466
FXUS61 KBOX 171921
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
321 PM EDT THU SEP 17 2026
WHAT HAS CHANGED
NO SIGNIFICANT FORECAST CHANGES.
KEY MESSAGES
- SHOWER CHANCES THURSDAY EVENING INTO FRIDAY MORNING, FOLLOWED
BY DRIER CONDITIONS FRIDAY.
- DRIER CONDITIONS FRIDAY AND SATURDAY.
- NEXT CHANCE FOR RAIN SUNDAY INTO MONDAY. THERE REMAINS
UNCERTAINTY IN THE DETAILS SUCH AS COVERAGE, TIMING, AMOUNTS.
SHOWERS MAY LINGER THROUGH EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...SHOWER CHANCES THURSDAY EVENING INTO FRIDAY
MORNING, FOLLOWED BY DRIER CONDITIONS FRIDAY.
CLOUDS ARE INCREASING AND SHOWERS ARE ON THE DOORSTEP OF
SOUTHERN NEW ENGLAND, CROSSING THE REGION THROUGH THIS
AFTERNOON AND EVENING BEFORE EXITING THE COASTAL WATERS EARLY
FRIDAY MORNING. THESE SHOWERS ARE ASSOCIATED WITH A NORTHERN-
STREAM SHORTWAVE TROUGH; HOWEVER, THERE IS LESS-THAN-IDEAL
FORCING OVER SOUTHERN NEW ENGLAND. GUIDANCE CONSENSUS SHOWS THE
BEST FORCING/LIFT ACROSS NORTHERN MASSACHUSETTS (MAINLY NORTH OF
RT. 2) AND INTO SOUTHERN VERMONT AND NEW HAMPSHIRE. PWATS ARE
QUITE ANOMALOUS FOR MID-SEPTEMBER, NEARING 2+ INCHES, WHICH IS
NEAR THE MAXIMUM OF CLIMATOLOGY BASED ON SOUNDING CLIMATOLOGY AT
CHATHAM. TODAY'S SUITE OF HIGH-RES GUIDANCE IS IN PRETTY GOOD
AGREEMENT THAT SHOWERS MOVE INTO FAR WESTERN AREAS OF SOUTHERN
NEW ENGLAND AS EARLY AS 3-4 PM, APPROACHING THE I-95 CORRIDOR
BETWEEN 7-9 PM. THE THREAT OF THUNDER IS LOW, THOUGH NOT ZERO.
THERE IS ALSO A LOW THREAT OF LOCALIZED HEAVY DOWNPOURS DUE TO
THE ANOMALOUS MOISTURE IN THE ATMOSPHERE, BUT THESE SHOWERS ARE
MOVING AT A GOOD PACE. NEVERTHELESS, RAINFALL AMOUNTS WILL BE
HIGHLY VARIABLE GIVEN THE SHOWERY NATURE. THERE IS POTENTIAL FOR
AS MUCH AS A HALF INCH OF RAIN IN THE VICINITY OF RT. 2 IN
NORTHERN MASSACHUSETTS AND INTO SOUTHERN VERMONT AND SOUTHERN
NEW HAMPSHIRE, WITH MUCH LESS THE FARTHER SOUTH YOU GO.
KEY MESSAGE 2...DRIER CONDITIONS FRIDAY AND SATURDAY.
A FEW EARLY MORNING SHOWERS ARE POSSIBLE ACROSS CAPE COD AND THE
ISLANDS; OTHERWISE, A TRANSIENT HIGH PRESSURE SYSTEM MOVING OUT
OF THE SOUTHERN CANADIAN PRAIRIES BRINGS A DRY STRETCH OF
WEATHER FRIDAY AND SATURDAY. SEASONABLY MILD TEMPERATURES ARE
EXPECTED FRIDAY, WITH HIGHS IN THE MIDDLE 70S AND ELEVATED DEW
POINTS INITIALLY IN THE LOWER 60S, THOUGH THOSE FALL INTO THE
UPPER 40S BY FRIDAY AFTERNOON. BREEZY NW WINDS IN THE AFTERNOON
WITH GUSTS 20-25 MPH, MAINLY ACROSS THE INTERIOR. THEN A SHIFT
TO MORE FALL-LIKE CONDITIONS ON SATURDAY. A CHILLY START FOR
MOST, WITH LOWS IN THE LOWER TO MIDDLE 40S, WHILE URBAN AREAS
REMAIN IN THE LOWER 50S. NOT OUT OF THE QUESTION THAT UPPER 30S
OCCUR ALONG THE EAST SLOPES OF THE BERKSHIRES AND ACROSS
NORTHERN WORCESTER COUNTY. OTHERWISE, A CRISP AFTERNOON WITH
SUNSHINE AND HIGHS IN THE MIDDLE TO UPPER 60S. LIGHT EAST WINDS
WILL LEAD TO SLIGHTLY LOWER TEMPERATURES FOR EASTERN COASTAL
COMMUNITIES, WITH LOCATIONS LIKE BOSTON PERHAPS NOT CLIMBING OUT
OF THE LOWER 60S. DEW POINTS IN THE 40S WILL ADD TO THE CRISP
FEEL.
KEY MESSAGE 3...NEXT CHANCE FOR RAIN SUNDAY INTO MONDAY. THERE
REMAINS UNCERTAINTY IN THE DETAILS SUCH AS COVERAGE, TIMING,
AMOUNTS. SHOWERS MAY LINGER THROUGH EARLY NEXT WEEK.
STILL HAVE TIMING CONCERNS FOR RAINFALL SUNDAY INTO MONDAY.
WHILE A HIGH PRESSURE SHOULD BE MOVING OFF THE COAST SATURDAY
NIGHT, IT MAY STILL HAVE TOO MUCH INFLUENCE TO PREVENT RAINFALL
FROM OVERSPREADING OUR REGION DURING THE MORNING. STILL FAVORING
RAINFALL ARRIVING FROM WEST TO EAST SUNDAY AFTERNOON INTO SUNDAY
NIGHT. ANOTHER HIGH PRESSURE OVER EASTERN CANADA SHOULD BECOME
MORE OF AN INFLUENCE OVER THE COURSE OF MONDAY. THUS, NOT
CERTAIN HOW MANY SHOWERS WILL REMAIN MONDAY MORNING. THINKING
THE GREATEST RISK FOR LINGERING SHOWERS WILL BE TOWARDS THE
SOUTH COAST.
THE POTENTIAL RAIN AMOUNTS WILL DEPEND ON THE EXACT TRACK OF
THIS LOW PRESSURE, WHICH IS STILL VARIABLE ACROSS GUIDANCE THIS
FAR OUT IN TIME. THIS VARIANCE TRANSLATES QUITE CLEARLY TO THE
RAIN TOTALS ACROSS BOTH DETERMINISTIC AND ENSEMBLE GUIDANCE.
MOISTURE SHOULD NOT BE THAT MUCH OF A LIMITATION. OVERALL,
STILL LOOKING LIKE ANOTHER SOAKING RAINFALL FOR MOST. FAVORING
THE HIGHEST RAINFALL TOTALS TOWARDS THE SOUTH COAST OF NEW
ENGLAND AT THIS TIME.
THE FORECAST TREND IS FOR DRIER WEATHER TUESDAY AND WEDNESDAY.
IT APPEARS THAT ANOTHER LOW PRESSURE COULD APPROACH FROM THE
MID ATLANTIC STATES SOMETIME TOWARDS THURSDAY.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH TONIGHT...MODERATE CONFIDENCE.
PREDOMINANTLY VFR WITH AREAS OF MVFR THIS AFTERNOON. SSW WINDS
AT 5-10 KT. EXCEPTION IS BOS, WHERE ENE WINDS CONTINUE THROUGH
LATE AFTERNOON. SHOWERS ARRIVE DURING THE AFTERNOON HOURS FROM W
TO E, WITH CHANCES CONTINUING TO INCREASE THROUGH THE EVENING.
SHOWERS ARE MORE LIKELY TO DEVELOP AFTER 21Z FOR THE WESTERN
TERMINALS AND AFTER 00Z FOR THE MORE EASTERN TERMINALS.
OVERNIGHT, MVFR WITH AREAS OF IFR AND PATCHY FOG. SHOWERS
CONTINUE TO MOVE ACROSS THE REGION FROM WEST TO EAST, EXITING
THE CAPE/ISLANDS AROUND 12Z. SW WINDS 5-10 KT, SHIFTING TO NW
06-12Z AS THE FRONT MOVES THROUGH.
FRIDAY AND FRIDAY NIGHT...HIGH CONFIDENCE.
AREAS OF MVFR LINGER ACROSS CAPE COD AND THE ISLANDS THROUGH
14/15Z, OTHERWISE VFR. NNW WINDS 8-12 KT WITH GUSTS UP TO 20
KT, THOUGH GUSTS DIMINISH AFTER SUNSET. THE EXCEPTION WILL BE
THE CAPE AND ISLAND TERMINALS, WHERE GUSTS CONTINUE INTO THE
OVERNIGHT HOURS. ACROSS THE INTERIOR, NORTHERLY WINDS LESS THAN
5 KT.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
ENE WINDS BECOME S AROUND 23/00Z. SHRA CHANCES INCREASE AFTER
23Z; HAVE OPT'D FOR VCSH DURING THAT TIME SINCE PROBABILITIES
ARE LOWER. HIGHER CONFIDENCE IN SHRA AFTER 01Z, CONTINUING
THROUGH 07/08Z WITH MVFR CEILINGS, THOUGH CANNOT RULE OUT
BRIEFLY FALLING TO IFR DURING PERIODS OF SHRA. VFR FRIDAY WITH
NNW GUSTS UP TO 20 KT.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY THROUGH SATURDAY NIGHT: VFR.
SUNDAY: MVFR/IFR CONDITIONS POSSIBLE. SHRA LIKELY.
SUNDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.
SHRA LIKELY.
MONDAY THROUGH MONDAY NIGHT: VFR. BREEZY. SLIGHT CHANCE SHRA.
TUESDAY: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT. SLIGHT CHANCE
SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH SATURDAY...HIGH CONFIDENCE.
A ROUND OF SHOWERS PUSHES ACROSS THE WATERS TONIGHT INTO EARLY
TOMORROW MORNING. SEAS REMAIN 2-3 FT, THOUGH PORTIONS OF THE
SOUTHERN WATERS MAY APPROACH 4 FT HEADING INTO TOMORROW MORNING.
WINDS SHIFT TO THE NW TOMORROW MORNING, WITH SOME GUSTS UP TO 20 KT
POSSIBLE. HIGH PRESSURE BUILDS IN FROM THE WNW FRIDAY AFTERNOON AND
REMAINS WITH US THROUGH SATURDAY. BRIEFLY FRIDAY NIGHT INTO EARLY
SATURDAY, GUSTS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA.
CONFIDENCE IN GUSTS EXCEEDING 25 KT IS LOW; HOWEVER, GUSTS OF 20 TO
25 KT SEEM LIKELY. FUTURE FORECAST UPDATES MAY INCLUDE AN ADVISORY
IF CONFIDENCE IN HIGHER GUSTS INCREASES. OTHERWISE, NICE CONDITIONS
ON SATURDAY WITH SEAS 2-3 FT AND ENE WINDS LESS THAN 15 KT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT.
SATURDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
SUNDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
CHANCE OF RAIN SHOWERS.
SUNDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS. RAIN
SHOWERS LIKELY.
MONDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. SEAS UP TO 5 FT. CHANCE OF RAIN SHOWERS.
MONDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
LOCAL GUSTS UP TO 30 KT. SEAS UP TO 5 FT. CHANCE OF RAIN
SHOWERS.
TUESDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 30 KT. SEAS UP TO 5 FT. CHANCE OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
DISCUSSION...BELK/DOOLEY
AVIATION...BELK/DOOLEY
MARINE...BELK/DOOLEY
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