503
FXUS61 KBOX 282313
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
713 PM EDT TUE APR 28 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES.
KEY MESSAGES
- COASTAL LOW CLOUDS MOVE INLAND TONIGHT.
- BENEFICIAL RAINFALL WEDNESDAY NIGHT INTO THURSDAY.
- COOLER PATTERN PREVAILS FRIDAY THROUGH WEEKEND BUT MOSTLY DRY.
DISCUSSION
KEY MESSAGE 1...COASTAL LOW CLOUDS MOVE INLAND TONIGHT.
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH WEDNESDAY WITH RIDGING
ALOFT AND DRY WEATHER EXPECTED. HOWEVER, AN INVERTED TROUGH FROM LOW
PRESSURE THAT IS WELL OFFSHORE WAS PRODUCING SOME LOW CLOUDS THAT
CAN BE SEEN ON SATELLITE SOUTH AND EAST OF CAPE COD. THESE LOW
CLOUDS WERE BEING HELD OFFSHORE BY DAYTIME HEATING BUT WILL
EVENTUALLY EXPAND INLAND TONIGHT AS BOUNDARY LAYER COOLS, MOST
LIKELY ACROSS MUCH OF EASTERN MA AND RI, PERHAPS AS FAR WEST AS
WORCESTER PER MODEL CROSS SECTIONS. MOIST E/NE FLOW WILL ALSO
PRODUCE AREAS OF FOG, AND PERHAPS SOME SPOTTY DRIZZLE, MAINLY
NEAR CAPE COD AND THE ISLANDS.
KEY MESSAGE 2...BENEFICIAL RAINFALL WEDNESDAY NIGHT INTO THURSDAY.
WE MAY SEE SOME SHOWERS SNEAK INTO EASTERN MA WEDNESDAY EVENING
ASSOCIATED WITH INVERTED TROUGH, OTHERWISE SHOWERS WILL BECOME MORE
WIDESPREAD WEDNESDAY NIGHT INTO THURSDAY WITH PASSAGE OF UPPER
TROUGH FROM OHIO VALLEY AND SECONDARY SURFACE LOW THAT TRACKS FROM
MID ATLANTIC TO CAPE COD. TIMING HAS SPED UP A BIT AND NOW IT LOOKS
LIKE MOST OF THE RAIN WILL COME TO AN END EARLY THURSDAY AFTERNOON
AS DRY SLOT COMES THROUGH QUICKLY.
SPEED OF SYSTEM, COMBINED WITH MODEST DYNAMICS AND MOISTURE, WILL
LIMIT RAINFALL TOTALS FROM BEING EXCESSIVE, BUT MOST AREAS SHOULD
STILL PICK UP 0.25 TO 1.00" OF MUCH NEEDED RAINFALL, PERHAPS A
LITTLE MORE IN NORTHERN MA.
ASTRO TIDES ARE FAIRLY LOW SO COASTAL FLOODING IS NOT MUCH OF A
CONCERN ALONG E MA COAST. PERSISTENT ONSHORE FLOW MAY BRING A SURGE
OF UP TO 1 FOOT LATER IN WEEK, BUT BY THEN WINDS TURN OFFSHORE AS
SURFACE LOW LIFTS FARTHER TO THE NORTH.
KEY MESSAGE 3...COOLER PATTERN PREVAILS FRIDAY THROUGH WEEKEND BUT
MOSTLY DRY.
BLOCKY PATTERN TAKES HOLD LATER THIS WEEK AND OVER WEEKEND AS UPPER
LOW TAKES UP RESIDENCE OVER SOUTHERN ONTARIO. SOUTHERN NEW ENGLAND
SHOULD BE FAR ENOUGH REMOVED FROM COLDEST AIR ALOFT TO KEEP US
MOSTLY DRY, ESPECIALLY GIVEN W/NW FLOW, BUT PATTERN CERTAINLY FAVORS
DIURNAL CLOUDS AND PERHAPS A FEW AFTERNOON SPRINKLES FRIDAY,
SATURDAY, AND SUNDAY.
IT DOES LOOK LIKE UPPER LOW MAY LIFT FARTHER NORTH EARLY NEXT WEEK,
ALLOWING FOR MORE OF A ZONAL FLOW ACROSS NORTHERN TIER OF STATES
WHICH WOULD LEAD TO DRIER AND MILDER WEATHER MONDAY AND TUESDAY.
HOWEVER, MODELS ARE NOTORIOUS FOR BREAKING DOWN THESE BLOCKY
PATTERNS TOO QUICKLY, SUCH THAT IT MAY TAKE A LITTLE LONGER TO SEE
IMPROVING CONDITIONS. FOR NOW, FORECAST REFLECTS MODEL BLEND TO IRON
OUT THE UNCERTAINTY.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
00Z TAF UPDATE:
ONLY MINOR ADJUSTMENTS THIS CYCLE, PRIMARILY SLOWING THE INLAND
PROGRESSION OF MARINE STRATUS BY ~2 HOURS. OVERALL TREND REMAINS
UNCHANGED.
IFR CEILINGS DEVELOP QUICKLY AFTER SUNSET ALONG THE COAST, THEN
EXPANDS INLAND TO ROUGHLY KORH BETWEEN 04Z-06Z. VFR CONDITIONS
PERSIST FATHER WEST. PATCHY -DZ/BR EXPECTED ACROSS CAPE COD AND THE
ISLANDS.
ON WEDNESDAY, SLOW IMPROVEMENT AT BEST. CEILINGS MAY BRIEFLY LIFT TO
MVFR NEAR THE COAST LATE MORNING TO EARLY AFTERNOON, BUT IFR LIKELY
REDEVELOPS BY MID TO LATE AFTERNOON WITH A CHANCE OF -SHRA/-DZ. VFR
CONTINUES ACROSS THE WESTERN TERMINALS.
BY WEDNESDAY NIGHT, MVFR/IFR CONDITIONS BECOME MORE WIDESPREAD AS
SHOWERS OVERSPREAD THE REGION, CONTINUING INTO THURSDAY.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. IMPROVEMENT TO MVFR
THU MAY BE OPTIMISTIC, IFR CEILINGS COULD PERSIST ALL DAY.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
THURSDAY: MVFR/IFR CONDITIONS POSSIBLE. BREEZY. CHANCE SHRA.
THURSDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.
SLIGHT CHANCE SHRA.
FRIDAY: VFR. BREEZY.
FRIDAY NIGHT THROUGH SATURDAY NIGHT: VFR.
SUNDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH THE END OF THE WEEK.
PERSISTENT E/NE WINDS CONTINUE AS HIGH PRESSURE REMAINS OVER THE
MARITIMES AND LOW PRESSURE MEANDERS WELL OFFSHORE SE OF 40/70
BENCHMARK FOR NEXT FEW DAYS.
NE WINDS MAY APPROACH SCA AROUND CAPE COD WITH 20KT GUSTS BUT MAIN
ISSUE WILL BE ROUGH SEAS OF 5 TO 8 FEET ON OUTER WATERS THROUGH
THU WHERE SCA REMAINS POSTED. MAY HAVE TO EXTEND IT INTO RHODE
ISLAND AND BLOCK ISLAND SOUNDS SHOULD CONFIDENCE INCREASE IN
LATER FORECASTS.
OTHERWISE, AREAS OF FOG AND DRIZZLE SHOULD DEVELOP TONIGHT,
ESPECIALLY ON SOUTH COASTAL WATERS, WITH LITTLE IMPROVEMENT WED.
SHOWERS EXPECTED WED NIGHT AND THU AS LOW PRESSURE TRACKS FROM THE
MID ATLANTIC TO CAPE COD AND GULF OF MAINE.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
THURSDAY: WINDS LESS THAN 25 KT. ROUGH SEAS UP TO 10 FT. RAIN
SHOWERS.
THURSDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. SLIGHT
CHANCE OF RAIN SHOWERS.
FRIDAY THROUGH FRIDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO
5 FT.
SATURDAY THROUGH SATURDAY NIGHT: WINDS LESS THAN 25 KT. AREAS
OF SEAS APPROACHING 5 FT. SLIGHT CHANCE OF RAIN SHOWERS.
SUNDAY: 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 6 PM EDT THURSDAY FOR ANZ250-
254>256.
DISCUSSION...JWD
AVIATION...DOOLEY/JWD
MARINE...JWD
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