139
FXUS61 KBOX 190459
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1159 PM EST SUN JAN 18 2026
WHAT HAS CHANGED
DESPITE MARGINAL BOUNDARY LAYER TEMPERATURES, BANDS OF MODERATE
TO HEAVY SNOW HAVE DEVELOPED ACROSS MUCH OF SE MASSACHUSETTS
AND THE CAPE. SNOWFALL REPORTS IN THESE AREAS INDICATE THAT
AROUND 1-3 INCHES OF SNOW HAS ALREADY FALLEN WITH AN ADDITIONAL
2-4 INCHES POSSIBLE. HEAVIEST SNOW WILL CONTINUE THROUGH 06Z
BEFORE GRADUALLY TAPERING TOMORROW MORNING. AS A RESULT, HAVE
OPTED TO ADJUST SNOW TOTALS TO 4-6" WITH LOCALIZED AMOUNTS UP
TO 7 INCHES POSSIBLE.
KEY MESSAGES
- PLOWABLE SNOW TONIGHT WITH TOTAL ACCUMULATIONS OF 3-5" WITH
LOCALIZED 6" AMOUNTS POSSIBLE ACROSS EASTERN MA/RI. HEAVIEST
SNOW/WORST OF THE TRAVEL CONDITIONS BETWEEN 6 PM AND 2 AM.
SNOW ENDS FROM WEST TO EAST BETWEEN 3AM AND 9AM MONDAY.
- ARCTIC FRONT DELIVERS COLD CONDITIONS TUESDAY, WITH SOME
MODERATION WEDNESDAY AND THURSDAY. COLDER AGAIN NEXT WEEKEND.
- QUICK MOVING CLIPPER LATE WEDNESDAY INTO EARLY THURSDAY BRINGS
THE NEXT CHANCE FOR LIGHT PRECIPITATION.
DISCUSSION
KEY MESSAGE 1...PLOWABLE SNOW TODAY-TONIGHT WITH TOTAL ACCUMULATIONS
OF 2-6" WITH LOCALIZED 7" AMOUNTS POSSIBLE ACROSS EASTERN
MA/RI. HEAVIEST SNOW/WORST OF THE TRAVEL CONDITIONS BETWEEN 5 PM
AND 1 AM...BUT SNOW SHOWERS MAY LINGER FOR THE MON AM COMMUTE.
AN ELONGATED SHORTWAVE TROUGH STRETCHING FROM THE NORTHERN GREAT
LAKES DOWN INTO THE GULF COAST WILL SPIN UP A COASTAL LOW OFFSHORE,
PASSING JUST SOUTHEAST OF THE BENCHMARK THIS EVENING. GUIDANCE HELD
STEADY, WITH TOTAL QPF ACROSS THE REGION RANGING FROM 1/2 TO 3/4
INCHES, SOUTH AND EAST OF THE I-95 CORRIDOR, INCLUDING THE CAPE AND
ISLANDS. QPF TICKED UP A BIT NORTH AND WEST OF THE I-95 CORRIDOR ALL
THE WAY TO THE NORTHERN BERKSHIRES WITH 1/4 TO 1/2 INCH OF QPF. HOW
THIS TRANSLATES INTO SNOWFALL ACCUMULATION WILL DEPEND HEAVILY ON
TEMPERATURES AND WHERE MID-LEVEL FORCING SETS UP. TEMPERATURES
DURING THIS EVENT WILL BE MARGINAL, WITH INLAND AREAS STAYING NEAR
FREEZING AND THE CAPE AND ISLANDS STAYING AT OR ABOVE FREEZING. WITH
THE BEST MID-LEVEL FORCING NEAR THE CAPE AND ISLANDS, WE WILL LIKELY
SEE SNOW AT TEMPERATURES UP TO 36F AS SNOW RATES WILL BE ABLE TO
OVERCOME THE WARM TEMPS. THE PRIMARY SOURCE OF UNCERTAINTY IS THE
TEMPERATURE AT WHICH SNOW WILL ACCUMULATE ON PAVED SURFACES. BECAUSE
OF THE WARM TEMPS, WE CONTINUED TO TREND TOTAL ACCUMULATIONS DOWN TO
0.5-1.5 INCHES FOR THE OUTER CAPE AND THE ISLANDS; HOWEVER, IF TEMPS
COOL BELOW FREEZING, SNOW ACCUMULATIONS COULD EXCEED 2-4.
THE HIGHEST CONFIDENCE IN SNOW ACCUMULATIONS REMAINS ALONG THE I-95
CORRIDOR IN EASTERN MA AND INTO RI, WHERE GOOD MID-LEVEL FORCING AND
TEMPERATURES NEAR OR BELOW FREEZING WILL OVERLAP. SNOW
ACCUMULATIONS IN THIS AREA WILL RANGE FROM 3-5 INCHES, WITH
LOCALIZED SPOTS UP TO 6 INCHES POSSIBLE. TO THE NORTH AND WEST OF
THE I-95 CORRIDOR, MID-LEVEL FORCING BEGINS TO DROP OFF; HOWEVER,
COOLER TEMPERATURES WILL ALLOW SNOW RATIOS TO BE HIGHER, RANGING
BETWEEN 12-1 TO 16-1. SNOW TOTALS NORTH AND WEST OF THE I-95
CORRIDOR, INCLUDING ALL OF CT, WILL RANGE FROM 2-4 INCHES, WITH
LOCALIZED AREAS OF 5 INCHES.
AFTER THE LULL IN SNOWFALL THIS AFTERNOON, STEADY LIGHT SNOW WILL
BEGIN TO OVERSPREAD THE REGION ONCE AGAIN THROUGH 6 PM. SNOW RATES
WILL START TO TICK UP AFTER 6 PM, INCREASING TO 0.5 TO 1.5 INCHES
PER HOUR. SNOW BECOMES LIGHT AGAIN AFTER 2-4 AM AND TAPERS OFF FROM
WEST TO EAST THROUGH 6-9 AM THIS MORNING. SNOW SHOWERS MAY LINGER
OVER EASTERN MA UNTIL NOON, BUT ADDITIONAL ACCUMULATIONS WILL BE
LIGHT. THE MOST DIFFICULT TRAVEL PERIOD WILL BE BETWEEN 6 PM AND 2
AM TONIGHT. HOWEVER, WITH LINGERING SNOW SHOWERS INTO MONDAY
MORNING, THE AM COMMUTE WILL LIKELY BE IMPACTED.
LOW TEMPERATURES ON MONDAY MORNING ARE EXPECTED TO DROP INTO THE LOW
TO MID-20S ACROSS THE REGION, WHICH COULD CAUSE ANY STANDING WATER
FROM MELTING SNOW TO REFREEZE, ESPECIALLY ON UNTREATED SURFACES.
HIGH TEMPERATURES MONDAY AFTERNOON REBOUND INTO THE LOW TO MID 30S,
ALLOWING SOME MELTING. WINDS BECOME GUSTY OUT OF THE WSW MONDAY
AFTERNOON AT 15-20MPH, MAKING IT FEEL LIKE THE LOW TO MID 20S.
KEY MESSAGE 2...ARCTIC FRONT RELIEVERS COLD CONDITIONS TUESDAY, WITH
SOME MODERATION WEDNESDAY AND THURSDAY. COLDER AGAIN NEXT WEEKEND.
A POTENT ARCTIC COLD FRONT CROSSES THE REGION MONDAY NIGHT INTO
TUESDAY, USHERING IN MUCH COLDER TEMPERATURES AND GUSTY WINDS. 925MB
TEMPERATURES FALL TO AROUND -15C, WITH STEEP LOW-LEVEL LAPSE RATES
APPROACHING 10C/KM, SUPPORTING EFFICIENT BOUNDARY-LAYER MIXING AND
TRANSPORT OF STRONGER WINDS TO THE SURFACE. GUSTS ON TUESDAY RANGE
FROM 25 TO 35 MPH, WITH A FEW GUSTS NEAR 40 MPH POSSIBLE ACROSS THE
HIGHER TERRAIN. COMBINED WITH HIGH TEMPERATURES IN THE TEENS AND
20S, WIND CHILLS FALL INTO THE SINGLE DIGITS TO LOWER TEENS TUESDAY
AFTERNOON, THEN INTO THE 0F TO -10F RANGE TUESDAY NIGHT. WHILE COLD,
CONDITIONS ARE EXPECTED TO FALL SHY OF A COLD WEATHER ADVISORY. THIS
ARCTIC INTRUSION IS SHORT-LIVED, WITH MODERATING TEMPERATURES
WEDNESDAY AFTERNOON INTO THE UPPER 20S TO LOWER 30S, FOLLOWED BY MID
30S TO LOWER 40S ON THURSDAY. GLOBAL GUIDANCE SUGGESTS ANOTHER
ARCTIC AIR MASS MAY ARRIVES NEXT WEEKEND, WITH HIGHS RETURNING TO
THE SINGLE DIGITS.
KEY MESSAGE 3...QUICK MOVING CLIPPER LATE WEDNESDAY INTO EARLY
THURSDAY BRINGS THE NEXT CHANCE FOR LIGHT PRECIPITATION.
THE NEXT CHANCE FOR PRECIPITATION ARRIVES MIDWEEK, THOUGH CONFIDENCE
REMAINS LOW. SYNOPTIC PATTERN FEATURES A MID-LEVEL LOW OVER HUDSON
BAY WITH EMBEDDED SHORTWAVE ENERGY ROTATING AROUND THE CYCLONIC
FLOW, SUPPORTING THE POTENTIAL DEVELOPMENT OF A WEAK ALBERTA CLIPPER
TRACKING SOUTHEAST FROM THE CANADIAN ROCKIES. AS TYPICAL WITH
CLIPPERS, MOISTURE LIMITED. WHILE TEMPERATURES WEDNESDAY AFTERNOON
MAY BE MARGINAL THE SYSTEM COULD PASS DURING THE EVENING OR
OVERNIGHT AS TEMPERATURES FALL BELOW FREEZING, INTRODUCING THE
POTENTIAL FOR LIGHT SNOW ACCUMULATIONS. WITH LITTLE DOWNSTREAM
BLOCKING, THE SYSTEM IS EXPECTED TO BE PROGRESSIVE. ENSEMBLES
GUIDANCE REMAINS UNIMPRESSIVE, WITH PROBABILITIES FOR SNOWFALL
EXCEEDING ONE INCH GENERALLY IN THE 10-20% RANGE ACROSS INTERIOR
SOUTHERN NEW ENGLAND. WHILE NEAR THE COAST, TEMPERATURES COULD BE
WARM ENOUGH FOR LIGHT RAIN SHOWERS WITH SOUTHWEST FLOW.
AVIATION /06Z MONDAY THROUGH FRIDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE...
MODERATE CONFIDENCE.
SNOW WILL GRADUALLY TAPER OFF FROM WEST TO EAST IN THE 10-14Z
PERIOD. CHANCE FOR CONTINUED SNOW SHOWERS THROUGH 15Z ESPECIALLY
FOR THE FAR EASTERN TERMINALS ON THE CAPE AND ISLANDS. EXPECT
IFR/MVFR CEILINGS AND VISIBILITIES TO CONTINUE THRU 15Z UNTIL
DRIER AIR STARTS MOVING IN. CONDITIONS WILL TREND TOWARD VFR
THIS AFTERNOON, WITH WEST WINDS GUSTING 20KT OR HIGHER IN MANY
AREAS, ESPECIALLY AFTER 18Z.
MONDAY NIGHT IS EXPECTED TO FEATURE VFR CONDITIONS WITH
INCREASING WEST WINDS. GUSTS MAY INCREASE TO 30KTS AFTER 00Z AND
PERSIST THROUGH THE NIGHT.
KBOS TERMINAL... HEAVIEST SNOW BEGINS TO WIND DOWN IN THE
NEXT 1-2 HOURS. ADDITIONAL SNOW SHOWERS DEVELOP THRU 14-15Z THIS
MORNING.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. BULK OF THE SNOW
WINDS DOWN IN THE NEXT 1-3 HOURS WITH LINGERING SNOW SHOWERS
THROUGH 10Z.
OUTLOOK /TUESDAY THROUGH FRIDAY/...
TUESDAY THROUGH WEDNESDAY: VFR. BREEZY.
WEDNESDAY NIGHT: VFR. BREEZY. SLIGHT CHANCE SN.
THURSDAY: VFR. BREEZY. CHANCE RA, CHANCE SN.
THURSDAY NIGHT: VFR. BREEZY. SLIGHT CHANCE SN.
FRIDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH TUESDAY...HIGH CONFIDENCE.
* GALE WARNING FOR ALL WATERS EXCEPT NARRAGANSETT BAY AND
BOSTON HARBOR MONDAY EVENING THROUGH TUESDAY MORNING.
TONIGHT THROUGH MONDAY NIGHT... HIGH CONFIDENCE IN TRENDS, MODERATE
CONFIDENCE IN GALE WATCH.
DEPARTING LOW PRESSURE BRINGS A PERIOD OF INCREASING WEST WINDS WITH
SEAS BUILDING 5-8 FEET TODAY, WITH UP TO 10 FEET ACROSS THE SOUTHERN
OUTER WATERS. WESTERLY WINDS INCREASE DURING THE LATE AFTERNOON INTO
EARLY EVENING. A STRONG ARCTIC COLD FRONT CROSSES THE WATERS
OVERNIGHT INTO EARLY TUESDAY, BRINGING WESTERLY GALES. INCREASING
COLD AIR ADVECTION MAY ALSO RESULT IN FREEZING SPRAY ACROSS ALL
WATERS LATE TONIGHT INTO TUESDAY MORNING. THE THEME TUESDAY WILL BE
GRADUALLY DECREASING SEAS AS BROAD HIGH PRESSURE APPROACHES FROM THE
SOUTHWEST. SEAS WILL LIKELY REMAIN BETWEEN 5 AND 7 FEET THROUGH MUCH
OF THE DAY.
OUTLOOK /TUESDAY THROUGH FRIDAY/...
TUESDAY: STRONG WINDS WITH GUSTS UP TO 35 KT. AREAS OF ROUGH
SEAS. FREEZING SPRAY.
TUESDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS
WITH GUSTS UP TO 30 KT. LOCAL ROUGH SEAS. FREEZING SPRAY.
WEDNESDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
WEDNESDAY NIGHT THROUGH THURSDAY: LOW RISK FOR SMALL CRAFT
ADVISORY WINDS WITH GUSTS UP TO 25 KT. AREAS OF ROUGH SEAS.
CHANCE OF RAIN.
THURSDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS
WITH GUSTS UP TO 30 KT. AREAS OF ROUGH SEAS. CHANCE OF FREEZING
SPRAY, SLIGHT CHANCE OF RAIN, SLIGHT CHANCE OF SNOW.
FRIDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. AREAS OF SEAS APPROACHING 5 FT. CHANCE OF FREEZING
SPRAY.
BOX WATCHES/WARNINGS/ADVISORIES
CT...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR CTZ002>004.
MA...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MAZ002>023-
026.
RI...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR RIZ001>007.
MARINE...GALE WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING FOR
ANZ230>234-236-251.
GALE WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING FOR
ANZ235-237.
GALE WATCH FROM 10 AM EST MONDAY THROUGH TUESDAY MORNING FOR
ANZ250-254>256.
DISCUSSION...DOOLEY/FT
AVIATION...FT/NASH
MARINE...FT
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