329
FXUS61 KBOX 161834
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
234 PM EDT TUE SEP 16 2025
SYNOPSIS
DRY WEATHER WITH TEMPERATURES NEAR OR JUST WARMER THAN AVERAGE
THROUGH MID WEEK. A LOW CHANCE FOR SHOWERS FOR COASTAL PARTS OF
SOUTHERN NEW ENGLAND WEDNESDAY NIGHT INTO THURSDAY NIGHT AS A
LOW PASSES OFFSHORE. MORE AUTUMN-LIKE TEMPERATURES POSSIBLE FOR
THIS WEEKEND FOLLOWING A COLD FRONT.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
* QUIET WEATHER OVERNIGHT WITH SEASONABLE TEMPERATURES
VERY LITTLE CHANGE IN THE SYNOPTIC PATTERN TONIGHT, THUS THE QUIET
WEATHER WILL PERSIST. AN AREA OF SURFACE HIGH PRESSURE CENTERED OVER
NORTHERN NEW ENGLAND WILL GRADUALLY SHIFT EAST OVER THE GULF OF MAINE
OVERNIGHT. THIS WILL CONTINUE TO SUPPORT ONSHORE FLOW OUT OF THE
EAST/SOUTHEAST OVER SOUTHERN NEW ENGLAND. AS TEMPERATURES COOL
OVERNIGHT, WE SHOULD SEE A RETURN OF LOW-STRATUS AND POSSIBLY SOME
PATCHY FOG ACROSS EASTERN MA. EXPECT SIMILAR LOW TEMPERATURES TO
LAST NIGHT IN THE UPPER 40S TO LOW 50S.
SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/
KEY MESSAGES
* MIX OF SUN AND CLOUDS AGAIN WEDNESDAY WITH HIGHS IN THE LOW 70S
* SHOWER CHANCES INCREASING TOMORROW EVENING INTO TOMORROW NIGHT AS
LOW-PRESSURE APPROACHES SOUTHERN NEW ENGLAND FROM THE SOUTH
WEDNESDAY
HIGH PRESSURE TO OUR EAST AND RIDGING ALOFT CONTINUE TO SUPPRESS THE
NORTHWARD MOVEMENT OF A LOW-PRESSURE SYSTEM OFF THE MID-ATLANTIC
COAST FOR MUCH OF THE DAY TOMORROW. CONDITIONS ON WEDNESDAY WILL BE
SIMILAR TO TUESDAY WITH SOME LOW CLOUDS AND FOG EARLY TRANSITIONING
TO PARTLY SUNNY SKIES BY LATE MORNING/EARLY AFTERNOON. AS LOW-
PRESSURE TO THE SOUTH SLOWLY ADVANCES NORTH/NORTHEAST, THERE WILL BE
INCREASING CHANCES FOR A FEW ISOLATED TO SCATTERED SHOWERS SHOWERS,
MAINLY ALONG THE SOUTH COAST. NONETHELESS, EXPECT MOST OF TOMORROW
TO BE DRY.
WEDNESDAY NIGHT
LOW PRESSURE TO OUR SOUTH FINALLY LIFTS EAST/NORTHEAST BRINGING A
PERIOD OF SHOWERS TO AT LEAST THE SOUTHEASTERN HALF OF SOUTHERN NEW
ENGLAND. SOME UNCERTAINTY WITH RESPECT TO HOW FAR INLAND SHOWERS
PROGRESS, BUT LATEST GUIDANCE SUGGESTS THAT SOUTHEAST MA, THE CAPE,
AND ISLANDS WILL HAVE THE GREATEST LIKELIHOOD OF OBSERVING
APPRECIABLE RAINFALL. CLOUD COVER AND HIGHER DEWPOINTS WILL KEEP
TEMPERATURES MILD IN THE MID TO UPPER 50S WEDNESDAY NIGHT.
LONG TERM /THURSDAY THROUGH TUESDAY/
KEY MESSAGES:
* CHANCE FOR SHOWERS INCREASES WEDNESDAY NIGHT WITH LOW PASSING
OFFSHORE, THOUGH SOAKING RAIN NOT EXPECTED
* DRIER AND COOLER WEATHER MOVES IN BEHIND A DRY COLD FRONT FRIDAY,
CONTINUING THROUGH THE WEEKEND
THE LOW PASSING SOUTH OF THE REGION WILL INCREASE THE CHANCES FOR
SHOWERS WEDNESDAY NIGHT INTO THURSDAY MORNING. ENSEMBLE GUIDANCE IS
LEANING TOWARDS THE HIGHEST CHANCES FOR RAIN REMAINING SOUTH AND
EAST OF I-84. THE GEFS REMAINS THE DRIEST OF THE ENSEMBLES, KEEPING
PROBABILITIES FOR >0.1" OF RAINFALL OVER 24 HOURS BELOW EVEN 10
PERCENT FOR SOUTHERN NEW ENGLAND. THE ECMWF ENS AND GEPS CONTINUE TO
HAVE UP TO 30-35 PERCENT PROBABILITIES UP TO BOSTON FOR >0.1" OVER
24 HOURS BY THURSDAY AFTERNOON, INCREASING FURTHER SOUTH. MEAN PWAT
VALUES PEAK LATE WEDNESDAY NIGHT/EARLY THURSDAY MORNING AROUND 1.4"
ACROSS SOUTHERN NEW ENGLAND. HOWEVER, WIDESPREAD SOAKING RAINS ARE
NOT EXPECTED DUE TO THE LACK OF FORCING AND ANTECEDENT DRY AIR
ALOFT. ONCE THIS LOW PASSES, QUIET CONDITIONS RETURN BY THURSDAY
NIGHT.
A COLD FRONT IS STILL EXPECTED TO MOVE THROUGH THE REGION FRIDAY
AFTERNOON AND EVENING, LEAVING COOLER AND DRIER CONDITIONS IN ITS
WAKE. 925 MB TEMPERATURES FALL AS LOW AS 5C FRIDAY NIGHT AFTER
INCREASING TO CLOSE TO 20C AHEAD OF THE FRONT DURING THE AFTERNOON
THURSDAY AND FRIDAY. SATURDAY WILL FEEL MORE AUTUMN-LIKE WITH HIGH
PRESSURE AND A DRIER AIRMASS BUILDING IN BEHIND THE FRONT AND 925 MB
TEMPERATURES AROUND 10C DURING THE DAY SUPPORTING HIGHS MOSTLY IN
THE 60S. LOWS MAY EVEN DIP INTO THE UPPER 30S FOR SOME SPOTS IN THE
INTERIOR. WITH THE INCOMING DRY AIR, WE COULD SEE AN ELEVATED FIRE
RISK SATURDAY. TEMPERATURES BEGIN TO WARM AGAIN GOING INTO THE START
OF NEXT WEEK WITH CONTINUED HIGH PRESSURE.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH 00Z...HIGH CONFIDENCE.
VFR. LIGHT EAST/NORTHEAST WINDS.
TONIGHT...HIGH CONFIDENCE.
MAINLY VFR WITH IFR/MVFR AT ORH/BED. LOWER CEILINGS/VSBYS AT BOS
ARE UNCERTAIN AS THE INLAND EXTENT OF LOWER CEILINGS AND VSBYS
ACROSS EASTERN MA IS UNCERTAIN. INCLUDED A TEMPO GROUP FROM
08-12Z FOR IFR CIGS AND MVFR VSBYS TO ENCOMPASS THE MOST LIKELY
TIME OF LOWER CEILINGS AT BOS. ELSEWHERE VFR WITH LIGHT EASTERLY
WINDS.
WEDNESDAY...HIGH CONFIDENCE.
GENERALLY VFR WITH PATCHES OF MVFR IN SHRA ALONG THE SOUTH
COAST, ESPECIALLY THE CAPE AND ISLANDS. WINDS E UP TO 10 KTS.
WEDNESDAY NIGHT...HIGH CONFIDENCE
MAINLY MVFR CEILINGS WITH -SHRA. LIGHT EASTERLY WINDS.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF
FOG BANK OVER BOSTON HARBOR MAY RESULT IN A BRIEF PERIOD OF
LOWER VSBYS THIS AFTERNOON. ALSO A CHANCE FOR MORE FOG/LOW
CEILINGS EARLY TOMORROW, BUT CONFIDENCE IS MODERATE AS MOST
FORECAST GUIDANCES KEEPS THIS WEATHER INLAND.
BDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
WEDNESDAY NIGHT: VFR. CHANCE SHRA, PATCHY FG.
THURSDAY: VFR. SLIGHT CHANCE SHRA, PATCHY FG.
THURSDAY NIGHT THROUGH FRIDAY: VFR. WIDESPREAD FG.
FRIDAY NIGHT: VFR. BREEZY. WIDESPREAD FG.
SATURDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH WEDNESDAY NIGHT...HIGH CONFIDENCE.
SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH 00Z THURSDAY.
ELSEWHERE, SEAS ARE EXPECTED TO REMAIN BELOW 5 FT THROUGH THE AT
LEAST WEDNESDAY NIGHT.
WINDS EXPECTED TO REMAIN LIGHT OVER THE EASTERN WATERS AND
REMAIN GENERALLY AROUND 15 KTS OVER THE SOUTHERN WATERS. GUSTS
TO 20 KTS ARE POSSIBLE, BUT SHOULD REMAIN INFREQUENT.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
WEDNESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY
APPROACHING 5 FT. CHANCE OF RAIN SHOWERS, PATCHY FOG. LOCAL
VISIBILITY 1 NM OR LESS.
THURSDAY: WINDS LESS THAN 25 KT. CHANCE OF RAIN SHOWERS, PATCHY
FOG. LOCAL VISIBILITY 1 NM OR LESS.
THURSDAY NIGHT: WINDS LESS THAN 25 KT. SLIGHT CHANCE OF RAIN
SHOWERS, PATCHY FOG. LOCAL VISIBILITY 1 NM OR LESS.
FRIDAY: WINDS LESS THAN 25 KT. WIDESPREAD FOG. LOCAL VISIBILITY
1 NM OR LESS.
FRIDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. AREAS OF SEAS APPROACHING 5 FT. WIDESPREAD
FOG.
SATURDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR ANZ256.
SYNOPSIS...BELK/HRENCECIN/FT
NEAR TERM...RM
SHORT TERM...RM
LONG TERM...HRENCECIN
AVIATION...KJC/RM
MARINE...KJC/RM
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