435
FXUS61 KBOX 060617
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
117 AM EST TUE JAN 6 2026
WHAT HAS CHANGED
A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THE THREAT OF FREEZING
RAIN ACROSS PORTIONS OF SOUTHERN NEW ENGLAND. MOST LOCATIONS ALONG
THE I-95 CORRIDOR EXPERIENCE A LIGHT GLACE OF ICE, THOUGH LOCATIONS
ACROSS INTERIOR SOUTHERN NEW ENGLAND MAY SEE ICE ACCUMULATION
BETWEEN 0.1" AND 0.2". PLAN ON SLICK TRAVEL TUESDAY EVENING
THROUGH WEDNESDAY MORNING.
KEY MESSAGES
- MIXED PRECIPITATION EXPECTED TUESDAY NIGHT INTO WEDNESDAY
MORNING.
- MILDER WITH RAIN LATER IN THE WEEK BUT NO FLOODING EXPECTED.
DISCUSSION
KEY MESSAGE 1...MIXED PRECIPITATION EXPECTED TUESDAY NIGHT INTO
WEDNESDAY MORNING.
STARTING OFF EARLY THIS MORNING, A FEW SLICK SPOTS FROM A FEW SNOW
SHOWERS OVERNIGHT. TODAY IS DRY AND CLOUDY WITH HIGH TEMPERATURES IN
THE MIDDLE 30S. THE MORE IMPACTFUL WEATHER ARRIVES THIS EVENING AS A
LOW-PRESSURE SYSTEM/MID-LEVEL SHORTWAVE TRACKS ACROSS THE REGION.
THIS IS A FAST MOVING SYSTEM, PUSHING EAST OF THE GULF OF MAINE BY
WEDNESDAY. AS THE LOW-PRESSURE SYSTEM TRACKS JUST NORTH OF OUR
REGION, THE BEST LIFT AND MOISTURE IS DISPLACED OVER CENTRAL NEW
ENGLAND. THAT SAID, STILL FEEL CONFIDENT IN ICING ACROSS INTERIOR
SOUTHERN NEW ENGLAND. WHILE SURFACE TEMPERATURES REMAIN BELOW
FREEZING, YOU MAY THINK, WHY ISN'T THIS SNOW? WELL, ~1,500 FEET
ABOVE THE GROUND TEMPERATURES ARE ROUGHLY +3C, THIS WARM NOSE
EXTENDS FROM 900MB TO 800MB. AS THE SNOW FALLS THROUGH THIS LAYER IT
MELTS, BECOMING A RAIN DROP, AND THEN FALLS INTO A SHALLOW FREEZING
LAYER AT THE SURFACE. IT'S HERE WERE THE REFREEZING ON UNTREATED
SURFACES OCCURS. THIS IS WELL VISUALIZED ON FORECAST BUFKIT
SOUNDINGS, WITH THE WAA FROM SOUTHWESTERLY WINDS. WHERE WE EXPECT
THE GREATEST ICE ACCUMULATION, BERKSHIRES AND THE WORCESTER HILLS,
WITH 0.1" AND 0.2" OF ICE ACCUMULATION IS POSSIBLE. THE LOWER
ELEVATIONS WILL EXPERIENCE LESS, 0.01" TO 0.1", ENOUGH TO MAKE
UNTREATED SIDEWALKS, DRIVEWAYS, ROADWAYS SLICK! THIS LEAD TO A
WINTER WEATHER ADVISORY ACROSS MUCH OF MASSACHUSETTS, THE EXCEPTION
BEING SOUTHEAST MASSACHUSETTS, CAPE COD, AND THE ISLANDS. AND
NORTHERN/CENTRAL RHODE ISLAND AND ALL OF NORTHERN CONNECTICUT.
TIMING WISE, ARRIVING TO WESTERN AREAS BETWEEN 6PM AND 8PM, EASTERN
AREAS BETWEEN 9PM AND 11PM. EXPECT ROAD CONDITIONS WILL DETERIORATE
SOON AFTER, ESPECIALLY UNTREATED SURFACES. THROUGHOUT THE NIGHT,
TEMPERATURES WILL GRADUALLY RISE, WITH THE THREAT OF FREEZING RAIN
RETREATING FROM SOUTH TO NORTH, MAINLY BETWEEN 3AM AND 7AM. THE FLOW
BECOMES WEST/NORTHWEST BY LATE WEDNESDAY MORNING, A FEW CAA
RAIN/SNOW SHOWERS ARE POSSIBLE THROUGH MIDAFTERNOON WITH HIGHS IN
THE MIDDLE TO UPPER 30S. WITH CAA, EXPECTING BREEZY WINDS AND GUSTS
20 TO 30 MPH.
KEY MESSAGE 2...MILDER WITH RAIN LATER IN THE WEEK. NO FLOODING
EXPECTED.
THERE IS GOOD AGREEMENT AMONG ENSEMBLE GUIDANCE FOR A PATTERN CHANGE
LATER IN THE WEEK FAVORING MILDER TEMPERATURES, ESPECIALLY FOR
FRI/SAT. A SUBTROPICAL RIDGE BUILDS IN FROM THE SOUTH INTO FRIDAY
WITH A FAIRLY POTENT NORTHERN STREAM SHORTWAVE TROUGH MOVING ACROSS
THE GREAT LAKES/QUEBEC OVER THE WEEKEND. A JET OF STRONG SW FLOW
WILL HELP ADVECT IN ABOVE NORMAL MOISTURE INTO THE REGION, AROUND
200-250 PERCENT OF NORMAL. GIVEN THE MILD AIRMASS IN PLACE, THIS
WILL SUPPORT A ROUND OR TWO OF RAIN IN THE FRIDAY TO SATURDAY
TIMEFRAME. COMPARING AGAINST CLIMATOLOGY THE MOISTURE ISN'T
CONSIDERABLY ANOMALOUS AND WITH THE FAIRLY PROGRESSIVE NATURE OF THE
PATTERN DOESN'T RAISE FLAGS FOR EXCESSIVE RAINFALL. THIS ALIGNS WITH
ENSEMBLES SHOWING A RANGE OF 0.25" TO 0.60" OF RAIN IN THE MORE
LIKELY RANGE. ADDITIONAL SNOWMELT WILL NEED TO BE CONSIDERED AS
WELL, BUT CURRENTLY ENSEMBLE RIVER FORECASTS HAVE NO INDICATION OF
FLOODING CONCERNS.
RELATIVELY COOLER AIR MOVES BEHIND THE SYSTEM BRINGING SEASONABLE
TEMPERATURES SUNDAY INTO EARLY NEXT WEEK. GUSTY SW WINDS ARE
POSSIBLE ON SUNDAY.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH -GREATER THAN 60 PERCENT.
THROUGH 12Z... MODERATE CONFIDENCE.
LOW-END VFR AND MVFR CEILINGS, PERIODIC SN WILL LEAD TO MVFR
VISIBILITY, 3SM TO 5SM. OPT'D TO HANDLE THIS WITH TEMPO FOR THE
TERMINALS WITH THE BEST CHANCE OF SNOW. ANY SNOW ACCUMULATION ARE
MINIMAL, LESS THAN AN INCH. POCKET OF FZRA IS POSSIBLE BETWEEN 04Z-
07Z FOR TERMINAL IN RI AND SE MA. OTHERWISE, RA FOR THE CAPE AND
ISLANDS. WINDS ARE FAIRLY LIGHT WITH VARIABLE WIND DIRECTION.
TODAY... HIGH CONFIDENCE.
DRY, VFR FOR MOST TERMINALS, CAPE COD AND THE ISLANDS TERMINALS
REMAIN MVFR. LIGHT E/NE WIND 5 TO 8 KNOTS.
TONIGHT... MODERATE CONFIDENCE.
IFR AND LIFR CEILINGS WITH SCATTERED TO WIDESPREAD RA AND FZRA
OVERSPREADS THE REGION FROM WEST TO EAST, BETWEEN 00Z AND 05Z.
CANNOT RULE OUT A BRIEF PERIOD OF SN, FOR TERMINALS ALONG AND NORTH
OF RT.2 IN NORTHERN MASSACHUSETTS. ICE ACCRETION POSSIBLE AT KBDL &
KORH, LESS LIKELY FOR KBOS & KPVD. AS FOR CAPE COD AND THE ISLANDS,
EXPECTING RAIN ONLY. WINDS ARE LIGHT AND VARIABLE.
WEDNESDAY... MODERATE CONFIDENCE.
IFR, CONTINUED SHOWERS, BEST CHANCE FOR REMAINING FZRA WILL BE IN
NORTHERN MA, WHILE AREAS SOUTH DEAL WITH RA. DRYING FROM WEST TO
EAST BETWEEN 15Z-18Z, ALONG WITH SLOW IMPROVEMENTS TO CEILINGS.
WINDS ARE WESTERLY, 10 TO 15 KNOTS, GUSTING 20 KNOTS.
KBOS TERMINAL... MODERATE CONFIDENCE.
MVFR, PERIODIC SNOW SHOWERS BETWEEN 04Z-07Z, MINOR ACCUMULATION OF A
FEW TENTHS OF AN INCH. DRY CONDITIONS TODAY, WITH RAIN ARRIVING BY
EARLY EVENING. LOW CHANCE OF FREEZING RAIN TUESDAY NIGHT, WILL NEED
TO BE WATCHED, BUT LEFT OUT OF TAF FOR NOW DUE TO LOW CONFIDENCE.
KBDL TERMINAL... MODERATE CONFIDENCE.
FEW SNOW SHOWERS THROUGH 06Z, MINOR ACCUMULATIONS POSSIBLE. MVFR
CEILINGS, BECOMING VFR BY 12Z. DRY FOR MUCH OF TODAY, THEN A WINTRY
MIXTURE AFTER 00Z. POSSIBLE FREEZING RAIN, OPT'D TO INCLUDE A PROB30
FOR THIS THREAT. IFR TO LIFR OVERNIGHT INTO EARLY WEDNESDAY.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY NIGHT: VFR. BREEZY.
THURSDAY THROUGH THURSDAY NIGHT: VFR.
FRIDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. BREEZY. RA LIKELY.
FRIDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. BREEZY.
CHANCE RA.
SATURDAY: MAINLY MVFR, WITH AREAS IFR POSSIBLE. BREEZY. RA
LIKELY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY THROUGH WEDNESDAY... HIGH CONFIDENCE.
AN AREA OF HIGH PRESSURE REMAINS ANCHORED OFF SHORE TODAY WITH LIGHT
WINDS AND RELATIVELY DRY CONDITIONS. A WARM FRONT OVERSPREADS THE
REGION EARLY THIS EVENING WITH PERIODS OF RAIN OVERNIGHT. SEAS ARE
1' TO 3' TODAY, INCREASING 2' TO 4' OVERNIGHT. LIGHT E/NE WIND
TODAY, THEN E/SE TONIGHT.
WEDNESDAY, LOW-PRESSURE SYSTEM EXITS THE GULF OF MAINE, INCREASING
WIND FROM THE W, GUSTING BETWEEN 20 TO 30 KNOTS. OCCASIONAL RAIN
SHOWERS TAPPER OFF FROM SOUTHWEST TO NORTHEAST DURING THE LATE
MORNING INTO THE EARLY AFTERNOON. INCREASING SEAS ACROSS THE
SOUTHERN WATERS, BETWEEN 4' AND 8', EASTERN WATERS 2' TO 5'. THESE
CONDITIONS WILL LEAD TO A SMALL CRAFT ADVISORY.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY NIGHT: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS.
THURSDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT.
THURSDAY NIGHT: WINDS LESS THAN 25 KT.
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 25 KT. SEAS LOCALLY APPROACHING 5 FT. CHANCE OF RAIN.
FRIDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. LOCAL ROUGH SEAS. RAIN LIKELY.
SATURDAY: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS. RAIN
LIKELY.
BOX WATCHES/WARNINGS/ADVISORIES
CT...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
WEDNESDAY FOR CTZ002>004.
MA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
WEDNESDAY FOR MAZ002>017-026.
RI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
WEDNESDAY FOR RIZ001>004.
MARINE...NONE.
DISCUSSION...DOOLEY/MENSCH
AVIATION...DOOLEY/MENSCH
MARINE...DOOLEY/MENSCH
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