FXUS61 KBOX 241423
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1023 AM EDT FRI MAR 24 2023
 SYNOPSIS
DRY AND SEASONABLE TODAY AS HIGH PRESSURE BUILDS IN FROM THE
GREAT LAKES AND SOUTHEAST CANADA A FRONTAL SYSTEM SATURDAY WILL
BRING A WINTRY MIX ACROSS THE INTERIOR AND HIGHER TERRAIN, WITH
A COLD RAIN ELSEWHERE WINTRY MIX AND RAIN TAPERING OFF
SATURDAY NIGHT THEN DRY WEATHER RETURNS SUNDAY INTO MONDAY WITH
ABOVE NORMAL TEMPERATURES LOW CONFIDENCE IN UNSETTLED WEATHER
SOMETIME IN THE TUESDAY THROUGH THURSDAY PERIOD
 &&
NEAR TERM /UNTIL 6 PM THIS EVENING/
1025 AM UPDATE
NO CHANGES IN THE LATEST UPDATE HAVE JUST BROUGHT THINGS IN
LINE WITH CURRENT OBSERVATIONS FORECAST REMAINS ON TRACK
PREVIOUS DISCUSSION
HIGH PRES BUILDS TO THE ACROSS THE GT LAKES AND SE CANADA TODAY WITH
A MODEST NORTHERLY FLOW BRINGING A DRY AIRMASS AS PWATS GENERALLY
LESS THAN 025" WHILE THE COLUMN IS DRY, THERE WILL BE A LOT OF
HIGH CLOUDS STREAMING ACROSS THE REGION ACCOMPANYING A STRONG UPPER
JET WITHIN THE CONFLUENT FLOW ALOFT ACROSS NEW ENG THESE HIGH
CLOUDS ARE ALREADY MOVING IN WHICH WILL LEAD TO FILTERED SUNSHINE
TODAY 925 MB TEMPS AROUND 0-3C SUPPORTING HIGHS MID/UPPER 40S HIGH
TERRAIN AND 50-55 DEGREES ELSEWHERE OVERALL, A PLEASANT EARLY
SPRING DAY WITH A MODEST NW BREEZE
&&
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/
TONIGHT
HIGH PRES BUILDS TO THE NORTH TONIGHT WITH CONTINUED DRY AIRMASS
THERE MAY BE A WINDOW FOR RADIATIONAL COOLING AS HIGHS CLOUDS THIN
OUT, BUT CLOUDS WILL BE INCREASING OVERNIGHT AHEAD OF THE NEXT
SYSTEM WE BLENDED IN SOME OF THE COLDER MOS GUIDANCE TO TREND THE
FORECAST MINS A BIT COLDER THAN NBM, WITH LOWS MID 20S TO LOWER 30S
WINDS WILL BE LIGHT N/NE
SATURDAY
ROBUST MID LEVEL LOW LIFTS NE INTO THE GT LAKES WITH A MID LEVEL
WARM FRONT MOVING ACROSS THE REGION A BAND OF ENHANCED MOISTURE AND
LIFT ASSOCIATED WITH THIS MID LEVEL FRONT WILL BRING A PERIOD OF
PRECIP TO SNE ONSET TIMING IS A BIT UNCERTAIN AS THERE WILL BE SOME
LOW LEVEL DRY AIR TO OVERCOME, BUT IT APPEARS PRECIP WILL DEVELOP
FROM WEST TO EAST FROM MID MORNING INTO EARLY AFTERNOON FROM WEST TO
EAST ANTECEDENT LOW LEVEL COLD AIR WILL BE IN PLACE, WHILE SW MID
LEVEL JET BRINGS A WARM NOSE IN THE 800-700 MB LAYER NORTHWARD INTO
THE REGION WHICH WILL SET THE STAGE FOR A WINTRY MIX IN THE
INTERIOR A BRIEF PERIOD OF SNOW IS POSSIBLE AT THE ONSET ACROSS
NORTHERN MA BUT WARMING ALOFT WILL BRING A QUICK CHANGEOVER TO SLEET
WITH MINIMAL SNOW ACCUM, MOSTLY LESS THAN AN INCH SOUNDINGS SHOW A
RELATIVELY DEEP LOW LEVEL COLD LAYER SUPPORTIVE OF A PERIOD OF SLEET
IN THE INTERIOR AS DEVELOPING SECONDARY LOW TO THE SOUTH WILL HELP
TO LOCK IN THE LOW LEVEL COLD AIR BUT MIXING WITH RAIN AS THE
BOUNDARY LAYER WARMS POCKETS OF FREEZING RAIN WILL BE CONFINED TO
HIGHER ELEVATIONS OF THE BERKSHIRES WHERE TEMPS WILL REMAIN NEAR
FREEZING ALONG THE I-95 CORRIDOR TO THE SOUTH COAST, MAINLY RAIN IS
EXPECTED, BUT SOME SLEET MAY MIX IN AT TIMES AS 925 MB TEMPS ARE
COLD HIGHS RANGE FROM MID 30S TO LOWER 40S, AND EASTERLY WINDS WILL
BE INCREASING AND BECOMING GUSTY IN THE AFTERNOON, ESPECIALLY NEAR
THE COAST AND HIGHER ELEVATIONS
&&
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
HIGHLIGHTS
* WINTRY MIX AND COLD RAIN TAPERING OFF LATE SAT INTO EARLY SUN NOT
OUT OF THE QUESTION THERE ARE A FEW RUMBLES OF THUNDER ACROSS THE
SOUTH COAST
* DRY WEATHER RETURNS SUN/MON WITH NEAR TO ABOVE NORMAL TEMPS WILL
BE A BIT BREEZY ON SUN CANNOT COMPLETELY RULE OUT FIRE WEATHER
CONCERNS, BUT DEPENDS ON HOW MUCH PRECIP FALLS ON SAT
* LOW CONFIDENCE IN UNSETTLED WEATHER SOMETIME IN THE TUE TO THU
TIMEFRAME
SATURDAY NIGHT INTO EARLY SUNDAY
A CUTOFF LOW/TROUGH WILL BE SITUATED OVER THE CENTRAL GREAT
LAKES/ONTARIO SAT EVENING THE TROUGH WILL LIFT INTO NORTHERN NEW
ENGLAND/QUEBEC BY EARLY SUN A DEEP LOW WILL BE LOCATED OVER THE
CENTRAL GREAT LAKES/ONTARIO SAT EVENING, WHILE A SECONDARY LOW
BEGINS DEVELOPING ALONG THE SOUTH COAST THE SECONDARY LOW DEEPENS
AS THE NIGHT PROGRESSES AND LIFTS INTO THE GULF OF MAINE BY EARLY
SUN
WILL STILL HAVE A WINTRY MIX OF SLEET/FREEZING RAIN ACROSS THE
HIGHER TERRAIN DURING THE EVENING EXPECT THAT THE MIX WILL CONTINUE
TO RETREAT NORTHWARD AS THE NIGHT PROGRESSES AS THE 925 HPA TEMPS
WARM TO ABOVE 0 DEGREES CELSIUS BY ROUGHLY 03-06Z AS A RESULT AM
EXPECTING A CHANGEOVER TO PLAIN RAIN BEFORE THE PRECIP COMPLETELY
TAPERS OFF EARLY ON SUNDAY AS THE SECONDARY LOW LIFTS INTO THE GULF
OF MAINE
DO HAVE SOME CONCERNS THAT PRECIP MAY END A BIT QUICKER THAN
CURRENTLY FORECAST GIVEN THE TRACK OF THE 700 HPA LOW WILL SEE A
DRY SLOT PUNCH INTO SOUTHERN NEW ENGLAND THIS WOULD LIKELY BRING AN
END TO THE PRECIP QUICKER THAN WE'VE CURRENTLY GOT ADVERTISED WILL
NOTE THAT DID ADD A MENTION OF THUNDER ACROSS THE SOUTH COAST AS
THE DRY SLOT PUNCHES IN WILL SEE MID LEVEL LAPSE RATES STEEPEN TO
ROUGHLY 6-8 DEGREES CELSIUS SHOULD SEE A FEW HUNDRED J/KG OF MUCAPE
AVAILABLE, SO ISOLATED THUNDERSTORMS WILL BE POSSIBLE LOW
TEMPERATURES WILL BE IN THE 30S ACROSS THE REGION HEADING INTO SUN
SUNDAY THROUGH MONDAY
A SHORTWAVE RIDGE BUILDS OVER ONTARIO INTO QUEBEC ON SUN BEFORE
FLATTENING OUT ANOTHER RIDGE BUILDS FROM THE MID/UPPER MISSISSIPPI
RIVER VALLEY LATE ON SUN INTO THE CENTRAL/EASTERN GREAT LAKES BY
LATE MON HIGH PRESSURE NUDGES INTO THE REGION FOR MUCH OF THIS
PERIOD FROM ONTARIO AND THE GREAT LAKES
GENERALLY EXPECTING DRY AND QUIET WEATHER THROUGH MUCH OF THIS
PERIOD COULD BE A BIT BREEZY AT TIMES ON SUN AS THE PRESSURE
GRADIENT WILL BE TIGHT DUE TO THE EXITING SYSTEM AND HIGH NUDGING
IN WILL SEE 925 HPA WINDS OF ROUGHLY 20-40 KTS WITH W TO WNW FLOW
ALOFT ON SUN SHOULD NOT BE TOO DIFFICULT TO MIX THIS DOWN PER
NAM/GFS BUFKIT SOUNDINGS THINKING THAT THERE COULD BE 25-40 MPH
GUSTS AT TIMES WITH THE HIGHEST SPEEDS ACROSS THE HIGHER TERRAIN
WILL SEE AN END TO THE GUSTY WINDS LATE ON SUN INTO MON AS THE
PRESSURE GRADIENT RELAXES AS THE HIGH BUILDS MORE FIRMLY INTO OUR
REGION
GIVEN THE STRONGER WNW/W FLOW ON SUN HAVE BUMPED UP TEMPS DUE TO THE
EXCELLENT MIXING EXPECTED OPTED TO BUMP UP TEMPS TOWARD THE 75TH
PERCENTILE OF GUIDANCE THE RESULT WILL BE HIGHS GENERALLY IN THE
50S, BUT THERE WILL BE SOME 60 DEGREE READINGS ACROSS THE CT AND
MERRIMACK VALLEYS STILL MILD ON MON, BUT MIXING IS NOT EXPECTED TO
BE AS DEEP HIGHS GENERALLY IN THE 50S
LASTLY, CANNOT COMPLETELY RULE OUT THERE ARE A FEW SHOWERS THAT
SPREAD INTO OUR REGION LATE ON MON LOT OF UNCERTAINTY AT THIS POINT
AS IT APPEARS TO BE THE RESULT OF SOME CONVECTION THAT FIRES NEAR
THE OH VALLEY HAVE STUCK WITH THE NBM FOR NOW GIVEN THE
UNCERTAINTY, WHICH HAS SLIGHT CHANCES OF PRECIP DOES NOT APPEAR IT
WOULD RESULT IN A WASHOUT EVEN IF IT COMES TO FRUITION
TUESDAY THROUGH THURSDAY
CONSIDERABLE UNCERTAINTY DURING THIS TIMEFRAME THERE IS A LOT OF
SPREAD FROM RUN TO RUN ENSEMBLE AND DETERMINISTIC GUIDANCE IN THIS
WINDOW THINKING THAT THE LARGE UNCERTAINTY HAS TO DO WITH THE
CONVECTIVE ACTIVITY ACROSS THE SOUTHEASTERN US TO THE TN VALLEY
THERE ARE SOME MEMBERS WITHIN THE GEPS/EPS/GEFS GUIDANCE DEPICTING A
COASTAL SYSTEM IMPACTING OUR REGION AND COULD BE AS SNOW GIVEN THE
SIGNIFICANT SPREAD IN GUIDANCE HAVE STUCK WITH THE NBM FOR NOW,
WHICH FEATURES SLIGHT CHANCES TO CHANCES OF PRECIPITATION THINK
THIS IS REASONABLE FOR NOW GIVEN THE CONSIDERABLE AMOUNT OF SPREAD
AMONGST GUIDANCE AND LACK OF RUN TO RUN CONSISTENCY
&&
AVIATION /15Z FRIDAY THROUGH TUESDAY/
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT
MEDIUM - 30 TO 60 PERCENT
HIGH - GREATER THAN 60 PERCENT
TODAYHIGH CONFIDENCE
VFR WITH HIGH CLOUDS GRADUALLY DECREASING THIS AFTERNOON WINDS
OUT OF THE NW AT 5-10 KTS COULD SEE SOME 15-20 KT GUSTS ACROSS
THE REGION UNTIL ROUGHLY 14-16Z
TONIGHTHIGH CONFIDENCE
VFR WITH MID/HIGH CLOUDS INCREASING, ESPECIALLY LATE WINDS
SHIFTING TO THE NE/E WITH SPEEDS AROUND 5-10 KTS
SATURDAYHIGH CONFIDENCE IN TRENDS LOWER CONFIDENCE IN EXACT
DETAILS
CONDITIONS DETERIORATING TO MVFR/IFR WITH RAIN AND MIXED PRECIP
OVERSPREADING THE REGION BY LATE MORNING A BRIEF PERIOD OF
SNOW MAINLY CONFINED TO NORTH OF THE PIKE FOR A FEW HOURS AFTER
PRECIP ONSET OTHERWISE, RAIN AND SLEET MIX INTERIOR AND ALL
RAIN IN THE COASTAL PLAIN POCKETS OF FREEZING RAIN POSSIBLE
OVER THE BERKSHIRES IN THE AFTERNOON WINDS OUT OF THE E AND
INCREASING 10-15 KTS BY THE AFTERNOON GUSTS OF 20-30 KTS DURING
THE AFTERNOON
KBOS TERMINALHIGH CONFIDENCE IN TAF
KBDL TERMINALHIGH CONFIDENCE IN TAF
OUTLOOK /SATURDAY NIGHT THROUGH TUESDAY/
SATURDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE WINDY WITH GUSTS
UP TO 30 KT CHANCE RA, FZRA LIKELY
SUNDAY: VFR WINDY WITH GUSTS UP TO 35 KT
SUNDAY NIGHT: VFR WINDY WITH AREAS OF GUSTS UP TO 30 KT
MONDAY: VFR BREEZY
MONDAY NIGHT: VFR BREEZY SLIGHT CHANCE RA, SLIGHT CHANCE SN
TUESDAY: VFR SLIGHT CHANCE RA
&&
MARINE
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT
MEDIUM - 30 TO 60 PERCENT
HIGH - GREATER THAN 60 PERCENT
TODAY THROUGH SATURDAYHIGH CONFIDENCE
A PERIOD OF 25 KT GUSTS EXPECTED THIS MORNING ACROSS EASTERN MA
WATERS WITH A SURGE OF COLD ADVECTION, OTHERWISE EXPECT NW WINDS
BELOW 20 KT, SHIFTING TO NE TONIGHT WITH SEAS SUBSIDING INCREASING
EAST WINDS SAT WITH 25-30 KT GUSTS DEVELOPING IN THE AFTERNOON AS
LOW LEVEL JET LIFTS NORTH ACROSS THE WATERS THERE IS SOME RISK FOR
MARGINAL GALE FORCE WINDS LATE SAT/SAT EVENING RAIN DEVELOPING SAT
WITH REDUCED VSBYS
OUTLOOK /SATURDAY NIGHT THROUGH TUESDAY/
SATURDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS
WITH GUSTS UP TO 30 KT ROUGH SEAS UP TO 8 FT RAIN, ISOLATED
THUNDERSTORMS
SUNDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 25 KT AREAS OF ROUGH SEAS
SUNDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT SEAS UP TO 5 FT
MONDAY: WINDS LESS THAN 25 KT SEAS LOCALLY APPROACHING 5 FT
MONDAY NIGHT THROUGH TUESDAY: WINDS LESS THAN 25 KT SEAS
LOCALLY APPROACHING 5 FT SLIGHT CHANCE OF RAIN
&&
BOX WATCHES/WARNINGS/ADVISORIES
CTNONE
MANONE
RINONE
MARINESMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ231-
250-251
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
ANZ254>256
&&
SYNOPSISKJC/BL
NEAR TERMKJC/GAUCHER
SHORT TERMKJC
LONG TERMBL
AVIATIONKJC/BL
MARINEKJC/BL
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