780
FXUS61 KBOX 170005
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
805 PM EDT SUN AUG 16 2026
WHAT HAS CHANGED
RAINFALL COVERAGE AND AMOUNTS HAVE TRENDED LOWER FOR LATE TONIGHT
INTO MONDAY.
KEY MESSAGES
- WIDESPREAD SHOWERS EXPECTED TONIGHT INTO TUESDAY ALTHOUGH THE
OVERALL RAINFALL TOTALS HAVE CONTINUED TO TREND DOWN.
- SCATTERED SHOWERS AND A FEW STORMS POSSIBLE LATER
TUESDAY. INCREASED CHANCES FOR SHOWERS ARRIVE FOR LATE-WEEK.
DISCUSSION
KEY MESSAGE 1...WIDESPREAD SHOWERS EXPECTED TONIGHT INTO
TUESDAY ALTHOUGH THE OVERALL RAINFALL TOTALS HAVE CONTINUED TO
TREND DOWN.
A LOW PRESSURE SYSTEM OFF THE SOUTHERN LONG ISLAND WATERS WILL
MOVE EAST TONIGHT BRINGING A WIDESPREAD WAVE OF RAIN SHOWERS TO
SOUTHERN NEW ENGLAND, SOME OF WHICH IS ALREADY BEGINNING TO
SLOWLY PUSH INTO NORTHERN NJ/ SOUTHERN NY. DEWPOINTS HAVE BEEN
STEADILY RISING THROUGHOUT THE DAY, AND WILL CONTINUE TO DO SO
INTO THE NIGHT AS PROLONGED SOUTHWESTERLY FLOW ADVECTS PWATS OF
1.8-2.0 INCHES INTO THE REGION. LATEST GUIDANCE HAS INDICATED
THE LOW WILL REMAIN FAR ENOUGH SOUTH TO KEEP THE HEAVIEST
RAINFALL ALONG THE SOUTH COAST, CAPE & ISLANDS, SOUTHERN RI, AND
SOUTHERN CT. SHOWERS WILL SLOWLY PUSH EAST AND OVERSPREAD THE
REGION AROUND SUNSET, WITH HIGHEST CHANCES FOR HEAVIEST RAINFALL
BETWEEN MIDNIGHT AND SUNRISE MONDAY MORNING. THE COMMUTE MONDAY
WILL LIKELY BE WET AS SHOWERS LINGER ACROSS RI AND EASTERN MA
THROUGH THE MORNING AND EARLY AFTERNOON, WITH THE CAPE AND
ISLANDS SEEING THE RAIN HANG ON INTO THE EARLY EVENING. RAINFALL
TOTALS HAVE CONTINUED TO TREND LOWER WITH EACH ROUND OF MODEL
GUIDANCE... LATEST TRENDS INDICATE BETWEEN 0.10" AND 0.33", WITH
NANTUCKET AND THE OUTER CAPE POSSIBLY SEEING NEAR 0.50".
DEWPOINTS WILL REMAIN HIGHER (NEAR 70) EVEN ONCE THE RAIN STOPS,
SO LOOKING AT A MUGGY AND OVERCAST EVENING/NIGHT MONDAY.
KEY MESSAGE 2...SEASONABLY WARM TEMPERATURES AND MODERATE
HUMIDITY RETURN THROUGH THE MIDDLE OF NEXT WEEK, FOLLOWED BY
INCREASING SHOWER CHANCES LATE IN THE WEEK.
HIGH PRESSURE SLOWLY BUILDS IN TUESDAY SUPPORTING INCREASING
SUNSHINE AND DRY CONDITIONS FOR MUCH OF THE DAY. A MIX OF
DIURNAL HEATING, RESIDUAL MOISTURE, AND A WEAK SHORTWAVE IN THE
FLOW MAY HELP TRIGGER SCATTERED SHOWERS IN THE
AFTERNOON/EVENING. INSTABILITY WILL LIKELY BE MARGINAL, BUT
ENOUGH TO SUPPORT THE POTENTIAL FOR A FEW THUNDERSTORMS IN THE
MIX AS WELL. TEMPERATURES RANGE IN THE UPPER 70S TO LOW 80S
PERHAPS A LITTLE WARMER FOR THE CT VALLEY.
FLOW ALOFT STAYS ZONAL WEDNESDAY THROUGH FRIDAY. A STRONGER
SHORTWAVE TROUGH MOVES THROUGH EASTERN CANADA LATER WEDNESDAY
THROUGH THURSDAY ACCOMPANIED BY A COLD FRONT. THERE IS POTENTIAL
FOR A LEADING SHORTWAVE TO TRIGGER A FEW SHOWERS LATE WEDNESDAY
NIGHT, OTHERWISE WEDNESDAY IS LIKELY TO REMAIN DRY. THE MAIN
SHORTWAVE MOVES THROUGH THURSDAY ACCOMPANIED BY BETTER ASCENT
AND PLUME OF SLIGHTLY ABOVE NORMAL MOISTURE. THIS WILL BRING AN
INCREASED RISK FOR SHOWERS THURSDAY. ENSEMBLE PROBABILITIES
RANGE 50 TO 80 PERCENT WITH HIGHER END OF PROBABILITIES OVER THE
SOUTH COAST, SOUTHEAST MA, AND CAPE/ISLANDS.
WE'LL BE IN A POST-FRONTAL AIRMASS FRIDAY RESULTING IN SLIGHTLY
COOLER TEMPERATURES IN THE MID 70S TO LOW 80S AND A DOWNTICK IN
HUMIDITY. OVERALL, HIGH PRESSURE IS LIKELY TO PUSH IN FROM THE
WEST BRINGING MAINLY DRY CONDITIONS. HOWEVER, THERE ARE
INDICATIONS ACROSS MODEL GUIDANCE OF A BOUNDARY STALLING
OFFSHORE WITH A SERIES OF EMBEDDED SHORTWAVES RIDING THAT
BOUNDARY FRIDAY THROUGH THE WEEKEND. THIS MAY BRING PERIODIC
CHANCES FOR SHOWERS, PERHAPS SOME THUNDERSTORMS IF THE WAVES
ALIGN WITH DIURNAL HEATING. THE HIGHER RISK FOR SHOWERS WILL
THE FOR SOUTH COAST EXTENDING TO CAPE COD/ISLANDS.
AVIATION /00Z MONDAY THROUGH FRIDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
00Z TAF UPDATE...
TONIGHT...HIGH CONFIDENCE IN TRENDS, MODERATE CONFIDENCE IN
TIMING.
MAINLY VFR CONDITIONS PERSIST THIS EVENING. SCATTERED SHOWERS
ARRIVE FROM WEST TO EAST TONIGHT 00-04Z FOR INTERIOR REACHING
I-95 CORRIDOR 05-07Z. MVFR/LOCALIZED IFR CEILINGS ACCOMPANY THE
SHOWERS SPREADING ACROSS THE INTERIOR BETWEEN 04Z AND 08Z AND
REACH THE I-95 CORRIDOR 10-12Z. S WINDS GENERALLY 6-12 KNOTS.
MONDAY...MODERATE CONFIDENCE (CEILINGS)
LOW END MVFR WITH LOCALIZED IFR/LIFR CEILINGS POSSIBLE.
SCATTERED SHOWERS WITH THE HIGHER CHANCES THROUGH EARLY
AFTERNOON. ISOLATED SHOWERS POSSIBLE THROUGH 00Z. SSE WINDS
8-15 KTS, TURNING MORE E/ENE LATE AFTERNOON.
MONDAY NIGHT...MODERATE CONFIDENCE.
IFR/LOCALIZED LIFR CEILINGS POSSIBLE WITH PATCHY FG. LIGHT N
WINDS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEABREEZE SHOULD KICK
OUT 20Z-22Z TIME FRAME. VFR PERSISTS TODAY AND MOST OF
TONIGHT...BUT MVFR WITH LOCALIZED IFR CONDITIONS SHOULD ARRIVE
TOWARD THE MONDAY MORNING PUSH.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /TUESDAY THROUGH FRIDAY/...
TUESDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. SLIGHT CHANCE
SHRA.
TUESDAY NIGHT THROUGH WEDNESDAY: VFR.
WEDNESDAY NIGHT: VFR. SLIGHT CHANCE SHRA.
THURSDAY: VFR. CHANCE SHRA, SLIGHT CHANCE TSRA.
THURSDAY NIGHT: VFR. SLIGHT CHANCE SHRA.
FRIDAY: VFR.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH MONDAY NIGHT...HIGH CONFIDENCE.
SOUTH-SOUTHWESTERLY WINDS INCREASE TO AROUND 20 KT TONIGHT,
THEN SHIFT TO SOUTHEAST MONDAY MORNING THEN EAST BY LATE
AFTERNOON, WITH GUSTS OF 20 TO 25 KT. SEAS BUILD TO 5 TO 8 FT BY
EARLY MONDAY MORNING AS THE LOW APPROACHES. SMALL CRAFT
ADVISORIES REMAIN IN EFFECT THROUGH MONDAY NIGHT.
THE RISK FOR RIP CURRENTS INCREASES MONDAY ALONG SOUTH-FACING
BEACHES, THEN TUESDAY ALONG EAST-FACING BEACHES, AS ROUGH SEAS
AND LONG-PERIOD SWELLS SETTLE IN BEHIND THE DEPARTING SYSTEM.
OUTLOOK /TUESDAY THROUGH FRIDAY/...
TUESDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
WEDNESDAY THROUGH WEDNESDAY NIGHT: WINDS LESS THAN 25 KT.
THURSDAY THROUGH THURSDAY NIGHT: WINDS LESS THAN 25 KT. CHANCE
OF RAIN SHOWERS, SLIGHT CHANCE OF THUNDERSTORMS.
FRIDAY: WINDS LESS THAN 25 KT. SLIGHT CHANCE OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM TO 11 PM EDT MONDAY FOR ANZ231-
232-250-251-254.
SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 2 AM EDT TUESDAY FOR
ANZ233>235-237-255-256.
DISCUSSION...MCMINN/MENSCH
AVIATION...MCMINN/MENSCH
MARINE...MCMINN/MENSCH
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