626
FXUS61 KBOX 171144
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
644 AM EST FRI JAN 17 2025
SYNOPSIS
PLENTY OF SUNSHINE WITH TEMPERATURES MODERATING TO SEASONABLE LEVELS
THIS AFTERNOON. AN APPROACHING COLD FRONT WILL RESULT IN A SOUTHERLY
FLOW OF EVEN MILDER AIR FOR SATURDAY WITH A PERIOD OF RAIN SHOWERS
SATURDAY AFTERNOON INTO EARLY EVENING. DRY WEATHER SHOULD PREVAIL
FOR THE FIRST PART OF SUNDAY BEHIND THE COLD FRONT. A WAVE OF LOW
PRESSURE WILL RIDE UP AND ALONG THE FRONT AND LIKELY BRING AN
ACCUMULATING/PLOWABLE SNOWFALL LATER SUNDAY AND ESPECIALLY SUNDAY
NIGHT. THIS WILL BE FOLLOWED BY AN ARCTIC OUTBREAK LATER MONDAY
INTO WEDNESDAY WITH WIND CHILLS LIKELY DROPPING TO BETWEEN 10 AND 15
BELOW ZERO.
NEAR TERM /UNTIL 6 PM THIS EVENING/
KEY MESSAGES:
* WARMER WITH HIGH TEMPERATURES AROUND NORMAL
MID-LEVEL RIDGING AND WEAK HIGH PRESSURE WILL SUPPORT A DRY DAY
ACROSS SOUTHERN NEW ENGLAND. LIGHT NW WINDS THIS MORNING WILL
TRANSITION TO SW IN THE AFTERNOON AS THE SURFACE HIGH PUSHES
OFFSHORE. TEMPERATURES ALOFT WARM A FEW DEGREES FROM YESTERDAY
SUPPORTING MORE SEASONABLE HIGH TEMPERATURES IN THE MID 30S TO
NEAR 40. MOST AREAS WILL EXPERIENCE MINIMAL CLOUD COVER WITH THE
EXCEPTION OF THE CAPE AND ISLANDS WHERE THERE WILL BE LINGERING
CLOUDS THROUGH EARLY AFTERNOON. CAN'T RULE OUT A STRAY SNOW
SHOWER OR FLURRY ACROSS THE OUTER CAPE TODAY, BUT OTHERWISE IT
WILL BE DRY TODAY.
SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/
KEY MESSAGES:
* ABOVE NORMAL TEMPERATURES AND BREEZY CONDITIONS SATURDAY.
* RAIN SHOWERS DEVELOPING IN THE AFTERNOON, BECOMING MORE
WIDESPREAD BY THE EVENING.
FRIDAY NIGHT:
A WEAK MID-LEVEL SHORTWAVE APPROACHES FROM THE WEST WHICH WILL
BRING OUR NEXT CHANCE OF PRECIPITATION SATURDAY. WINDS FROM THE
SW BECOME MORE ENHANCED OVERNIGHT AS THE PRESSURE GRADIENT
STRENGTHENS. CLOUDS INCREASE AHEAD OF A WEAK WARM FRONT. WITH
THE COOLER AIRMASS EXITED AND INCREASED CLOUD COVER, TONIGHT
WILL TREND WARMER THAN THE PREVIOUS COUPLE OF NIGHTS. LOW
TEMPERATURES RANGE IN THE LOW TO MID 20S ACROSS THE INTERIOR AND
MID TO UPPER 20S CLOSER TO THE COASTLINE.
SATURDAY:
A WEAK SHORTWAVE TROUGH AND COLD FRONT APPROACHES THE REGION
SATURDAY. MOISTURE GRADUALLY INCREASES INTO THE AFTERNOON WITH
PRECIPITABLE WATER VALUES AROUND 150-200% OF NORMAL BY EARLY
EVENING. THIS WAVE WILL BRING A BROAD AREA OF ASCENT SUPPORTING
OUR NEXT CHANCE OF PRECIPITATION. SHOWERS BEGIN TO DEVELOP IN
THE AFTERNOON FROM WEST TO EAST, BECOMING MORE WIDESPREAD MID-
AFTERNOON TO EARLY EVENING.
THERE WILL WILL BE A GOOD AMOUNT OF WAA ADVECTION AHEAD OF THIS
SYSTEM WITH 850MB TEMPERATURES WARMING 5-8C FROM FRIDAY
BRINGING HIGHS INTO THE 40S, POTENTIALLY 50 IN SPOTS. THIS WILL
PUT US AROUND 6-12 DEGREES WARMER THAN NORMAL. THAT MEANS THIS
WILL FALL AS RAIN WITH THE EXCEPTION OF THE BERKSHIRES WHICH
WILL SEE LIGHT SNOW. IT WILL ALSO BE BREEZY SATURDAY WITH A LOW
LEVEL JET/ENHANCED GRADIENT POSITIONED ACROSS THE REGION. NO
IMPACTFUL WINDS ARE EXPECTED, BUT GUSTS 20-25 MPH ARE POSSIBLE.
LONG TERM /SUNDAY THROUGH THURSDAY/
KEY MESSAGES...
* RAIN SHOWERS DEPART THE REGION EARLY SAT EVENING
* PLOWABLE SNOWFALL LIKELY LATE SUN/SUN NIGHT ENDING BY MON AM
* ARCTIC OUTBREAK MON/TUE/WED WITH WIND CHILLS -10 TO -15 BELOW ZERO
* ACTUAL LOWS MON NIGHT/TUE NIGHT SINGLE DIGITS WITH SOME BELOW ZERO
* ACTUAL HIGHS TUE & WED ONLY IN THE MIDDLE TEENS TO THE LOWER 20S
DETAILS...
SATURDAY NIGHT...
THE ASSOCIATED SHORTWAVE/COLD FRONT WILL BE PUSHING EAST OF THE
REGION SAT EVENING TAKING THE DEEPER MOISTURE/FORCING WITH IT. SO
LINGERING SHOWERS WILL BE EXITING THE REGION FROM WEST TO EAST
DURING THE FIRST PART OF SAT EVENING. OTHERWISE...A DRIER NORTHWEST
FLOW OF AIR WILL BE WORKING INTO THE REGION. WE EXPECT PARTIAL
CLEARING...BUT THE AIRMASS INITIALLY BEHIND THIS FRONT IS NOT THAT
COLD. LOW TEMPS SAT NIGHT SHOULD ONLY BOTTOM OUT IN THE UPPER 20S TO
THE MIDDLE 30S.
SUNDAY AND SUNDAY NIGHT...
THE FIRST PART OF SUNDAY SHOULD FEATURE DRY WEATHER AND PROBABLY
WILL SEE SOME PARTIAL SUNSHINE IN THE MORNING. GIVEN THE AIRMASS
BEHIND THE INITIAL FRONT IS NOT THAT COLD...HIGH TEMPS SHOULD TOP
OFF IN THE UPPER 30S TO THE MIDDLE 40S.
THE MAIN CONCERN WITH THIS FORECAST REVOLVES AROUND THE INCREASING
CONFIDENCE IN AN ACCUMULATING/PLOWABLE SNOW EVENT LATER SUN AND
ESPECIALLY SUN NIGHT ACROSS THE REGION. THAT BEING SAID...THERE IS
STILL CONSIDERABLE SPREAD AMONGST THE GUIDANCE AND THIS FORECAST IS
NOT SET IN STONE. THE BIGGEST QUESTION IS HOW FAR NORTHWEST AN
ANAFRONTAL WAVE TRACKS TO THE COAST. THE 00Z NAM IS THE EASTERN
OUTLIER WITH A SHUTOUT ACROSS SOUTHERN NEW ENGLAND AS A WEAK WAVE OF
LOW PRESSURE TRACKS WELL SOUTHEAST OF THE BENCHMARK. MEANWHILE...THE
00Z RGEM CONTINUES TO BE THE WESTERN OUTLIER WITH A SIGNIFICANTLY
STRONGER LOW PRESSURE SYSTEM THAT TRACKS MUCH FURTHER NORTHWEST
ACROSS SOUTHEAST MA. THIS SOLUTION IS SO FAR WEST THAT PTYPE WOULD
MAINLY BE RAIN ACROSS THE COASTAL PLAIN WITH MOST OF THE SNOW ACROSS
THE INTERIOR.
GIVEN THE CONSIDERABLE DIFFERENCES BETWEEN THE NAM/RGEM...THERE
REMAINS PLENTY OF UNCERTAINTY ON THE EXACT OUTCOME. WHILE NO
SOLUTIONS CAN BE RULED OUT AT THIS POINT...WE ARE FAVORING THE
GEFS/EPS ENSEMBLES ALONG WITH THE UKMET THAT SUPPORT A MIDDLE GROUND
WITH THE WAVE OF LOW PRESSURE TRACKING NEAR THE BENCHMARK. THIS
SOLUTION WOULD BRING A PERIOD OF ACCUMULATING/PLOWABLE SNOWFALL
WHICH MAY START AS A BRIEF PERIOD OF RAIN. A VERY PRELIMINARY
SNOWFALL FORECAST INDICATES THAT 2-6" OF SNOW IS POSSIBLE ACROSS A
GOOD PORTION OF THE REGION...WHICH IS SUPPORTED BY THE LATEST NBM
MODEL. THAT IS THE MOST LIKELY SOLUTION BASED ON THE CURRENT
DATA...BUT GIVEN THAT THERE STILL IS A LARGE SPREAD IN THE MODELS
THIS IS NOT SET IN STONE. THERE STILL IS A LOW RISK FOR LITTLE IF
ANY SNOWFALL IF THE STORM TRACK TRENDS EAST LIKE THE NAM OR A FAR
WESTERN SOLUTION LIKE THE RGEM...WHICH WOULD SUPPORT MAINLY RAIN ON
THE COASTAL PLAIN. THERE ALSO WOULD BE A LOW PROBABILITY FOR A SWATH
OF OVER 6"+ OF SNOW WITH A STRONGER LOW PRESSURE SYSTEM TRACKING
JUST INSIDE THE BENCHMARK. BUT RIGHT NOW ODDS FAVORING MORE ON THE
ORDER OF A 2-6" TYPE OF SNOW FOR MOST LOCATIONS...BUT PROBABLY LESS
TOWARDS THE CAPE/ISLANDS WHERE PTYPE ISSUES ARE MORE LIKELY.
MONDAY THROUGH WEDNESDAY...
THE GOOD NEWS IS THAT THE STEADY SNOW WILL PRETTY MUCH BE OVER BY
DAYBREAK MON. OTHERWISE...THE MAIN STORY WILL BE AN ARCTIC OUTBREAK
AND LIKELY THE COLDEST WEATHER SINCE EARLY FEBRUARY 2023! THE ARCTIC
AIRMASS BEGINS TO WORK INTO THE REGION MON ON BLUSTERY NW WINDS.
HIGHS ON MON PROBABLY MAINLY IN THE LOWER TO MIDDLE 20S WITH THE
BITTERLY COLD AIR WORKS INTO THE REGION LATE MON/MON NIGHT AND
CONTINUING INTO WED. OVERNIGHT LOW TEMPS WILL BE IN THE SINGLE
DIGITS MON NIGHT AND TUE NIGHT WITH SOME BELOW ZERO READINGS IN THE
OUTLYING LOCATIONS...ESPECIALLY TUE NIGHT WHEN WINDS START TO
DIMINISH. HIGH TEMPS TUE AND WED WILL ONLY BE IN THE MIDDLE TEENS TO
THE LOWER 20S. BLUSTERY NORTHWEST WINDS WILL PROBABLY DROP WIND
CHILLS INTO THE -10 TO -15 BELOW ZERO. COLD WEATHER ADVISORIES WILL
LIKELY BE NEEDED.
THURSDAY...
THE CORE OF THE COLDEST AIR WILL BEGIN TO DEPART...BUT THINKING HIGH
TEMPS WILL STILL BE QUITE COLD IN THE 20S TO NEAR 30.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
FORECAST CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE...
TODAY...HIGH CONFIDENCE.
ANY LINGERING MVFR CONDITIONS MAINLY TOWARDS THE CAPE/ISLANDS
SHOULD IMPROVE TO VFR WELL BEFORE DAYBREAK. VFR TODAY EXCEPT
PERHAPS FOR SOME MARGINAL MVFR CEILINGS FLIRTING WITH THE OUTER-
CAPE AT TIMES FROM OCEAN EFFECT CLOUDS. NW WINDS 5-10 KNOTS
SHIFT TO SW AFTER 20Z.
TONIGHT...HIGH CONFIDENCE.
VFR. LIGHT/CALM WINDS EARLY THIS EVENING BECOME S LATER TONIGHT
AT SPEEDS OF 10 KNOTS OR LESS.
SATURDAY...MODERATE CONFIDENCE.
VFR CONDITIONS THROUGH MID MORNING OR SO GRADUALLY DETERIORATE
TO MVFR THRESHOLDS IN THE AFTERNOON AND EARLY EVENING.
LOCALIZED IFR CONDITIONS POSSIBLE BY EARLY EVENING. RAIN
SHOWERS WILL ALSO OVERSPREAD THE REGION DURING THE AFTERNOON
HOURS FROM WEST TO EAST. A FEW SCATTERED SHOWERS ARE POSSIBLE
AFTER 15Z. S WINDS OF 10 TO 15 KNOTS WITH GUSTS AROUND 25
KNOTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK /SUNDAY THROUGH TUESDAY/...
SATURDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. BREEZY.
SLIGHT CHANCE SHRA, PATCHY BR.
SUNDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY. CHANCE
SN.
SUNDAY NIGHT: MAINLY IFR, WITH LOCAL MVFR POSSIBLE. BREEZY. SN
LIKELY.
MARTIN LUTHER KING JR DAY THROUGH TUESDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH- GREATER THAN 60 PERCENT.
HIGH CONFIDENCE.
GENERALLY LIGHT WINDS (15 KT AND LESS) AND SEAS ARE EXPECTED
THROUGH FRIDAY NIGHT. A SYSTEM WILL BRING A ROUND OF RAIN
SATURDAY AFTERNOON AND EVENING. SEAS APPROACH 5 FT FOR THE
OUTER WATERS BY EARLY AFTERNOON SATURDAY WITH WINDS 25-30 KTS.
THIS WILL BE SHORT-LIVED WITH WINDS/SEAS DECREASING OVERNIGHT
INTO SUNDAY.
OUTLOOK /SUNDAY THROUGH TUESDAY/...
SATURDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT. CHANCE OF RAIN SHOWERS, PATCHY FOG.
SUNDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
CHANCE OF RAIN.
SUNDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. SEAS UP TO 5 FT. RAIN, CHANCE OF SNOW.
VISIBILITY 1 TO 3 NM.
MARTIN LUTHER KING JR DAY THROUGH MONDAY NIGHT: MODERATE RISK
FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP TO 25 KT. AREAS OF
ROUGH SEAS. FREEZING SPRAY, SLIGHT CHANCE OF SNOW SHOWERS.
TUESDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. AREAS OF SEAS APPROACHING 5 FT. FREEZING SPRAY,
SLIGHT CHANCE OF SNOW SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
SYNOPSIS...FRANK/MENSCH
NEAR TERM...MENSCH
SHORT TERM...MENSCH
LONG TERM...FRANK
AVIATION...FRANK/MENSCH
MARINE...FRANK/MENSCH
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