814
FXUS61 KBOX 241111
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
711 AM EDT MON MAR 24 2025
SYNOPSIS
A FRONTAL SYSTEM MOVING IN THIS MORNING WILL BRING A ROUND OF
INTERIOR SNOW TO WINTRY MIX, WITH PLAIN RAIN EXPECTED FOR THE
COASTAL PLAIN. A MINOR ACCUMULATION OF SNOW AND SLEET IS EXPECTED
WITH VERY LIMITED IMPACTS THIS MORNING BEFORE TRANSITIONING OVER TO
PLAIN RAIN IN INTERIOR SOUTHERN NEW ENGLAND. DRYING OUT FOR TUESDAY,
BUT THERE IS POTENTIAL FOR ANOTHER ROUND OF SHOWERS MID-WEEK AS A
SYSTEM TRACKS TO THE SOUTHEAST OF NEW ENGLAND. THURSDAY TRENDS DRIER
WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL. A WEAK SYSTEM
BRINGS CHANCES FOR SCATTERED SHOWERS THURSDAY NIGHT INTO EARLY
FRIDAY.
NEAR TERM /UNTIL 6 PM THIS EVENING/
KEY MESSAGES...
* WARM FRONTAL PRECIPITATION MOVES IN THIS MORNING IN THE FORM OF
BOTH RAIN AND SNOW; VERY LIGHT IF ANY ACCUMULATIONS EXPECTED
OUTSIDE OF THE HIGH ELEVATIONS.
* SNOW CHANGES TO RAIN FOR MOST BY MID MORNING, FOR THE HIGHEST
ELEVATIONS BY MID AFTERNOON.
REGIONAL RADAR ALREADY SHOWS RETURNS MOVING INTO WESTERN CT AT THIS
HOUR, BUT IT IS A BIT DECEIVING. BUFKIT SOUNDINGS SHOW SOME VERY DRY
AIR IN THE LOW LEVELS AND SURFACE OBS INDICATE A DEWPOINT DEPRESSION
15 TO 20 DEGREES. THUS, WE'RE NOT SEEING ANY OF THIS PRECIPITATION
MAKING IT TO THE GROUND UNTIL AS FAR WEST SW PA AND CENTRAL NJ. AS
SOUTHERLY FLOW PICKS UP OVER THE NEXT SEVERAL HOURS THIS WILL SERVE
TO BOTH INCREASE SURFACE MOISTURE AND TEMPERATURES. THUS, AS THE
BOUNDARY LAYER SATURATES WE'LL EVENTUALLY SEE RAIN AND INTERIOR SNOW
MAKE IT TO THE GROUND AS WE GET CLOSER TO SUNRISE. THE BIGGEST
IMPEDIMENT TO SEEING AN IMPACTFUL SNOWFALL WILL BE THAT DRY AIR
DELAYING PRECIP ONSET, ALLOWING MORE TIME FOR WARMING LOW LEVELS.
REGARDLESS, SOUTHERLY FLOW AND THE DIRUNAL TEMPERATURE CURVE WILL
LEAD TO MOST LOCATIONS CHANGING TO RAIN BY MID TO LATE MORNING SO
IMPACTS ARE EXPECTED TO BE MINIMAL. THE HIGHEST ELEVATIONS OF THE
BERKSHIRES AND WORCESTER HILLS WILL BE TOUGHEST TO SCOUR OUT THAT
SUBFREEZING AIR AND THE LAST TO CHANGE, SO EXPECTING THE MOST
ACCUMULATION THERE, UP TO AN INCH OR SO. MODEL SOUNDINGS DO INDICATE
POTENTIAL FOR A WINTRY MIX (INCLUDING A BRIEF PERIOD OF SLEET OR
FREEZING RAIN) GIVEN A 900 MB WARM NOSE, BUT ANY OCCURRENCE SHOULD
BE ISOLATED IN NATURE. ELSEWHERE SOME NON ACCUMULATING FLAKES TO A
QUICK COATING IS POSSIBLE BEFORE BEING WASHED AWAY BY RAIN.
THE REST OF THE DAY IS COOL AND RAW WITH RAIN, LOW CLOUDS, AND HIGHS
ONLY REACHING THE 40S. DRIER AIR ABOVE 850 MB WILL BRING AN END TO
THE RAIN FROM WEST TO EAST BETWEEN 5 PM AND 9 PM.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/
KEY MESSAGES...
* DRY MONDAY NIGHT AND TUESDAY.
* WARMER ON TUESDAY WITH HIGHS IN THE LOW TO MID 50S.
DESPITE THE QUICK ARRIVAL OF THE MID/UPPER LEVEL DRY SLOT MONDAY
EVENING LOW LEVEL MOISTURE GETS TRAPPED UNDER A LOW LEVEL INVERSION
AROUND 925 MB. THIS MEANS THOSE LOW CLOUDS MAY STICK AROUND ALL
NIGHT UNTIL THE INVERSION MIXES OUT TUESDAY MORNING. THEN, EXPECT
MORE SUN, THOUGH DIURNAL MID CLOUDS INCREASE IN THE AFTERNOON.
DESPITE A COOLER AIRMASS OVERHEAD, MORE SUN AND THE DOWNSLOPE
COMPONENT OF THE WESTERLY WINDS SHOULD ALLOW TEMPS TO BE WARMER THAN
MONDAY, IN THE LOW TO MID 50S.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
KEY MESSAGES:
* POTENTIAL FOR SYSTEM TO BRING A ROUND OF SHOWERS WEDNESDAY.
* SCATTERED SHOWERS POSSIBLE THURSDAY NIGHT INTO EARLY FRIDAY.
* MORE UNSETTLED WEATHER POSSIBLE FOR THE WEEKEND.
WEDNESDAY - FRIDAY:
AN UPPER LEVEL TROUGH REMAINS ANCHORED ACROSS THE NORTHEAST WITH AN
EMBEDDED SHORTWAVE TROUGH MOVING THROUGH THE FLOW WEDNESDAY. THIS
WILL TRACK A SYSTEM NEAR THE REGION BRING OUR NEXT SHOT AT SEEING
PRECIPITATION. DETAILS STILL NEED TO BE IRONED OUT ESPECIALLY WITH
THE TRACK WHICH WILL IMPACT QPF AND PRECIPITATION CHANCES. ENSEMBLE
GUIDANCE SHOWS DECENT AGREEMENT AMONG MEMBERS WITH THE SURFACE LOW
TRACKING SOUTHEAST OF SOUTHERN NEW ENGLAND. PROBABILITIES FOR >0.10"
OF QPF ARE HIGHEST ACROSS THE CAPE AND ISLANDS WHERE THEY RANGE FROM
50 TO 70 PERCENT ACROSS VARIOUS ENSEMBLE GUIDANCE. RAIN AMOUNTS WILL
DEPEND ON HOW THE SURFACE LOW TRACKS, BUT OVERALL THIS STILL
LOOKS LIKE LIGHTER RAIN EVENT ON MOST GUIDANCE.
THURSDAY WILL FEATURE A BRIEF DRY PERIOD WITH A TRANSIENT AREA OF
HIGH PRESSURE BUILDING IN FROM THE SOUTH. DESPITE THIS, HIGH
TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL IN THE MID 40S TO
UPPER 40S. A WEAK EMBEDDED SHORTWAVE WITHIN TROUGH ALOFT MAY BRING
ANOTHER ROUND OF LOW COVERAGE/SCATTERED SHOWERS LATER THURSDAY INTO
EARLY FRIDAY. THE HIGHER ELEVATIONS OF THE INTERIOR MAY SEE A FEW
SNOW SHOWERS. THERE IS A LOW CHANCE FOR LIGHT SNOW ACCUMULATION FOR
THE HIGH POINTS OF THE BERKSHIRES OVERNIGHT. BREEZY CONDITIONS
FRIDAY WITH HIGHS IN THE UPPER 40S TO LOW 50S IN MOST SPOTS.
WEEKEND:
ENSEMBLES SUGGEST THAT THE PARADE OF SHORTWAVES CONTINUE INTO NEXT
WEEKEND. THERE IS THE POTENTIAL FOR YET ANOTHER AREA OF LOW PRESSURE
LATER SATURDAY INTO SUNDAY. ENSEMBLES EVEN SUGGEST A PERIOD OF
WINTRY PRECIPITATION AT THE ONSET, BUT DETAILS ARE FAR FROM CERTAIN
AT THIS TIME.
AVIATION /11Z MONDAY THROUGH FRIDAY/
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE:
TODAY: HIGH CONFIDENCE IN TRENDS, THOUGH SOME UNCERTAINTY ON
TIMING OF PRECIPITATION.
VFR TO START THEN DECREASING TO IFR LATE MORNING AND AFTERNOON
IN RA. ARRIVAL OF PRECIP AND MVFR CEILINGS/VISBYS AROUND
08-12Z, WHICH WOULD START AS A PERIOD OF LIGHT SNOW MIXED WITH
PL MIXING IN FOR INTERIOR TERMINALS. THERE IS A LOW PROBABILITY
OF A BRIEF PERIOD OF FZRA AT BAF DURING THE TRANSITION FROM SN
TO RA. LITTLE ACCUM OF SN OR FZRA IF ANY BEFORE 12Z. SN/SNPL CHANGING
TO RA FOR THE INTERIOR AIRPORTS BETWEEN 14-17Z. ELSEWHERE,
OTHER THAN A BRIEF PERIOD OF WET SNOW AT ONSET FOR PVD, BED AND
BOS AROUND 13-14Z, VAST MAJORITY OF PRECIP IS RA. RA FOR THE
CAPE/ISLANDS. PRECIP ENDS FROM WEST TO EAST 20-23Z, BUT CEILINGS
MAY STILL BE LOW AS DRYSLOT MOVES IN ALOFT AND TRAPS CLOUD
COVER AROUND. SE TO S WINDS 10 TO 15 KT WITH GUSTS NEAR THE
SOUTH COAST AROUND 25 KT. SOME LOW LEVEL SHEAR POSSIBLE FOR PVD
AND THE CAPE AIRPORTS BETWEEN 18 AND 20Z. LOW LEVEL SHEAR MAY
CONTINUE THRU 23Z ACROSS THE CAPE.
TONIGHT: HIGH CONFIDENCE.
INITIAL MVFR-IFR CEILINGS SLOWLY IMPROVE TO MVFR, MAINLY AFTER
MIDNIGHT. SW WINDS DECREASING TO AROUND 5 KT OR LESS.
TUESDAY: HIGH CONFIDENCE.
VFR. WSW WINDS 10-15 KTS GUSTING 15 TO 20 KTS.
BOS TAF...MODERATE CONFIDENCE IN TAF. SMALL PROBABILITY OF SN
MIXING IN AT THE ONSET OF PRECIPITATION.
BDL TAF...MODERATE CONFIDENCE IN TAF. PRECIPITATION MAY BEGIN
AS LATE AS 13Z.
OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/...
TUESDAY NIGHT: VFR. SLIGHT CHANCE RA.
WEDNESDAY: VFR. CHANCE RA.
WEDNESDAY NIGHT: VFR.
THURSDAY THROUGH FRIDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
HIGH CONFIDENCE.
SMALL CRAFT ADVISORIES IN EFFECT FOR MONDAY INTO TUESDAY.
SE WINDS INCREASE TO AROUND 15-25 KT WITH GUSTS TO 30 KT THIS
MORNING AND CONTINUE INTO THE AFTERNOON. WINDS BECOMING S AND
DECREASING TO AROUND 10-15 KT TONIGHT. SEAS INCREASE THIS MORNING TO
AROUND 4-8 FT, HIGHEST ON THE SOUTHERN OFFSHORE WATERS. RAIN
DEVELOPS THIS MORNING AND CONTINUES INTO EARLY TONIGHT, WITH VSBYS
DECREASING TO 2-4 MILES.
DRY MONDAY NIGHT AND TUESDAY. WINDS WILL BE SW 10 TO 15 KT, GUSTING
15 TO 20 KT TUESDAY AFTERNOON.
OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/...
TUESDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT. SLIGHT CHANCE OF RAIN.
WEDNESDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. CHANCE OF RAIN.
WEDNESDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT. SLIGHT CHANCE OF RAIN.
THURSDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT.
THURSDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. AREAS OF SEAS APPROACHING 5 FT.
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 25 KT. SEAS UP TO 5 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230-
236.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ231>235-237-
251.
SMALL CRAFT ADVISORY UNTIL 5 AM EDT TUESDAY FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR ANZ254>256.
SYNOPSIS...BW/FT
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...FT
AVIATION...BW/FT
MARINE...BW/FT
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