHES FROM THE NW WITH A PLUME
OF BETTER MOISTURE (PWATS BACK OVER 1" BY MID DAY). STILL, SATURDAY
LOOKS DRY; IT'S NOT UNTIL SUNDAY THAT A MORE ROBUST SHORTWAVE LOOKS
TO ROUND THE BROADER TROUGH AND DROP THROUGH SNE BRINGING A BETTER
COMBINATION OF LIFT AND MOISTURE LEADING TO WIDESPREAD RAIN CHANCES.
THERE IS, HOWEVER, STILL DISAGREEMENT AMONGST THE GLOBAL GUIDANCE AS
TO 1) HOW QUICKLY THIS ARRIVES AND 2) IF IT'S MORE TRANSIENT OR IF
IT STICKS AROUND WELL INTO NEXT WEEK. THE MERIDIONAL NATURE OF THE
FLOW WOULD LEAD ONE TO BELIEVE IT WILL BE STUBBORN TO EXIT AND MEAN
UNSETTLED WEATHER WELL INTO NEXT WEEK.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE:
THROUGH 00Z FRIDAY: HIGH CONFIDENCE.
VFR; N WINDS AROUND 5-10 KT, EXCEPT SE AT BOS.
TONIGHT: HIGH CONFIDENCE.
VFR, THOUGH A COLD FRONTAL PASSAGE FROM NORTH TO SOUTH FROM
02-06Z WILL BRING A PERIOD OF FEW TO BKN 040-060 BASES UPON ITS
PASSAGE, ALONG WITH NE WINDS 10-15 KT NEAR THE COAST AND 5-10 KT
INLAND.
FRIDAY AND FRIDAY NIGHT: HIGH CONFIDENCE.
VFR THROUGH THIS PERIOD. NE WINDS 5-10 KT INLAND, NE TO E 10-15
KTS FOR THE EASTERN COASTAL AIRPORTS. WINDS FRI NIGHT TO BECOME
LIGHT AND VARIABLE.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH MONDAY/...
VFR.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
SCAS CONTINUE OVER THE WATERS THROUGH LATE THIS AFTERNOON FOR
WATERS ADJACENT TO AND SOUTHEAST OF CAPE COD AND NANTUCKET WITH
NORTHERLY GUSTS 20-25 KT AND SEAS 3-5 FT.
NE WINDS THEN DEVELOP TONIGHT FROM NORTH TO SOUTH AS A COLD
FRONT DROPS SOUTHWARD; THIS MAY BRING A BRIEF PERIOD OF 20-25 KT
GUSTS TO THE NORTHEAST WATERS BUT SEEMS TOO LIMITED IN COVERAGE
AND DURATION TO WARRANT SCAS. WINDS TONIGHT SHOULD RANGE
BETWEEN 15-20 KT (WITH OCCASIONAL GUSTS TO 25 KT NORTHEAST
WATERS), WHICH THEN SLOWLY EASE INTO FRI AND FRI NIGHT. SEAS 4FT
OR LESS ALL WATERS TONIGHT THRU FRI.
OUTLOOK /SATURDAY THROUGH MONDAY/...
SATURDAY THROUGH SUNDAY NIGHT: WINDS LESS THAN 25 KT.
MONDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ254-
255.
SYNOPSIS...LOCONTO/MENSCH
NEAR TERM...LOCONTO
SHORT TERM...LOCONTO
LONG TERM...MENSCH
AVIATION...LOCONTO/MENSCH
MARINE...LOCONTO/MENSCH
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