145
FXUS61 KBOX 021921
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
221 PM EST MON MAR 2 2026
WHAT HAS CHANGED
WINTER WEATHER ADVISORIES POSTED FOR TUESDAY AFTERNOON TO
WEDNESDAY MORNING FOR INTERIOR SOUTHERN NEW ENGLAND FOR LIGHT
ACCRETION OF ICING AND MINOR SNOW AND SLEET ACCUMULATION.
THERE IS ALSO INCREASING CONFIDENCE ON A PERIOD OF A WINTRY MIX
THURSDAY NIGHT INTO FRIDAY ACROSS NORTHERN MA.
KEY MESSAGES
- WINTRY MIX OF SNOW, SLEET AND FREEZING RAIN BRINGS SLIPPERY
ROADS TO INTERIOR SOUTHERN NEW ENGLAND TUE AFTERNOON AND
EVENING; BRIEF WET SNOW CHANGES TO PLAIN RAIN AND MINIMAL TO
NIL IMPACT FOR THE MA/RI COASTAL PLAIN.
- DRY AND VERY PLEASANT WEATHER ARRIVES WEDNESDAY, FEELING MILD
WITH MARCH SUNSHINE, LIGHT WINDS AND HIGHS IN THE UPPER 40S TO
LOWER 50S.
- A PERIOD OF WINTRY PRECIP REMAINS POSSIBLE THU NIGHT INTO
EARLY FRI.
- PATTERN CHANGE TOWARDS MILDER WEATHER THIS WEEKEND AND
POTENTIALLY WARMER NEXT WEEK.
DISCUSSION
215 PM UPDATE:
KEY MESSAGE 1...WINTRY MIX OF SNOW, SLEET AND FREEZING RAIN BRINGS
SLIPPERY ROADS TO INTERIOR SOUTHERN NEW ENGLAND TUE AFTERNOON AND
EVENING; BRIEF WET SNOW CHANGES TO PLAIN RAIN AND MINIMAL TO NIL
IMPACT FOR THE MA/RI COASTAL PLAIN.
QUASI-STATIONARY FRONTAL BOUNDARY LYING ACROSS THE OH VALLEY AND MID-
ATLANTIC PIEDMONT REGION WILL LIFT NORTHWARD ON TUE, SPREADING
CLOUDS AND WARM-FRONTAL PRECIPITATION NORTHWARD INTO SOUTHERN NEW
ENGLAND TUE STARTING MAINLY DURING THE EARLY TO MID-AFTERNOON HOURS.
THIS PRECIP WILL BE FALLING INTO A RETREATING MODIFIED-ARCTIC
AIRMASS COMING OUT OF ANOTHER CHILLY NIGHT TONIGHT. HOWEVER THE
COMBINATION OF ONSHORE/EAST FLOW AND ASSOCIATED WARMING SURFACE
TEMPS ALONG THE COASTAL PLAIN TO GO ALONG WITH LIMITED SURFACE
HEATING BEFORE TURNING OVERCAST DURING THE MORNING HOURS COULD
OFFSET EVAPORATIVE/WET-BULB COOLING UNTIL PRECIP ARRIVES. GIVEN THE
NOW-DELAYED ARRIVAL OF PRECIP AND QUESTIONS ON HOW SOON ARRIVAL OF
CLOUDS COME IN, HOW COLD SURFACE TEMPS COULD STILL PROVE TO BE A
CHALLENGE; UTILIZED SOME OF THE COLDER 2-M TEMPS GIVEN THE POTENTIAL
FOR WET-BULBING WHICH MODEL-BLENDED SOLUTIONS TEND TO WASH OUT OR
NOT RESOLVE AS WELL.
WE STILL EXPECT A WINTRY MIX OF SNOW/SLEET/FREEZING RAIN IN INTERIOR
SOUTHERN NEW ENGLAND DURING THE AFTERNOON AND EVENING HOURS WHERE
WINTER WEATHER ADVISORIES HAVE BEEN POSTED FROM TUE NOONTIME TIL
EARLY WED MORNING. THE MAIN IMPACT IN THOSE AREAS IS FROM ICING,
WITH UP TO A TENTH OF AN INCH OF ICE ACCRETION, AND UP TO AN INCH OF
COMBINED SNOW/SLEET ACCUMULATION AT OUTSET. IT IS SOMEWHAT
DEBATABLE/UNCERTAIN HOW MUCH ROAD IMPACT THERE MAY BE DURING
THE TUE AFTERNOON DRIVE, AND THAT'S ESPECIALLY THE CASE IF CLOUD
COVER IS SLOW TO ARRIVE AND ENDS UP PERMITTING SEVERAL HOURS OF
STRONG EARLY-MARCH SUN TO WARM UP PAVEMENT; FEEL MORE CONFIDENT
IN AT LEAST SLIPPERY ROAD CONDITIONS DEVELOPING BY THE EARLY
EVENING HOURS, AS TEMPS HOVER OR SLIGHTLY COOL ON LIGHT NE
DRAINAGE WINDS WHICH WILL HELP SUSTAIN FROZEN P-TYPES IN
INTERIOR SOUTHERN NEW ENGLAND UNTIL PRECIP COMES TO AN END WED
MORNING.
IN THE COASTAL PLAIN, A BRIEF PERIOD OF WET SNOW DURING THE
EARLY TO MIDAFTERNOON TUESDAY SHOULD MIXOVER WITH RAIN WITH
TEMPS IN THE MID 30S, THEN CHANGE TO A PLAIN RAIN FOR THE
REMAINDER OF THE EVENING WHERE ADVERSE ROAD IMPACTS SHOULD PROVE
MINIMAL.
KEY MESSAGE 2...DRY AND VERY PLEASANT WEATHER ARRIVES
WEDNESDAY, FEELING MILD WITH MARCH SUNSINE, LIGHT WINDS AND
HIGHS IN THE UPPER 40S TO LOWER 50S.
SHORT WAVE RIDGING IN FAST FLOW ALOFT ADVECTS ACROSS SNE, PROVIDING
A VERY PLEASANT, DRY WED ACROSS SNE. MILD WITH HIGHS IN THE UPPER
40S AND LOW 50S. IT FEEL EVEN MILDER GIVEN LIGHT WINDS AND FULL
MARCH SUNSHINE.
KEY MESSAGE 3...A PERIOD OF WINTRY PRECIP REMAINS POSSIBLE THU
NIGHT INTO EARLY FRI.
FAST, WAVY ZONAL UPPER AIR PATTERN YIELDS THE NEXT PRECIP EVENT FOR
SNE THU NIGHT INTO FRI. 1040 MB ANTICYCLONE OVER SOUTHEAST QUEBEC
INTO THE MARITIMES WILL YIELD A WEDGE OF SHALLOW COLD AIR INTO SNE.
THIS WILL SUPPORT THE RISK OF A WINTRY MIX THIS PERIOD, WITH HIGHEST
PROBS OF AN ICY MIX ACROSS NORTHERN MA. IT'S POSSIBLE THIS SHALLOW
COLD AIR COULD BLEED FARTHER SOUTH, WITH A LOW RISK OF A WINTRY MIX
NEAR OR INTO THE I-95 CORRIDOR. JUST TOO EARLY TO TELL, THIS NEEDS
TO BE WATCHED. NOT A MAJOR WINTER EVENT, BUT IT ONLY TAKES A SMALL
AMOUNT OF ICE TO IMPACT TRAVEL. STAY TUNED.
KEY MESSAGE 4...PATTERN CHANGE TOWARD MILDER WEATHER THIS
WEEKEND AND POTENTIALLY WARMER NEXT WEEK.
GOOD MULTI-MODEL AGREEMENT ON A PATTERN CHANGE BEGINNING THIS
WEEKEND AND CONTINUING INTO NEXT WEEK, WITH A SOUTHEAST/WESTERN
ATLANTIC RIDGE. THIS WILL PROMOTE SW UP THE EASTERN SEABOARD INTO
SNE, WITH TEMPS RISING INTO THE LOW 50S SATURDAY, AND POSSIBLY LOW
60S AWAY FROM THE SOUTH COAST SUNDAY AND MONDAY. DEW PTS WILL BE
RISING INTO THE LOW 50S THEN, SO DEFINITELY A MILD FEEL TO THE
AIRMASS, ALONG WITH ACCELERATING THE EROSION OF THE THE SNOW PACK
WITH DEW PTS RISING INTO THE 50S AND SW WINDS 10-15 MPH PROVIDING
SOME MIXING AROUND THE SNOWCOVER.
AVIATION /19Z MONDAY THROUGH SATURDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE:
THROUGH 12Z TUESDAY: HIGH CONFIDENCE.
VFR. LIGHT NORTHERLY WINDS BECOME SW LATE IN THE AFTERNOON, AND
BECOME S/SW 5 KT OR LESS THRU TONIGHT.
TUESDAY: MODERATE CONFIDENCE.
VFR SHOULD GENERALLY PREVAIL THRU AT LEAST 17Z TUE, ALTHOUGH
WITH LOWERING CEILINGS. CONDITIONS DETERIORATE TO MVFR AFTER 18Z
WITH WINTRY MIX OF PRECIP TYPES, THEN TO IFR LATE-DAY.
PREDOMINANT SN/FZRA INTERIOR SNE WITH MINOR SNOW/ICE ACCUMS AND
ICY RUNWAYS MORE LIKELY FOR THOSE AIRPORTS; COASTAL SNE AIRPORTS
(PVD, BOS, CAPE) INITIAL LIGHT SNOW MIXED WITH RAIN WITH NIL
ACCUM AND MAINLY WET RUNWAYS, CHANGING TO PLAIN RAIN AFTER 22Z.
WINDS BECOME SE/ESE AROUND 5-10 KT.
TUESDAY NIGHT: MODERATE CONFIDENCE.
IFR/LIFR CEILINGS, WITH FZRA MAINLY HIGHER TERRAIN OF SOUTHERN
NEW ENGLAND AND PLAIN RAIN FOR THE MAJORITY OF SOUTHERN NEW
ENGLAND. PRECIP ENDS FROM WEST TO EAST AFTER 10Z, BUT RAIN MAY
LINGER ALONG THE SOUTH COAST INTO EARLY WED AM. ESE WINDS 5-10
KT LIGHTEN AND SHIFT TO W/WNW AS PRECIP ENDS WEST TO EAST.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. VFR, ESE WINDS 5 KT OR
LESS CONTINUE THRU 22Z BEFORE FLIPPING TO S. THESE CONDITIONS
CONTINUE THRU TUE AM, MVFR DEVELOPS AFTER 19Z TUE, WITH BRIEF
PERIOD OF 4SM -SNRA 21-23Z BEFORE BECOMING RA BY 23Z. NIL ACCUM
AND WET RUNWAYS EXPECTED GIVEN AIR TEMPS 32-35F.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. VFR THRU AT LEAST 16Z
TUE. CEILINGS DETERIORATE TO MVFR/IFR WITH LIGHT SNOW,
TRANSITIONING TO FREEZING RAIN BETWEEN ~21-02Z. IT IS MORE
UNCERTAIN HOW LONG FREEZING RAIN MAY LAST AS TEMPS MAY HOVER
AROUND 31-33F OVERNIGHT.
OUTLOOK /TUESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY: VFR. SLIGHT CHANCE RA, SLIGHT CHANCE FZRA.
WEDNESDAY NIGHT: VFR. SLIGHT CHANCE SN.
THURSDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. CHANCE RA.
THURSDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE. BREEZY. CHANCE
RA, FZRA LIKELY.
FRIDAY: MVFR/IFR CONDITIONS POSSIBLE. BREEZY. RA LIKELY, FZRA
LIKELY.
FRIDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE. SLIGHT CHANCE RA.
SATURDAY: MAINLY VFR, WITH AREAS IFR POSSIBLE. BREEZY. SLIGHT
CHANCE RA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH TUESDAY NIGHT...HIGH CONFIDENCE.
WINDS AND SEAS REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS
THROUGH AT LEAST TUESDAY AFTERNOON, WITH SOUTH TO SOUTHEAST
WINDS AROUND 10-15 KT. SEAS MAY BEGIN TO BUILD LATE TUESDAY
NIGHT INTO WEDNESDAY TO AROUND 4-6 FT ON THE SOUTHEAST OUTER
WATERS, WHICH COULD PROMPT SMALL CRAFT ADVISORIES. REDUCED
VISIBILITIES POSSIBLE IN SNOW TO RAIN TUESDAY AFTERNOON.
OUTLOOK /TUESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. SLIGHT
CHANCE OF RAIN, SLIGHT CHANCE OF FREEZING RAIN.
WEDNESDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT. SLIGHT CHANCE OF RAIN.
THURSDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
CHANCE OF RAIN.
THURSDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT. RAIN LIKELY.
FRIDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. AREAS OF ROUGH SEAS. RAIN LIKELY.
FRIDAY NIGHT THROUGH SATURDAY: WINDS LESS THAN 25 KT. AREAS OF
ROUGH SEAS. SLIGHT CHANCE OF RAIN.
BOX WATCHES/WARNINGS/ADVISORIES
CT...WINTER WEATHER ADVISORY FROM NOON TUESDAY TO 7 AM EST
WEDNESDAY FOR CTZ002>004.
MA...WINTER WEATHER ADVISORY FROM NOON TUESDAY TO 7 AM EST
WEDNESDAY FOR MAZ002>012-014-026.
RI...WINTER WEATHER ADVISORY FROM NOON TUESDAY TO 7 AM EST
WEDNESDAY FOR RIZ001.
MARINE...NONE.
DISCUSSION...LOCONTO/NOCERA
AVIATION...LOCONTO/NOCERA
MARINE...LOCONTO/NOCERA
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