737
FXUS61 KBOX 201725
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
125 PM EDT FRI MAR 20 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES.
KEY MESSAGES
- WINDY WITH SHOWERS TONIGHT BUT RAINFALL WILL NOT BE
SIGNIFICANT.
- RAIN ARRIVES SUNDAY WHICH COULD START OR END AS SOME WET SNOW.
MINOR ACCUMULATIONS POSSIBLE ESPECIALLY IN NORTHERN MA AND IN
HIGHER ELEVATIONS.
- BELOW AVERAGE TEMPERATURES TO START THE WORK WEEK THEN
MODERATING TEMPERATURES AND SOME SHOWERS POSSIBLE WEDNESDAY
AND FRIDAY.
DISCUSSION
KEY MESSAGE 1...WINDY WITH SHOWERS TONIGHT BUT RAINFALL WILL
NOT BE SIGNIFICANT.
APPROACHING COLD FRONT WILL BRING A PERIOD OF SHOWERS TO MUCH OF
SOUTHERN NEW ENGLAND TONIGHT, MAINLY IN 6 PM TO MIDNIGHT TIME FRAME,
BUT A LITTLE LATER ON CAPE COD AND ISLANDS. NOT MUCH IN WAY OF
DYNAMICS OR DEEP MOISTURE PRESENT AHEAD OF FRONT, SO RAINFALL IS
EXPECTED TO BE LIGHT, MAINLY 0.25 TO PERHAPS 0.75 INCH.
AHEAD OF FRONT, TIGHTENING PRESSURE GRADIENT AND INCREASING LOW
LEVEL JET (AS HIGH AS 45-55KT) WILL BRING WINDY CONDITIONS TO
MUCH OF REGION. FORECAST SOUNDINGS SHOW SHALLOW MIXING LAYER
WHICH WILL PREVENT STRONGEST WINDS ALOFT FROM REACHING SURFACE,
BUT WE SHOULD STILL SEE GUSTS ON ORDER OF 25-35 MPH AND PERHAPS
UP TO 40 MPH IN A FEW LOCATIONS. LOOKS LIKE GUSTS WILL FALL
SHORT OF WIND ADVISORY CRITERIA. WINDS DIMINISH OVERNIGHT AS
FRONT PUSHES THROUGH AND LOW LEVEL JET HEADS OFFSHORE.
HIGH PRESSURE BUILDS INTO NEW ENGLAND SATURDAY. EXPECTING A BREEZY
DAY WITH GUSTS OF 20-30 MPH DUE TO COLD ADVECTION AND DEEP MIXING
ALOFT, BUT MARCH SUNSHINE SHOULD OFFSET COLD ADVECTION AND HELP
HIGHS GET WELL INTO 40S AND LOWER 50S.
KEY MESSAGE 2...RAIN ARRIVES SUNDAY WHICH COULD START OR END
AS SOME WET SNOW. MINOR ACCUMULATIONS POSSIBLE ESPECIALLY IN
NORTHERN MA AND IN HIGHER ELEVATIONS.
TIMING IS EVERYTHING AND IN THIS CASE WILL DETERMINE WHETHER OR NOT
WE SEE SOME WET SNOW SUNDAY MORNING (IF PRECIPITATION BEGINS EARLY)
OR AS THINGS WIND DOWN LATER SUNDAY NIGHT AND MONDAY MORNING (IF
ENOUGH COLD AIR CAN SINK SOUTHWARD SOONER).
WE'RE GETTING INTO WINDOW FOR HIGH-RES GUIDANCE AND THERE ARE HINTS
THAT SOME SCATTERED SNOW SHOWERS COULD SNEAK INTO SOUTHERN NEW
ENGLAND SUNDAY MORNING DUE TO WEAK WARM ADVECTION AND ENOUGH COLD
AIR STILL IN PLACE, ESPECIALLY NORTH OF MASS PIKE (AS SEEN ON 3KM
NAM AND RRFS). THAT'S SOMETHING THAT WILL BE RESOLVED AS WE GET
CLOSER IN TIME BUT AT THIS POINT DOES NOT LOOK TO BE IMPACTFUL.
OVERALL, THIS LOOKS TO BE A RAIN EVENT FOR SOUTHERN NEW ENGLAND
WITH MOST OF RAIN FALLING SUNDAY EVENING INTO EARLY MONDAY
MORNING AS FRONTAL BOUNDARY LIES JUST TO OUR NORTH, KEEPING US
IN WARM SECTOR. MODELS DO SAG FRONT SOUTHWARD LATER SUNDAY
NIGHT, ALLOWING COLDER AIR TO SEEP SOUTHWARD, BUT BY THEN ALL OF
THE APPRECIABLE LIFT AND DEEPER MOISTURE SHOULD BE EXITING
REGION.
SHOULD FRONT DROP SOUTH SOONER, HOWEVER, WE WOULD SEE AN EARLIER
CHANGEOVER TO SNOW AND WOULD SEE SOME MINOR SNOW ACCUMULATIONS,
ESPECIALLY NORTH OF MASS PIKE AND IN HIGHER ELEVATIONS. LATEST
ENSEMBLES CONTINUE TO SHOW LOW CHANCES (20-30%) OF 1" OR MORE OF
SNOW FOR THOSE LOCATIONS, BUT IT WOULD NOT TAKE MUCH OF A SHIFT
SOUTHWARD TO BRING A LITTLE MORE SNOW. ELSEWHERE, EVEN IF IT SNOWS,
LITTLE OR NO ACCUMULATION IS EXPECTED. MODEL SNOW DEPTH CHANGE MAPS
WILL GIVE BEST DEPICTION IN THIS CASE BUT WE'VE SEEN 12Z NAM WHICH
IS DEFINITELY AN OUTLIER RIGHT NOW. IT CLOSES OFF 850 LOW NEAR CAPE
COD WHICH BRINGS STRONGER LIFT AND DEEPENS COLDER AIR QUICKLY MONDAY
MORNING, SOMETHING NOT SUPPORTED BY MAJORITY OF GUIDANCE WHICH
FAVORS A MORE PROGRESSIVE SYSTEM. SOMETHING TO WATCH THOUGH.
ONE OTHER THING TO MENTION IS WE ARE IN A PERIOD OF HIGH
ASTRONOMICAL TIDES THROUGH THE WEEKEND. THE EARLY MONDAY MORNING
HIGH TIDE (2-4 AM) ALONG E MA COAST IS ONE WE ARE KEEPING AN EYE ON
SINCE THE ASTRONOMICAL TIDE IS 11.0 FT AT BOSTON AND 3.8 FT AT
NANTUCKET. RIGHT NOW THE HIGHER-END SCENARIO WITH A SURGE OF 1.0
FEET KEEPS BOTH BELOW FLOOD STAGE BUT WITH INCREASING N/NE WINDS
AROUND THE TIME OF HIGH TIDE (DEPENDING ON HOW FAST THE FRONT DROPS
SOUTH), THE SURGE COULD END UP BEING A LITTLE HIGHER. WORST CASE
RIGHT NOW LOOKS TO BE SPLASHOVER OR LOWER-END MINOR COASTAL FLOODING.
KEY MESSAGE 3...BELOW AVERAGE TEMPERATURES TO START THE WORK
WEEK THEN MODERATING TEMPERATURES AND SOME SHOWERS POSSIBLE
WEDNESDAY AND FRIDAY.
HIGH PRESSURE BRINGS DRY WEATHER MONDAY AND TUESDAY ALONG WITH
SEASONABLE TEMPERATURES FOR LATE MARCH, ALTHOUGH IT LOOKS LIKE WE'RE
IN FOR A COUPLE OF COLD MORNINGS BOTH DAYS. UPPER PATTERN SHOWS
FAIRLY RAPID WEST TO EAST FLOW ALOFT WHICH MAKES IT DIFFICULT TO
TIME SHORT WAVES MOVING THROUGH, BUT IT DOES APPEAR WE COULD SEE
SOME SHOWERS WEDNESDAY AND AGAIN FRIDAY AS A SERIES OF WEAK LOWS
CROSS THE REGION. WE SHOULD ALSO SEE A MODERATING TREND IN
TEMPERATURES BUT IT MAY BE COLD ENOUGH INITIALLY BOTH DAYS FOR SOME
WET SNOW AT ONSET ACROSS INTERIOR.
AVIATION /16Z FRIDAY THROUGH TUESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE: HIGH CONFIDENCE (60%).
VFR CONDITIONS THIS AFTERNOON GIVE WAY TO MVFR AND EVENTUALLY IFR AS
A BAND OF SHOWERS MOVES THROUGH SOUTHERN NEW ENGLAND, STARTING
AROUND 21Z IN WESTERN MA, REACHING BDL-ORH-BED AROUND 23Z, BOS-PVD
AROUND 00Z, AND FMH/HYA/ACK 02-03Z. SHOWERS LAST ABOUT 6 HOURS AND
LEAVE IFR CIGS/VSBYS IN THEIR WAKE, BEFORE IMPROVEMENT TO VFR SAT
MORNING AS WINDS SHIFT TO NW.
MAIN CONCERN IS WIND, ESPECIALLY THROUGH EARLY TONIGHT WITH S/SW
WINDS GUSTING TO 20-30KT AND LLWS WITH 020 WINDS 190/40-50KT. WINDS
SUBSIDE LATER TONIGHT AND BECOME W, THEN NW SAT MORNING, AS
FRONT MOVES OFFSHORE. A FEW 20KT GUSTS EXPECTED INTO EARLY SAT
AFTERNOON.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. PEAK GUSTS EXPECTED JUST
BEFORE 00Z SAT WITH BRIEF 35KT GUSTS POSSIBLE.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /SUNDAY THROUGH TUESDAY/...
SUNDAY: MAINLY VFR, WITH AREAS MVFR POSSIBLE. BREEZY. CHANCE
RA, CHANCE SN.
SUNDAY NIGHT: MAINLY MVFR, WITH AREAS IFR POSSIBLE. BREEZY. RA
LIKELY, CHANCE SN.
MONDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. BREEZY. CHANCE RA,
CHANCE SN.
MONDAY NIGHT THROUGH TUESDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH THE WEEKEND.
SCAS REMAIN POSTED THROUGH TONIGHT FOR INCREASING S/SW WINDS GUSTING
AS HIGH AS 30KT. IT'S POSSIBLE A FEW GUSTS REACH MARGINAL GALE FORCE
(34KT) BUT WE DON'T THINK THAT WILL BE WIDESPREAD OR LAST MORE THAN
AN HOUR OR TWO AT MOST. SHOWERS MOVE THROUGH WATERS TONIGHT AND
SHOULD EXIT WATERS EAST OF CAPE COD OVERNIGHT.
NW WINDS BEHIND FRONT SATURDAY SHOULD REMAIN BELOW SCA BUT IT WILL
REMAIN IN PLACE FOR OUTER WATERS WHERE SEAS WILL TAKE AWHILE LONGER
TO FALL BELOW 5 FT.
COLD FRONT DROPPING SOUTH ACROSS WATERS MONDAY MAY BE ACCOMPANIED BY
PERIOD OF 20-25KT N/NE WINDS.
OUTLOOK /SUNDAY THROUGH TUESDAY/...
SUNDAY: WINDS LESS THAN 25 KT. CHANCE OF RAIN.
SUNDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT. RAIN LIKELY.
MONDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. AREAS OF ROUGH SEAS. CHANCE OF RAIN.
MONDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. ROUGH SEAS UP TO 9 FT.
TUESDAY: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SATURDAY FOR ANZ230-236.
SMALL CRAFT ADVISORY UNTIL 5 AM EDT SATURDAY FOR ANZ231>235-
237-251.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT SATURDAY FOR ANZ250-
254>256.
DISCUSSION...JWD
AVIATION...JWD
MARINE...JWD
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