269
FXUS61 KBOX 270758
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
258 AM EST SAT DEC 27 2025
WHAT HAS CHANGED
CONFIDENCE IN A PERIOD OF FREEZING RAIN CONTINUES TO INCREASE FOR
SUNDAY NIGHT INTO EARLY MONDAY MORNING. THE HIGHEST CHANCES OF ICE
ACCRETION EXCEEDING A TRACE WILL BE IN LOW-LYING AREAS NORTH OF THE
MASS PIKE. FREEZING RAIN WILL TRANSITION TO A LIGHT TO MODERATE RAIN
MONDAY MORNING. GROWING CONCERN FOR STRONG POST-FRONTAL WINDS ON
TUESDAY.
KEY MESSAGES
- LINGERING FLURRIES OVER THE EASTERN COAST GIVE WAY TO SUNNY
BUT COLD DAY.
- STORM SYSTEM LIKELY BRINGS A PERIOD OF FREEZING RAIN SUNDAY
NIGHT INTO EARLY MONDAY BEFORE TRANSITIONING TO PLAIN RAIN
LATER MONDAY MORNING. THE BEST CHANCE FOR ICE ACCUMULATION OF
GREATER THAN A TRACE IS NORTH OF THE MA PIKE, ESPECIALLY IN
THE NORTHERN CT RIVER VALLEY.
- GROWING CONCERN FOR STRONG POST-FRONTAL WINDS ON TUESDAY. HIGH
PROBABILITIES FOR 46MPH GUSTS IN THE HIGH TERRAIN.
DISCUSSION
KEY MESSAGE 1...LINGERING FLURRIES OVER THE EASTERN COAST GIVE
WAY TO SUNNY BUT COLD DAY.
A FEW LAST ROUNDS OF HEAVIER SNOW PASS THROUGH BEFORE SUNRISE,
BRINGING AN ADDITIONAL COATING TO 2" ACROSS SOUTHERN NEW ENGLAND. A
DEFORMATION ZONE SETTING UP OFFSHORE BRINGS NORTHEASTERLY WINDS
TODAY, ALLOWING FOR OCEAN EFFECT FLURRIES TO LINGER THROUGH THE
MORNING ALONG THE SOUTH SHORE AND COASTAL PLAIN. THIS WILL LIKELY
BRING STORM TOTALS TO 2"-5", WITH HIGHEST TOTALS ACROSS WESTERN
CT/MA.
A DRY AND CHILLY AIRMASS MOVES IN BEHIND THE STORM TODAY INTO
SUNDAY. TEMPERATURES THIS AFTERNOON PEAK IN THE MID 20S TO LOW 30S,
BUT LOW WINDS WILL ALLOW FOR GOOD RADIATIONAL COOLING AND DROP
TEMPERATURES INTO THE SINGLE DIGITS ACROSS THE INTERIOR AND MID
TEENS ACROSS THE SOUTH SHORE AND COASTAL PLAIN.
KEY MESSAGE 2...STORM SYSTEM LIKELY BRINGS A PERIOD OF FREEZING
RAIN SUNDAY NIGHT INTO EARLY MONDAY BEFORE TRANSITIONING TO
PLAIN RAIN LATER MONDAY MORNING. THE BEST CHANCE FOR ICE
ACCUMULATION OF GREATER THAN A TRACE IS NORTH OF THE MA PIKE,
ESPECIALLY IN THE NORTHERN CT RIVER VALLEY.
A NEGATIVELY TILTED TROUGH BECOMES POSITIVELY TILTED AS IT ENTERS
THE GREAT LAKES AND THE OHIO RIVER VALLEY. THIS SENDS A STRONG WARM
FRONT INTO THE NORTHEAST WELL AHEAD OF THE PARENT SURFACE LOW BACK
OVER MICHIGAN. BUFKIT SOUNDINGS ARE A BIT CONCERNING HEADING INTO
SUNDAY NIGHT, WITH PRECIPITATION ARRIVING AS TEMPERATURES BELOW 2KFT
ARE WELL BELOW FREEZING AND A DEEP WARM NOSE EXTENDING FROM 2-6KFT.
THIS KIND OF PROFILE IS VERY CONDUCIVE TO FREEZING RAIN, AS PRECIP
WILL NOT HAVE ENOUGH TIME TO REFREEZE BEFORE REACHING THE SURFACE.
GUIDANCE HAS BEEN RELATIVELY CONSISTENT OVER THE LAST COUPLE OF DAYS
IN CALLING FOR A PERIOD OF FREEZING RAIN FROM SUNDAY EVENING INTO
THE EARLY HOURS OF MONDAY, BEFORE TRANSITIONING TO REGULAR RAIN BY
SUNRISE MONDAY. THE HIGHEST CONFIDENCE FOR ICE ACCRETION GREATER
THAN A TRACE IS IN LOW-LYING AREAS NORTH OF THE MASS PIKE,
ESPECIALLY IN THE NORTHERN CT RIVER VALLEY. WE SHOULD GET A MUCH
BETTER SENSE OF HOW MUCH ICE TO EXPECT AFTER THE 12Z HREF RUN, WHICH
USES THE FREEZING RAIN ACCUMULATION MODEL (FRAM), A FAR MORE
RELIABLE METHOD THAN STANDARD MODEL ICE ACCRETION.
SURFACE TEMPERATURES BEGIN TO CATCH UP WITH THE WARMER TEMPERATURES
ALOFT AND WARM ABOVE FREEZING NEAR OR BEFORE SUNRISE ON MONDAY,
ALLOWING FREEZING RAIN TO TRANSITION TO PLAIN RAIN. THE DRY SLOT
WORKS IN BEHIND THE WARM FRONT, ALLOWING RAIN TO TAPER OFF FOR THE
AFTERNOON. THE COLD FRONT IS EXPECTED TO ARRIVE SOMETIME LATE MONDAY
AND COULD BRING ANOTHER QUICK ROUND OF RAIN.
KEY MESSAGE 3...GROWING CONCERN FOR STRONG POST-FRONTAL WINDS
ON TUESDAY. HIGH PROBABILITIES FOR 46MPH GUSTS IN THE HIGH
TERRAIN.
THERE IS A GROWING CONCERN FOR A PERIOD OF STRONG WINDS BEHIND THE
COLD FRONT ON TUESDAY AS THE PRESSURE GRADIENT BECOMES VERY TIGHT,
SQUEEZED BY THE OCCLUDING 975 MB LOW OVER QUEBEC AND A BUILDING
SURFACE HIGH NEAR THE GULF. THE GFS CURRENTLY HAS THE MOST ROBUST
850MB JET WITH WINDS NEARING 55 KNOTS, WHILE THE EURO AND CANADIAN
SHOW A MORE MODEST 35-40 KNOT JET. THE NBM IS ALREADY SHOWING HIGH
PROBABILITIES OF 60-80% FOR 46 MPH WINDS (WIND ADVISORY CRITERIA)
ACROSS THE HIGH TERRAIN AND NEAR THE CAPE AND ISLANDS. THE
PROBABILITY OF 58MPH GUSTS (HIGH WIND WARNING) IS STILL LOW AT THIS
TIME, AT 10-30%, MAINLY NEAR THE HIGH TERRAIN.
AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
SATURDAY THROUGH SUNDAY...HIGH CONFIDENCE IN TRENDS. MODERATE
CONFIDENCE ON TIMING.
SNOW SHOWERS MAY LINGER THROUGH 12-15Z FOR EASTERN MA INTO THE CAPE
AND ISLANDS. OTHERWISE, TURNING VFR WITH NNE WINDS AT 10-15 KTS AND
A FEW SPORADIC GUSTS UP TO 20KTS. WINDS BACK TO NNE 5-10KTS TONIGHT
INTO SUNDAY.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE ON
TIMING.
MVFR/IFR EARLY THIS MORNING UNDER LINGERING SNOW BANDS. IMPROVING TO
VFR 10-12Z WITH INCREASING NORTHERLY WINDS AND A FEW SPORADIC GUSTS
THROUGHOUT THE MORNING.
KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE ON
TIMING.
MVFR IMPROVING TO VFR 10-12Z. NORTHERLY WINDS 5-10KTS THROUGH THE
PERIOD.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE. BREEZY. RA, CHANCE
FZRA.
MONDAY: MVFR/IFR CONDITIONS POSSIBLE. BREEZY. RA.
MONDAY NIGHT: VFR. WINDY WITH GUSTS UP TO 35 KT. CHANCE RA.
TUESDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. WINDY WITH GUSTS
UP TO 35 KT.
TUESDAY NIGHT: VFR. WINDY WITH GUSTS UP TO 35 KT.
WEDNESDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH SUNDAY
WINDS TURN NE AROUND 20 KNOTS AS A CLIPPER SYSTEM BRINGS
MODERATE SNOW TO THE SOUTHERN WATERS, WITH LIGHT SNOW IN THE
NORTHERN WATERS TONIGHT INTO SATURDAY MORNING. SEAS BETWEEN 2-5
FT. WINDS TURN LIGHT SW LATE IN THE DAY SUNDAY AND SEAS DROP
BELOW 5FT.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. CHANCE OF RAIN, CHANCE OF FREEZING RAIN.
MONDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 30 KT. AREAS OF ROUGH SEAS. RAIN.
MONDAY NIGHT: MODERATE RISK FOR GALE FORCE WINDS WITH LOCAL
GUSTS UP TO 45 KT. ROUGH SEAS UP TO 17 FT. CHANCE OF RAIN.
TUESDAY: GALE FORCE WINDS WITH GUSTS UP TO 45 KT. ROUGH SEAS UP
TO 17 FT. SLIGHT CHANCE OF SNOW.
TUESDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 40 KT. ROUGH SEAS
UP TO 14 FT.
WEDNESDAY: STRONG WINDS WITH GUSTS UP TO 30 KT. ROUGH SEAS UP
TO 12 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR CTZ002.
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
CTZ003-004.
MA...WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR MAZ009.
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MAZ002>004-008-010>012-016>021.
RI...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
RIZ001>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ250-
256.
SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR ANZ254-255.
DISCUSSION...MCMINN/KP
AVIATION...MCMINN/KP
MARINE...KP
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