525  
FXUS61 KBOX 221108  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
608 AM EST THU FEB 22 2024  
   
SYNOPSIS
 
 
HIGH PRESSURE IN PLACE OVER SOUTHERN NEW ENGLAND MOVES OFFSHORE  
TODAY. AN ELONGATED WARM FRONT THEN MOVES INTO SOUTHERN NEW  
ENGLAND TONIGHT, BRINGING A ROUND OF LIGHT PRECIPITATION, SOME  
OF WHICH WILL BE FROZEN NORTH OF THE MASSACHUSETTS TURNPIKE.  
HOWEVER SNOW AND ICE ACCUMULATIONS ARE NOT EXPECTED TO BE  
SIGNIFICANT. LOW PRESSURE THEN BRINGS A MORE WIDESPREAD LIGHT  
RAIN TO SOUTHERN NEW ENGLAND ON FRIDAY. A BRIEF SHOT OF BELOW  
NORMAL TEMPERATURES AND BLUSTERY CONDITIONS LIES BEHIND THIS  
SYSTEM FOR SATURDAY. TEMPERATURES THEN BEGIN A WARMING TREND  
STARTING LATER ON SUNDAY, WITH ABOVE NORMAL TEMPERATURES  
BECOMING FAVORED FOR EARLY TO MID NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
345 AM UPDATE:  
 
AN ELONGATED RIDGE OF SFC HIGH PRESSURE REMAINS ESTABLISHED OVER  
SOUTHERN NEW ENGLAND EARLY THIS MORNING. IT'S PROVEN TO BE A REALLY  
CHALLENGING SKY COVER FORECAST; DESPITE MOST GUIDANCE INSISTING ON  
CLOUD COVER, THE REALITY IS THAT CLOUD COVERAGE IS PRETTY POCKMARKED  
WITH ONLY LOCALIZED OVERCAST STRATUS WHILE OTHERS ARE CLEAR,  
GENERALLY FAR LESS THAN GUIDANCE HAD INDICATED. THAT'S ALSO LED TO A  
WIDE RANGE OF TEMPS RANGING FROM THE MID TEENS IN MORE PERSISTENT  
CLEAR AREAS, AND AS MILD AS THE MID TO UPPER 20S WHERE OVERCAST  
EXISTS. WELL TO OUR WEST OVER THE OH VALLEY LIES AN ELONGATED WEST  
TO EAST STREAM OF MOISTURE ASSOCIATED WITH A WEAK WARM FRONT, WITH  
THICKENING MIDLEVEL CLOUD COVER EXTENDING AS FAR EAST AS CENTRAL  
PA/CENTRAL NY. THIS FEATURE WILL HAVE SOME BEARING ON THE FORECAST  
FOR TONIGHT.  
 
REALLY HARD TO GLEAN MUCH AS FAR AS A TREND IN SKY COVER GOES,  
ALTHOUGH THERE SEEMS TO BE AN INCREASE OVER THE LAST COUPLE HRS  
ALONG THE COASTLINES AND IN PORTIONS OF THE INTERIOR. SKY COVER  
FORECAST AND ITS INFLUENCE ON TEMPS TODAY IS LOW CONFIDENCE; IT IS  
POSSIBLE WE SEE A GREATER INCREASE OVER THE NEXT FEW HRS, BUT THE  
LOW CLOUDS (WHERE THEY DO EXIST) PROBABLY WILL SCOUR OUT BY MID  
MORNING THOUGH THROUGH MIXING EFFECTS. THUS THINK WE END UP WITH A  
MORE SUN THAN CLOUDS LOOK FOR A FEW HOURS TODAY, ALTHOUGH THE STREAM  
OF MID TO HIGH CLOUDS SHOULD END UP ADVECTING IN BY THE AFTERNOON.  
HIGH PRESSURE IN PLACE GRADUALLY SHIFTS OFFSHORE BY AFTERNOON, SO  
THAT INCREASE IN MID TO HIGH CLOUDS LATER TODAY SHOULD ALSO BE  
ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS. HIGHS SHOULD  
REACH INTO THE UPPER 30S TO THE LOWER-MID 40S TODAY.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/
 
 
345 AM UPDATE:  
 
UNSETTLED WEATHER IN THIS PERIOD, AS A WARM FRONT SPREADS AN INITIAL  
PERIOD OF LIGHT PRECIPITATION TONIGHT, SOME OF WHICH LOOKS TO BE OF  
THE FROZEN TYPE ESPECIALLY NORTH OF THE MASS PIKE. A MORE FOCUSED  
PERIOD OF STEADIER LIGHT RAINS IS ANTICIPATED INTO FRIDAY ASSOCIATED  
WITH THE PASSAGE OF A BROAD/WEAK AREA OF LOW PRESSURE NOW OVER THE  
CENTRAL PLAINS. MORE DETAILS BELOW...  
 
FOR TONIGHT...WARM FRONTAL PRECIPITATION NOW OVER THE OH VALLEY  
SPREADS INTO SOUTHERN NEW ENGLAND AROUND EARLY TO MID EVENING FOR  
WESTERN MA AND CT, THEN SPREADING ENE INTO PARTS OF RI AND  
CENTRAL/NORTHEAST MA AROUND MIDNIGHT. IT LOOKS LIKE THE PRECIP WOULD  
BE MORE FOCUSED NORTH AND WEST OF I-95, WITH LITTLE IF ANY PRECIP  
ALONG AND SOUTHEAST OF I-95 FOR TONIGHT. SURFACE TEMPS SHOULD BE  
COLD ENOUGH TO SUPPORT A REALLY LIGHT AND SLUSHY MIX OF WET SNOW OR  
FREEZING RAIN NORTH OF THE MASS PIKE GIVING WARMING LOW LEVELS; RAIN  
MAY END UP MIXING WITH SNOW AT OUTSET FOR THE SPRINGFIELD, HARTFORD  
AND WORCESTER CORRIDORS BUT ANY SNOW WOULD BE SHORT LIVED BEFORE  
TRANSITIONING OVER TO PLAIN RAIN. HIGH-POP/LOW-QPF SCENARIO FOR  
AREAS NORTH AND WEST OF I-95; THE ABSENCE OF STRONGER FORCING  
SUPPORTS ANY SNOW OR ICE ACCUMULATIONS NORTH OF THE MASS PIKE BEING  
LIMITED TO SLUSHY COATINGS OF SNOW WITH PATCHY TRACE-ICING  
POTENTIALLY LIMITED TO ELEVATED SURFACES AND BRIDGES. AFTER  
COORDINATION WITH NWS ALBANY AND GRAY, WE OPTED TO HOLD OFF ON  
WINTER WEATHER ADVISORIES GIVEN THE LIMITED OVERALL ADVERSE IMPACT  
AND WE FELT THIS SCENARIO WOULD LIKELY BE BEST HANDLED WITH SPS  
AVENUES; WILL LET LATER SHIFTS MAKE THAT DECISION IN THE  
UNLIKELY CASE THAT QPF INCREASES MORE THAN CURRENTLY EXPECTED.  
TEMPS WILL ALSO BE STEADILY WARMING IN THE FACE OF SOUTHERLY  
FLOW. AND AS MENTIONED, SOUTH OF I-95, LITTLE IF ANY  
PRECIPITATION IS EXPECTED AND THAT SHOULD BE IN THE FORM OF  
PLAIN RAIN WERE ANY TO MATERIALIZE. WITH SOME WETBULBING, EXPECT  
LOWS IN THE 20S TO AROUND FREEZING TO OCCUR AS PRECIP BEGINS,  
THEN WITH A STEADY NON-DIURNAL WARMING TREND AS WE MOVE INTO THE  
FRIDAY MORNING HRS.  
 
FOR FRIDAY...LOW PRESSURE THEN TREKS FROM NJ/NY TO NEAR OR JUST  
SOUTHEAST OF THE I-95 CORRIDOR BEFORE MOVING OFFSHORE LATER IN  
THE DAY. INCREASED PWATS AND SOMEWHAT BETTER FORCING SHOULD  
SUPPORT A BLOSSOMING OF STEADIER LIGHT RAINS; WHILE RAIN SHOULD  
BE ONGOING IN THE INTERIOR; IT SHOULD REACH THE I-95 CORRIDOR  
INTO SOUTHEAST NEW ENGLAND BY MID TO LATE FRIDAY MORNING. SYSTEM  
IS PROGRESSIVE SO WHILE WE ARE LOOKING AT A CLOUDY DAY WITH  
PERIODS OF LIGHT RAIN, WE'RE NOT EXPECTING A SIGNIFICANT RAIN  
MAKER. RAINS LOOK TO RANGE FROM A TENTH TO A QUARTER INCH.  
THOUGH WARM ADVECTION SHOULD CONTINUE, LIMITED MIXING, CLOUD  
COVER AND PERIODS OF RAIN SHOULD YIELD HIGHS ONLY IN THE LOWER  
TO MID 40S. OVERALL, FRIDAY IS LOOKING TO FEATURE WEATHER  
CONDITIONS THAT FEW WOULD DESCRIBE AS ENJOYABLE: A PLAIN RAIN  
WITH TEMPS IN THE LOWER 40S.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
 
 
HIGHLIGHTS  
 
* COLD AND WINDY THIS WEEKEND  
 
* GRADUAL UPTICK IN TEMPERATURES THROUGH THE MIDDLE OF NEXT WEEK  
 
* NO IMPACTFUL WEATHER UNTIL POSSIBLY THE MIDDLE OF NEXT WEEK  
 
SATURDAY AND SUNDAY  
 
A POST COLD FRONTAL AIR MASS WILL SETTLE OVER THE REGION LATE FRIDAY  
NIGHT INTO SATURDAY BEHIND AN EXITING LOW PRESSURE SYSTEM. STRONG  
CAA WILL ALLOW -5 TO -10 CELSIUS AIR AT 925 HPA TO SETTLE OVER  
SOUTHERN NEW ENGLAND. THIS WILL SUPPORT SEASONABLY COLD TEMPERATURES  
THIS WEEKEND WITH LOW TEMPS IN THE LOW TO UPPER 20S SATURDAY MORNING  
AND LOW TO UPPER TEENS ON SUNDAY MORNING. SATURDAY AND SUNDAY  
AFTERNOON WILL FEATURE HIGH TEMPS IN THE LOW TO MID 30S AND MID TO  
UPPER 30S RESPECTIVELY. AIR MASS WILL BE BONE DRY, SO EXPECT PLENTY  
OF SUNSHINE, BUT DEEP MIXING UNDER CAA WILL SUPPORT SUSTAINED  
NORTHWEST WINDS FROM 10 TO 20 MPH WITH GUSTS UP TO 30 MPH ON  
SATURDAY AFTERNOON. BY SUNDAY, A MID-LEVEL RIDGE AXIS WILL BUILD IN  
FROM THE WEST ALLOWING FOR A WIND SHIFT TO THE WEST/SOUTHWEST. THIS  
WILL BEGIN A WARMING TREND THAT WILL CARRY INTO LATE NEXT WEEK.  
 
MONDAY AND TUESDAY  
 
HIGH PRESSURE BUILDS OVER THE EASTERN US EARLY NEXT WEEK. THIS WILL  
SUPPORT A DEEP SOUTHWEST FLOW PATTERN THAT WILL ALLOW FOR ABOVE  
NORMAL TEMPERATURES TO ADVECT INTO THE NORTHEAST THROUGH THE MIDDLE  
OF NEXT WEEK. 925 HPA TEMPS RISE ABOVE 0 CELSIUS EARLY NEXT WEEK  
WHICH SHOULD SUPPORT HIGH TEMPS IN THE UPPER 40S/LOW 50S ON BOTH  
MONDAY AND TUESDAY. THERE ARE NO STRONG SIGNALS FOR PRECIPITATION  
EARLY NEXT WEEK, BUT IN A WARM ADVECTION PATTERN WITH INCREASING  
MOISTURE, WE CAN'T RULE OUT THE POSSIBILITY OF SOME SHOWERS,  
ESPECIALLY WITH ANY EMBEDDED SHORT-WAVES THAT COULD POTENTIALLY  
TRAVERSE OVER THE REGION.  
 
WEDNESDAY  
 
THE ENSEMBLE SITUATIONAL AWARENESS TABLE IS HIGHLIGHTING SOME  
ANOMALOUSLY HIGH VALUES OF MOISTURE AND WIND SPEEDS DURING THE  
WEDNESDAY/THURSDAY TIME FRAME NEXT WEEK. THIS WILL BE A PERIOD OF  
THE FORECAST TO KEEP AN EYE ON AS IT WILL GIVE US OUR NEXT  
OPPORTUNITY FOR IMPACTFUL WEATHER. THERE IS AGREEMENT AMONG THE 3  
GLOBAL DETERMINISTIC MODELS FOR A ROBUST COLD FRONT TO PUSH ACROSS  
THE EASTERN US DURING THE MIDDLE OF NEXT WEEK. THIS MAY INTRODUCE AN  
OPPORTUNITY FOR SUBSTANTIAL RAINFALL AND POSSIBLY STRONG WINDS IN  
SOUTHERN NEW ENGLAND. WON'T DIVE TOO DEEP INTO THE DETAILS GIVEN THE  
UNCERTAINTY AT 7 DAYS OUT, BUT WE'LL BE WATCHING THIS PERIOD OF THE  
FORECAST CLOSELY AS WE HEAD INTO NEXT WEEK.  
 

 
   
AVIATION /11Z THURSDAY THROUGH MONDAY/
 
 
FORECAST CONFIDENCE LEVELS:  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
12Z TAF UPDATE  
 
TODAY: MODERATE CONFIDENCE.  
 
MVFR CIGS LIKELY FOR SEVERAL HOURS TODAY OVER THE WESTERN  
TERMINALS, THOUGH IT'S POSSIBLE THE DECK OF STRATUS VISIBLE ON  
SATELLITE COULD MIX OUT A TOUCH FROM OVC/BKN TO SCT AFTER  
SUNRISE. STRATUS OFF THE EAST COAST SHOULD ALSO MIX OUT AFTER  
SUNRISE, BUT DID LEAVE A TEMPO GROUP AT BOS FOR A POSSIBLE  
PERIOD OF MVFR CIGS THROUGH 13Z. OTHERWISE, SHOULD BE MAINLY VFR  
CONDITIONS WITH MODEST SOUTH/SOUTHWEST WINDS.  
 
TONIGHT: HIGH CONFIDENCE IN TRENDS, MODERATE IN TIMING/PRECIP  
TYPE DETAILS  
 
CATEGORIES DETERIORATE TO MVFR-IFR-LIFR LEVELS AS WARM FRONT  
SPREADS IN LIGHT WINTRY MIXED PRECIP OR RAIN. BEST CHANCE AT  
FROZEN PRECIP AT OUTSET AT BDL, ORH, BED NORTH AND WEST, WITH  
MAINLY RAIN SOUTH. FROZEN P-TYPES A MIX OF SNOW, RAIN/SNOW OR  
FREEZING RAIN OF LIGHT INTENSITY LEADING TO LITTLE ACCUM  
(COATINGS, PERHAPS A LIGHT GLAZE OF ICING). MAINLY RAIN FOR PVD,  
BOS AND THE CAPE AIRPORTS, WITH A GRADUAL TRANSITION FROM  
FROZEN PRECIP TO RAIN BY DAWN. LIGHT SW WINDS.  
 
FRIDAY: MODERATE TO HIGH CONFIDENCE.  
 
SECONDARY LOW PRESSURE MOVES IN FROM NY/NJ AND BRINGS STEADY  
LIGHT RAIN AND CONTINUED IFR-LIFR CEILINGS. RAIN ENDS FROM WEST  
TO EAST 18-00Z. LOW PRESSURE TRACKING NEAR THE I-95 CORRIDOR TO  
BRING CONTINUED MAINLY S/SW WINDS 4-8 KT SOUTH AND EAST OF I-95,  
WITH WINDS NORTH AND WEST OF I-95 BECOMING NE, N THEN NW BY  
MID AFTERNOON.  
 
KBOS TAF...MODERATE CONFIDENCE IN TAF. VFR AT LEAST INITIALLY  
BUT THERE COULD BE MVFR BASES AT TIMES THRU 13-14Z THU. IF MVFR  
CEILINGS DEVELOP, THEY WOULD BE SHORT LIVED AND SHOULD TREND TO  
VFR BY MID-MORNING, BEFORE CEILINGS START TO DETERIORATE TO  
MVFR AND IFR AFTER 03Z FRI. WINDS LIGHT SOUTH, INCREASING A BIT  
TO AROUND 4-8 KT TODAY.  
 
KBDL TAF...MODERATE CONFIDENCE IN TAF. MVFR/VFR BASES SHOULD  
SCATTER TO SCT-BKN VFR POTENTIALLY EARLY IN THE DAY. CEILINGS  
DETERIORATE TO MVFR-IFR BY 00Z WITH A MIX OF RAIN AND SNOW,  
TRENDING TO LIGHT RAIN LATE TONIGHT. ACCUMULATIONS SHOULD BE NIL  
WITH MAINLY SLUSHY RUNWAYS. LIGHT S/SW WINDS.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
FRIDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.  
CHANCE RA, SLIGHT CHANCE FZRA.  
 
SATURDAY THROUGH MONDAY: VFR. BREEZY.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS:  
 
LOW - LESS THAN 30 PERCENT.  
MEDIUM - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
345 AM UPDATE:  
 
OVERALL HIGH FORECAST CONFIDENCE.  
 
SCAS CONTINUE WITH NO CHANGES IN SPACE OR TIME WITH THOSE, WITH  
THE RISK BEING FROM BUILDING SEAS OVER 5 FT.  
 
WINDS TODAY AND INTO EARLY TONIGHT ARE LIGHT SOUTHERLY, GENERALLY  
10 KT OR LESS AND COULD BE VARIABLE AT TIMES THIS MORNING.  
HOWEVER WILL SEE SOUTHERLY WINDS INCREASE TO AROUND 15 TO 20 KT  
BY 12Z FRIDAY. SW SPEEDS MAY GET NEAR SCA LEVELS ON FRIDAY,  
AHEAD OF A WEAK AREA OF LOW PRESSURE THAT MOVES OVER THE WATERS  
LATER FRIDAY INTO FRIDAY NIGHT. EXPECT SEAS TO BUILD TODAY AND  
TONIGHT TO AROUND 5-8 FT AND REMAIN ABOVE 5 FT THROUGH FRIDAY.  
 
DRY WEATHER EXPECTED TODAY AND INTO EARLY TONIGHT, ALTHOUGH  
INCREASING RISK FOR RAINS LATER IN THE OVERNIGHT AND ESPECIALLY  
INTO FRIDAY. RAIN COULD REDUCE VISIBILITY TO 1-3 MILES.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
FRIDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE OF  
RAIN.  
 
SATURDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 30 KT. AREAS OF ROUGH SEAS.  
 
SATURDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS.  
 
SUNDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT.  
 
SUNDAY NIGHT: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 25 KT. SEAS UP TO 5 FT.  
 
MONDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 25 KT. SEAS UP TO 5 FT. SLIGHT CHANCE OF RAIN.  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST  
FRIDAY FOR ANZ235-237.  
SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ250.  
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST  
FRIDAY FOR ANZ251.  
SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ254>256.  
 

 
 

 
 
SYNOPSIS...LOCONTO/RM  
NEAR TERM...LOCONTO  
SHORT TERM...LOCONTO  
LONG TERM...RM  
AVIATION...LOCONTO/RM  
MARINE...LOCONTO/RM  
 
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