318
FXUS61 KBOX 290849
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
349 AM EST THU JAN 29 2026
WHAT HAS CHANGED
COLD WEATHER ADVISORIES ISSUED FOR THE RISK OF DANGEROUS WIND
CHILLS TONIGHT INTO FRIDAY MORNING. THOSE MAY NEED TO BE
EXTENDED INTO FRIDAY NIGHT AND SATURDAY MORNING. THERE IS A
GROWING POTENTIAL FOR ACCUMULATING SNOW, GUSTY WINDS AND COASTAL
FLOODING FOR EASTERN AND SOUTHEAST NEW ENGLAND SUNDAY AND SUNDAY
NIGHT, ALTHOUGH THERE IS STILL UNCERTAINTY IN THE SPECIFIC
DETAILS.
KEY MESSAGES
- STRONGER SHOT OF ARCTIC AIR PRODUCES DANGEROUS COLD/LOW WIND
CHILLS TONIGHT INTO FRIDAY MORNING, POSSIBLY INTO FRIDAY NIGHT
TO EARLY SATURDAY AS WELL. SIGNIFICANT ACCRETION OF FREEZING
SPRAY IS ALSO EXPECTED FOR VESSELS NAVIGATING THE WATERS.
- WHILE DETAILS ARE STILL UNCERTAIN, THERE IS A GROWING
POTENTIAL FOR A COASTAL STORM TO BRING ACCUMULATING SNOW AND
GUSTY WINDS TO EASTERN AND SOUTHEASTERN NEW ENGLAND SUNDAY AND
SUNDAY NIGHT, TO GO ALONG WITH THE POTENTIAL FOR COASTAL
FLOODING FOR THE SUNDAY MORNING/EVENING HIGH TIDES.
DISCUSSION
KEY MESSAGE 1...STRONGER SHOT OF ARCTIC AIR PRODUCES DANGEROUS
COLD/LOW WIND CHILLS TONIGHT INTO FRIDAY MORNING, POSSIBLY INTO
FRIDAY NIGHT TO EARLY SATURDAY AS WELL. SIGNIFICANT ACCRETION OF
FREEZING SPRAY IS ALSO EXPECTED FOR VESSELS NAVIGATING THE WATERS.
MUCH BELOW NORMAL TEMPERATURES CONTINUE THROUGH THE WORKWEEK INTO
THIS WEEKEND, TO GO ALONG WITH DRY WEATHER, BEING GOVERNED BY AN
ACTIVE NORTHERN STREAM AND SUSTAINED WNW MIDLEVEL FLOW. HOWEVER
STARTING LATER THIS AFTERNOON, A SHOT OF EVEN STRONGER ARCTIC AIR
BUILDS INTO SOUTHERN NEW ENGLAND. 850 MB TEMPS DROP TO A FRIGID -20
TO -22C THROUGH TONIGHT, WHICH MODIFIES ONLY VERY SLIGHTLY INTO FRI.
THE COMBINATION OF THIS LEVEL OF LOW-LEVEL COLD AIR WITH THE
EXISTING SNOWPACK SHOULD FAVOR WIDESPREAD SUB-ZERO AIR TEMPERATURES
AT LEAST TONIGHT BUT POTENTIALLY INTO FRIDAY EVENING/EARLY SATURDAY
AS WELL. WNW WINDS AROUND 15 TO 20 MPH PICKING UP TONIGHT GIVEN
THESE AIR TEMPS WILL LEAD TO DANGEROUS COLD AND LOW WIND CHILLS.
AFTER COORDINATION, WE'VE HOISTED COLD WEATHER ADVISORIES FOR MUCH
OF SOUTHERN NEW ENGLAND EXCEPT FOR THE CAPE AND ISLANDS STARTING
TONIGHT THROUGH 11 AM FRIDAY MORNING. CERTAINLY THE NAME OF THE
HEADLINE MIGHT LEAD ONE TO UNDERSELL THE RISK AS WE HAVE COLD
WEATHER 5 MONTHS OUT OF THE YEAR, SO A REMINDER THIS HEADLINE IS
MEANT TO ADDRESS DANGEROUS COLD LEADING TO FROSTBITE GIVEN PROLONGED
EXPOSURE. THE LOWEST WIND CHILLS LOOK TO BE IN THE HIGHER TERRAIN
WITH VALUES IN THE 20 TO 25 BELOW ZERO RANGE; THOUGH IT IS MORE
MARGINAL IN THE LOWER ELEVATIONS WITH VALUES IN THE 15 TO 20 BELOW
RANGE, IT JUST MADE MORE SENSE FROM A MESSAGING STANDPOINT TO EXPAND
THE HEADLINE INTO MOST OF THE REST OF SOUTHERN NEW ENGLAND. FOR THE
CAPE AND ISLANDS, VALUES AROUND 5 TO 10 BELOW ZERO LOOK MORE LIKELY
AND FELT WAS TOO MARGINAL FOR THOSE LOCATIONS. THE LOWEST OF THE
WINDCHILLS SHOULD BE TAKING PLACE JUST BEFORE SUNRISE, BUT WILL SET
THE STAGE FOR A FRIGID FRIDAY WITH HIGHS ONLY IN THE SINGLE DIGITS
TO MID TEENS. REGARDLESS, DRESS IN LAYERS AND LIMIT TIME OUTDOORS,
AND ALSO CHECK IN ON THE ELDERLY AND PETS TO ENSURE THEY ARE
PREPARED FOR THIS COLD. ADDITIONAL COLD WEATHER ADVISORIES COULD BE
NEEDED FOR FRIDAY NIGHT INTO SATURDAY MORNING, BUT THE POTENTIAL FOR
SOME CLOUD COVER WORKING SOUTHWARD FROM NORTHERN NEW ENGLAND AND
LIGHTER WINDS CAST UNCERTAINTY.
THIS ARCTIC AIR COULD ALSO LEAD TO SUBSTANTIAL ACCRETION OF ICING ON
VESSELS OVER THE WATERS; HEAVY FREEZING SPRAY WARNINGS AND FREEZING
SPRAY ADVISORIES HAVE ALSO BEEN ISSUED FOR THE WATERS.
KEY MESSAGE 2...WHILE DETAILS ARE STILL UNCERTAIN, THERE IS A
GROWING POTENTIAL FOR A WINTER STORM TO BRING ACCUMULATING SNOW
AND GUSTY WINDS TO EASTERN AND SOUTHEASTERN NEW ENGLAND SUNDAY
AND SUNDAY NIGHT, TO GO ALONG WITH THE POTENTIAL FOR COASTAL
FLOODING FOR THE SUNDAY MORNING/EVENING HIGH TIDES.
CONTINUING TO MONITOR LATEST DEVELOPMENTS REGARDING A SIGNIFICANT
COASTAL STORM WHICH COULD AFFECT SOUTHERN NEW ENGLAND SUNDAY. THERE
IS A GROWING POTENTIAL FOR ACCUMULATING SNOW AND GUSTY WINDS FOR
CAPE COD, THE ISLANDS AND PERHAPS FURTHER WESTWARD INTO SOUTH SHORE
AND THE I-95 CORRIDOR. WHILE INTERIOR SOUTHERN NEW ENGLAND SEEMS
LESS LIKELY FOR SIGNIFICANT IMPACTS, BY NO MEANS CAN THEY BE RULED
OUT OF THE WOODS.
ENSEMBLE MEANS AND THEIR INDIVIDUAL MEMBERS ARE SHOWING INCREASING
CONSENSUS AND ENSEMBLE-MEMBER-CLUSTERING TOWARD A RAPIDLY-
STRENGTHENING INITIAL COASTAL LOW PRESSURE JUST OFFSHORE THE
NC/SC COASTLINE SATURDAY, IN VICINITY OF THE GULFSTREAM OCEAN
CURRENT. THAT MUCH HAS BECOME MORE CLEAR. BY SATURDAY
NIGHT/EARLY SUNDAY, AS THE PRIMARY CYCLONE PULLS AWAY WELL EAST
OF CAPE HATTERAS, ECMWF EPS/GEM GEPS/GEFS ENSEMBLE MEAN SEA
LEVEL PRESSURE FIELD THEN BECOMES RATHER LARGE, WITH SOME
BAGGINESS IN THE ENSEMBLE MEAN ISOBARS ORIENTED TO THE NORTHEAST
OF THE MAIN LOW CENTER. WHAT HAS BECOME A TREND ACROSS THE
DETERMINISTIC MODEL SUITE, AND IS PROBABLY THE CAUSE OF THE
BAGGINESS TO THE ISOBARS IN THE ENSEMBLES, IS THE DEVELOPMENT OF
SECONDARY (SPURIOUS?) LOWS EAST OF THE MAIN CYCLONE'S CENTER AS
IT STARTS TO PULL AWAY FROM THE NC OUTER BANKS. PERHAPS THIS IS
DUE TO CONVECTIVE FEEDBACK ISSUES GIVEN THE STRONG AIR-SEA
BAROCLINIC SETTING - HARD TO REALLY KNOW. WHY IS THIS EVEN
IMPORTANT? THE MODELS HANDLE THIS VERY COMPLICATED INTERACTION,
MOVING FORWARD IN TIME, IN VARIED WAYS. THIS RANGES FROM A
CONSOLIDATION OF LOWS AS IT NEARS OR PASSES SOUTH OF 40N/70W,
WHICH IS REALLY A BEST- CASE SCENARIO FOR US, AS THE SYSTEM'S
PRECIP SHIELD WOULD PASS FAR ENOUGH SE FOR A MORE GLANCING BLOW
TO CAPE COD, THE ISLANDS AND PERHAPS SOUTH SHORE. ON THE OTHER
HAND, MODELS LIKE YESTERDAY'S ECMWF SHOW THE POTENTIAL FOR ONE
OF THESE LOWS TO, FOR LACK OF A BETTER TERM, "SLINGSHOT"
NORTH/NORTHWEST TOWARD OUR FAR EASTERN COASTLINE LATER SUNDAY
INTO SUNDAY NIGHT. THAT SOLUTION WOULD BE THE WORST OF ALL
POSSIBLE OUTCOMES, WHICH WOULD SPREAD A LARGER PRECIP SHIELD
MUCH FURTHER WESTWARD THAN JUST THE EASTERN SNE COAST, GENERATE
A PERIOD OF STRONG TO POTENTIALLY DAMAGING NE/N WIND GUSTS,
WHILE ALSO SIGNIFICANTLY ELEVATING THE RISK FOR COASTAL
FLOODING. IT IS STILL TOO EARLY TO SAY WHICH ONE OF THOSE
POSSIBLE SOLUTIONS, OR SOMETHING IN BETWEEN, IS MORE LIKELY.
WE'RE NOW FOUR DAYS FROM A POSSIBLE IMPACT, AND WITH STILL
QUITE A BIT OF UNCERTAINTY AND WAFFLING/WOBBLING IN THE MODELS,
WILL TAKE A MORE PROBABILISTIC APPROACH WHEN IT COMES TO
DELINEATING POSSIBLE HAZARDS. THE RISK FOR ACCUMULATING
SNOWFALL, POTENTIALLY SIGNIFICANT, IS INCREASING FOR THE CAPE
AND ISLANDS AND SOUTHEAST NEW ENGLAND. NBM 5.0 24-HR PROBS OF
EXCEEDING SNOWFALL OF 6 OR MORE INCHES ARE NOW IN THE MODERATE
TO HIGH (50-65%) RANGE FOR THE CAPE AND ISLANDS; VALUES THEN
TAPER TO LOWER TO MODERATE (35-50%) RANGE FOR THE BOSTON-
PROVIDENCE I-95 CORRIDOR EASTWARD TOWARD SOUTH SHORE AND SOUTH
COAST, WITH LOW (20% OR LESS) FROM THE NORTH SHORE WESTWARD
THROUGH THE REMAINDER OF SNE. THE 24-HR NBM 5.0 PROBS OF A FOOT
OR MORE OF SNOW ARE IN THE 40-50% RANGE FOR THE THE CAPE AND
ISLANDS, AND ARE AROUND 25-35% FOR SOUTH SHORE. THE
PROBABILISTIC WINTER STORM SEVERITY INDEX NOW SHOWS HIGH
(50-70%) PROBS OF MODERATE WINTER STORM IMPACTS SOUTH AND EAST
OF I-95. AFTER A COORDINATION CALL WITH WPC, WE AGREED TO WAIT
ANOTHER MODEL CYCLE OR TWO BEFORE WINTER STORM WATCHES ARE
CONSIDERED TO GET A BETTER HANDLE ON THE WESTWARD EXTENT OF THE
PRECIP SHIELD.
HOW CLOSE ANY DEEPENING LOW PRESSURE GETS TO OUR EASTERN COAST
WILL ALSO DETERMINE HOW STRONG NE TO N WINDS DEVELOP, AS WELL AS
COASTAL FLOODING GIVEN THAT THERE IS A FULL MOON THIS WEEKEND.
STEVENS INSTITUTE GUIDANCE SUGGESTS A 1.5 TO 2.5 FT STORM SURGE
WITH WAVE ACTION, WITH THE MAIN RISK BEING FOR EASTERN MA GIVEN
NE TO N WIND TRAJECTORIES - BOSTON, SOUTH SHORE, CAPE COD,
NANTUCKET. THAT GUIDANCE OFFERS WIDESPREAD MINOR TO MODERATE
COASTAL FLOODING FOR BOTH THE SUNDAY MORNING AND SUNDAY EVENING
HIGH TIDES. AS WITH ANY COASTAL FLOOD FORECAST, TIMING OF THE
PEAK SURGE WITH HIGH TIDE WILL BE CRITICAL, AS WILL THE EFFECT
OF WAVE RUN-UP/WAVE ACTION. BEACH EROSION ALSO COULD BE POSSIBLE
GIVEN 20+ FT WAVES OFFSHORE.
THE BOTTOM LINE IS THAT WHILE THERE IS STILL QUITE A BIT OF
UNCERTAINTY IN HOW FAR WEST WOULD THE SNOW SHIELD ADVANCE
SUNDAY/SUNDAY NIGHT, THE CHANCES FOR SIGNIFICANT ACCUMLATING
SNOW AND GUSTY WINDS ARE ON THE INCREASE FOR EASTERN AND
SOUTHEAST NEW ENGLAND.
AVIATION /08Z THURSDAY THROUGH MONDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAFS: HIGH CONFIDENCE.
VFR. LIGHT WNW WINDS AT 5-10 KNOTS TONIGHT AND THURSDAY.
INCREASING WEST WINDS THURSDAY NIGHT WITH LLWS POSSIBLE IN THE
EVENING.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
VFR. LIGHT WNW WINDS AROUND 10 KNOTS THROUGH THURSDAY
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
VFR. LIGHT WNW WINDS THROUGH THURSDAY. COULD BE SOME LLWS
TOWARDS THURSDAY EVENING AS WINDS ALOFT INCREASE FASTER THEN
SURFACE WINDS.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT.
FRIDAY NIGHT: VFR. BREEZY.
SATURDAY: VFR.
SATURDAY NIGHT: VFR. STRONG WINDS WITH LOCAL GUSTS UP TO 40 KT.
SLIGHT CHANCE SN.
SUNDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. STRONG WINDS WITH
GUSTS UP TO 55 KT. CHANCE SN.
SUNDAY NIGHT: VFR. STRONG WINDS WITH GUSTS UP TO 60 KT. CHANCE
SN.
MONDAY: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
NW WINDS TODAY AT 15-20 KNOTS INCREASING TO 25-30 KNOTS TONIGHT.
SEAS INCREASE TO 5-6 FEET AGAIN TONIGHT WITH THE HIGHER WINDS.
LIGHT TO MODERATE FREEZING SPRAY LIKELY TODAY ESSPICALLY
BETWEEN MVY AND ACK. MODERATE TO HEAVY FREEZING SPRAY EXPECTED
TONIGHT AND LASTING INTO FRIDAY EVENING. BEST CHANCE FOR HEAVY
FREEZING SPRAY IS IN THE MVY AND ACK SOUNDS.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 30 KT. LOCAL ROUGH SEAS. FREEZING SPRAY, SLIGHT CHANCE OF
FREEZING RAIN.
FRIDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. AREAS OF SEAS APPROACHING 5 FT. FREEZING
SPRAY LIKELY.
SATURDAY: WINDS LESS THAN 25 KT.
SATURDAY NIGHT: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO
45 KT. LOCAL ROUGH SEAS. FREEZING SPRAY, CHANCE OF SNOW. LOCAL
VISIBILITY 1 NM OR LESS.
SUNDAY: MODERATE RISK FOR STORM FORCE WINDS WITH GUSTS UP TO
60 KT. ROUGH SEAS UP TO 22 FT. SNOW LIKELY, FREEZING SPRAY.
VISIBILITY 1 NM OR LESS.
SUNDAY NIGHT: GALE FORCE WINDS WITH GUSTS UP TO 45 KT. ROUGH
SEAS UP TO 24 FT. FREEZING SPRAY, CHANCE OF SNOW. AREAS OF
VISIBILITY 1 NM OR LESS.
MONDAY: LOW RISK FOR GALE FORCE WINDS WITH GUSTS UP TO 35 KT.
ROUGH SEAS UP TO 21 FT. FREEZING SPRAY.
BOX WATCHES/WARNINGS/ADVISORIES
CT...COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
FRIDAY FOR CTZ002>004.
MA...COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
FRIDAY FOR MAZ002>021-026.
RI...COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
FRIDAY FOR RIZ001>004-006-007.
MARINE...FREEZING SPRAY ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST
FRIDAY FOR ANZ231-235>237-250-251-254-256.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST
FRIDAY FOR ANZ231-251.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 PM EST FRIDAY
FOR ANZ232>235-237.
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 PM
EST FRIDAY FOR ANZ232>234-255.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST FRIDAY
FOR ANZ250-254.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST
SATURDAY FOR ANZ255-256.
DISCUSSION...LOCONTO
AVIATION...LOCONTO/KP
MARINE...LOCONTO/KP
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