966  
FXUS61 KBOX 210850  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
350 AM EST THU NOV 21 2024  
   
SYNOPSIS  
 
A SLOW-MOVING LOW PRESSURE AREA SPREADS WELCOMED STEADY LIGHT  
TO MODERATE RAIN TODAY, BEFORE TAPERING TO INTERMITTENT RAIN  
SHOWERS TONIGHT INTO EARLY FRIDAY. RAIN COULD MIX WITH SLUSHY  
WET SNOW ABOVE 1500 FEET ELEVATION TONIGHT BUT NO WINTRY IMPACTS  
ARE EXPECTED. ANOTHER ROUND OF STEADY LIGHT RAIN MOVES THROUGH  
EASTERN NEW ENGLAND FRIDAY AFTERNOON AND EVENING. LOW PRESSURE  
SLOWLY PROGRESSES INTO THE MARITIMES FOR THE WEEKEND, WITH GUSTY  
NORTHWEST WINDS AND MORE CLOUDS THAN SUN ARE ANTICIPATED. DRY  
WEATHER THEN RETURNS FOR MONDAY BEFORE AN UNSETTLED WEATHER  
PATTERN DEVELOPS AGAIN FOR THE MIDDLE OF NEXT WEEK.  
 
 
   
NEAR TERM /UNTIL 6 AM THIS MORNING/  
 
TODAY  
 
THE FORECAST FOR TODAY CAN BE SUMMED UP IN ONE WORD. WET. A MUCH  
NEEDED OF SOAKING OF RAIN FOR SOUTHERN NEW ENGLAND TODAY AS AN AREA  
OF LOW-PRESSURE MEANDERS OFF THE SOUTH COAST OF SOUTHERN NEW ENGLAND  
BEFORE RETROGRADING NORTH AND WEST OVER NEW YORK OVERNIGHT. SHOWERS  
BEGIN MOVING INTO WESTERN MA/CT DURING THE 5-7AM TIME FRAME BEFORE  
BECOMING A STEADY MODERATE RAIN BETWEEN 7 AND 10 AM. SHOWERS LIKELY  
DON'T REACH THE EASTERN AREAS UNTIL AFTER 8AM, BECOMING A MODERATE  
STEADY RAIN BETWEEN 10AM AND NOON. EXPECT PERIODS OF MODERATE  
RAINFALL TO PERSIST RIGHT THROUGH THIS EVENING WITH INCREASING WINDS  
OUT OF THE EAST FROM 10 TO 15 MPH. RAIN AND CLOUDS KEEP TEMPERATURES  
IN THE UPPER 40S/LOW 50S.  
 
 
   
SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/  
 
TONIGHT  
 
STEADY MODERATE RAIN CONTINUES THROUGH ABOUT MIDNIGHT BEFORE SHOWER  
ACTIVITY BEGINS TO WANE AS THE ASSOCIATED SURFACE LOW-PRESSURE  
CIRCULATIONS RETROGRADES WEST INTO EASTERN NEW YORK. WHILE WIDESPREAD  
SHOWER ACTIVITY WILL COME TO AN END, BROAD CYCLONIC FLOW ALOFT MAY  
CONTINUE TO SUPPORT A FEW LINGERING SHOWERS INTO THE PRE-DAWN HOURS.  
WINDS GRADUALLY SHIFT TO THE SOUTH/SOUTHWEST BY SUNRISE TOMORROW.  
LOW TEMPS BOTTOM OUT IN THE MID TO UPPER 30S. CAN'T RULE OUT A FEW  
SNOW SHOWERS AT THE HIGHER ELEVATIONS OF THE BERKSHIRES AND  
NORTHERN WORCESTER HILLS, BUT WE WOULD NOT EXPECT ANY ACCUMULATION.  
 
TOMORROW  
 
GENERALLY A COOL/CLOUDY UNSETTLED DAY TOMORROW AS A BROAD UPPER-  
LEVEL LOW MEANDERS OVER THE NORTHEAST. WE SHOULD DRY OUT FOR A FEW  
HOURS IN THE MORNING BEFORE SHOWERS REDEVELOP BY LATE MORNING/EARLY  
AFTERNOON. THIS WILL OCCUR AS THE UPPER-LOW BEGINS TO SHIFT EAST  
OVER THE ATLANTIC WATERS. SHOWER ACTIVITY WON'T BE AS WIDESPREAD AND  
PERSISTENT COMPARED TO WHAT IS EXPECTED TODAY, BUT AN ADDITIONAL  
TENTH TO QUARTER OF AN INCH CAN BE EXPECTED MAINLY EAST OF I-495.  
TEMPERATURES WILL BE CLOSE TO NORMAL AGAIN IN THE UPPER 40S/LOW 50S.  
SOUTHERLY WINDS GRADUALLY BECOME SOUTHEASTERLY/EASTERLY AGAIN BY THE  
AFTERNOON.  
 
 
   
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/  
 
HIGHLIGHTS:  
 
* CLOUDY, DAMP AND OVERCAST FRI NIGHT, WITH STEADY RAINS BREAKING  
OUT IN THE COASTAL PLAIN.  
 
* GUSTY NW WINDS THIS WEEKEND, WITH MORE CLOUDS ON SAT ALONG WITH  
OFF-AND-ON SHOWERS. SEASONABLE TEMPS BUT THE WINDS WILL MAKE IT  
FEEL COOLER.  
 
* DRY FOR MONDAY, BUT TURNING MORE UNSETTLED INTO MIDWEEK.  
 
DETAILS:  
 
FRIDAY NIGHT:  
 
CLOUDY, DAMP AND UNSETTLED CONDITIONS FOR SOUTHERN NEW ENGLAND  
CONTINUE INTO FRI NIGHT WITH VERTICALLY-STACKED CIRCULATION  
CONTINUING TO MEANDER AROUND WESTERN NEW ENGLAND/SOUTHERN NY  
VICINITY. HOWEVER THERE STILL LOOKS TO BE A ROUND OF STEADIER LIGHT  
RAINS WHICH DEVELOP/ROTATE NNW FROM THE SOUTHERN WATERS INTO EASTERN  
MA, THE CAPE AND THE ISLANDS. LOOKING AT GEFS/EPS/GEPS ENSEMBLE  
MEMBERS, THERE IS A SIGNIFICANT ENOUGH MAJORITY OF MEMBERS WHICH  
KEEP THIS SECONDARY BURST OF STEADIER RAINS INTO THE MA/RI COASTAL  
PLAIN WITH LIGHTER INTERMITTENT PRECIP OVER WESTERN MA/CT. HOWEVER  
QPF AMTS ARE STILL PRETTY VARIABLE; WHILE QPF AMTS ARE MORE COMMONLY  
IN THE QUARTER TO HALF INCH RANGE IN THE COASTAL PLAIN THRU FRI  
NIGHT, THERE ARE A MINORITY OF MEMBERS UP TO 3/4THS AN INCH. BY  
EARLY SAT AM, THIS BAND OF STEADIER RAINS SHOULD SHIFT NNE INTO  
COASTAL ME/NH AS THE BROADER UPPER LEVEL LOW BEGINS TO PULL  
OFFSHORE.  
 
THE WEEKEND:  
 
ENSEMBLES CONTINUE TO TREND TOWARD A SLOWER NE DEPARTURE OF THE  
UPPER-LEVEL LOW AND ITS COLD POCKET OF AIR ALOFT FOR THE WEEKEND.  
THUS A TREND TOWARD CLOUDIER CONDITIONS FOR SAT WITH OFF-AND-ON  
LIGHT SHOWERS, WITH BETTER CHANCES IN EASTERN AND NORTHERN MA, CAPE  
AND ISLANDS. LESS CLOUD COVER IN GENERAL FOR SUNDAY, WITH MORE  
IN/AROUND THE TERRAIN BUT WITH DRIER CONDITIONS. HIGHS ON SAT IN THE  
40S TO AROUND 50, AND WITH A PRETTY STRONG NWLY GRADIENT FLOW AND  
CLOUD COVER, LOWS MAY ONLY FALL INTO THE UPPER 30S TO LOW 40S. WITH  
LESS CLOUD COVER, HIGHS SUN IN THE 40S TO LOWER 50S WITH LOWS IN THE  
30S SUN NIGHT.  
 
THE COOLER TEMPERATURES ALOFT AND A ROBUST NW GRADIENT FLOW WILL  
ALSO CONTRIBUTE TO RATHER BLUSTERY TO GUSTY NW WINDS THROUGH THE  
WEEKEND. MODEL SOUNDINGS ALSO CONTINUE TO SHOW MIXING UP TO ABOUT  
900 MB ON SAT, AND SLIGHTLY HIGHER AROUND 850 MB FOR SUN WITH A  
LITTLE LESS CLOUD COVER AND SLIGHTLY WARMER TEMPS. FOR SAT, NW GUSTS  
COULD REACH INTO THE 25 TO 30 MPH RANGE DURING THE DAYTIME HRS.  
STRONGEST 925 MB JET OF 35-40 KT MOVES THRU SAT NIGHT INTO EARLY ON  
SUN, AND WE SHOULD STILL REALIZE GUSTS AROUND 20-25 MPH INTO THE  
EVENING FOR MOST AREAS, BUT COULD PUNCH UP TO AROUND 35-45 MPH OVER  
THE BERKSHIRES, HILLS IN WORCESTER COUNTY AS WELL AS THE CAPE AND  
ISLANDS. STILL SEE GUSTS IN THE 25 TO 35 MPH RANGE FOR SUNDAY THRU  
THE EARLY AFTERNOON, THEN BEGINNING TO SUBSIDE LATE IN THE DAY AS  
GRADIENT STARTS TO RELAX AND LOW LEVEL JET CORE SHIFTS OFFSHORE.  
POTENTIAL FOR GALE HEADLINES FOR THE WATERS, ALTHOUGH OVER LAND,  
CONFIDENCE IN GUSTS REACHING ADVISORY LEVELS IS LOWER BUT COULD BE  
POSSIBLE IF WE MIX DEEPER. WILL REASSESS GUSTS AS WE GET INTO THE  
MESOSCALE MODEL FORECAST HORIZON.  
 
MONDAY:  
 
STILL LOOKING AT PRETTY TRANQUIL WEATHER CONDITIONS FOR MON WITH  
WEAK SHORTWAVE RIDGING ALOFT AND MODEST SW WINDS ALLOWING FOR HIGHS  
IN THE LOW TO MID 50S.  
 
MONDAY NIGHT THROUGH WEDNESDAY NIGHT:  
 
A MORE ACTIVE WEATHER PATTERN IS INDICATED BY MOST OF THE ENSEMBLES  
INTO THE EARLY TO MIDDLE PART OF NEXT WEEK, AS SLOW-EVOLVING TROUGH  
ENERGY CIRCULATING OVER THE WEST COAST/PAC NW BEGINS TO EJECT  
EASTWARD OFF THE ROCKIES. AT LEAST ONE FRONTAL SYSTEM MOVES IN  
DURING THIS PERIOD, AROUND THE MON NIGHT/TUE TIMEFAME, ALTHOUGH  
THERE ARE STILL SIGNIFICANT DIFFERENCES IN STRENGTH WITH THIS  
POTENTIAL SYSTEM. FORECAST CONFIDENCE IS STILL ON THE LOW SIDE IN  
THIS PERIOD AND STAYED FAIRLY CLOSE TO NBM FORECASTS FOR THIS PERIOD  
UNTIL THOSE DIFFERENCES SHAKE OUT.  
 
 
   
AVIATION /09Z THURSDAY THROUGH MONDAY/  
 
FORECAST CONFIDENCE LEVELS:  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
06Z TAF UPDATE:  
 
THROUGH 12Z THURSDAY: HIGH CONFIDENCE IN TRENDS, MODERATE ON  
TIMING.  
 
MVFR STRATUS INITIALLY (IFR AT ORH) WITH DRY WEATHER FOR AT  
LEAST ANOTHER COUPLE HRS. STEADY LIGHT TO MODERATE RA WITH VSBYS  
3-6 SM NOW OVER THE LOWER HUDSON VALLEY THEN BREAKS OUT INTO  
BAF/BDL AROUND 08-10Z, AND INTO CENTRAL MA/RI BY ~10-12Z. BETTER  
CHANCE FOR STEADIER RAINS EASTERN AIRPORTS JUST AFTER 12Z.  
CEILINGS MAY TREND CLOSER TO MVFR/BORDERLINE IFR RANGE AS STEADY  
RAIN BREAKS OUT. LIGHT E WINDS TO START BUT WILL INCREASE TO  
AROUND 7-10 KT THRU 12Z THURS.  
 
TODAY: MODERATE CONFIDENCE.  
 
3-5 SM RA SPREADS ACROSS ALL AIRPORTS EARLY THIS AM, WHICH  
CONTINUES INTO EARLY TONIGHT. RAIN WILL BECOME INCREASINGLY  
WIND-DRIVEN AS E WINDS INCREASE TO AROUND 10-15 KT WITH  
GUSTS 20-25 KT NEAR THE E MA COAST.  
 
MVFR/IFR CEILINGS CONTINUE, THOUGH CEILINGS LIKELY TO DANCE  
BETWEEN 800-1500 FT MOST OF THE DAY. TOOK A PESSIMISTIC  
APPROACH WITH THE TAFS INDICATING IFR, HOWEVER THERE COULD BE  
MVFR INTERVALS IN BETWEEN BUT DIFFICULT TO PINPOINT A TIMING.  
 
TONIGHT: MODERATE CONFIDENCE.  
 
WIDESPREAD 3-6 SM STEADY RA EARLY TONIGHT TRENDS TO MORE OF AN  
INTERMITTENT -SHRA OR EVEN -DZ BETWEEN 00-06Z, EARLIEST SOUTH  
AND LATER NORTH. STEADIER LIGHT RAIN LIKELY TO CONTINUE AT  
BAF/BDL. IMPROVEMENT IN CEILINGS TOWARD OVC MVFR INTERIOR, AND  
BECOME BKN/OVC VFR OVER EASTERN/SOUTHEAST NEW ENGLAND. WINDS  
START E AROUND 10-15 KT WITH GUSTS 20-25 KT, THOUGH WILL BECOME  
SE/S AROUND 10-14 KT WITH LESSER GUSTS TO AROUND 20 KT.  
 
FRIDAY: MODERATE CONFIDENCE.  
 
MVFR CEILINGS WITH PERIODS OF -RA INTERIOR CT/MA, BKN/OVC VFR  
CEILINGS WITH INITIALLY DRY WX EASTERN AIRPORTS. LATER IN THE  
AFTERNOON A BAND OF RAIN MOVES NORTHWARD FROM THE OCEAN AND  
SPREADS ACROSS EASTERN MA/RI, EXACT TIMING UNCERTAIN BUT LIKELY  
NOT SOONER THAN 18Z. SE TO S WINDS AROUND 7-14 KT WITH GUSTS UP  
TO 20 KT.  
 
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CIGS INITIALLY,  
TRENDING IFR/MVFR WITH 3-6 SM RA DEVELOPING AROUND ~12-13Z.  
CIGS COULD FLIP BETWEEN IFR-MVFR LEVELS FREQUENTLY TODAY.  
WIND-DRIVEN RAIN ON ENE/E WINDS AROUND 15 KT TODAY WITH GUSTS  
20-25 KT. RA TAPERS OFF AROUND 03Z TO A INTERMITTENT  
LIGHT -SHRA, WITH WINDS BECOMING SE AROUND 10-13 KT.  
 
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CIGS INITIALLY,  
TRENDING IFR-MVFR W/ 3-6 SM RA DEVELOPING AROUND ~08-10Z. STEADY  
LIGHT TO MODERATE RA CONTINUES THRU ABOUT 02Z BEFORE LIGHTENING  
UP. E WINDS AROUND 10 KT TODAY, BECOMING SE TONIGHT.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
FRIDAY NIGHT: MAINLY MVFR, WITH LOCAL IFR POSSIBLE. BREEZY. RA  
LIKELY.  
 
SATURDAY: MAINLY VFR, WITH LOCAL IFR POSSIBLE. WINDY WITH LOCAL  
GUSTS UP TO 30 KT. CHANCE RA.  
 
SATURDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. WINDY  
WITH GUSTS UP TO 35 KT. SLIGHT CHANCE RA.  
 
SUNDAY: VFR. WINDY WITH GUSTS UP TO 35 KT.  
 
SUNDAY NIGHT: VFR. BREEZY.  
 
MONDAY: VFR.  
 
 
   
MARINE  
 
FORECASTER CONFIDENCE LEVELS:  
 
LOW - LESS THAN 30 PERCENT.  
MEDIUM - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
TODAY THROUGH FRIDAY  
 
CONDITIONS DETERIORATE OVER THE COASTAL WATERS TODAY AS AN AREA OF  
LOW-PRESSURE MOVES OVER THE SOUTH COASTAL WATERS. SEAS BUILD TO 6 TO  
8 FEET BY THE MID-AFTERNOON HOURS WITH MODERATE EASTERLY WINDS  
GUSTING TO 30 KNOTS. A FEW GALE FORCE GUSTS MAY BE POSSIBLE OVER THE  
EASTERN MARINE ZONES NEAR THE MIDNIGHT HOUR, BUT GENERALLY  
EXPECTING GUSTS TO STAY IN THE SCY RANGE. WE SHOULD SEE  
IMPROVING CONDITIONS DURING DURING THE DAY FRIDAY, BUT STILL  
EXPECT 5 FOOT SEAS OVER THE OUTER MARINE ZONES THROUGH FRIDAY  
EVENING. WINDS OVER THE COASTAL WATERS ON FRIDAY WILL BE  
EASTERLY FROM 10 TO 20 KNOTS WITH A FEW GUSTS UP TO 25 KNOTS  
POSSIBLE.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
FRIDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. RAIN.  
 
SATURDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 30 KT. AREAS OF ROUGH SEAS. RAIN LIKELY.  
 
SATURDAY NIGHT: MODERATE RISK FOR GALE FORCE WINDS WITH GUSTS  
UP TO 35 KT. ROUGH SEAS UP TO 11 FT. CHANCE OF RAIN.  
 
SUNDAY: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS UP TO  
10 FT.  
 
SUNDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 30 KT. AREAS OF ROUGH SEAS.  
 
MONDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.  
 
 
   
BOX WATCHES/WARNINGS/ADVISORIES  
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST  
FRIDAY FOR ANZ231>234-251.  
SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ235-237.  
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST  
SATURDAY FOR ANZ250-254-255.  
SMALL CRAFT ADVISORY UNTIL 7 AM EST SATURDAY FOR ANZ256.  
 
 
 
 
 
SYNOPSIS...LOCONTO/RM  
NEAR TERM...RM/NOCERA  
SHORT TERM...RM  
LONG TERM...LOCONTO  
AVIATION...LOCONTO/RM  
MARINE...LOCONTO/RM  
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