547
FXUS61 KBOX 300628
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
228 AM EDT SAT MAY 30 2026
WHAT HAS CHANGED
UPGRADED THE WIND ADVISORY TO A HIGH WIND WARNING FOR CAPE COD AND
NANTUCKET. EXPANDED THE WIND ADVISORY TO INCLUDE ALL OF EASTERN
MASSACHUSETTS AND RHODE ISLAND.
KEY MESSAGES
- LOW PRESSURE SYSTEM BRINGS RAIN AND AREAS OF STRONG TO DAMAGING
WINDS TONIGHT AND SATURDAY.
- COOLER THAN NORMAL TEMPERATURES EARLY NEXT WEEK WITH HIT-OR-
MISS SHOWER/THUNDERSHOWER CHANCES DURING THE DAYTIME HOURS
MONDAY AND TUESDAY.
- MONITORING POSSIBLE OFFSHORE LOW DEVELOPMENT AROUND MIDWEEK,
WHICH COULD PASS FAR ENOUGH SOUTH TO ALLOW FOR WARMING
TEMPERATURES, OR LEAD TO A CONTINUATION OF COOLER THAN NORMAL
TEMPERATURES AND POSSIBLE RAINS WITH A CLOSER PASS.
DISCUSSION
KEY MESSAGE 1...LOW PRESSURE SYSTEM BRINGS RAIN AND AREAS OF STRONG
TO DAMAGING WINDS TONIGHT AND SATURDAY.
HIGHLY AMPLIFIED PATTERN RESULTS IN AN ANOMALOUSLY STRONG ALBEIT
QUICK-HITTING STORM SYSTEM TONIGHT AND SATURDAY. SYSTEM WILL BRING
PERIODS OF HEAVY RAIN AND SHOWERS, BUT THE BIGGER ISSUE WILL BE A
PERIOD OF STRONG WINDS ON SATURDAY.
A PERIOD OF STRONG TO DAMAGING WINDS CONTINUES TO BE OF GREATEST
CONCERN WITH THIS SYSTEM. SYNOPTICALLY, STRONG WINDS WILL STEM FROM
A DEEPENING AREA OF LOW PRESSURE AND ASSOCIATED PRESSURE RISES AS IT
PULLS AWAY. GUIDANCE SHOWS 3HR PRESSURE RISE VALUES OF 5-7 MB/3HR AS
THE SYSTEM WINDS UP AND PULLS OFF THE COAST OF MA SATURDAY
AFTERNOON. THE LATEST HREF ENSEMBLE GUIDANCE GREATLY EXPANDED THE
AREA OF GUSTS 35-45 MPH AND NOW SHOWS THE POTENTIAL ISOLATED HIGHER
GUSTS (45-55 MPH) WELL INTO THE I-95 CORRIDOR. THIS SEEMS REASONABLE
GIVEN THAT THE LLJ JET MORE LIKELY SHIFTS ACROSS EAST SOUTHERN NEW
ENGLAND THROUGH THE DAY. THE DEGREE OF MIXING HAS COME INTO MUCH
BETTER AGREEMENT AMONG GUIDANCE WITH 1000-950MB LAPSE RATES LIKELY
INCREASING TO 8-10C/KM SATURDAY AFTERNOON! FOR THESE REASONS, THE
WIND ADVISORY HAS BEEN EXPANDED FURTHER INLAND. PART OF THE
RATIONALE IN EXPANDING THE ADVISORIES INLAND IS INCREASING
CONFIDENCE IN AN APPARENT TREND TOWARDS GREATER MIXING IN THE LOWEST
100MB. SOMEWHAT UNUSUALLY, THE CORE OF THE LLJ WILL BE FAIRLY CLOSE
TO THE SURFACE (BETWEEN 925 AND 850MB). THUS, THE MIXED LAYER WON'T
HAVE TO BE AS DEEP TO TAP INTO THE STRONG WINDS. THE OTHER
CHANGE WAS TO ISSUE A HIGH WIND WARNING FOR THE CAPE AND
NANTUCKET WHERE THE LLJ WILL SLIGHTLY STRONGER ON THE ORDER OF
55-65KT.
IN TERMS OF PRECIPITATION WITH THIS SYSTEM WE'RE LOOKING AT
PERIODS OF SHOWERS THAT BECOME MORE WIDESPREAD AFTER THE EVENING
COMMUTE INTO THIS EVENING AND TONIGHT. THERE COULD BE A FEW
EMBEDDED WEAK STORMS OR DOWNPOURS WITH SOME MEAGER MID-LEVEL
INSTABILITY. QUICK LULL IN THE ACTIVITY GIVES WAY TO MORE
WIDESPREAD RAINFALL SATURDAY MORNING AS LOW PRESSURE ROTATES
THROUGH. 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.
KEY MESSAGE 2...COOLER THAN NORMAL TEMPERATURES EARLY NEXT WEEK
WITH HIT-OR-MISS SHOWER/THUNDERSHOWER CHANCES DURING THE
DAYTIME HOURS MONDAY AND TUESDAY.
ENSEMBLE MEANS CONTINUE TO POINT TO 500 MB TROUGHING GOVERNING
SOUTHERN NEW ENGLAND'S WEATHER LATE THIS WEEKEND INTO A GOOD PORTION
OF NEXT WEEK, IN A SLOW-EVOLVING, BLOCKY 500 MB PATTERN. THERE ARE A
COUPLE OF UPPER LEVEL LOWS THAT WILL BE MOVING INTO AND/OR
MEANDERING AROUND SOUTHERN NEW ENGLAND.
THE FIRST OF THESE CLOSED UPPER LOWS SETTLES IN SUNDAY NIGHT AND
INTO MONDAY, BEFORE MOVING OFFSHORE INTO TUESDAY. REALLY NOT MUCH
CHANGE IN TERMS OF SENSIBLE WEATHER EACH DAY, WITH DIURNALLY-DRIVEN,
HIT-OR-MOSTLY-MISS SHOWERS OR LOW-TOPPED THUNDERSHOWERS POPPING UP
WITH THE COOL POCKET OF AIR ALOFT ASSOCIATED WITH THE CLOSED LOW.
THIS TYPE OF SHOWERY PATTERN ALSO MEANS NO ONE AREA CAN BE
GUARANTEED TO BE RAIN-FREE, BUT THERE WILL BE SEVERAL DRY PERIODS IN
BETWEEN. TEMPERATURES TREND SLIGHTLY COOLER THAN EARLY-JUNE NORMALS,
WITH VALUES IN THE MID 60S TO MID 70S WITH COMFORTABLE HUMIDITY
LEVELS. CLIMATOLOGICAL NORMALS RUN AROUND THE MID/UPPER 70S FOR
HIGHS.
KEY MESSAGE 3...MONITORING POSSIBLE OFFSHORE LOW DEVELOPMENT
AROUND MIDWEEK, WHICH COULD PASS FAR ENOUGH SOUTH TO ALLOW FOR
WARMING TEMPERATURES, OR LEAD TO A CONTINUATION OF COOLER THAN
NORMAL TEMPERATURES AND POSSIBLE RAINS WITH A CLOSER PASS.
MORE UNCERTAINTY DURING THE MID TO LATTER PART OF THE UPCOMING
WORKWEEK WITH REGARD TO THE NEXT SURGE OF VORT ENERGY DIVING
SOUTHWARD FROM THE CANADIAN MARITIMES. THIS FEATURE DIGS SOUTH/SOUTH-
SOUTHWEST TO A POSITION GENERALLY SOUTH OF 40N/70W INTO A WOUND-UP,
CLOSED MID/UPPER CIRCULATION AND ASSOCIATED SURFACE LOW. THE
PLACEMENT OF THIS CYCLONE, WHEN IT BEGINS TO EXIT FURTHER OFFSHORE
AND IF WE SEE ANY RAINY CONDITIONS ASSOCIATED WITH ITS
NORTH/NORTHEAST PASSAGE ARE ALL UNCLEAR AT THIS TIME. BESIDES JUST
RAIN CHANCES, THIS FEATURE'S LOCATION WILL ALSO DICTATE TEMPERATURES
AS SOME OF THE FURTHER-OFFSHORE/DRIER SOLUTIONS BRING IN SHORTWAVE
RIDGING ALOFT NORTH OF IT EXTENDING INTO NEW ENGLAND, WITH POTENTIAL
FOR DRIER WEATHER AND A CONSIDERABLE WARMUP IN TEMPS FOR AT LEAST
INTERIOR SOUTHERN NEW ENGLAND. ON THE OTHER HAND, A CLOSER PASS TO
SOUTHERN NEW ENGLAND WOULD BRING COOLER THAN NORMAL TEMPERATURES AND
PERHAPS SOME LIGHT RAINS. WE OFFERED TO NOT MAKE MANY CHANGES TO NBM
AT THIS POINT AND LET TRENDS DICTATE SUBSEQUENT ADJUSTMENTS TO THE
FORECAST.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE:
THROUGH 12Z: HIGH CONFIDENCE IN TAF/TRENDS BUT MODERATE ON
TIMING.
LINE OF MODERATE SHRA WITH A SOME EMBEDDED THUNDERSTORMS. TEMPO
MVFR VISIBILITIES POSSIBLE IN ANY STORMS. BRIEF LULL IN MOST
SHOWER ACTIVITY BY 09Z. WINDS SHIFT NW AT 10-15 KTS WITH GUSTS
20-25 KTS.
TOWARD 12Z, CEILINGS TREND TOWARD VFR-MVFR RANGE NORTHERN MA
WITH MODERATE RAIN NEARING THE VT/NH/MA BORDER, WITH WINDS
BECOMING NORTH AND INCREASING TO 15-18 KT WITH GUSTS 25-30 KT.
FOR BDL- PVD-CAPE AIRPORTS, VFR SHOULD STILL GOVERN, WITH NW
WINDS AROUND 10-13 KT / GUSTS TO 20 KT.
TODAY: MODERATE CONFIDENCE.
MAINLY MVFR CEILINGS. IFR IS POSSIBLE FOR THE EAST TERMINALS,
THOUGH LOWER CONFIDENCE. RAIN SPREADING SOUTH FROM NORTHERN MA;
MORE PERSISTENT RAINS FROM ORH EAST. LOW CHANCE FOR A FEW
EMBEDDED THUNDERSTORMS THOUGH LOWER CONFIDENCE ON LOCATION.
NE WINDS INCREASE SIGNIFICANTLY TO 18-25 KT, WITH GUSTS 30-45
KT, STRONGEST IN EASTERN MA. WILL TAKE UNTIL EARLY AFTERNOON
(17-20Z) FOR STRONG NE WINDS AND MODERATE RAIN TO DEVELOP
TOWARDS THE CAPE AND ISLANDS.
N-NE WIND GUSTS AND RAIN DECREASE GENERALLY FROM WEST TO EAST
AFTER 20Z WITH CEILINGS TRENDING VFR AS WELL. BOS SHOULD START
SEEING IMPROVEMENTS AROUND 22Z AND 00-04Z FOR THE CAPE AND
ISLANDS.
TONIGHT: HIGH CONFIDENCE.
MVFR WITH MODERATE RAIN AND NE WINDS 15-25 KT / GUSTS 35-40 KT
CAPE AND ISLANDS EARLY, BUT CONDITIONS IMPROVE TO WIDESPREAD VFR
BY 04Z SUNDAY. WINDS SHIFT TO N/NW AND DECREASE SIGNIFICANTLY
TO AROUND 5-10 KT, OCCURRING SOONEST IN NORTHERN MA.
KBOS...MODERATE CONFIDENCE IN TAF. STEADY MODERATE RAIN WITH
MVFR VISBY AND MVFR-IFR CEILINGS DEVELOPS 11-13Z, WITH STRONG
NE WINDS INCREASING TO 20-25 KT SUSTAINED/GUSTS TO 45 KT MOST OF
SAT.
KBDL...MODERATE CONFIDENCE IN TAF. LIGHT RAIN ARRIVES 13-15Z WITH
MVFR CEILINGS AND N WINDS GUSTING TO 30-35 KT MOST OF SAT.
RAIN/WINDS DECREASE AFTER 20Z WITH IMPROVING CEILINGS.
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
SUNDAY: VFR. SLIGHT CHANCE SHRA.
SUNDAY NIGHT: VFR. CHANCE SHRA.
MONDAY: VFR. SHRA LIKELY, CHANCE TSRA.
MONDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. SLIGHT
CHANCE SHRA.
TUESDAY THROUGH TUESDAY NIGHT: VFR. CHANCE SHRA.
WEDNESDAY: VFR. BREEZY. SLIGHT CHANCE SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
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...
STORM WARNING FOR ALL THE WATERS EXCEPT NARRAGANSETT BAY AND
BOSTON HARBOR WHERE GALE WARNINGS ARE IN EFFECT ON SATURDAY. A
A STRONG AREA OF LOW PRESSURE SYSTEM TRACKS ACROSS THE REGION
BRINGING GUSTY N-NE WINDS.
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
SUNDAY: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS. CHANCE OF RAIN
SHOWERS.
SUNDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE OF
RAIN SHOWERS.
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. SLIGHT CHANCE OF RAIN SHOWERS.
TUESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
SLIGHT CHANCE OF RAIN SHOWERS.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS. CHANCE
OF RAIN SHOWERS.
WEDNESDAY: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS. CHANCE
OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...WIND ADVISORY FROM 8 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR MAZ004>007-012>021-023-026.
HIGH WIND WARNING FROM 8 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR MAZ022-024.
RI...WIND ADVISORY FROM 8 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR RIZ001>008.
MARINE...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR ANZ230-236.
STORM WARNING UNTIL 8 PM EDT THIS EVENING FOR ANZ231>235-237-
250-251-254>256-280>283.
DISCUSSION...LOCONTO/FT
AVIATION...LOCONTO/MENSCH
MARINE...FT
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