530
FXUS61 KBOX 181941
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
341 PM EDT MON AUG 18 2025
SYNOPSIS
CANADIAN HIGH PRESSURE WILL BRING BELOW NORMAL TEMPERATURES/LOW
HUMIDITY TO THE REGION FOR MUCH OF THE WEEK. A DISTURBANCE
ALOFT MOVING THROUGH ON WEDNESDAY WILL BRING INCREASED
CLOUDINESS ALONG WITH RAIN CHANCES, ALTHOUGH HOW MUCH RAIN FALLS
IS STILL UNCERTAIN. LARGE SOUTHERLY SWELL FROM HURRICANE ERIN
WILL LEAD TO HIGH SURF AND DANGEROUS RIP CURRENTS FOR SOUTH-
FACING BEACHES TUESDAY THROUGH MUCH OF THE WORKWEEK, ALONG WITH
A PERIOD OF ENHANCED NORTHEAST BREEZES THURSDAY AND FRIDAY.
OTHERWISE, DRY WEATHER PREVAILS UNTIL SUNDAY. TEMPERATURES WILL
BE COOLER THAN NORMAL THROUGH THE WORKWEEK, THEN BEGIN A WARMING
TREND BY THE WEEKEND.
NEAR TERM /UNTIL 6 AM TUESDAY MORNING/
KEY MESSAGES...
* MUCH COOLER & LESS HUMID TODAY WITH HIGHS MAINLY IN THE 70S
* NE WINDS GUST 20-30 MPH ALONG THE COAST AND PERHAPS 35 MPH CAPE/ACK
DETAILS...
TODAY...
LARGE HIGH PRESSURE ACROSS QUEBEC NOSES DOWN IN THE WAKE OF LAST
EVENING/S COLD FRONTAL PASSAGE. THE RESULT IS A MUCH COOLER/MUCH
LESS HUMID AIRMASS THAT WILL BE WORKING INTO THE REGION. DESPITE
PLENTY OF SUNSHINE TODAY...HIGH TEMPERATURES WILL BE HELD IN THE 70S
ACROSS THE REGION ALONG WITH A STIFF NE BREEZE ESPECIALLY ALONG THE
COAST. IN FACT...HIGH TEMPERATURES ALONG MUCH OF THE EASTERN MA
COAST/CAPE AND NANTUCKET WILL BE HELD IN THE UPPER 60S TO LOWER 70S
WITH A GUSTY NE WIND. DEWPOINTS WILL DROP INTO THE 40S SO VERY
COMFORTABLE HUMIDITY AS WELL. THE NE WIND GUSTS OF 20 TO 30 MPH NEAR
THE COAST TODAY AND PERHAPS BRIEFLY UP TO 35 MPH ACROSS PARTS OF THE
CAPE/NANTUCKET. THOSE WINDS MAY BRING IN A TOUCH OF AN EARLY FALL
FEEL. OVERALL...A BEAUTIFUL DAY WITH LOW HUMIDITY BRINGING IDEAL
WEATHER FOR OUTDOOR ACTIVITIES.
SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/
KEY MESSAGES...
* UNSEASONABLY COOL TONIGHT WITH OVERNIGHT LOWS IN THE 40S & 50S
* ANOTHER BEAUTIFUL DAY ON TUE WITH LOW HUMIDITY & HIGHS IN THE 70S
DETAILS...
TONIGHT...
HIGH PRESSURE CONTINUING TO NOSE DOWN FROM QUEBEC WILL RESULT IN
DIMINISHING WINDS TONIGHT. THIS COUPLED WITH MAINLY CLEAR SKIES AND
A VERY DRY AIRMASS FOR AUGUST STANDARDS WILL BRING AN UNSEASONABLY
COOL NIGHT TO THE REGION. LOWS SHOULD BOTTOM OUT IN THE 40S ACROSS
MANY LOCATIONS OUTSIDE THE URBAN CENTERS. AND EVEN THE URBAN CENTERS
WILL SEE OVERNIGHT LOWS BOTTOM OUT IN THE LOWER TO MIDDLE 50S.
TUESDAY...
HIGH PRESSURE OVER QUEBEC WILL BRING US ANOTHER GORGEOUS DAY ON
TUESDAY. PLENTY OF SUNSHINE, COMFORTABLE HUMIDITY WITH HIGHS IN THE
70S. LESS WIND THAN TODAY ESPECIALLY ALONG THE COAST...SO IT WILL
FEEL A BIT MILDER IN THE AFTERNOON.
LONG TERM /WEDNESDAY THROUGH MONDAY/
KEY MESSAGES:
* INCREASING CLOUDS WED WITH RAIN CHANCES, ALTHOUGH THERE IS LOW
CONFIDENCE ON THE EXACT PLACEMENT OF RAINS AND HOW MUCH FALLS.
SOAKING RAIN IS VIEWED AS UNLIKELY BUT POSSIBLE.
* DRY WEATHER WITH COOLER THAN NORMAL TEMPERATURES THROUGH THE
WORKWEEK, WARMING UP BY THE WEEKEND.
* LARGE SOUTHERLY SWELL FROM DISTANT ERIN WILL BRING HIGH
SURF/DANGEROUS RIP CURRENTS TO SOUTH-FACING BEACHES THROUGH LATE
WEEK.
* NORTHEASTLY BREEZES BECOME ENHANCED OUT OVER THE CAPE AND ISLANDS
THU/FRI. POSSIBLE GALE-FORCE GUSTS.
DETAILS:
FORECAST CHALLENGE IN THIS PORTION OF THE FORECAST IS ON WED. A
SHORTWAVE TROUGH MOVING THROUGH THE GT LAKES REGION IS PROGGED TO
TRANSLATE ESE THROUGH THE NEW ENGLAND/NORTHERN MID-ATLC REGION ON
WED, AS THE SPRAWLING SW-NE RIDGE AXIS INITIALLY IN PLACE WEAKENS
SOMEWHAT. NWP CONTINUES TO VARY PRETTY SUBSTANTIALLY BOTH ON QPF
PLACEMENT AND IN MAGNITUDE, WHICH UNFORTUNATELY RENDERS A LOW-
CONFIDENCE FORECAST. SOME SOLUTIONS OFFERING VERY LITTLE TO NIL QPF
AT ALL WITH SEVERAL DAYS OF DRY OR AT LEAST GENERALLY DRY WEATHER
WINNING OUT, WHILE SOME WETTER SOLUTIONS SHOW SOME ENHANCED MOISTURE
AND DEPICT SOME RATHER EYE-POPPING QPF VALUES (UPWARDS OF 2 INCHES
IN THE NAM). DID NOTE THE 12Z ECMWF AND ITS 12Z ENSEMBLE HAVE TICKED
UP SOME IN TODAY'S GUIDANCE, WHICH COULD BE A TELL IN TERMS OF WHERE
GUIDANCE MAY GO, AND ITS ENSEMBLES NOW SHOW A 30-40% PROB OF QPF AT
OR ABOVE 0.5" WITH LOW PROBS OF 24-HR QPF AT OR ABOVE AN INCH, WHILE
THE OTHER GLOBAL ENSEMBLES ARE NOT NEARLY AS BULLISH OR AS HIGH.
CURRENTLY VIEW THE BULLISH NAM AS A WET OUTLIER, AND IT ALSO DOESN'T
HAVE SUPPORT FROM THE 15Z SREF EITHER. WITH THIS DEGREE OF
UNCERTAINTY RANGING FROM A DRY OUTCOME TO POTENTIALLY A PRETTY WET
ONE, THINK IT IS BEST TO STAY THE COURSE WITH A BLENDED OUTCOME
(NBM) AND LET TRENDS OVER THE NEXT FEW MODEL CYCLES DICTATE
ADJUSTMENTS. REGARDLESS, CERTAINLY WILL SEE QUITE A BIT OF CLOUD
COVER AND THE POTENTIAL FOR RAIN SHOWERS, BUT THERE IS STILL QUITE A
BIT OF UNCERTAINTY ON THE PLACEMENT AND AMT OF QPF THAT WILL NEED TO
BE ADJUSTED PENDING TRENDS. AFTER WEDNESDAY, THE NEXT BEST CHANCE
FOR RAIN MAY NOT OCCUR UNTIL SUNDAY AS RIDGING REASSERTS ITSELF.
TC ERIN IS STILL FORECAST TO PASS WELL SOUTHEAST OF 40N/70W BY FRI.
ITS MAIN INFLUENCE WILL BE BUILDING OFFSHORE WAVES REACHING NEARLY
20 FT SOUTH OF NANTUCKET BY FRI, TO GO ALONG WITH LARGE SOUTHERLY
SWELL LEADING TO SEVERAL DAYS OF HIGH SURF AND DANGEROUS RIP
CURRENTS FOR BEACHES WITH SOUTHERN EXPOSURES. WITH AN EXTENDED SPELL
OF DRY WEATHER AND THAT WATER TEMPS REMAIN AT THEIR CLIMATOLOGICALLY
WARMEST, BEACHGOERS/SWIMMERS FLOCKING TO THE BEACH COULD BE
PARTICULARLY VULNERABLE NOW THAT WE ARE INTO LATE IN SUMMER AND
BEACHES BECOME LESS STAFFED BY LIFEGUARDS. HIGH SURF ADVISORIES HAVE
BEEN ISSUED THROUGH THURS, AND WE MAY NEED TO CONSIDER
EXTENDING THESE INTO FRI OR INTO PART OF THE WEEKEND. NE WINDS
WILL ALSO BECOME ENHANCED OVER SOUTHEAST NEW ENGLAND ON THURS
AND INTO FRI, WITH GUSTS 25-30 MPH OVER LAND AND THE POTENTIAL
FOR GALE- FORCE GUSTS OVER THE SOUTHEAST WATERS. THE WINDS AND
WAVE ACTION MAY ALSO ELEVATE THE RISK FOR COASTAL BEACH EROSION
OVER THE ISLANDS.
COOLER THAN NORMAL TEMPS AND COMFORTABLE HUMIDITY LEVELS ARE
EXPECTED THROUGH AT LEAST FRI WITH ONSHORE FLOW LEADING TO
COOLER HIGH TEMPS (70S) WITH STRONG DIURNAL RANGES AND EFFICIENT
RADIATIONAL COOLING MOST NIGHTS (50S). WE DO START A WARM-UP
TOWARD THE WEEKEND WITH RISING HUMIDITY LEVELS BUT NOT LOOKING
AT HAZARDOUS HEAT OR HUMIDITY.
AVIATION /20Z MONDAY THROUGH SATURDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE...
TODAY...HIGH CONFIDENCE.
VFR. BREEZY, NE WINDS 7 TO 15 KNOTS WITH GUSTING 25 TO 30
KNOTS, ESPECIALLY NEAR THE COAST.
TONIGHT...HIGH CONFIDENCE.
VFR. WINDS DIMINISH AND BECOME LIGHT AND VARIABLE.
TUESDAY...HIGH CONFIDENCE.
VFR. ESE WINDS 5 TO 10 KNOTS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY: VFR. SLIGHT CHANCE SHRA.
WEDNESDAY NIGHT: VFR. BREEZY. SLIGHT CHANCE SHRA.
THURSDAY: VFR. BREEZY.
THURSDAY NIGHT: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT.
FRIDAY: VFR. WINDY WITH GUSTS UP TO 30 KT.
FRIDAY NIGHT: VFR. BREEZY.
SATURDAY: BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY THROUGH TUESDAY...HIGH CONFIDENCE.
LARGE HIGH PRESSURE OVER QUEBEC COMBINED WITH A COOLER AIRMASS WILL
BE WELL MIXED OVER THE WATERS TODAY. THIS WILL RESULT IN NE WIND
GUSTS OF 20 TO 30 KNOTS AND CHOPPY SEAS...SO SMALL CRAFT HEADLINES
ARE POSTED FOR ALL OUR WATERS. THE PRESSURE GRADIENT WEAKENS TONIGHT
AND TUE ALLOWING WINDS TO DIMINISH BELOW SMALL CRAFT ADVISORY
THRESHOLDS. HOWEVER...LARGE SOUTHERLY SWELL FROM MAJOR HURRICANE
ERIN WILL RESULT IN SEAS AT OR ABOVE 5 FEET FOR PORTIONS OF OUR
SOUTHERN WATERS OVERNIGHT INTO TUESDAY. IN FACT...THEY WILL BE
RAMPING UP FURTHER INTO MID-WEEK SO SMALL CRAFT HEADLINES WILL
REMAIN POSTED FOR OUR SOUTHERN WATERS FOR AN EXTENDED PERIOD OF TIME.
OUTLOOK /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY THROUGH WEDNESDAY NIGHT: WINDS LESS THAN 25 KT. AREAS
OF ROUGH SEAS. SLIGHT CHANCE OF RAIN SHOWERS.
THURSDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 30 KT. ROUGH SEAS UP TO 16 FT.
THURSDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS
UP TO 17 FT.
FRIDAY: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO 35 KT.
ROUGH SEAS UP TO 15 FT.
FRIDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. ROUGH SEAS UP TO 11 FT.
SATURDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. ROUGH SEAS UP TO 8 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...HIGH SURF ADVISORY FROM 8 AM TUESDAY TO 8 PM EDT THURSDAY FOR
MAZ020>024.
RI...HIGH SURF ADVISORY FROM 8 AM TUESDAY TO 8 PM EDT THURSDAY FOR
RIZ006>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230-
250-251.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR
ANZ231>235-237.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR ANZ254>256.
SYNOPSIS...LOCONTO/MCMINN
NEAR TERM...MCMINN
SHORT TERM...MCMINN
LONG TERM...LOCONTO
AVIATION...LOCONTO/MCMINN
MARINE...LOCONTO/MCMINN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page