274
FXUS61 KBOX 061110
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
710 AM EDT MON JUL 6 2026
WHAT HAS CHANGED
THE FLOOD WATCH HAS BEEN EXPANDED ACROSS THE REST OF SOUTHEAST
MASSACHUSETTS INTO TUESDAY.
KEY MESSAGES
- PERIODS OF HEAVY RAIN & POSSIBLY A FEW EMBEDDED T-STORMS TODAY
INTO TUE ACROSS PARTS OF CT/RI/SE MA. LOCALIZED FLASH FLOODING
POSSIBLE DEPENDENT ON IF THE HEAVIEST BANDS SETUP IN OUR REGION.
OTHERWISE...RAIN OVERSPREADS THE REST OF THE REGION THROUGH TONIGHT
BUT AMOUNTS WILL BE LIGHTER ESPECIALLY NEAR THE NH BORDER.
- SUMMER WARMTH & HUMIDITY RETURN FOR THE LATTER HALF OF THE
WEEK. MAINLY DRY WEATHER RETURNS WED INTO THU...BUT THE RISK
FOR A FEW SHOWERS & T-STORMS MAY RETURN BY FRI PERHAPS
LINGERING INTO SAT.
DISCUSSION
KEY MESSAGE 1...PERIODS OF HEAVY RAIN & POSSIBLY A FEW EMBEDDED
T-STORMS TODAY INTO TUE ACROSS PARTS OF CT/RI/SE MA. LOCALIZED
FLASH FLOODING POSSIBLE DEPENDENT ON IF THE HEAVIEST BANDS SETUP
IN OUR REGION. OTHERWISE...RAIN OVERSPREADS THE REST OF THE REGION
THROUGH TONIGHT BUT AMOUNTS WILL BE LIGHTER ESPECIALLY NEAR THE NH
BORDER.
THE MAIN FORECAST CONCERN IS THE POTENTIAL FOR LOCALIZED FLASH
FLOODING ACROSS PARTS OF CT/RI/SE MA INTO TUE. THIS REMAINS A VERY
DIFFICULT FORECAST AS THE NARROW BANDS OF POTENTIALLY EXTREMELY
HEAVY RAIN ARE QUITE DIFFICULT TO FORECAST IN TERMS OF TIMING AND
LOCATIONS. HOWEVER...THE ENVIRONMENT IN PLACE DOES FAVOR THE
POTENTIAL FOR THEM TO FORM. WE WILL DISCUSS THIS IN MORE DETAIL
BELOW.
THE ENVIRONMENT IN PLACE IS FAVORABLE FOR THE POTENTIAL OF LOCALIZED
FLASH FLOODING. WEAK HIGH PRESSURE ACROSS EASTERN CANADA WAS
ENFORCING A SHALLOW BOUNDARY IN THE VICINITY OF CT/NY/NJ. THIS
BOUNDARY WAS BEING IMPINGED UPON BY A MODEST SOUTHEAST LLJ COUPLED
WITH A PWAT PLUME OF 1.5 TO 2.0+ INCHES. THE IDEA THOUGH IS THAT YOU
ARE COMBINING WINTER-LIKE SYNOPTIC FEATURES WITH SUMMERTIME MOISTURE
PARAMETERS. THAT COMBINATION CAN LEAD TO LOCALIZED EXTREME RAINFALL
EVENTS. THIS POTENTIAL IS INDICATED BY VARIOUS MODEL SUITES PRINTING
OUT NARROW BANDS OF VERY HIGH QPF. THE ISSUE IS THAT THESE NARROW
BANDS OF POTENTIALLY EXTREME QPF ARE DEPICTED IN A LOT OF DIFFERENT
LOCATIONS DEPENDING ON WHAT MODEL YOU ARE LOOKING AT. THIS IS QUITE
COMMON IN THESE CASES THAT THE MODELS ARE GOOD AT INDICATING THE
POTENTIAL FOR A LOCALIZED TORRENTIAL RAIN EVENTS...BUT STRUGGLE TO
PIN THE LOCATION.
GIVEN THE ABOVE...WE HAVE EXPANDED THE FLOOD WATCH FROM CT/RI ACROSS
THE REST OF SOUTHEAST MA. WE ARE LOOKING AT WIDESPREAD RAINFALL
AMOUNTS OF 1-3"...BUT LOCALIZED 4-6" AMOUNTS WOULD BE POSSIBLE
WITHIN 6 HOURS IF ANY NARROW BANDS SETUP. NOT ALL THE MODELS SHOW
THESE NARROW BANDS DEVELOPING...BUT MANY OF THE CAMS DO AND IT IS
REASONABLE GIVEN THE PARAMETERS IN PLACE. IF THEY DO DEVELOP...SOME
CAMS FOCUS IT TO OUR SOUTH WHILE OTHER BRING IT INTO OUR REGION.
REGARDLESS...THE FLOOD WATCH IS CERTAINLY WARRANTED GIVE THE
POTENTIAL IF THESE BANDS ARE REALIZED.
ACROSS THE REST OF THE REGION...RAIN AMOUNTS WILL BE LIGHTER
ESPECIALLY TOWARDS THE NH BORDER. IN FACT...IT MAY TAKE UNTIL LATER
TONIGHT FOR THE STEADY RAIN TO FINALLY REACH NORTHEAST MA. PERIODS
OF RAIN WILL PERSIST INTO TUESDAY ESPECIALLY ACROSS EASTERN MA/RI AS
CLOSED 850 MB LOW MAY SETUP A MID LEVEL DEFORMATION ZONE.
KEY MESSAGE 2...SUMMER WARMTH & HUMIDITY RETURN FOR THE LATTER HALF
OF THE WEEK. MAINLY DRY WEATHER RETURNS WED INTO THU...BUT THE RISK
FOR A FEW SHOWERS & T-STORMS MAY RETURN BY FRI PERHAPS LINGERING
INTO SAT.
AS THE SHORTWAVE DEPARTS THE REGION...A MID LEVEL RIDGE AXIS BUILDS
OVER THE REGION WITH MAINLY DRY WEATHER RETURNING WED INTO AT LEAST
A GOOD PART OF THU. RISING HEIGHT FIELDS SHOULD ALLOW SUMMER-LIKE
WARMTH AND HUMIDITY TO RETURN. HIGHS MAY TAKE A RUN AT 90 IN SOME
SPOTS BY THU. THE NEXT SHORTWAVE TROUGH MAY BRING THE RISK FOR A FEW
SHOWERS AND THUNDERSTORMS RETURNING BY FRI WHICH MAY LINGER INTO
SAT. THIS WILL DEPEND ON THE TIMING OF THE SHORTWAVE/COLD FRONT.
AVIATION /12Z MONDAY THROUGH FRIDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE...
TODAY THROUGH TUESDAY...MODERATE CONFIDENCE.
VFR CONDITIONS EARLY THIS MORNING WILL GRADUALLY DETERIORATE TO MVFR
LEVELS TODAY INTO TONIGHT FROM SOUTHWEST TO NORTHEAST WITH BRIEF
BOUTS OF IFR CONDITIONS POSSIBLE TOO. THIS WILL BE ASSOCIATED WITH
PERIODS OF RAIN...WHICH MAY FALL HEAVY AT TIMES ACROSS PARTS OF
CT/RI/SE MA WHERE THERE MAY EVEN BE AN EMBEDDED T-STORM OR TWO. THE
PROCESS OF LOWER CIGS/VSBYS AND STEADY RAIN WILL BE SLOWEST TO
ARRIVE ACROSS NORTHEAST MA...WHERE IT MAY TAKE UNTIL THIS EVENING OR
EVEN LATER FOR MVFR CONDITIONS TO DEVELOP. PERIODS OF RAIN WILL
CONTINUE INTO TUE ESPECIALLY ACROSS EASTERN MA/RI. MVFR WITH
LOCALIZED IFR CONDITIONS WILL ALSO CONTINUE INTO TUE. E WINDS 6-12
KNOTS TODAY GRADUALLY BECOMING NE AT 8-16 KNOTS BY TUE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/...
TUESDAY NIGHT: MAINLY VFR, WITH AREAS IFR POSSIBLE. BREEZY.
SLIGHT CHANCE SHRA.
WEDNESDAY: VFR. BREEZY.
WEDNESDAY NIGHT: VFR.
THURSDAY THROUGH THURSDAY NIGHT: VFR. BREEZY.
FRIDAY: VFR. BREEZY. CHANCE SHRA, CHANCE TSRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY THROUGH TUESDAY...HIGH CONFIDENCE.
WEAK HIGH PRESSURE OVER EASTERN CANADA WILL COMBINED WITH LOW
PRESSURE TRACKING SOUTH OF THE WATERS. THE RESULT WILL BE E WIND
GUSTS OF 20 TO 30 KNOTS DEVELOPING FROM SOUTH TO NORTH TODAY INTO
TONIGHT AND CONTINUING INTO TUE SHIFTING TO MORE OF A NE DIRECTION.
THEREFORE...HAVE SMALL CRAFT HEADLINES FOR THE OPEN WATERS AND SEAS
BUILDING TO BETWEEN 3 AND 5 FEET.
OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/...
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE
OF RAIN SHOWERS.
WEDNESDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT.
WEDNESDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT.
THURSDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
THURSDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. SEAS UP TO 5 FT. SLIGHT CHANCE OF RAIN
SHOWERS.
FRIDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
SLIGHT CHANCE OF RAIN SHOWERS, SLIGHT CHANCE OF THUNDERSTORMS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR CTZ002>004.
MA...FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR MAZ017>022.
RI...FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR RIZ001>008.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 8 PM EDT TUESDAY FOR
ANZ231>234-250-251-254.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT
TUESDAY FOR ANZ235-237-255-256.
DISCUSSION...FRANK
AVIATION...FRANK/RM
MARINE...FRANK
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page