922
FXUS61 KBOX 201705
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1205 PM EST TUE JAN 20 2026
WHAT HAS CHANGED
THERE HAVE BEEN NO SIGNIFICANT CHANGES SINCE THE LAST FORECAST
UPDATE.
KEY MESSAGES
- COLD AND DRY WITH WIND CHILLS IN THE TEENS OR LOWER THROUGH
WEDNESDAY MORNING.
- NEAR-NORMAL TO WARMER THAN NORMAL TEMPERATURES MIDWEEK AS A WEAK
CLIPPER THE SYSTEM BRINGS SOME HIGHER TERRAIN LIGHT SNOW AND LIGHT
RAIN FOR THE COASTAL PLAIN WEDNESDAY NIGHT.
- AN ARCTIC AIRMASS ARRIVES FRIDAY NIGHT WITH DANGEROUS COLD AND
WIND CHILLS AND CONTINUES THROUGH THE WEEKEND. MONITORING A
LATE- WEEKEND COASTAL STORM THAT POSES A LOW RISK AT THE
MOMENT FOR HIGH IMPACTS IN SOUTHERN NEW ENGLAND.
DISCUSSION
KEY MESSAGE 1...COLD AND DRY WITH WIND CHILLS IN THE TEENS OR
LOWER THROUGH WEDNESDAY MORNING.
A COLD FRONT MOVING THROUGH EARLY THIS MORNING WILL BRING AN ARCTIC
AIRMASS TO SOUTHERN NEW ENGLAND THROUGH WEDNESDAY MORNING. WITH
925MB TEMPERATURES AROUND -16C AND 850MB TEMPERATURES NEAR -22C,
SURFACE TEMPERATURES THIS AFTERNOON WILL STRUGGLE TO REACH THE MID-
20S. ANY MELTED SNOW FROM YESTERDAY WILL HAVE ALREADY REFROZEN
OVERNIGHT, AND UNTREATED SURFACES COULD BE SLIPPERY FOR THE MORNING
COMMUTE. AS WINDS PICK UP THIS MORNING TO 15-25MPH, WIND CHILLS/FEEL-
LIKE TEMPERATURES WILL PLUMMET TO NEAR 0 FOR MOST OF SOUTHERN NEW
ENGLAND... LOW TEENS FOR THE CAPE/ISLANDS. WINDS DROP OFF THIS
EVENING 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 WARMER THAN NORMAL TEMPERATURES
MIDWEEK AS A WEAK CLIPPER THE SYSTEM BRINGS LOW CHANCES OF HIGHER
TERRAIN SNOW SHOWERS AND LIGHT RAIN FOR THE COASTAL PLAIN WEDNESDAY
NIGHT.
TEMPERATURES WILL CONTINUE TO MODERATE WEDNESDAY NIGHT AND THURSDAY
AS WARMER SOUTHWEST FLOW CONTINUES AHEAD OF A BROAD, SHALLOW MID
LEVEL TROUGH MOVING OVER THE GREAT LAKES BY THURSDAY. THIS WILL PUSH
925 MB TEMPS FROM -10C ON WEDNESDAY TO AROUND -1C ON THURSDAY; WE
CAN EXPECT THIS TO RESULT IN MUCH MILDER THURSDAY MORNING LOWS (20S
TO LOW 30S) AND WARMER THAN AVERAGE HIGHS THURSDAY (UPPER 30S TO
LOW 40S). THIS WARM AIR IS ADVECTED OVERHEAD ON A ROBUST LLJ, MOST
OF WHICH SHOULD REMAIN ALOFT OVERNIGHT; HOWEVER, WE'LL SEE BREEZY
CONDITIONS ESPECIALLY OVER THE WATERS. THIS ACCOMPANIES A
PROGRESSIVE ALBERTA CLIPPER THAT SLIDES THROUGH TO OUR NORTH ON
THURSDAY, AHEAD OF WHICH WE'LL SEE SOME LIGHT RAIN/HIGH ELEVATION
SNOW SHOWERS WEDNESDAY NIGHT. VERY LITTLE MOISTURE TO WORK WITH WITH
PWATS OF 0.2" TO 0.4" AND AS SUCH EXPECTING ONLY A COATING TO A HALF
INCH OF SNOW IN THE WORCESTER HILLS AND NORTHERN BERKSHIRES.
KEY MESSAGE 3...AN ARCTIC AIRMASS ARRIVES FRIDAY NIGHT WITH
DANGEROUS COLD AND WIND CHILLS AND CONTINUES THROUGH THE WEEKEND.
MONITORING A LATE- WEEKEND COASTAL STORM THAT POSES A LOW RISK AT
THE MOMENT FOR HIGH IMPACTS IN SOUTHERN NEW ENGLAND.
WE CONTINUE TO EXPECT A SIGNIFICANT PATTERN CHANGE TO END THE WEEK
AND CARRY US THROUGH THE WEEKEND COURTESY OF AN INTRUSION OF TRULY
ARCTIC AIR INTO THE EASTERN CONUS. IN NEW ENGLAND WE'LL SEE A MOSTLY
DRY COLD FRONT SWING THROUGH SOMETIME FRIDAY USHERING IN THE COLDEST
AIR OF THE SEASON SO FAR. GLOBAL ENSEMBLE GUIDANCE HAS HELD STEADY
(EPS) OR INCREASED (GEFS) THE MAGNITUDE OF THE COLD IN THE LAST 12-
24 HOURS WITH 850MB TEMPS BETWEEN -25 AND -30C WHILE ENSEMBLE
SITUATIONAL AWARENESS TABLES SHOWS SURFACE TEMPS 3 STANDARD
DEVIATIONS BELOW NORMAL. WE'RE LOOKING AT ACTUAL TEMPERATURES
DROPPING INTO THE NEGATIVE SINGLE DIGITS (HIGH TERRAIN) AND SINGLE
DIGITS FRIDAY NIGHT ONWARD, AND THIS IS ACCOMPANIED BY GUSTY WINDS
MAKING TEMPERATURES "FEEL LIKE" -15 TO -20 (HIGH TERRAIN) AND THE
NEGATIVE SINGLE DIGITS.
TOO SOON TO SPEAK WITH ANY CONFIDENCE ON A STORM THAT WILL BE
PASSING TO OUR SOUTH LATE NEXT WEEKEND, POTENTIALLY BRINGING A
PERIOD OF SNOW. AT THE MOMENT SIGNS POINT TO THE MORE SIGNIFICANT
IMPACTS BEING CONTAINED SOUTH INTO THE MID-ATLANTIC AND BEYOND.
AGAIN, LOW CONFIDENCE AS THE EXACT TRACK WITH DICTATE WHO GETS SNOW
AND HOW MUCH. WHAT'S NOT IN QUESTION IS THAT WE'LL HAVE PLENTY OF
COLD AIR AROUND.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z UPDATE...
THROUGH 00Z: HIGH CONFIDENCE.
VFR. WEST WINDS GUSTING 20-25 KNOTS, BECOMING LIGHT AFTER 00Z.
TONIGHT: HIGH CONFIDENCE.
VFR. WEST WINDS 5-10 KNOTS.
WEDNESDAY: HIGH CONFIDENCE.
VFR. SOUTHWEST WINDS 5-10 KNOTS.
WEDNESDAY NIGHT: MODERATE CONFIDENCE.
INCREASING MID-LEVEL CLOUDINESS. LOW-END MVFR CLOUD BASES AROUND
3000 FEET POSSIBLE. SCATTERED -SN.
KBOS TERMINAL...
VFR. GUSTY W WINDS 23-27 KNOTS THROUGH THIS EVENING.
KBDL TERMINAL...
VFR. INCREASING W WINDS THROUGH THIS EVENING WITH GUSTS OF
20-25 KNOTS.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.
SLIGHT CHANCE RA, SLIGHT CHANCE FZRA, SLIGHT CHANCE SN.
THURSDAY: VFR. BREEZY. SLIGHT CHANCE FZRA.
THURSDAY NIGHT THROUGH SATURDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
REST OF TODAY THROUGH WEDNESDAY...
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 THROUGH TUESDAY
NIGHT AS AIR TEMPS DROP INTO THE 20S. WARMING UP WEDNESDAY WITH
LIGHTER WINDS.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS
WITH GUSTS UP TO 30 KT. AREAS OF ROUGH SEAS. CHANCE OF FREEZING
RAIN, 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. LOCAL ROUGH SEAS.
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 30 KT. SEAS UP TO 5 FT.
FRIDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 30 KT. AREAS OF
ROUGH SEAS. FREEZING SPRAY, SLIGHT CHANCE OF SNOW.
SATURDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. LOCAL ROUGH SEAS. FREEZING SPRAY, SLIGHT CHANCE OF
SNOW.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ230-
231-236-251.
SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR ANZ232>235-
237.
SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR ANZ250-
254>256.
DISCUSSION...BW/MCMINN
AVIATION...MCMINN/RM
MARINE...BW/MCMINN
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