348
FXUS61 KBOX 310506
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1206 AM EST SAT JAN 31 2026
WHAT HAS CHANGED
- COLD WEATHER ADVISORIES HAVE BEEN EXTENDED INTO FRIDAY NIGHT
AND SATURDAY MORNING FOR HAZARDOUS WIND CHILLS.
- A WINTER STORM WATCH CONTINUES FOR CAPE COD AND THE ISLANDS,
WITH THE RISK OF ACCUMULATING SNOW AND STRONG WINDS SUNDAY
CONFINED TO THIS AREA, FROM A POWERFUL OFFSHORE WINTER STORM.
- THE POTENTIAL FOR WIDESPREAD MODERATE COASTAL FLOODING
HAS DECREASED DUE TO A MORE OFFSHORE STORM TRACK.
- GALE WARNINGS HAVE BEEN ISSUED FOR THE NEARSHORE WATERS
INCLUDING BOSTON HARBOR AND NARRAGANSETT BAY.
- DRY, CHILLY START TO NEXT WEEK WITH CHANCES FOR ANOTHER ROUND
OR TWO OF SNOW IN THE SECOND HALF OF THE WEEK.
KEY MESSAGES
- FRIGID TEMPERATURES TONIGHT INTO SATURDAY MORNING.
- A POWERFUL OCEAN STORM LOOKS MORE LIKELY TO PASS FARTHER
OFFSHORE OF SOUTHERN NEW ENGLAND SUNDAY INTO SUNDAY NIGHT.
GREATEST OVERALL IMPACTS FROM ACCUMULATING SNOW AND STRONG
WINDS WILL BE ACROSS SOUTHEAST COASTAL PLYMOUTH COUNTY, CAPE
COD AND THE ISLANDS SUNDAY AND SUNDAY NIGHT. MUCH LIGHTER
ACCUMULATING SNOW WITH LESSER OVERALL IMPACT FURTHER INLAND
INTO SOUTHEAST MA, WITH LITTLE IF ANY IMPACT INTO THE BOSTON-
PROVIDENCE CORRIDOR SUNDAY.
- MINOR TO PERHAPS MODERATE COASTAL FLOODING SUNDAY INTO MONDAY
ALONG THE EASTERN MASSACHUSETTS COAST.
- DRY, CHILLY START TO NEXT WEEK WITH CHANCES FOR ANOTHER ROUND
OR TWO OF SNOW IN THE SECOND HALF OF THE WEEK.
DISCUSSION
KEY MESSAGE 1...FRIGID TEMPERATURES ONCE AGAIN TONIGHT INTO
SATURDAY MORNING.
COLD WEATHER ADVISORIES HAVE BEEN EXTENDED INTO TONIGHT AND
SATURDAY MORNING, WITH ACTUAL AIR TEMPS FALLING TO ZERO TO MINUS
10 ACROSS THE REGION! THESE TEMPS WERE DERIVED FROM THE NBM AND
THE COLDER MOS GUIDANCE, GIVEN LIGHT WINDS TONIGHT. HOWEVER, A
SUFFICIENT LIGHT WNW BREEZE AT 5-10 MPH TO GENERATE COLDER WIND
CHILLS FROM MINUS 10 TO MINUS 15, WHICH MEETS OUR EXTREME COLD
ADVISORY CRITERIA. HENCE, WE EXTENDED THE COLD WEATHER ADVISORY
INTO TONIGHT/EARLY SAT MORNING FOR MOST OF RI/MA/CT. WE EXCLUDED
THE SOUTH COAST AS WIND CHILLS THERE ARE MORE IN THE ZERO TO
MINUS 5 RANGE. STILL VERY COLD, BUT SHY OF CRITERIA.
NONETHELESS, DANGEROUS COLD FOR ANYONE OUTDOORS TONIGHT/EARLY
SATURDAY.
KEY MESSAGE 2...12Z MODELS CONTINUE THE TREND FROM THE
OVERNIGHT GUIDANCE, TRACKING A POWERFUL VERTICALLY STACKED LOW
(SUB 970 MB) A FAIRLY GOOD DISTANCE SOUTHEAST OF THE 40N/70W
BENCHMARK. HOWEVER, GIVEN ITS VERY LARGE CIRCULATION AND PRECIP
SHIELD, COMBINED WITH OCEAN EFFECT SNOW (OES) BANDS, ALONG WITH
POSSIBLE 850-700 MB FGEN SNOW BANDS CLIPPING THE CAPE AND
ISLANDS, WE DECIDED TO HOLD WITH THE WINTER STORM WATCH FOR THIS
REGION. SUFFICIENT GUIDANCE SUPPORTING 0.3 TO 0.6 INCHES OF QPF
OVER THIS AREA, WHICH INCLUDES THE 3KM NAM, CANADIAN, ICON, AI
MODELS AND SOME ENSEMBLE MEMBERS. THEREFORE THIS SUPPORTS A RISK
OF 4-7" ACROSS THE CAPE AND ISLANDS, WITH HIGHEST TOTALS OVER
ACK AND THE OUTER CAPE GIVEN OES ENHANCEMENT. AS WE KNOW,
NORTHWEST OF THE MID LEVEL FGEN BANDS, THERE IS STRONG
SUBSIDENCE. THUS, A SHARP CUTOFF IN ACCUMULATING SNOW NORTHWEST
OF THE CAPE COD CANAL. HENCE, WE LOWERED SNOW TOTALS OVER
SOUTHEAST MA TO 1-2", UP TO 3" SOUTHEAST COASTAL PLYMOUTH COUNTY
GIVE OES. THEN AN INCH OR LESS IN THE BOSTON-PROVIDENCE
CORRIDOR, WITH A SHUTOUT WESTWARD INTO CT/WESTERN-CENTRAL MA.
SNOW WILL ADVANCE SOUTH TO NORTH EARLY SUNDAY MORNING AND
CONTINUING THROUGH THE DAY AND INTO SUNDAY NIGHT.
REGARDING WINDS, DESPITE THE LOW TRACKING WELL SOUTHEAST OF THE
40N/70W BENCHMARK, THE SUB 970 MB LOW AND ITS LOW LEVEL NNE JET
WILL SCRAP CAPE COD AND THE ISLANDS WITH 50-55 KT AT 925 MB
SUNDAY AFTERNOON. MODEL SOUNDINGS INDICATE NNE WINDS GUSTING UP
TO 45 KT/50 MPH ARE POSSIBLE ACROSS THE CAPE AND ISLANDS, WITH
LESS WIND NORTHWEST OF THE CANAL, WITH DIMINISHING WIND FIELD
ALOFT COMBINED WITH A MORE NORTHERLY WIND TRAJECTORY THERE.
THESE WIND SPEEDS ARE COVERED IN THE WINTER STORM WATCH.
KEY MESSAGE 3...MINOR TO PERHAPS MODERATE COASTAL FLOODING
SUNDAY INTO MONDAY ALONG THE EASTERN MASSACHUSETTS COAST.
THE POTENTIAL FOR MODERATE COASTAL FLOODING CONTINUES TO
DECREASE AS GUIDANCE CONTINUES TO TAKE THIS SYSTEM FURTHUR
OFFSHORE, BUT AREAS OF MODERATE FLOODING SHOULD BE LIMITED TO
LOCATIONS SOUTH OF BOSTON, ESPECIALLY ON CAPE COD (BAY SIDE),
MARTHA'S VINEYARD, AND NANTUCKET, AND IS MORE LIKELY DURING THE
SUNDAY EVENING AND MIDDAY MONDAY HIGH TIDES.
ENSEMBLE GUIDANCE STILL SHOWS LARGE RANGES IN POSSIBLE WATER
LEVELS FOR NANTUCKET AND DENNIS, WHICH IS TIED TO UNCERTAINTY IN
STORM TRACK AND TIMING OF THE HIGHEST SURGE. FARTHER NORTH,
THESE FORECAST RANGES ARE MUCH SMALLER WHICH INDICATES HIGHER
CONFIDENCE IN MINOR FLOODING IMPACTS FROM BOSTON TO THE
MERRIMACK RIVER.
SINCE WE STILL HAVE A GOOD AMOUNT OF UNCERTAINTY, WE DECIDED TO
MAINTAIN THE COASTAL FLOOD WATCH. IF THE STORM TRENDS EVEN
FARTHER OFFSHORE, WATER LEVELS AND IMPACTS WOULD BE LOWER THAN
CURRENTLY FORECAST, AND WOULD LIKELY RESULT IN MINOR IMPACTS FOR
MUCH OF THE COASTLINE. ADDITIONALLY, THE TIMING OF THE HIGHEST
SURGE APPEARS TO BE NEAR LOW TIDE SUNDAY AFTERNOON, BUT IF IT IS
DELAYED (OR ARRIVES SOONER) IT WOULD COINCIDE CLOSER TO HIGH
TIDE AND WOULD LEAD TO HIGHER WATER LEVELS AND GREATER IMPACTS,
ALTHOUGH A REASONABLE HIGH- END SCENARIO WOULD STILL BE WITHIN
THE MODERATE FLOOD CATEGORY.
AS A REMINDER:
MINOR FLOODING REFERS TO SHALLOW FLOODING UP TO 1 FOOT DEEP AND
CAN RESULT IN TEMPORARY ROAD CLOSURES ON MORE VULNERABLE
COASTAL ROADS.
MODERATE FLOODING REFERS TO FLOODING 1 TO 3 FEET DEEP AND CAN
CAUSE MORE WIDESPREAD ROAD CLOSURES, DAMAGE TO SHOREFRONT
PROPERTY, AND DEBRIS ON COASTAL ROADS FROM LARGE WAVES. VEHICLES
LEFT IN FLOOD PRONE AREAS CAN ALSO BE FLOODED.
KEY MESSAGE 4...DRY, CHILLY START TO NEXT WEEK WITH CHANCES FOR
ANOTHER ROUND OR TWO OF SNOW IN THE SECOND HALF OF THE WEEK.
AS THIS WEEKEND'S STORM WRAPS UP SUNDAY NIGHT AND MOVES OUT
MONDAY, HIGH PRESSURE BEGINS TO BUILD IN OVER THE GREAT LAKES
AND SOUTHERN ONTARIO. THIS WILL BRING A DRYING OUT PERIOD TO
SOUTHERN NEW ENGLAND FOR THE START OF NEXT WEEK ALONG WITH
EASING WINDS AS THE PRESSURE GRADIENT RELAXES. AFTERNOON HIGHS
MONDAY AND TUESDAY ARE LIKELY TO HOVER RIGHT AROUND 32F,
ALLOWING FOR A LITTLE BIT OF MELTING OF SNOW. HOWEVER, GIVEN THE
CLEAR SKIES AND LIGHT WINDS, TEMPERATURES PLUMMET OVERNIGHT AND
RANGE FROM SINGLE DIGITS TO MID TEENS ACROSS SOUTHERN NEW
ENGLAND, REFREEZING ANY SNOWMELT AND CREATING SLICK SPOTS ON
UNTREATED SURFACES.
LEADING INTO THE SECOND HALF OF NEXT WEEK, WE'RE STARTING TO
KEEP AN EYE ON A COUPLE OF SYSTEMS WITH POSSIBLE IMPACTS TO
SOUTHERN NEW ENGLAND. THE FIRST IS A COASTAL LOW DEVELOPING
SOMEWHERE OFF THE COAST OF NC/SC AND MOVING NORTHEAST, POSSIBLY
BRINGING A QUICK ROUND OF SNOW SHOWERS TO THE REGION
THURSDAY/FRIDAY. THE SECOND IS A LOW SWEEPING OUT OF THE
CANADIAN ROCKIES AND ACROSS THE GREAT LAKES LATE FRIDAY INTO
SATURDAY, POSSIBLY BRINGING GUSTY WINDS, COLDER TEMPERATURES,
AND ANOTHER ROUND OF SNOW. MODEL GUIDANCE SHOWS A LARGE AMOUNT
OF UNCERTAINTY GIVEN THESE EVENTS ARE STILL 6-7 DAYS AWAY, BUT
SOMETHING TO BE AWARE OF OVER THE NEXT WEEK OR SO.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z UPDATE...
THROUGH SATURDAY...HIGH CONFIDENCE.
VFR. LIGHT WNW WINDS UNDER 10 KNOTS TODAY
SATURDAY NIGHT...MODERATE CONFIDENCE.
VFR AND DRY WEATHER, BUT MVFR/VFR CIGS ARRIVE TOWARD MORNING IN
EASTERN MA.
SUNDAY/SUN NIGHT...MODERATE CONFIDENCE.
PERIODS OF LIGHT SNOW/FLURRIES THIS PERIOD WITH A COMBINATION
OF MVFR/VFR CONDITIONS. NORTH WINDS 15-25 KT SUNDAY, BECOME NNW
SUN NIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF THRU SATURDAY.
LIGHT WNW WINDS TODAY AROUND 10 KNOTS
KBDL TERMINAL...HIGH CONFIDENCE IN TAF THROUGH SATURDAY.
VFR. LIGHT WNW WINDS TODAY UNDER 10 KNOTS.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. STRONG WINDS WITH
GUSTS UP TO 45 KT. CHANCE SN.
SUNDAY NIGHT: VFR. STRONG WINDS WITH AREAS OF GUSTS UP TO
45 KT. SLIGHT CHANCE SN.
MONDAY THROUGH MONDAY NIGHT: VFR. BREEZY.
TUESDAY THROUGH TUESDAY NIGHT: VFR.
WEDNESDAY: VFR. SLIGHT CHANCE SN.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
DIMINISHING WINDS AND SEAS TODAY AS HIGH PRESSURE BUILDS IN.
A POWERFUL OCEAN STORM WHICH TRACKS WELL SOUTH AND EAST OF THE
WATERS ON SUNDAY. POTENTIAL FOR HIGH END GALES TO LOW END STORM
FORCE NE GUSTS TO 40-50 KT OVER THE WATERS STARTING SUNDAY
MORNING. SEAS EXPECTED TO BUILD TO 15-20 FT ON THE WATERS EAST
OF CAPE COD RESULTING IN DANGEROUS CONDITIONS FOR MARINERS. IN
ADDITIONS, AREAS OF LIGHT TO MODERATE FREEZING SPRAY WILL
DEVELOP SAT NIGHT/SUN MORNING AND AGAIN SUN NIGHT.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
MONDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 30 KT. ROUGH SEAS UP TO 16 FT. FREEZING SPRAY LIKELY.
MONDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS.
TUESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
WEDNESDAY: WINDS LESS THAN 25 KT. SLIGHT CHANCE OF SNOW.
BOX WATCHES/WARNINGS/ADVISORIES
CT...COLD WEATHER ADVISORY UNTIL 10 AM EST SATURDAY FOR CTZ002>004.
MA...COLD WEATHER ADVISORY UNTIL 10 AM EST SATURDAY FOR MAZ002>019-
026.
COASTAL FLOOD WATCH FROM SUNDAY MORNING THROUGH MONDAY
AFTERNOON FOR MAZ007-015-016-019-022>024.
WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 4 AM EST MONDAY
FOR MAZ019-022>024.
RI...COLD WEATHER ADVISORY UNTIL 10 AM EST SATURDAY FOR RIZ001>004.
MARINE...GALE WARNING FROM 7 AM SUNDAY TO 1 AM EST MONDAY FOR ANZ230.
FREEZING SPRAY ADVISORY UNTIL 1 AM EST SATURDAY FOR ANZ231-235-
237-250-251-254-256.
GALE WARNING FROM 4 AM SUNDAY TO 4 AM EST MONDAY FOR ANZ231-
232.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST SATURDAY FOR
ANZ232>234-255.
FREEZING SPRAY ADVISORY FROM 4 AM TO 1 PM EST SUNDAY FOR
ANZ233>237-251-256.
GALE WARNING FROM 6 AM SUNDAY TO 1 AM EST MONDAY FOR ANZ233-
234.
GALE WARNING FROM 3 AM SUNDAY TO 1 AM EST MONDAY FOR ANZ235-
237.
GALE WARNING FROM 5 AM TO 11 PM EST SUNDAY FOR ANZ236.
SMALL CRAFT ADVISORY UNTIL 1 AM EST SATURDAY FOR ANZ250-
254>256.
GALE WARNING FROM 7 AM SUNDAY TO 4 AM EST MONDAY FOR ANZ250.
GALE WARNING FROM 6 AM SUNDAY TO 4 AM EST MONDAY FOR ANZ251.
STORM WARNING FROM 7 AM SUNDAY TO 4 AM EST MONDAY FOR ANZ254-
255.
GALE WARNING FROM 4 AM SUNDAY TO 1 AM EST MONDAY FOR ANZ256.
DISCUSSION...MCMINN/KP/JWD/NOCERA
AVIATION...KP
MARINE...KP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page