257  
FXUS61 KBOX 110555  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
155 AM EDT WED JUL 11 2018  
   
SYNOPSIS
 
 
A COLD FRONT MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS  
TONIGHT, MAINLY ALONG AND SOUTH OF THE PIKE. HURRICANE CHRIS IS  
EXPECTED TO PASS WELL SOUTHEAST OF NANTUCKET WEDNESDAY. HIGH  
PRESSURE WILL BUILD OVER THE REGION THURSDAY AND FRIDAY,  
RESULTING IN MAINLY DRY WEATHER ALONG WITH SEASONABLE  
TEMPERATURES AND COMFORTABLE HUMIDITY. A RETURN TO HOT WEATHER  
IS EXPECTED LATER THIS WEEKEND INTO EARLY NEXT WEEK. WHILE A FEW  
THUNDERSTORMS CANNOT BE RULED OUT THIS WEEKEND INTO EARLY NEXT  
WEEK, DRY WEATHER LOOKS TO DOMINATE THE MAJORITY OF THE TIME.  
 

 
   
NEAR TERM /UNTIL 6 AM THIS MORNING/
 
 
150 AM UPDATE...  
 
SCATTERED SHOWERS AND ISOLATED T-STORMS ACROSS N RI AND  
ADJACENT SE MA. ACTIVITY IS BEHIND THE FRONT WITHIN THE KI AXIS  
IN THE UPPER 30S. A FEW SHOWERS OR AN ISOLATED T-STORM SHOULD  
REACH/REDEVELOP ALONG THE SOUTH COAST AND CAPE COD TOWARD  
DAYBREAK AS KI AND ELEVATED INSTABILITY AXIS HOLDS TOGETHER AS  
IT MOVES SOUTH TOWARD THE SOUTH COAST.  
 
PREVIOUS DISCUSSION...  
 
COLD FRONT IS SOUTH OF THE MASS PIKE AND WILL MOVE SLOWLY SOUTH  
TO THE SOUTH COAST AFTER MIDNIGHT. SHOWERS DIMINISHING ACROSS NE  
MA, BUT APPROACHING MID LEVEL TROUGH AND COOLING TEMPS ALOFT  
WILL HELP TO SUSTAIN SOME ELEVATED INSTABILITY. THIS COMBINED  
WITH K INDEX AXIS IN THE UPPER 30S SUGGEST A RENEWED  
DEVELOPMENT OF SCATTERED SHOWERS AND POSSIBLY AN ISOLD T-STORM  
NEAR THE COLD FRONT, MAINLY SOUTH OF THE PIKE. THIS IS REFLECTED  
IN FORECAST POPS SO FORECAST ON TRACK. TEMPS STILL PRETTY WARM  
AWAY FROM THE SOUTH COAST, IN THE 70S TO LOWER 80S, BUT WILL  
COOL INTO THE 60S OVERNIGHT WITH NORTHERLY FLOW.  
 
ACK MAY SEE A BRIEF PERIOD OF FOG JUST BEFORE SUNRISE TOMORROW  
AS SW WINDS DIMINISH AFTER THE FRONTAL PASSAGE AND AN INVERSION  
REMAINS OVERHEAD.  
 

 
   
SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/
 
 
WEDNESDAY...  
 
COLD FRONT WILL BE SITTING JUST EAST OF NANTUCKET COME SUNRISE  
TOMORROW MORNING WITH SOME POSSIBLE LINGERING SHOWERS AND  
THUNDERSTORMS ACROSS RI AND SE MASS.  
 
AS THE FRONT MOVES OFFSHORE AND INSTABILITY ERODES THROUGHOUT  
THE MORNING, ANY LINGERING SHOWERS AND THUNDERSTORMS WILL  
DISSIPATE ACROSS SE NEW ENGLAND.  
 
THERE'S A SMALL CHANCE FOR ISOLATED SHOWERS TOMORROW AFTERNOON  
ACROSS NORTHERN CT AND CENTRAL MA GIVEN CYCLONIC FLOW AND  
COOLING TEMPS ALOFT, BUT THESE WILL LIKELY BE SHORT LIVED WITH  
VERY LITTLE IMPACT.  
 
TROPICAL STORM CHRIS IS EXPECTED TO PASS 300 MILES TO OUR SE,  
RESULTING IN HIGH SURF AND DANGEROUS RIP CURRENTS ALONG SOUTH  
COASTAL BEACHES. HIGH SURF ADVISORIES MAY BE NEEDED.  
 
WEDNESDAY WILL BE MUCH COOLER THAN TODAY AS WINDS OUT OF THE NE  
KEEP THE REGION IN THE MID 70S. THE WARMEST TEMPERATURES ARE  
LIKELY TO BE IN THE CONNECTICUT RIVER VALLEY WHERE HARTFORD MAY  
SEE 80 DEGREES. BEHIND THE COLD FRONT, HUMIDITY WILL DECREASE AS  
DEWPOINTS WILL BE IN THE MID TO UPPER 50S ACROSS THE REGION.  
 
WEDNESDAY NIGHT...  
STRONG NE WINDS AND HIGH SURF WILL CONTINUE INTO THE EVENING  
AS TS CHRIS DEPARTS THE REGION AND CONTINUES MOVING NE. SKIES  
WILL BE MOSTLY CLEAR AS A 1024MB HIGH BUILDS INTO NEW ENGLAND,  
ALLOWING TEMPERATURES TO COOL INTO THE 50S OVERNIGHT.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
 
 
HIGHLIGHTS...  
 
* MAINLY DRY THU/FRI WITH SEASONABLE TEMPERATURES AND COMFORTABLE  
HUMIDITY  
 
* HOT WEATHER RETURNS LATE THIS WEEKEND INTO EARLY NEXT WEEK AND  
WHILE A FEW THUNDERSTORMS ARE POSSIBLE, DRY WEATHER SHOULD  
DOMINATE MOST OF THIS TIME  
 
DETAILS...  
 
THURSDAY AND FRIDAY...  
 
WITH CHRIS PASSING WELL SE OF THE 40N/70W BENCHMARK, AND MOVING  
FARTHER AWAY THURSDAY, ANY LINGERING SOUTH SWELL SHOULD  
DIMINISH. HIGH PRESSURE TO OUR NORTH WILL GRADUALLY OVERSPREAD  
OUR REGION, PROVIDING DRY WEATHER. EXPECTING NEAR NORMAL  
TEMPERATURES THROUGH THIS PERIOD. HUMIDITY INCREASES FRIDAY FROM  
THURSDAY, BUT STILL EXPECTED TO REMAIN RELATIVELY COMFORTABLE.  
 
THIS WEEKEND INTO EARLY NEXT WEEK...  
 
TRICKY PATTERN SHIFT DURING THIS TIME. A MID LEVEL TROUGH SHOULD  
LIFT OUT TO SOME EXTENT, WITH A DEEPER MID LEVEL TROUGH POISED  
TO ARRIVE TOWARDS THE MIDDLE OF NEXT WEEK. IT WILL ALL COME DOWN  
TO TIMING, WHICH REMAINS QUESTIONABLE DUE TO THE FAIRLY ZONAL  
FLOW. IN MOST CASES, EXPECTING TEMPERATURES TO START RISING THIS  
WEEKEND INTO EARLY NEXT WEEK, AT LEAST AWAY FROM ANY OCEAN  
INFLUENCE.  
 
HUMIDITY SHOULD SLOWLY INCREASE, TOO. WITH NO SYNOPTIC FEATURE  
TO REALLY FORCE THE ISSUE, ANY SHOWERS AND THUNDERSTORMS WOULD  
BE MORE OF THE AIRMASS VARIETY, DRIVEN ALMOST ENTIRELY BY  
DIURNAL HEATING. WHILE WE CANNOT ENTIRELY RULE OUT A FEW SHOWERS  
AND THUNDERSTORMS DURING THIS TIME, MUCH OF THIS PERIOD SHOULD  
REMAIN DRY FOR MOST LOCATIONS.  
 

 
   
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH THURSDAY/...HIGH CONFIDENCE.  
 
THROUGH 12Z...  
MAINLY VFR. SCATTERED SHOWERS AND ISOLATED T-STORMS FOCUSED  
ACROSS RI AND SE MA, SHOULD REACH THE SOUTH COAST AND CAPE COD  
TOWARD DAYBREAK. LOW RISK OF PATCHY FOG OVER ACK TOWARD  
DAYBREAK.  
 
TODAY...  
MAINLY VFR CIGS. A FEW LINGERING SHOWERS POSSIBLE ALONG THE  
SOUTH COAST EARLY. A FEW SHOWERS ALSO POSSIBLE IN NORTHERN CT  
AND WESTERN MA THIS AFTERNOON. N/NE WINDS.  
 
TONIGHT...  
MAINLY VFR, BUT AREAS OF IFR/LIFR FOG POSSIBLE OVER ACK.  
 
THURSDAY...VFR. SEA BREEZES LIKELY.  
 
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.  
 
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.  
 
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...  
 
THURSDAY NIGHT THROUGH FRIDAY NIGHT: VFR.  
 
SATURDAY THROUGH SATURDAY NIGHT: VFR. SLIGHT CHANCE SHRA.  
 
SUNDAY: VFR. SLIGHT CHANCE SHRA, ISOLATED TSRA.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH THURSDAY/...HIGH CONFIDENCE.  
 
DIMINISHING WINDS TONIGHT WITH WIND SHIFT TO N BEHIND THE COLD  
FRONT. A FEW SHOWERS OR AN ISO T-STORM OR TWO WITH GUSTY WINDS  
POSSIBLE TONIGHT. NE WINDS 10-20 KT WED AFTERNOON ACROSS THE SE  
COASTS. WITH CHRIS OFF TO OUR SE, SEAS MAY BUILD UP TO 8 FT  
POSSIBLE OVER THE SOUTHERN WATERS. A HIGH SURF ADVISORY MAY BE  
NEEDED. WITH STRONG NE WINDS AND BUILDING SOUTHERLY SWELL,  
CHOPPY CONDITIONS ON THE WATERS IS POSSIBLE.  
 
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...  
 
THURSDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING  
5 FT.  
 
THURSDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING  
5 FT.  
 
FRIDAY THROUGH FRIDAY NIGHT: WINDS LESS THAN 25 KT.  
 
SATURDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.  
 
SATURDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS  
APPROACHING 5 FT. SLIGHT CHANCE OF RAIN SHOWERS.  
 
SUNDAY: WINDS LESS THAN 25 KT.  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS  
EVENING FOR ANZ231>234.  
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EDT  
THURSDAY FOR ANZ235-254>256.  
 

 
 

 
SYNOPSIS...BELK/CORREIA  
NEAR TERM...KJC  
SHORT TERM...NOCERA/CORREIA  
LONG TERM...BELK  
AVIATION...BELK/KJC  
MARINE...BELK/NOCERA/CORREIA  
 
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