374
FXUS61 KBOX 191724
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
124 PM EDT TUE AUG 19 2025
SYNOPSIS
BELOW NORMAL TEMPERATURES WITH LOW HUMIDITY REMAIN IN THE REGION FOR
MUCH OF THIS WEEK BEFORE A WARMING TREND KICKS IN AT THE END OF THE
WEEK. A SHORTWAVE MOVING THROUGH WEDNESDAY WILL INCREASE CLOUD COVER
AND BRING RAIN CHANCES TO SOUTHERN NEW ENGLAND, BUT AMOUNTS ARE
STILL UNCERTAIN. BREEZY CONDITIONS ACROSS THE REGION PREVAIL
THURSDAY AND FRIDAY, WITH WINDS POSSIBLY REACHING GALE-FORCE OVER
THE CAPE AND ISLANDS. ANOTHER CHANCE FOR RAIN RETURNS HEADING INTO
THE START OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
* ANOTHER DAY OF COOLER TEMPERATURES AND LOWER HUMIDITY.
AN EXPANSIVE HIGH PRESSURE OVER NORTHERN QUEBEC CONTINUES TO MOVE
EAST, BRINGING NORTHEAST FLOW TO SOUTHERN NEW ENGLAND. WIND OFF THE
OCEAN IS HELPING TO MITIGATE TEMPERATURES ALONG THE EASTERN COAST,
AND A DRY AIRMASS IS HELPING TO KEEP THE HUMIDITY AT BAY. HIGH
TEMPERATURES THIS AFTERNOON LIKELY IN THE LOW TO MID 70S ACROSS THE
AREA, WITH THE EASTERN SHORES STRUGGLING TO REACH MUCH ABOVE 70.
DEWPOINTS SLIGHTLY HIGHER THAN YESTERDAY... LOW TO MID 50S, EXCEPT
HIGH 40S ACROSS THE INTERIOR. CLOUDS CONTINUE TO BUILD IN THROUGHOUT
THE AFTERNOON AND EVENING, LEADING TO SLIGHTLY WARMER TEMPERATURES
TONIGHT... IN THE MID TO HIGH 50S.
SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/
KEY MESSAGES:
* RAIN CHANCES RETURN MIDWEEK, ALTHOUGH EXACT RAINFALL TOTALS
ARE STILL UNCERTAIN.
A QUICK SHORTWAVE MOVES THROUGH NEW ENGLAND WEDNESDAY, BRINGING RAIN
CHANCES TO THE AREA. GUIDANCE IS STILL STRUGGLING TO COME TO AN
AGREEMENT ON EXACT PLACEMENT, BUT GENERALLY THINKING SOUTH OF THE
MASS PIKE WILL SEE THE HEAVIEST RAINFALL. THE ECMWF, NBM, AND
CANADIAN ALL FAVOR ROUGHLY 1" QPF/24 HOURS ACROSS SOUTHERN CT AND
RI, THE GFS FAVORS 1.25" QPF/24 HOURS ACROSS NORTHERN CT, AND THE
NAM STAYS THE FURTHEST NORTH WITH A SWATH OF 1.5" QPF/24 HOURS
ACROSS INTERIOR MA. THE LATEST HREF GUIDANCE HAS MAINLY SCATTERED
SHOWERS ACROSS THE REGION THROUGH THE AFTERNOON WEDNESDAY WITH LOW
PROBS FOR THUNDER IN WESTERN MA INTO CT.
HIGH TEMPERATURES WEDNESDAY WILL LIKELY BE IN THE LOW 70S ACROSS
EASTERN MA AS EASTERLY WINDS CONTINUE. SLIGHTLY COOLER TEMPS WITH
HIGHS IN THE MID 60S AND DOWN INTO THE UPPER 50S IN THE HIGHER
ELEVATIONS OF THE WESTERN PARTS OF THE REGION WITH CONTINUED CLOUD
COVER.
LONG TERM /THURSDAY THROUGH TUESDAY/
KEY MESSAGES:
* LARGE SOUTHERLY SWELL FROM DISTANT ERIN WILL BRING HIGH SURF AND
DANGEROUS RIP CURRENTS TO SOUTH-FACING BEACHES THROUGH THE LATTER
PART OF THIS WEEK
* NORTHEAST WINDS INTENSIFY OVER THE CAPE AND ISLANDS
THURSDAY/FRIDAY AND COULD REACH GALE-FORCE
* ANOTHER CHANCE FOR SOME RAIN ARRIVES SUNDAY ALONG WITH A WEEKEND
WARM-UP
THE MAIN STORY FOR THIS PERIOD OF THE FORECAST IS THE DANGEROUS TO
LIFE-THREATENING SURF AND RIP CURRENT RISK ACROSS OUR SOUTH-FACING
BEACHES. THIS ELEVATED RISK IS DUE TO THE PASSAGE OF HURRICANE ERIN
FAR TO OUR SOUTHEAST BY FRIDAY, WHICH WILL BE CHURNING UP
SIGNIFICANT SWELL THAT WILL EVENTUALLY MAKE ITS WAY TO OUR COASTS;
WAVES SOUTH OF NANTUCKET MAY REACH UP TO 20 FT. ALONG WITH ELEVATED
SURF, THE GRADIENT BETWEEN ERIN AND THE CANADIAN HIGH PRESSURE
SETTLED OVER SOUTHERN NEW ENGLAND WILL LEAD TO AMPLIFIED NE WINDS
OVER THE CAPE AND ISLANDS THAT COULD REACH GALE-FORCE STRENGTH.
MODEL GUIDANCE IS INDICATING WINDS AT 850 MB APPROACHING 50 KTS OVER
THE ISLANDS BY FRIDAY MORNING AND EVEN UP TO 55 KTS AT 925 MB. ASIDE
FROM THE CAPE AND ISLANDS, THE REST OF SOUTHERN NEW ENGLAND CAN
EXPECT A GENERALLY BREEZY THURSDAY AND FRIDAY BEFORE THE GRADIENT
SLACKENS WITH ERIN'S INFLUENCE DIMINISHING AS IT MOVES FURTHER INTO
THE ATLANTIC.
THROUGH THE REST OF THE WEEK, HIGH AND LOW TEMPERATURES REMAIN
RELATIVELY CONSISTENT. LOWS REMAIN IN THE 50S AND LOW 60S AND HIGHS
REMAIN IN THE 70S BEFORE A WARMING TREND KICKS IN FOR THE WEEKEND.
MORE SEASONABLY NORMAL TEMPERATURES CAN BE EXPECTED HEADING INTO THE
WEEKEND AS HIGHS RETURN TO THE LOW 80S. THE NEXT CHANCE FOR SOME
RAIN ARRIVES SOMETIME SUNDAY AS ANOTHER DISTURBANCE MOVES INTO THE
REGION AS PART OF A TROUGH SETTLED OVER MUCH OF ONTARIO INTO
QUEBEC.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE:
THROUGH TONIGHT...HIGH CONFIDENCE.
VFR. ESE WINDS 5 TO 10 KNOTS.
WEDNESDAY AND WEDNESDAY NIGHT...HIGH CONFIDENCE IN TRENDS, LOW
CONFIDENCE IN TIMING AND PLACEMENT OF SHRA.
VFR EARLY BECOMING MVFR THROUGH THE DAY FROM WEST TO EAST WITH
ARRIVAL OF SHRA. E WINDS 5-10 KTS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
THURSDAY: VFR. BREEZY. SLIGHT CHANCE SHRA.
THURSDAY NIGHT: VFR. WINDY WITH AREAS OF GUSTS UP TO 35 KT.
FRIDAY: VFR. WINDY WITH GUSTS UP TO 35 KT.
FRIDAY NIGHT: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT.
SATURDAY THROUGH SATURDAY NIGHT: VFR. BREEZY.
SUNDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY. SLIGHT
CHANCE SHRA, SLIGHT CHANCE TSRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH WEDNESDAY...HIGH CONFIDENCE.
LARGE SOUTHERLY SWELL FROM MAJOR HURRICANE ERIN WILL RESULT IN
SEAS AT OR ABOVE 5 FEET FOR PORTIONS OF OUR SOUTHERN WATERS
TODAY, RAMPING UP THROUGH MID-WEEK. FOR THIS REASON, SMALL CRAFT
ADVISORIES WILL REMAIN IN EFFECT ACROSS THE SOUTHERN WATERS FOR
AN EXTENDED PERIOD. A HIGH SURF ADVISORY ALSO GOES INTO EFFECT
THIS MORNING FOR SOUTHERN COASTAL AREAS, INCLUDING THE CAPE. RIP
CURRENTS WILL BECOME A SIGNIFICANT CONCERN AS THE WEEK GOES ON
WITH THIS ELEVATED SURF.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
THURSDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 30 KT. ROUGH SEAS UP TO 14 FT. SLIGHT CHANCE OF
RAIN SHOWERS.
THURSDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 40 KT. ROUGH SEAS
UP TO 18 FT. SLIGHT CHANCE OF RAIN SHOWERS.
FRIDAY: MODERATE RISK FOR GALE FORCE WINDS WITH GUSTS UP TO
40 KT. ROUGH SEAS UP TO 17 FT.
FRIDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 30 KT. ROUGH SEAS UP TO 12 FT.
SATURDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. ROUGH SEAS UP TO 10 FT.
SATURDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. ROUGH SEAS UP TO 8 FT.
SUNDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. SEAS UP TO 5 FT. SLIGHT CHANCE OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...HIGH SURF ADVISORY UNTIL 8 PM EDT THURSDAY FOR MAZ020>024.
RI...HIGH SURF ADVISORY UNTIL 8 PM EDT THURSDAY FOR RIZ006>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR ANZ254>256.
SYNOPSIS...LOCONTO/MCMINN
NEAR TERM...MCMINN
SHORT TERM...MCMINN
LONG TERM...LOCONTO
AVIATION...BW/MCMINN
MARINE...LOCONTO/BW
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