292
FXUS61 KBOX 191925
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
225 PM EST MON JAN 19 2026
WHAT HAS CHANGED
CONFIDENCE CONTINUES TO INCREASE FOR A PROLONGED ARCTIC OUTBREAK
BEGINNING AT THE END OF THIS WEEK INTO THIS WEEKEND. CONFIDENCE
REMAINS LOW IN THE LATE WEEKEND COASTAL STORM.
KEY MESSAGES
- COLD AND DRY TONIGHT THROUGH TUESDAY NIGHT. WIND CHILL INDEX
NEAR OR BELOW ZERO TONIGHT THROUGH WEDNESDAY
- NEAR-NORMAL TO MILD TEMPERATURES MIDWEEK. A WEAK CLIPPER
SYSTEM BRINGS LOW CHANCES OF HIGHER TERRAIN SNOW SHOWERS AND
LIGHT RAIN FOR THE COASTAL PLAIN.
- INCREASING CONFIDENCE IN AN ARCTIC OUTBREAK BEGINNING FRIDAY
NIGHT WITH DANGEROUS COLD AND WIND CHILLS, WHILE LOW
CONFIDENCE REMAINS IN A LATE- WEEKEND COASTAL STORM.
DISCUSSION
KEY MESSAGE 1...COLD AND DRY TONIGHT THROUGH TUESDAY NIGHT.
WIND CHILL INDEX NEAR OR BELOW ZERO TONIGHT THROUGH WEDNESDAY
A COLD FRONT WILL BRING AN ARCTIC AIR MASS TO THE REGION TONIGHT AND
LAST THROUGH TUESDAY NIGHT. STRONG CAA WILL BRING 850MB TEMPS DOWN
TO -20C BY TUESDAY MORNING, RESULTING IN AN EXTENDED PERIOD OF SUB-
FREEZING TEMPERATURES STARTING AT SUNSET TONIGHT. ANY MELTED SNOW
FROM TODAY WILL QUICKLY REFREEZE TONIGHT, AND UNTREATED SURFACES
COULD BECOME SLIPPERY. TEMPERATURES TAKE A DIVE OFF THE DEEP END
TONIGHT, DROPPING INTO THE SINGLE DIGITS TO LOW TEENS ACROSS THE
REGION. WITH WINDS PICKING UP TO 20-30MPH FROM CAA, THE WIND CHILL
INDEX/FEELS-LIKE TEMPERATURES WILL DROP TO NEAR OR SLIGHTLY BELOW
ZERO ACROSS THE REGION. CAA CONTINUES INTO TOMORROW, AND
TEMPERATURES ONLY WARM INTO THE MID-TEENS IN THE WEST AND MID-20S IN
THE EAST. GUSTY WINDS ALSO CONTINUE INTO TUESDAY WITH GUSTS OF 15-
25MPH. WIND CHILL INDEX WILL MAKE IT FEEL LIKE THE SINGLE DIGITS TO
LOW TEENS OUTSIDE. WINDS DROP OFF TUESDAY NIGHT AS HIGH PRESSURE
BUILDS IN JUST TO THE SOUTH. WITH CLEAR SKIES, LIGHT WINDS, AND
FRESH SNOWPACK, OVERNIGHT TEMPERATURES WILL DROP INTO THE SINGLE
DIGITS ACROSS THE REGION, WITH LOW TEENS NEAR THE COASTS.
KEY MESSAGE 2...NEAR-NORMAL TO MILD TEMPERATURES MIDWEEK. A WEAK
CLIPPER SYSTEM BRINGS LOW CHANCES OF HIGHER TERRAIN SNOW SHOWERS AND
LIGHT RAIN FOR THE COASTAL PLAIN.
AFTER A BRIEF SHOT OF ARCTIC AIR TEMPERATURES MODERATE FOR WEDNESDAY
AND THURSDAY, THIS PERIOD FEATURES A CHANCE OF PRECIPITATION MAINLY
BETWEEN WEDNESDAY EVENING AND THURSDAY. DRIVING THE WEATHER MIDWEEK ARE
A MID-LEVEL LOW OVER HUDSON BAY WITH EMBEDDED SHORTWAVE ENERGY ROTATING
AROUND THE CYCLONIC FLOW. THIS SUPPORTS DEVELOPMENT OF A WEAK ALBERTA
CLIPPER TRACKING SOUTHEAST FROM THE CANADIAN ROCKIES TOWARDS THE
NORTHEAST. AHEAD OF IT, A DEVELOPING SOUTHERLY LLJ WITH WIND SPEEDS 30
TO 50 KNOTS, WHICH ADVECTS A SOMEWHAT WARMER AIR MASS INTO SOUTHERN NEW
ENGLAND. NEAR-NORMAL TEMPERATURES WEDNESDAY AND AN INCREASING S-SSW
WIND. WARM ADVECTION RAIN AND/OR HIGHER TERRAIN SNOW SHOWERS ARE
POSSIBLE, 20-35 POP, FROM LATE WEDNESDAY THROUGH THE FIRST-HALF OF
THURSDAY. AS TYPICAL WITH MOST CLIPPERS, MOISTURE CONTENT IS LIMITED,
AS PWATS ARE BETWEEN 0.2" AND 0.4". WITH LITTLE DOWNSTREAM BLOCKING,
THE SYSTEM IS PROGRESSIVE. ENSEMBLES GUIDANCE REMAINS UNIMPRESSIVE,
WITH PROBABILITIES FOR SNOWFALL EXCEEDING ONE INCH GENERALLY LESS THAN
20% RANGE IN INTERIOR SOUTHERN NEW ENGLAND. THE LLJ WEAKENS THURSDAY,
STILL FAIRLY MILD FOR MID-JANUARY AS HIGHS RETURN TO THE UPPER 30S AND
LOW 40S.
KEY MESSAGE 3...INCREASING CONFIDENCE IN AN ARCTIC OUTBREAK BEGINNING
FRIDAY NIGHT WITH DANGEROUS COLD AND WIND CHILLS, WHILE LOW CONFIDENCE
REMAINS IN A LATE-WEEKEND COASTAL STORM.
WHILE STILL SEVERAL DAYS AWAY, CONFIDENCE CONTINUES TO INCREASE IN A
SIGNIFICANT ARCTIC OUTBREAK IMPACTING SOUTHERN NEW ENGLAND BEGINNING
LATE FRIDAY NIGHT AND PERSISTING THROUGH NEXT WEEKEND. AS NOTED IN
PRIOR DISCUSSIONS, A LOBE OF THE POLAR VORTEX IS FORECAST TO BREAK OFF
AND DRIVE MUCH COLDER AIR INTO THE REGION. THIS COLD AIR MASS DOES NOT
APPEAR TO BE SHORT-LIVED, WITH THE CLIMATE PREDICTION CENTER (CPC)
HIGHLIGHTING MUCH OF THE NORTHEAST, UPPER MIDWEST, AND GREAT LAKES
UNDER A MODERATE RISK FOR MUCH BELOW NORMAL TEMPERATURES INTO THE
MIDDLE OF NEXT WEEK. FOR THE UPCOMING WEEKEND, OVERNIGHT LOW
TEMPERATURES AND WIND CHILLS MAY FALL TO AROUND -20F IN THE HIGHER
TERRAIN AND -10F ACROSS THE COASTAL PLAIN. RAISING THE POTENTIAL FOR
COLD WEATHER ADVISORIES. THE MAGNITUDE OF THIS COLD IS NOTABLE, WITH
THE FORECAST 925MB TEMPERATURES ON THE ORDER OF -25C TO -30C, MORE
TYPICAL OF 500MB. THOSE WITH OUTDOOR PLANS THIS WEEKEND SHOULD CONTINUE
TO MONITOR THE FORECAST CLOSELY. GIVEN THESE CONDITIONS, MARINERS
SHOULD BE PREPARED FOR A HIGH LIKELIHOOD OF FREEZING SPRAY, THOUGH THE
EXTENT AND SEVERITY REMAIN UNCERTAIN AT THIS TIME.
IN ADDITION, THERE ARE INDICATIONS OF A POTENTIAL COASTAL SYSTEM LATE
NEXT WEEKEND. WHILE SOME GUIDANCE SUGGEST A SYSTEM MAY PASS OFFSHORE
SUNDAY INTO SUNDAY NIGHT, CONFIDENCE REMAINS LOW. RECENT AI-BASED
GUIDANCE FAVORS GREATER IMPACTS ACROSS SOUTHERN NEW ENGLAND; HOWEVER,
QPF MAY BE OVERSTATED AND MAY NOT ADEQUATELY RESOLVE A SHARP NORTHERN
GRADIENT. FOR NOW, MAINTAINED LOW-END POPS, REFLECTING ONLY A SLIGHT
CHANCE FOR SNOW SHOWERS.
AVIATION /18Z MONDAY THROUGH SATURDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE...
REST OF TODAY...MODERATE CONFIDENCE.
MIX OF VFR AND MVFR CIGS AS STRATOCUMULUS HAS FORMED ACROSS THE
REGION. CLOUDS WILL DISSIPATE AFTER SUNSET TONIGHT WITH CLEAR
SKIES. WINDS PICK UP THIS AFTERNOON GUSTING 20-30 KNOTS FROM THE
WSW.
TONIGHT...HIGH CONFIDENCE.
VFR. WSW WINDS GUSTING BETWEEN 20 AND 30 KNOTS
TUESDAY: HIGH CONFIDENCE.
VFR. WEST WINDS GUSTING 20-25 KNOTS, BECOMING LIGHT AFTER
SUNSET.
KBOS TERMINAL...
VFR WITH PERIODS OF MVFR POSSIBLE THIS AFTERNOON. WINDS BECOME
GUSTY THIS AFTERNOON THROUGH TUESDAY AT 25-30 KNOTS OUT OF THE
WSW.
KBDL TERMINAL...
VFR. INCREASING WSW WINDS TODAY THROUGH TUESDAY WITH GUSTS OF
20-25 KNOTS.
OUTLOOK /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY: VFR. BREEZY.
WEDNESDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.
SLIGHT CHANCE RA, SLIGHT CHANCE SN.
THURSDAY THROUGH FRIDAY NIGHT: VFR. BREEZY.
SATURDAY: VFR. BREEZY. SLIGHT CHANCE SN.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
REST OF TODAY THROUGH TUESDAY NIGHT...
COLD FRONT WILL BRING A PERIOD OF STRONG WESTERLY WINDS TO THE
WATERS TONIGHT THROUGH TUESDAY AFTERNOON WITH GUSTS OF 30-35
KNOTS. SEAS INCREASE TONIGHT HIGHEST IN THE SOUTHERN WATERS AT
10-13 FEET, AND 7-10 FEET IN THE NORTHERN WATERS. WINDS DECREASE
QUICKLY TUESDAY NIGHT, WITH GUSTS DROPPING BELOW 20 KNOTS. SEAS
ALSO GRADUALLY DIMINISH TO 4-6 FEET. WITH COLD ARCTIC AIR
MOVING OFFSHORE, EXPECTING LIGHT FREEZING SPRAY BOTH TONIGHT AND
TUESDAY NIGHT AS AIR TEMPS DROP INTO THE 20S.
OUTLOOK /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 25 KT. AREAS OF SEAS APPROACHING 5 FT.
WEDNESDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 30 KT. AREAS OF
ROUGH SEAS. SLIGHT CHANCE OF RAIN.
THURSDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. AREAS OF ROUGH SEAS. SLIGHT CHANCE OF RAIN.
THURSDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. AREAS OF ROUGH SEAS.
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH LOCAL
GUSTS UP TO 30 KT. SEAS UP TO 5 FT.
FRIDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 35 KT. AREAS OF
ROUGH SEAS. FREEZING SPRAY LIKELY, SLIGHT CHANCE OF SNOW.
SATURDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. LOCAL ROUGH SEAS. FREEZING SPRAY LIKELY,
SLIGHT CHANCE OF SNOW.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST TUESDAY FOR ANZ230-236.
GALE WARNING UNTIL 9 AM EST TUESDAY FOR ANZ231>235-237-250-251-
254>256.
DISCUSSION...DOOLEY/KP
AVIATION...KP
MARINE...KP
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