375  
FXUS61 KBOX 030455  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
1255 AM EDT THU JUL 3 2025  
   
SYNOPSIS
 
 
DRY AND PLEASANT WEATHER IS IN STORE FOR THE REGION TONIGHT  
OUTSIDE OF AN EVENING SPOT SHOWER OR TWO SOUTH OF I-90. VERY  
WARM TO HOT TEMPERATURES ON THURSDAY WILL LIKELY TRIGGER A ROUND  
OF SCATTERED SHOWERS & T-STORM ROUGHLY IN THE 2-10 PM TIME  
RANGE. QUIET FOR INDEPENDENCE DAY HEADING INTO THE WEEKEND, THEN  
HEAT AND HUMIDITY KICK UP FOR SUNDAY AND THE START OF NEXT  
WEEK. UNSETTLED WEATHER MAY MAKE A RETURN TUESDAY INTO  
WEDNESDAY.  
 

 
   
NEAR TERM /UNTIL 6 AM THIS MORNING/
 
 
KEY MESSAGES...  
 
* LOW CLOUDS AND FOG FORMATION CONFINED TO MAINLY IMMEDIATE SOUTH  
COAST, CAPE AND ISLANDS TONIGHT  
 
* DRY AND PLEASANT TONIGHT OUTSIDE OF A SPOT SHOWER OR TWO EARLY  
THIS EVENING SOUTH OF I-90 WITH LOWS BETWEEN 60 AND 70 DEGREES  
 
DETAILS...  
 
TONIGHT...  
 
ENOUGH DIURNAL HEATING AND LOW LEVEL MOISTURE REMAINS FOR A FEW  
SPOT SHOWERS POSSIBLE INTO THE FIRST HALF OF THE EVENING...BUT  
MOST LOCATIONS WILL REMAIN DRY.  
 
OTHERWISE...SHORTWAVE ENERGY WILL CONTINUE TO MOVE EAST AND  
FURTHER AWAY FROM THE REGION TONIGHT. THIS WILL TAKE A LOT OF  
THE REMAINING MID LEVEL CLOUD DECK WITH IT. THE ONLY ISSUE FOR  
TONIGHT IS FOR THE RE- DEVELOPMENT OF MORE LOW CLOUDS AND FOG  
NEAR THE IMMEDIATE SOUTH COAST, CAPE AND ISLANDS. THE SURFACE  
LOW LEVEL FLOW IS VEERED OUT...SO THINKING THIS LOW CLOUD/FOG  
THREAT WILL NOT MAKE IT MUCH FURTHER NORTH THAN THE IMMEDIATE  
SOUTH COAST AND THEREFORE ONLY IMPACT A VERY LIMITED AREA IN OUR  
CWA. OVERNIGHT LOW TEMPS MAY RANGE FROM NEAR 60 IN THE NORMALLY  
COOLEST OUTLYING LOCATIONS TO AROUND 70 IN THE URBAN HEAT  
ISLAND OF BOSTON. SO MOST LOCATIONS WILL SEE OVERNIGHT LOWS  
BOTTOM OUT IN THE 60S.  
 

 
   
SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/
 
 
KEY MESSAGES...  
 
* VERY WARM TO HOT ON THU WITH HIGHS MAINLY IN THE UPPER 80S TO NEAR  
90 BUT NOT AS HUMID AS THE LAST FEW DAYS  
 
* A FEW SEVERE THUNDERSTORMS POSSIBLE THU BETWEEN 2 & 10 PM WITH THE  
GREATEST RISK ACROSS INTERIOR MA & CT  
 
* DRIER & COOLER LATER THU NIGHT WITH LOWS IN THE 55-65 DEGREE RANGE  
 
DETAILS...  
 
THURSDAY AND THURSDAY NIGHT...  
 
A VERY WARM TO HOT DAY IS ON TAP FOR THURSDAY AHEAD OF AN  
APPROACHING SHORTWAVE TROUGH. VEERED OUT LOW LEVEL FLOW AND PLENTY  
OF SUNSHINE WILL ALLOW DEWPOINTS TO MIX OUT A BIT AND ALLOW HIGHS TO  
REACH THE UPPER 80S TO NEAR 90 IN MANY LOCATIONS. WESTERLY FLOW  
THOUGH WILL RESULT IN LESS HUMIDITY THAN THE PAST COUPLE OF  
DAYS...BUT IT STILL WILL BE VERY WARM TO HOT AFTERNOON.  
 
THE MAIN CONCERN THOUGH REVOLVES AROUND THE POTENTIAL FOR A FEW  
SEVERE THUNDERSTORMS THU PM...MAINLY IN THE 2-10 PM TIME FRAME WITH  
THE BEST CHANCE ACROSS INTERIOR MA & CT CLOSER TO THE MAIN  
SHORTWAVE/DYNAMICS. A FAIRLY IMPRESSIVE SHORTWAVE TROUGH ALOFT  
APPROACHES THE REGION THU AFTERNOON/EVENING WITH HEIGHT FALLS AND A  
500T DROPPING INTO THE -12C/-13C RANGE. THIS COLD POOL ALOFT WILL  
ASSIST IN CREATING MODEST MID LEVEL LAPSE RATES ON THE ORDER OF 6.5  
C/KM. INSTABILITY WILL NOT BE CRAZY ON THU...BUT GIVEN THE COLD POOL  
ALOFT SURFACE CAPES IN THE 750 TO 1500 J/KG RANGE ARE EXPECTED. IN  
ADDITION...0-6 KM SHEAR VALUES ON THE ORDER OF 30 TO 40 KNOTS WITH  
THE STRONGEST OF THOSE WIND FIELDS ACROSS INTERIOR MA AND CT.  
 
THIS INGREDIENTS ABOVE ARE SUPPORTIVE FOR THE POTENTIAL FOR A FEW  
SEVERE THUNDERSTORMS THU AFTERNOON INTO THE FIRST HALF OF THE  
EVENING WITH THE GREATEST RISK ACROSS INTERIOR MA AND CT. MAIN  
THREATS WILL BE LOCALLY DAMAGING WIND GUSTS GIVEN THE POTENTIAL FOR  
RATHER LARGE T/TD SPREADS AND STEEP LOW LEVEL LAPSE RATES. IN  
ADDITION...HAIL WILL ALSO BE A CONCERN GIVEN THE COLD POOL ALOFT AND  
ADEQUATE SHEAR. THIS IS ALSO SUPPORTED BY A LOT OF THE MACHINE  
LEARNING GUIDANCE INCLUDING THE CSU, NADOCAST AND HRRR NEURAL  
NETWORK WHICH ALSO SHOW THE GREATEST RISK FOR THIS ACROSS INTERIOR  
MA AND CT. THAT BEING SAID...THERE ARE SOME LIMITING FACTORS TOO.  
THE INSTABILITY IS RATHER MARGINAL AND SURFACE WINDS ARE VEERED OUT  
WHICH WILL LIMIT POTENTIAL CONVERGENCE. THIS MIGHT BE WHY A LOT OF  
THE CAMS LIMIT THE AREAL COVERAGE OF THE ACTIVITY.  
 
SO IN A NUTSHELL...WHILE THIS DOES NOT LOOK LIKE A WIDESPREAD SEVERE  
WEATHER OUTBREAK GIVEN LIMITED LOW LEVEL CONVERGENCE THE RISK FOR A  
FEW SEVERE THUNDERSTORMS EXISTS. INTERIOR MA AND CT MAY HAVE THE  
GREATEST RISK BEING CLOSER TO THE DYNAMICS/COLD POOL ALOFT AND THAT  
IS ALSO INDICATED WITH THE MACHINE LEARNING GUIDANCE.  
 
THE ACTIVITY SHOULD WIND DOWN BY THE SECOND HALF OF THU EVENING AS  
THE INSTABILITY WANES WITH THE LOSS OF DIURNAL HEATING.  
OTHERWISE...A DRIER WNW FLOW OF AIR WORKS INTO THE REGION THU NIGHT  
BEHIND THE COLD FRONT. OVERNIGHT LOWS SHOULD DROP INTO THE MIDDLE TO  
UPPER 50S IN THE OUTLYING LOCATIONS TO BETWEEN 60 AND 65 IN THE  
URBAN CENTERS.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
 
 
KEY MESSAGES:  
 
* DRY AND SUNNY FOR INDEPENDENCE DAY HEADING INTO THE WEEKEND  
 
* SUMMER HEAT AND HUMIDITY SUNDAY INTO THE START OF NEXT WEEK  
 
* POSSIBLY UNSETTLED WEATHER RETURNS TUESDAY/WEDNESDAY  
 
DETAILS...  
 
THE TROUGH RESPONSIBLE FOR THURSDAY'S EXPECTED UNSETTLED CONDITIONS  
MOVES OVER NEW ENGLAND AND OFF TO THE EAST FRIDAY. TEMPERATURES  
ALOFT WILL BE SLIGHTLY COOLER AS THIS TROUGH MAKES ITS EXIT,  
REMAINING UNDER 20C AT 925 MB. HIGHS FOR FRIDAY ARE EXPECTED TO BE  
IN THE LOW TO MID 80S ACROSS SOUTHERN NEW ENGLAND. QUIET WEATHER  
WILL PREVAIL FOR INDEPENDENCE DAY HEADING INTO THE WEEKEND AS  
SURFACE HIGH PRESSURE BUILDS IN. DRIER AIR ALSO MOVES IN OVER THE  
REGION, WHICH WILL BRING A WARM AND LESS HUMID START TO THE WEEKEND.  
 
MORE HUMID CONDITIONS MOVE IN GOING INTO SUNDAY AND THE START OF THE  
WEEK AS FLOW ALOFT SHIFTS MORE SW AND WINDS AT THE SURFACE BECOME  
MORE S. TEMPERATURES AT 925 MB INCREASE TO AROUND +25C DURING THE  
AFTERNOONS OF SUNDAY AND MONDAY; ENSEMBLES HAVE PROBABILITIES AT OR  
ABOVE 50 PERCENT OF TEMPERATURES GREATER THAN 90F ACROSS EASTERN MA  
INTO RI SUNDAY, THEN ACROSS ALL OF SOUTHERN NEW ENGLAND MONDAY  
(PROBS ALSO INCREASE THEN AS WELL COMPARED TO SUNDAY). NOT MUCH  
RELIEF CAN BE EXPECTED OVERNIGHT EITHER, WITH LOWS IN THE UPPER 60S  
AND LOW 70S.  
 
THE CHANCE FOR SOME UNSETTLED WEATHER RETURNS TUESDAY INTO WEDNESDAY  
WITH THE ARRIVAL OF A FRONTAL SYSTEM. IT'S A BIT FAR OUT TO  
DETERMINE THE FINER DETAILS OF WHAT TO EXPECT IN TERMS OF SHOWERS OR  
STORMS, BUT ENSEMBLE MEAN PWAT VALUES APPROACHING 2" MAY SIGNAL THE  
CHANCE FOR POSSIBLE DOWNPOURS OVER THE REGION. WHETHER THESE MAY BE  
WIDESPREAD OR ISOLATED IS STILL UNKNOWN.  
 

 
   
AVIATION /06Z THURSDAY THROUGH MONDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
06Z TAF UPDATE...  
 
TODAY AND TONIGHT...HIGH CONFIDENCE EXCEPT MODERATE CONFIDENCE  
ON THUNDERSTORM POTENTIAL AREAL COVERAGE AS WELL AS TIMING.  
 
VFR OUTSIDE OF ANY SCATTERED T-STORM THREATS AFTER 18Z INTO THE  
FIRST HALF OF THE EVENING. AREAL COVERAGE AND TIMING REMAINS  
UNCERTAIN WITH THIS ACTIVITY...BUT A FEW STRONG T-STORMS ARE  
POSSIBLE WHICH MAY CONTAIN LOCALLY STRONG WIND GUSTS AND HAIL  
TOO. THE GREATEST RISK IS ACROSS INTERIOR MA AND CT TERMINALS.  
W WINDS GENERALLY 5-10 KNOTS BECOMING MORE NW LATER TONIGHT.  
 
INDEPENDENCE DAY...HIGH CONFIDENCE.  
 
VFR. NW WINDS 5-10 KTS AT MOST TERMINALS.  
 
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. MAIN CONCERN IS THE RISK FOR  
A T-STORM IN THE VICINITY OF THE TERMINAL AFTER 19Z/20Z INTO  
THE EARLY EVENING HOURS.  
 
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. MAIN CONCERN IS THE RISK FOR  
A T-STORM IN THE VICINITY OF THE TERMINAL AFTER 18Z/19Z INTO  
THE EARLY EVENING HOURS.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
INDEPENDENCE DAY THROUGH SATURDAY NIGHT: VFR.  
 
SUNDAY THROUGH SUNDAY NIGHT: VFR. BREEZY.  
 
MONDAY: BREEZY.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MEDIUM - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
TONIGHT THROUGH THURSDAY NIGHT...HIGH CONFIDENCE.  
 
LINGERING MARGINAL 5 FOOT SEAS ACROSS OUR FAR SOUTHERN WATERS  
WILL DROP BELOW CRITERIA BY EARLY EVENING. OTHERWISE...THE  
PRESSURE GRADIENT WILL BE WEAK ENOUGH TO KEEP WINDS/SEAS BELOW  
SMALL CRAFT ADVISORY THRESHOLDS THROUGH THU NIGHT. THE MAIN  
CONCERN FOR MARINERS WILL BE AREAS OF FOG REDEVELOPING MAINLY  
ACROSS OUR SOUTHERN WATERS...WHICH MAY BECOME LOCALLY DENSE  
LATER TONIGHT INTO EARLY THU MORNING. WINDS WILL GENERALLY BE IN  
SW DIRECTION ON THE ORDER OF 7-15 KNOTS TONIGHT AND THU BEFORE  
SWITCHING TOO A MORE NW DIRECTION THU NIGHT BEHIND THE COLD  
FRONT.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
INDEPENDENCE DAY THROUGH SATURDAY NIGHT: WINDS LESS THAN 25 KT.  
 
SUNDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 30 KT. SEAS LOCALLY APPROACHING 5 FT.  
 
SUNDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 30 KT. SEAS UP TO 5 FT.  
 
MONDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 30 KT. AREAS OF SEAS APPROACHING 5 FT.  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...NONE.  
 

 
 

 
 
SYNOPSIS...FRANK/HRENCECIN  
NEAR TERM...FRANK  
SHORT TERM...FRANK  
LONG TERM...HRENCECIN  
AVIATION...BW/HRENCECIN  
MARINE...FRANK/HRENCECIN  
 
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