405
FXUS61 KBOX 191120
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
720 AM EDT SUN OCT 19 2025
SYNOPSIS
ANOTHER PLEASANT DAY CAN BE EXPECTED TODAY WITH MILD
TEMPERATURES AND BREEZY SOUTHERLY WINDS. A STRONG FRONTAL SYSTEM
ARRIVES EARLY MONDAY MORNING, AND BRINGS A QUICK LINE OF HEAVY
RAIN AND STRONG WINDS. THE FRONT MOVES OFFSHORE MONDAY AFTERNOON
WITH DRYING CONDITIONS AND CONTINUED BREEZY WINDS. DRIER
WEATHER RETURNS FOR TUESDAY, BUT ANOTHER FRONTAL SYSTEM ARRIVES
WEDNESDAY USHERS IN A COOLER, CLOUDIER, AND MORE UNSETTLED
WEATHER PATTERN FOR LATE IN THE WORKWEEK.
NEAR TERM /THROUGH TONIGHT/
KEY POINTS
* MILD AND BREEZY TODAY
THE UPPER-LEVEL RIDGE AXIS BEGINS TO MOVE OFFSHORE TODAY, ALLOWING
FLOW ALOFT TO TURN SW AHEAD OF A STRONG SHORTWAVE THROUGH OVER THE
OHIO RIVER VALLEY. WAA WITH THE SW FLOW ALOFT WILL BRING 850MB
TEMPS UP TO +11C TODAY, WHICH WILL TRANSLATE TO HIGH TEMPERATURES IN
THE UPPER 60S TO LOW 70S. SKIES START OFF MOSTLY SUNNY, BUT MORE
HIGH-LEVEL CLOUDS MOVE IN DURING THE AFTERNOON AHEAD OF THE
SHORTWAVE, LEAVING FILTERED SUNSHINE TO OVERCAST SKIES. WINDS
GRADUALLY INCREASE THROUGH THE DAY, GUSTING UP TO 20MPH FROM THE
SOUTH
SHORT TERM /MONDAY/
KEY POINTS
* STRONG FRONTAL SYSTEM MOVES THROUGH THE REGION MONDAY MORNING
* VERY HEAVY RAIN AND DIFFICULT DRIVING CONDITIONS LIKELY
* STRONG TO DAMAGING WINDS POSSIBLE
* RAIN ARRIVES IN WESTERN MA/CT AROUND 5-7AM AND EASTERN MA/RI
AROUND 8-11AM
TONIGHT:
CONTINUED WAA OVERNIGHT WILL KEEP OVERNIGHT TEMPS MILD, IN THE MID
TO UPPER 50S. WINDS ALOFT CONTINUE TO INCREASE AS A SOUTHERLY LLJ
AT 40-50 KNOTS MOVES INTO THE REGION. IT WILL BE TOUGH TO MIX THOSE
WINDS DOWN TO THE SURFACE AT NIGHT, BUT GUSTS OF 20-30MPH REMAIN
POSSIBLE. RAIN FOR THE MOST PART SHOULD HOLD OFF UNTIL CLOSER TO
DAYBREAK, BUT SOME SHOWERS AND LIGHT DRIZZLE ARE POSSIBLE AHEAD OF
THE MAIN LINE OF SHOWERS AND THUNDERSTORMS.
MONDAY
THE SHORTWAVE TROUGH ARRIVES ALONG WITH A STRONG SURFACE FRONT EARLY
MONDAY MORNING, AND MOVES QUICKLY OFFSHORE BY MID MONDAY AFTERNOON.
GUIDANCE IS IN RATHER GOOD AGREEMENT ON THE TIMING OF THE LINE OF
HEAVY RAIN OR FINE LINE. THE FINE LINE SHOULD BE APPROACHING
WESTERN MA/CT BETWEEN 5-7 AM AND ARRIVING AT THE I-95 CORRIDOR
BETWEEN 8-11 AM. THE LINE WILL THEN BE MOVING OFFSHORE, LIKELY
BY 1-2 PM IN THE AFTERNOON. ALTHOUGH FINE LINE WILL BE MOVING
RATHER QUICKLY, IT WILL PACK A PUNCH AS IT MOVES THROUGH AND
CREATE DISRUPTIONS TO THE MORNING COMMUTE. PWATS AHEAD OF THE
LINE WILL BE SURGING TO NEAR 1.5 INCHES, WHICH, COMBINED WITH
THE STRONG FORCING FROM THE SHORTWAVE, WILL LIKELY RESULT IN
RAIN RATES EXCEEDING 1-2 INCHES PER HOUR. STRONG TO POSSIBLY
DAMAGING WINDS MAY ALSO ACCOMPANY THE LINE AS LOW-LEVEL WINDS
AROUND 2KFT WILL BE APPROACHING 50-60MPH. THERE IS A LARGE
AMOUNT OF UNCERTAINTY ON WHETHER THESE WINDS ALOFT WILL BE ABLE
TO REACH THE GROUND, ESPECIALLY SO EARLY IN THE DAY WHEN A
NOCTURNAL INVERSION USUALLY EXISTS. HOWEVER, GUIDANCE SUGGESTS
MUCAPE VALUES COULD BE AROUND 200-400 J/KG, WHICH COULD LEAD TO
A COUPLE OF STRONGER CELLS/THUNDERSTORMS WITHIN THE GREATER LINE
AND LEAD TO THOSE STRONGER WINDS ALOFT REACHING THE SURFACE.
THE MAIN IMPACT OF THE LINE OF HEAVY RAIN WILL BE VERY DIFFICULT
DRIVING CONDITIONS FOR ROUGHLY 30-60 MINUTES ON MONDAY MORNING;
HOWEVER, I WOULD NOT RULE OUT THE POSSIBILITY OF A COUPLE
SEVERE WIND GUSTS INSIDE A STRONGER SHOWER/THUNDERSTORM.
TEMPERATURES ON MONDAY LIKELY DO NOT FOLLOW A DIURNAL CURVE, WITH
HIGH TEMPERATURES LIKELY BEING MET IN THE MORNING, REACHING THE MID-
60S. BEHIND THE RAIN AND THE FRONT, TEMPERATURES BEGIN TO FALL
INTO THE UPPER 50S. IT WILL STILL BE BREEZY BEHIND THE FRONT
WITH WSW GUSTS OF 20-25MPH.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
KEY MESSAGES:
* DRIER TUE BUT A MIX OF CLOUDS AND SUN WITH SEASONABLE TEMPS IN THE
LOW TO MID 60S.
* ANOTHER STRONG COLD FRONT MOVES IN FOR WED, HERALDING A COOLER AND
MORE UNSETTLED WEATHER PATTERN CHANGE IN STORE FOR LATE IN THE
WORKWEEK. TEMPS BY LATE WEEK TREND COOLER ON THE HIGHS WITH
SEASONABLE LOWS.
DETAILS:
PRETTY ACTIVE, CHANGEABLE WORKWEEK WEATHER-WISE, WITH ANOTHER
PRETTY STRONG COLD FRONTAL PASSAGE BOTH AGAIN ON WED. A DEEP
TROUGH THEN BECOMES ESTABLISHED LATE IN THE WEEK, USHERING IN A
COOLER, CLOUDIER AND MORE UNSETTLED WEATHER PATTERN TO CLOSE OUT
THE WORKWEEK.
BRIEF DRY WEATHER RETURNS ON TUE, STUCK BETWEEN STORM SYSTEMS, BUT
WITH A MIX OF CLOUDS AND SUN. HIGHS IN THE LOWER TO MID 60S WHICH IS
AROUND SEASONABLE. ANOTHER STRONG COLD FRONT THEN ARRIVES ON WED,
BRINGING ANOTHER PERIOD OF SOLID RAIN CHANCES; WHILE THE TIMING IS
STILL SUBJECT TO ADJUSTMENTS, CURRENT INDICATIONS ARE FOR A SIMILAR
TIMING OF RAINS AS THOSE OF MONDAY (MORNING TO EARLY AFTERNOON).
HIGHS ON WED IN THE MID 60S.
PASSAGE OF THIS SECOND COLD FRONT THEN USHERS IN A COOLER AND MORE
UNSETTLED WEATHER PATTERN CHANGE FOR LATE IN THE WEEK, AS DEEP
CYCLONIC FLOW ALOFT GOVERNS THE NORTHEAST STATES. EXPECT A PERIOD OF
COOLER, CLOUDIER WEATHER WITH PERHAPS A STRAY SHOWER OR TWO BUT NOT
WIDESPREAD NOR RESULTING IN ANY WASHOUTS. 850 MB TEMPS DROP TO NEAR
ZERO CELSIUS WHICH COULD BRING HIGHS IN THE 50S FOR THU AND FRI, A
LITTLE COOLER THAN NORMAL FOR LATE OCTOBER. NIGHTTIME LOWS MAY NOT
DROP AS FAR GIVEN CLOUD COVER, WITH LOWS IN THE MID 40S WHICH ARE
SLIGHTLY ABOVE NORMAL.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE:
TODAY... HIGH CONFIDENCE
VFR. INCREASING SOUTHERLY WINDS GUSTING UP TO 15-20 KNOTS.
TONIGHT...HIGH CONFIDENCE.
INCREASING MID-LEVEL CLOUDS. IFR-MVFR CEILING SPREAD FROM WEST
TO EAST 06Z-09Z. RAIN MAY ENTER WESTERN MA AND CT AS EARLY AS
09-11Z
MONDAY...HIGH CONFIDENCE
STRONG FRONTAL SYSTEM WILL BRING A QUICK ALBEIT HEAVY LINE OF
SHOWERS AND POSSIBLY A RUMBLE OF THUNDER MONDAY MORNING. THE
LINE SHOULD ENTER WESTERN MA BETWEEN 10-12Z, AND PROGRESS EAST
MOVING OFFSHORE BY 18Z. CIGS WILL QUICKLY DROP TO IFR/LIFR WITH
STRONG SSE WINDS GUSTING UP TO 40 KNOTS. BEHIND THE LINE, CIGS
GRADUALLY RISE TO VFR FOR THE AFTERNOON.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
VFR. INCREASING SOUTHERLY WINDS GUSTING UP TO 20 KNOTS IN THE
AFTERNOON
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
VFR. INCREASING SOUTHERLY WINDS GUSTING UP TO 20 KNOTS IN THE
AFTERNOON
OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...
MONDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.
CHANCE SHRA.
TUESDAY: VFR. BREEZY.
TUESDAY NIGHT: VFR. CHANCE SHRA.
WEDNESDAY: MAINLY VFR, WITH AREAS MVFR POSSIBLE. BREEZY. SHRA
LIKELY, SLIGHT CHANCE TSRA.
WEDNESDAY NIGHT THROUGH THURSDAY: VFR. BREEZY. SLIGHT CHANCE
SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH MONDAY...HIGH CONFIDENCE.
KEY POINT
* DANGEROUS MARINE CONDITIONS EXPECTED MONDAY MORNING TO EARLY
AFTERNOON
* SHORT PERIOD OF HEAVY RAIN AND GALE TO STORM FORCE WINDS
POSSIBLE.
TRANQUIL BOATING CONDITIONS EXPECTED TODAY WITH 2-4 FOOT SEAS AND
INCREASING SOUTHERLY WINDS AT 10-20 KNOTS. WINDS CONTINUE TO
INCREASE OVERNIGHT, GUSTING 20-30 KNOTS. A STRONG LINE OF
SHOWERS AND THUNDERSTORMS WILL APPROACH THE WATERS FROM THE WEST
EARLY MONDAY MORNING. THIS LINE IS EXPECTED TO BRING A BRIEF
PERIOD OF HEAVY RAIN AND STRONG WINDS ON THE ORDER OF 40-50
KNOTS. GIVEN THE SHORT DURATION, LIKELY UNDER 2 HOURS, THIS LINE
WILL BEST BE HANDLED WITH SHORT-FUSED SPECIAL MARINE WARNINGS
RATHER THAN LONGER-TERM GALE WARNINGS. NONETHELESS, DANGEROUS
MARINE CONDITIONS CAN BE EXPECTED ON MONDAY MORNING. SEAS
INCREASE TO 4-8 FEET BEHIND THE LINE AND WINDS REMAIN, TURNING
SSW AT 20-25 KNOTS FOR MONDAY AFTERNOON.
OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...
MONDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. AREAS OF ROUGH SEAS. CHANCE OF RAIN SHOWERS.
TUESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. CHANCE OF RAIN SHOWERS.
WEDNESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT. RAIN SHOWERS LIKELY, SLIGHT CHANCE OF THUNDERSTORMS.
WEDNESDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS
APPROACHING 5 FT. CHANCE OF RAIN SHOWERS.
THURSDAY: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS. SLIGHT
CHANCE OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 4 PM EDT MONDAY FOR ANZ230-
236.
SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM EDT MONDAY FOR
ANZ231>234.
SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 5 AM EDT TUESDAY FOR
ANZ235-237-250.
SMALL CRAFT ADVISORY FROM 2 AM TO 8 PM EDT MONDAY FOR ANZ251.
SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 8 AM EDT TUESDAY FOR
ANZ254-255.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR ANZ256.
SYNOPSIS...LOCONTO/KP
NEAR TERM...KP
SHORT TERM...KP
LONG TERM...LOCONTO/KP
AVIATION...MCMINN/KP
MARINE...KP
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