555
FXUS61 KBOX 291717
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
117 PM EDT FRI MAY 29 2026
WHAT HAS CHANGED
INCREASING CONFIDENCE IN STRONG GUSTY WINDS ON SATURDAY,
ESPECIALLY ACROSS EASTERN COASTAL AREAS. WIND ADVISORY ISSUED
FOR NORTHEAST MA, EAST COAST AND CAPE AND ISLANDS. ADJACENT
AREAS TO COAST STILL BEING CONSIDERED FOR HEADLINES. HELD OFF
DUE TO LARGER UNCERTAINTY.
KEY MESSAGES
- DRY FOR FIRST HALF OF TODAY WITH SHOWERS DEVELOPING LATE AFTERNOON
TO EARLY EVENING. LOW PRESSURE SYSTEM BRINGS RAIN AND GUSTY STRONG
WINDS TONIGHT AND SATURDAY.
- MAINLY DRY SUNDAY. UNSETTLED CONDITIONS RETURN BY MONDAY CONTINUING
THROUGH MID WEEK WITH PERIODIC CHANCES FOR SHOWERS AND COOLER
TEMPERATURES.
DISCUSSION
KEY MESSAGE 1...DRY FOR FIRST HALF OF TODAY WITH SHOWERS DEVELOPING
LATE AFTERNOON TO EARLY EVENING. LOW PRESSURE SYSTEM BRINGS RAIN AND
GUSTY STRONG WINDS TONIGHT AND SATURDAY.
THERE IS A GOOD CONSENSUS AMONG ENSEMBLE GUIDANCE FOR A BLOCKY UPPER
LEVEL PATTERN TO SET UP OVER THE NORTHEAST TODAY THROUGH EARLY NEXT
WEEK. SEVERAL SHORTWAVES MOVE THROUGH THE BROAD CYCLONIC FLOW ALOFT
BRINGING PERIODIC CHANCES FOR SHOWERS/RAIN.
THE FIRST WAVE FEATURES AN ANOMALOUS CLOSED UPPER LOW THAT DROPS
SOUTH ACROSS SOUTHERN NEW ENGLAND TONIGHT INTO SATURDAY. THE FIRST
HALF OF TODAY SHOULD REMAIN DRY WITH SCATTERED WARM FRONTAL SHOWERS
DEVELOPING LATER IN THE AFTERNOON AND EVENING. HIGH TEMPERATURES
WILL LIKELY BE SIMILAR TO THURSDAY IN THE UPPER 60S TO LOW 70S, WITH
SOME LOCATIONS IN THE MID 70S IN THE CT VALLEY. SHOWERS BECOME MORE
WIDESPREAD THIS EVENING AND TONIGHT WITH A FEW WAVES OF RAIN. THERE
IS VERY MARGINAL INSTABILITY PRESENT, WHICH MAY SUPPORT A FEW
EMBEDDED WEAK STORMS OR DOWNPOURS. THERE MAY BE A LULL SOMETIME
OVERNIGHT IN BETWEEN WAVES OF SHOWERS. AS THE LOW PRESSURE ROTATES
THROUGH IT WILL SHIFT ANOTHER ROUND OF SHOWERS SATURDAY MORNING.
SHOWERS SLOWLY DIMINISH AS THE LOW EXITS FURTHER OFFSHORE MID TO
LATE AFTERNOON. IT'S POSSIBLE FOR SHOWERS TO LINGER AS LATE AS THE
EVENING FOR THE OUTER CAPE/ISLANDS.
FOR RAIN TOTALS, ENSEMBLES RANGE RAIN TOTALS 0.20" TO 1.1" ACROSS
THE 25TH TO 75TH PERCENTILE RANGE WITH THE HIGHER AMOUNTS FAVORED IN
NORTHEAST MA. WHILE WE ARE ALREADY IN COOL TROUGHY FLOW, THE PASSAGE
OF THIS DEEP UPPER LOW WILL SHIFT A CORE OF ANOMALOUSLY COLD AIR
ALOFT ACROSS THE REGION SATURDAY. THIS WILL BRING US A FAIRLY COOL
DAY FOR LATE-MAY WITH HIGHS IN THE UPPER 40S AND LOW 50S. WITH THE
TIMING OF THE COLDER AIR AND THE SHOWERS, SOME MODEL GUIDANCE HINTS
AT POTENTIAL FOR A FEW SNOWFLAKES MIXING IN AT THE HIGHER
ELEVATIONS. IF THE COLD AIR ARRIVES IN A SIMILAR PERIOD OF BETTER
PRECIP RATES SOME SPOTS MAY COOL ENOUGH TO MIX IN SOME WET FLAKES.
THE NAM HAS SHOWN THE STRONGEST SIGNAL FOR THIS, BUT ALSO SHOWS A
COLDER AIRMASS IN PLACE WITH A WIDER FOOTPRINT COMPARED TO OTHER
GUIDANCE (TEMPS - UPPER 30S). SO OVERALL, CAN'T RULE OUT A WINTRY
MIX IN THE HIGHEST ELEVATIONS OF THE INTERIOR ALTHOUGH LITTLE IMPACT
EXPECTED.
THE BIGGER CONCERN WITH THIS SYSTEM IS THE STRONG WINDS. AS THE
SURFACE LOW PRESSURE TRACKS OFFSHORE, IT DEEPENS WITH A TIGHTENED
PRESSURE GRADIENT AND 45-60 KT 925MB LLJ. IF WINDS MIX EFFICIENTLY,
STRONG GUSTY N TO NE WINDS WILL BLANKET THE REGION. ENSEMBLE
GUIDANCE RANGES GUSTS 35-45 MPH WITH POTENTIAL FOR ISOLATED HIGHER
GUSTS (45-55 MPH) ALONG THE EAST COAST AND CAPE AND ISLANDS. THIS
SEEMS REASONABLE GIVEN THAT THE LLJ JET MORE LIKELY SHIFTS ACROSS
EAST SOUTHERN NEW ENGLAND THROUGH THE DAY. THE DEGREE OF MIXING IS
STILL UNCERTAIN WHICH HAS LED TO SPREAD ACROSS GUIDANCE IN GUST
MAGNITUDE AND THE EXTENT INLAND THE HIGHER MAGNITUDE GUSTS MAY
EXTEND. ACROSS ENSEMBLE GUIDANCE, THE ECMWF HAS BEEN CONSISTENTLY
STRONG WITH GUSTS COMPARED TO THE GEFS. HREF MEAN GUSTS SHOW SOME
AREAS ACROSS THE EAST ABOVE 45 MPH, MAINLY CONFINED TO THE COASTAL
AREAS AND CAPE/ISLANDS. RIGHT NOW THE RISK FOR ADVISORY CRITERIA IS
GREATER ACROSS NORTHEAST MA, EXTENDING DOWN THE EAST COASTAL REGION
AND INTO THE SOUTH COAST/BLOCK ISLAND, SOUTHEAST MA AND
CAPE/ISLANDS. CAPE AND ISLANDS AND THE NEAR-COASTAL AREAS HAVE THE
GREATER CONFIDENCE AT THE MOMENT BASED ON GUIDANCE, SO WENT WITH
ADVISORY TO START. REMAINING AREAS JUST OUTSIDE THOSE ZONES WILL
NEED TO BE CONSIDERED TODAY.
KEY MESSAGE 2...MAINLY DRY SUNDAY. UNSETTLED CONDITIONS RETURN BY
MONDAY CONTINUING THROUGH MID WEEK WITH PERIODIC CHANCES FOR
SHOWERS AND COOLER TEMPERATURES.
A FEW MORE WAVES MOVE THROUGH THE UPPER TROUGH PATTERN ALOFT BEYOND
SUNDAY INTO EARLY NEXT WEEK. THERE IS STILL SPREAD IN THE DETAILS OF
THE WAVES SUCH AS THE TIMING, BUT THEY WILL SUPPORT PERIODIC CHANCES
FOR SHOWERS AT LEAST THROUGH MID-WEEK. THERE IS A BETTER CONSENSUS
ON SHOWERS SUN NIGHT INTO MON AS A CLOSED LOW TRACKS ACROSS THE
REGION. REMAINING DAYS EARLY WEEK COULD SEE SCATTERED SHOWERS,
PERHAPS AN ISOLATED STORM. 850MB TEMPERATURES ANOMALIES LEAN BELOW
NORMAL EARLY NEXT WEEK LIKELY YIELDING TEMPERATURES IN THE 60S AND
LOW 70S THROUGH WEDNESDAY. THERE ARE SIGNS OF THE BLOCKY PATTERN
BREAKING DOWN LATER NEXT WEEK WHICH SHOULD HELP WARM TEMPERATURES
BACK UP.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE...
TODAY...HIGH CONFIDENCE.
MAINLY VFR TODAY OUTSIDE THE RISK FOR A FEW SHOWERS MAINLY
AFTER 20Z/21Z. NW WINDS MAY GUST TO AROUND 20 KNOTS OR SO INTO
MID AFTERNOON...BUT SEA BREEZES SHOULD KICK IN BY MID AFTERNOON
ALONG PORTIONS OF THE IMMEDIATE COAST.
TONIGHT AND SATURDAY...MODERATE CONFIDENCE.
VFR THIS EVENING OUTSIDE SCATTERED SHOWERS ESPECIALLY EAST OF
THE CT RIVER AND PARTICULARLY EASTERN MA. LOW RISK FOR A RUMBLE
OR TWO OF THUNDER. WE SHOULD THEN HAVE A LULL IN THE ACTIVITY
AFTER MIDNIGHT BEFORE THE UPPER LEVEL LOW DROPS SOUTH. A SHIELD
OF RAIN WILL DROP SOUTH WITH THE FOCUS EAST OF THE CT RIVER
VALLEY IN THE 9Z TO 15Z SAT TIME FRAME. CONDITIONS WILL LOWER TO
MVFR WITH POCKETS OF IFR CONDITIONS POSSIBLE. TOO. N-NE WINDS
WILL INCREASE WITH GUSTS ON THE ORDER 30-45 KNOTS WITH THE
STRONGEST OF THOSE ALONG THE COAST. WE MAY EVEN BRIEFLY SEE SOME WET
SNOW FLAKES MIX IN ACROSS THE HIGHEST TERRAIN. GRADUAL
IMPROVEMENT EXPECTED SATURDAY AFTERNOON AND EVENING FROM WEST TO
EAST.
KBOS...HIGH CONFIDENCE IN TAF BUT SOME UNCERTAINTY LINGERS ON
THE SPECIFIC TIMING OF THE SEA BREEZE... LIKELY BETWEEN
1730-18Z.
KBDL...HIGH CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH WEDNESDAY/...
SATURDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. STRONG WINDS
WITH GUSTS UP TO 45 KT. CHANCE RA.
SATURDAY NIGHT: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT.
SUNDAY: VFR.
SUNDAY NIGHT: VFR. SLIGHT CHANCE SHRA, SLIGHT CHANCE TSRA.
MONDAY: VFR. CHANCE SHRA, SLIGHT CHANCE TSRA.
MONDAY NIGHT: VFR. CHANCE SHRA.
TUESDAY: VFR. CHANCE SHRA, SLIGHT CHANCE TSRA.
TUESDAY NIGHT: VFR. CHANCE SHRA.
WEDNESDAY: VFR. BREEZY. CHANCE SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY AND TONIGHT...
GENERALLY TRANQUIL WITH WAVE HEIGHTS BETWEEN 1 AND 3 FEET FOR
MOST OF THE WATERS. WINDS FROM THE NW BETWEEN 5 AND 15 MPH WITH
GUSTS UP TO 20 MPH. WINDS AND SEAS INCREASING FROM THE NORTH
EARLY SATURDAY MORNING.
SATURDAY INTO SATURDAY NIGHT...
GALE WARNING FOR ALL THE WATERS ON SATURDAY AS A STRONG LOW
PRESSURE SYSTEM TRACKS ACROSS THE REGION BRINGING GUSTY N-NE
WINDS. THERE IS EVEN A CHANCE FOR AREAS OF STORM FORCE WINDS
WITH A STRONGER AREA OF LOW PRESSURE.
OUTLOOK /SATURDAY THROUGH WEDNESDAY/...
SATURDAY: MODERATE RISK FOR GALE FORCE WINDS WITH GUSTS UP TO
45 KT. ROUGH SEAS UP TO 12 FT. RAIN.
SATURDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 30 KT. AREAS OF ROUGH SEAS.
SUNDAY: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS.
SUNDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE OF
RAIN SHOWERS, SLIGHT CHANCE OF THUNDERSTORMS.
MONDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
CHANCE OF RAIN SHOWERS, SLIGHT CHANCE OF THUNDERSTORMS.
MONDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. CHANCE OF RAIN SHOWERS.
TUESDAY: WINDS LESS THAN 25 KT. CHANCE OF RAIN SHOWERS.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. SLIGHT CHANCE OF RAIN SHOWERS.
WEDNESDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE OF
RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...WIND ADVISORY FROM 10 AM TO 8 PM EDT SATURDAY FOR MAZ007-015-
016.
WIND ADVISORY FROM 10 AM SATURDAY TO 8 PM EDT SUNDAY FOR
MAZ019-021>024.
RI...NONE.
MARINE...GALE WARNING FROM 2 AM TO 8 PM EDT SATURDAY FOR ANZ230>237-250-
251-254>256-280>283.
DISCUSSION...MENSCH
AVIATION...FRANK/MCMINN
MARINE...MENSCH
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