902
FXUS61 KBOX 201102
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
702 AM EDT TUE OCT 20 2026
WHAT HAS CHANGED
CONFIDENCE CONTINUES TO INCREASE THAT A NOR'EASTER WILL REMAIN
OFFSHORE. WHILE IMPACTS TO LAND WILL BE MINIMAL, HAZARDOUS
CONDITIONS ARE EXPECTED FOR THE MARINE AND BOATING COMMUNITY DUE TO
LARGE WAVES AND GALE-FORCE WINDS.
KEY MESSAGES
- A NOR'EASTER PASSES OFFSHORE LATE WEDNESDAY INTO THURSDAY,
BRINGING A FEW SHOWERS TO AREAS EAST OF I-95. OTHERWISE, DRY
AND BREEZY CONDITIONS PREVAIL THROUGH THE MIDDLE PART OF THE
WEEK.
- FAIRLY COOL ON FRIDAY WITH A VERY LOW CHANCE OF AN EARLY
MORNING SHOWER. OTHERWISE, MODERATING TEMPERATURES AND DRY
CONDITIONS ARE EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...A NOR'EASTER PASSES OFFSHORE LATE WEDNESDAY INTO
THURSDAY, BRINGING A FEW SHOWERS TO AREAS EAST OF I-95. OTHERWISE,
DRY AND BREEZY CONDITIONS PREVAIL THROUGH THE MIDDLE PART OF THE
WEEK.
THERE WERE NO NOTABLE CHANGES TO THE NEAR AND SHORT-TERM FORECAST
DURING THE OVERNIGHT UPDATE. A BROAD 1030+ MB HIGH PRESSURE SYSTEM
SITUATED NORTHWEST OF SOUTHERN NEW ENGLAND WILL PROVIDE YET ANOTHER
DRY DAY ACROSS THE REGION. HOWEVER, THERE WILL LIKELY BE MORE
FILTERED SUNSHINE TODAY, ESPECIALLY ACROSS EASTERN PORTIONS OF
SOUTHERN NEW ENGLAND, WHILE AREAS FARTHER WEST ARE TREATED TO
ANOTHER MAINLY CLEAR DAY. 925 MB TEMPERATURES THIS AFTERNOON ARE
EXPECTED TO RANGE FROM +8C TO +10C, AND ANTICIPATE HIGHS REACHING
WELL INTO THE LOWER TO MIDDLE 60S ACROSS INTERIOR AREAS, WHILE THE
COASTAL PLAIN REMAINS IN THE UPPER 50S TO LOWER 60S. IN ADDITION,
WINDS INCREASE DUE TO A TIGHTENING PRESSURE GRADIENT BETWEEN THE
AFOREMENTIONED AREA OF HIGH PRESSURE AND A DEVELOPING NOR'EASTER OFF
THE NORTH CAROLINA COAST. THERE IS GOOD CONFIDENCE THAT BREEZY TO
GUSTY NORTHEAST WINDS WILL BE MOST PREVALENT EAST OF I-95, WITH
GUSTS OF 20 TO 30 MPH. THE STRONGEST GUSTS, 30 TO 40 MPH, ARE
EXPECTED ALONG THE EAST-FACING MASSACHUSETTS COASTLINE, CAPE COD,
AND THE ISLANDS. WHILE PREVIOUS GUIDANCE SUGGESTED A FEW GUSTS
EXCEEDING 45 MPH ACROSS NANTUCKET, CONFIDENCE IN THESE STRONGER
GUSTS HAS DECREASED AS THE LATEST GUIDANCE FAVORS A FARTHER OFFSHORE
TRACK.
THESE WINDS CONTINUE OVERNIGHT AND INTO WEDNESDAY AS THE NOR'EASTER
STRENGTHENS AND TRACKS NORTHEAST, WHILE RAIN CHANCES REMAIN FAIRLY
LOW DURING THIS TIME FRAME. CLOUDS INCREASE OVERNIGHT INTO
WEDNESDAY, WITH THE ADDED CLOUD COVER HELPING TO MODERATE OVERNIGHT
LOWS. TEMPERATURES ACROSS CAPE COD AND THE ISLANDS REMAIN IN THE
UPPER 40S TO LOWER 50S, WHILE INTERIOR LOCATIONS EXPERIENCE SOME
CLEARING EARLY IN THE NIGHT BEFORE CLOUDS INCREASE LATER. THIS
SHOULD ALLOW TEMPERATURES TO FALL INTO THE UPPER 30S TO LOWER 40S.
PREDOMINANTLY DRY CONDITIONS CONTINUE INTO WEDNESDAY, WITH
TEMPERATURES SLIGHTLY COOLER THAN TODAY, MAINLY DUE TO INCREASED
CLOUD COVER LIMITING DIURNAL HEATING. WIND CONDITIONS WILL BE NEARLY
IDENTICAL TO TODAY. DURING THIS TIME FRAME, WE CAN UTILIZE HIGH-
RESOLUTION GUIDANCE, INCLUDING THE CAMS, TO GET A BETTER SENSE OF
HOW THINGS MAY PLAY OUT. THERE IS A LOW CHANCE FOR A FEW SHOWERS,
MAINLY AFTER 18Z/2 PM WEDNESDAY, ACROSS NANTUCKET, MARTHA'S
VINEYARD, AND OUTER CAPE COD, INCLUDING CHATHAM.
CONFIDENCE REMAINS HIGH THAT A SLOW-MOVING NOR'EASTER WILL TRACK UP
THE COAST BUT REMAIN FAR ENOUGH OFFSHORE TO LIMIT SIGNIFICANT
IMPACTS TO LAND. HOWEVER, DANGEROUS MARINE CONDITIONS ARE
ANTICIPATED. AS PREVIOUS FORECASTERS HAVE MENTIONED, THE NAM HAS
SHOWN THE WESTERNMOST SOLUTION. THE 20/00Z RUN INDICATES THAT THE
NAM IS COMING MORE IN LINE WITH THE DETERMINISTIC GFS, WHILE THE
ECMWF REMAINS SOMEWHAT FARTHER EAST. GLOBAL ENSEMBLES ALSO CONTINUE
TO INDICATE THAT THIS NOR'EASTER WILL MAKE ITS CLOSEST APPROACH LATE
WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING BEFORE ACCELERATING
NORTHEAST INTO THE NORTHERN ATLANTIC. RAIN CHANCES REMAIN FAIRLY LOW
FOR MOST OF SOUTHERN NEW ENGLAND, WITH THE GREATEST CHANCE FOR
SHOWERS ACROSS THE CAPE AND ISLANDS FROM WEDNESDAY AFTERNOON INTO
EARLY THURSDAY MORNING. A FEW SHOWERS MAY ALSO REACH PORTIONS OF
EASTERN MA AND RI, THOUGH MOST LOCATIONS WILL REMAIN DRY. EVEN THEN,
ANY RAINFALL IS NOT EXPECTED TO PRODUCE NOTABLE IMPACTS.
NEVERTHELESS, WHILE THIS WILL NOT BE THE QUINTESSENTIAL NOR'EASTER
FOR THOSE ON LAND, IT CERTAINLY WILL BE FOR THE MARINE COMMUNITY.
LARGE WAVES OF 7 TO 13 FEET ARE EXPECTED TO BUILD OFFSHORE,
ACCOMPANIED BY GALE-FORCE WINDS OUT OF THE NORTH-NORTHEAST TO
NORTHEAST. WHILE ASTRONOMICAL TIDES ARE LOW, PERSISTENT WIND AND
WAVE ACTION MAY LEAD TO BEACH EROSION. ADDITIONAL DETAILS ON THE
HAZARDOUS MARINE CONDITIONS CAN BE FOUND IN THE MARINE DISCUSSION.
KEY MESSAGE 2...FAIRLY COOL ON FRIDAY WITH A VERY LOW CHANCE OF AN
EARLY MORNING SHOWER. OTHERWISE, MODERATING TEMPERATURES AND DRY
CONDITIONS ARE EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK.
AS THE NOR'EASTER PEELS OUT TO SEA, STRONG HIGH PRESSURE SETTLES IN
FOR THE UPCOMING WEEKEND. THERE IS ONE INTERESTING FEATURE WORTH
WATCHING, ALTHOUGH IT IS UNLIKELY TO CAUSE MORE THAN A SLIGHT
INCONVENIENCE. A MID-LEVEL COLD POOL ASSOCIATED WITH A ROBUST
NORTHERN-STREAM SHORTWAVE PASSES THROUGH EARLY FRIDAY. WHILE PWATS
WILL BE LIMITED BY THIS TIME, A SPOT SHOWER EARLY FRIDAY MORNING
CANNOT BE RULED OUT, WITH AREAS EAST OF I-95 HAVING THE GREATEST
CHANCE. OTHERWISE, HIGH PRESSURE PROMOTES SINKING AIR AND GENERALLY
QUIET WEATHER THIS WEEKEND INTO MONDAY OF NEXT WEEK. WITH THE COLD
POOL ALOFT, FRIDAY WILL BE THE COOLEST DAY, WITH HIGHS IN THE LOWER
50S. DEPENDING ON HOW QUICKLY WINDS DECOUPLE, SATURDAY MORNING COULD
FEATURE A FROSTY START, WITH LOWS IN THE UPPER 20S TO MIDDLE 30S.
FROM SATURDAY THROUGH MONDAY, TEMPERATURES SLOWLY MODERATE,
INCREASING A FEW DEGREES EACH DAY FOR BOTH HIGHS AND LOWS AS HIGH
PRESSURE ALLOWS FOR WAA ALOFT.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE:
TODAY AND TONIGHT...HIGH CONFIDENCE.
VFR TODAY AND FOR MOST OF TONIGHT. HOWEVER, MVFR CEILINGS RETURN
AFTER 08Z WEDNESDAY FOR TERMINALS ACROSS EASTERN MA AND RI. NORTH-
NORTHEAST WINDS GUST TO 20 TO 25 KNOTS ACROSS THE INTERIOR AND 30 TO
35 KNOTS AT COASTAL TERMINALS.
WEDNESDAY...HIGH CONFIDENCE.
A SHARP CEILING GRADIENT IS EXPECTED, WITH VFR CONDITIONS FOR
TERMINALS WEST OF I-95 AND MVFR CONDITIONS FOR AREAS TO THE EAST.
MAINLY A DRY DAY, THOUGH A FEW LATE-DAY SHOWERS ARE POSSIBLE ACROSS
THE ISLANDS. NORTHEAST WINDS GUST TO 20 TO 25 KNOTS ACROSS THE
INTERIOR AND 30 TO 35 KNOTS AT COASTAL TERMINALS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT: VFR. WINDY WITH GUSTS
UP TO 35 KT.
FRIDAY: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT.
FRIDAY NIGHT: VFR. BREEZY.
SATURDAY: VFR.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH WEDNESDAY...HIGH CONFIDENCE.
MARINERS SHOULD BE AWARE THAT DANGEROUS BOATING CONDITIONS WILL
PERSIST THROUGH AT LEAST THE MIDDLE PART OF THIS WEEK AS A
NOR'EASTER TRACKS UP THE COAST. HIGH PRESSURE OVER EASTERN CANADA,
COMBINED WITH LOW PRESSURE OFF THE CAROLINA COAST, WILL RESULT IN A
TIGHTENING NORTHEAST PRESSURE GRADIENT AND INCREASING WINDS THROUGH
WEDNESDAY. SMALL CRAFT ADVISORIES REMAIN IN EFFECT ACROSS OUR
NORTHERN WATERS, WITH GALE WARNINGS IN EFFECT FOR OUR SOUTHERN
WATERS. NORTHEAST WIND GUSTS OF 30 TO 40 KNOTS ARE EXPECTED, WITH
THE STRONGEST WINDS ACROSS OUR SOUTHERN WATERS, WHERE A FEW GUSTS
NEAR 45 KNOTS ARE POSSIBLE. SEAS BUILD TO 7 TO 13 FEET BY DAYBREAK
WEDNESDAY, WITH THE HIGHEST SEAS ACROSS THE SOUTHERN OUTER WATERS.
SEAS MAY BUILD FURTHER WEDNESDAY, POTENTIALLY APPROACHING 15 FEET
ACROSS PORTIONS OF THE OUTER WATERS. DANGEROUS MARINE CONDITIONS
WILL BE SLOW TO IMPROVE THROUGH THE SECOND HALF OF THE WEEK AS THE
NOR'EASTER GRADUALLY DEPARTS.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 40 KT. ROUGH
SEAS UP TO 14 FT. CHANCE OF RAIN SHOWERS, PATCHY FOG.
THURSDAY: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO 40 KT.
ROUGH SEAS UP TO 12 FT. SLIGHT CHANCE OF RAIN SHOWERS.
THURSDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS
UP TO 12 FT.
FRIDAY: STRONG WINDS WITH GUSTS UP TO 30 KT. ROUGH SEAS UP TO
13 FT. CHANCE OF RAIN SHOWERS.
FRIDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 30 KT. ROUGH SEAS UP TO 13 FT. SLIGHT CHANCE OF
RAIN SHOWERS.
SATURDAY: WINDS LESS THAN 25 KT. ROUGH SEAS UP TO 10 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT WEDNESDAY FOR ANZ230-236.
GALE WARNING UNTIL 8 PM EDT WEDNESDAY FOR ANZ231>235-237-
254>256-281>283.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR ANZ250-251.
DISCUSSION...DOOLEY
AVIATION...BW
MARINE...DOOLEY
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