178  
FXUS61 KBOX 111908  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
308 PM EDT WED JUL 11 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE BRINGS DRY WEATHER/SEASONABLE  
TEMPERATURES/COMFORTABLE HUMIDITY THROUGH FRIDAY. HURRICANE  
CHRIS WILL PASS WELL SOUTHEAST OF NANTUCKET. 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 /THROUGH TONIGHT/
 
 
THIS EVENING... DIURNAL CLOUDS AND WIDELY SCATTERED SHOWERS  
LINGER OVER WESTERN AND CENTRAL MASS AND NORTHERN CT, THEN  
DISSIPATE WITH SUNSET.  
 
SURFACE HIGH PRESSURE BUILDS OVER THE REGION. EXPECT A QUIET  
NIGHT WITH CLEARING SKIES AND DIMINISHING WIND. RADIATIONAL  
COOLING WILL RESULT IN LOW TEMPS DROPPING INTO THE 50S REGION  
WIDE, EXCEPT LOWER 60S FOR BOSTON.  
 
HURRICANE CHRIS PASSES OVER 300 MILES SE OF ACK TONIGHT WITH  
ONLY IMPACT BEING INCREASED SURF AND RIP CURRENT RISK FOR SOUTH  
COASTAL BEACHES. HOWEVER, SURF IS EXPECTED TO FALL A BIT SHORT  
OF HIGH SURF ADVISORY CRITERIA.  
 

 
   
SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
 
 
SURFACE HIGH PRESSURE REMAINS OVER NEW ENGLAND THURSDAY, THEN  
MOVES OFF TO THE EAST THURSDAY NIGHT. ANOTHER UPPER SHORTWAVE  
WILL MOVE IN FROM THE GREAT LAKES, SHARPENING THE UPPER TROUGH  
OVER OUR AREA. FORECAST CROSS-SECTIONS SHOW ENOUGH MOISTURE  
BETWEEN 700 AND 850 MB TO SUPPORT SOME CLOUDS, BUT JET DYNAMICS  
IS UNFAVORABLY PLACED AND STABILITY PARAMETERS UNFAVORABLE FOR A  
BUOYANT ENVIRONMENT.  
 
SO WE EXPECT A SUNNY DAY WITH LIGHT WINDS. THIS WILL ALLOW SEA  
BREEZES TO AGAIN DEVELOP ALONG THE COASTS. DEW POINTS WILL BE IN  
THE 50S, A DRY COMFORTABLE DAY. TEMPS ALOFT WILL BE SIMILAR TO  
THOSE TODAY, SO EXPECT MAX TEMPS LOW TO MID 80S INLAND AND MID  
70S ALONG THE COAST.  
 
FAIR SKIES AND LIGHT WIND WILL CONTINUE THE FAIR WEATHER  
THURSDAY NIGHT WITH MIN TEMPS IN THE 50S AND LOW 60S.  
 

 
   
LONG TERM /FRIDAY THROUGH WEDNESDAY/
 
 
OVERVIEW...  
 
MODEL GUIDANCE THIS MORNING SHOWS GOOD OVERALL AGREEMENT ON THE  
EVOLUTION OF THE SYNOPTIC PATTERN THROUGH NEXT TUESDAY. POTENT HIGH  
PRESSURE OVER THE CENTRAL AND WESTERN CONUS WILL LEAD TO SLIGHT  
HEIGHT FALLS OVER NEW ENGLAND. A COLD FRONT WILL MOVE INTO THE GREAT  
LAKES ON FRIDAY BUT BECOME MORE DIFFUSED WITH TIME AS IT MOVES  
TOWARDS THE NORTHEAST DURING THE WEEKEND. MEANWHILE, A POTENT UPPER  
LEVEL LOW WILL MOVE INTO ALBERTA RESULTING IN HEIGHTS RISING OVER  
THE NORTHEAST EARLY NEXT WEEK. THIS LOW WILL PUSH A FRONT TOWARDS  
THE REGION BY MID-WEEK.  
 
DETAILS...  
 
TEMPERATURES...  
 
SEASONABLE CONDITIONS TO START AS WEAK FRONT SLOWLY SWINGS THROUGH  
THE REGION. TEMPERATURES WILL RANGE INTO THE MID 80S ACROSS THE CT  
RIVER VALLEY TO MID 70S FOR THE MA EAST COAST THANKS TO ONSHORE SEA  
BREEZES. RISING HEIGHTS AND WAA ON SUNDAY AND HEAD OF APPROACHING  
FRONT ON WED WILL HELP INCREASE TEMPS TO ABOVE AVERAGE. ANOTHER  
ROUND OF 90 DEGREES IS POSSIBLE FOR PORTIONS OF THE REGION.  
CONDITIONS WILL ALSO TURN MUGGIER NEXT WEEK UNTIL MID-WEEK FRONTAL  
PASSAGE.  
 
PRECIPITATION...  
 
MAINLY DRY WEATHER FOR THE END OF THE WEEK, INTO THE WEEKEND AS  
APPROACHING FRONTAL SYSTEM WEAKENS. STILL CANNOT RULE OUT AN ISO  
SHOWER. POP-UP SHOWERS/THUNDERSTORMS ARE POSSIBLE ON MON AND TUESDAY  
IN THE WARM, MOIST AIRMASS. BUT THESE WILL BE MAINLY AIRMASS TYPE  
STORMS. BEST CHANCE FOR SOME MEASURABLE PRECIP APPEARS TO BE MID-  
NEXT WEEK PER LATEST ENSEMBLE GUIDANCE.  
 

 
   
AVIATION /19Z WEDNESDAY THROUGH MONDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.  
 
VFR CIGS. WIDELY SCATTERED SHOWERS ALSO POSSIBLE IN NORTHERN CT  
AND CENTRAL/WESTERN MA THIS AFTERNOON. N/NE WINDS.  
 
TONIGHT...  
MAINLY VFR, BUT AREAS OF IFR/LIFR FOG POSSIBLE OVER ACK AND  
PARTS OF OUTER CAPE COD.  
 
THURSDAY...VFR. SEA BREEZES LIKELY.  
 
THURSDAY NIGHT...VFR.  
 
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.  
 
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.  
 
OUTLOOK /FRIDAY THROUGH MONDAY/...  
 
FRIDAY THROUGH FRIDAY NIGHT: VFR.  
 
SATURDAY: VFR. SLIGHT CHANCE SHRA, ISOLATED TSRA.  
 
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 NIGHT/...HIGH CONFIDENCE.  
 
AN AREA OF HIGH PRESSURE MOVES OVER THE WATERS TONIGHT AND  
THURSDAY, THEN SHIFTS EAST THROUGH THE MARITIMES THURSDAY NIGHT.  
EXPECT LIGHT WIND THROUGH THE PERIOD ALTHOUGH WITH THE DIRECTION  
TRENDING FROM THE SOUTH THURSDAY NIGHT.  
 
THE LIGHT WIND WILL ALLOW SEA BREEZES TO FORM THURSDAY NEAR THE  
SHORE.  
 
MAIN ISSUE FOR THE WATERS WILL BE A LONG PERIOD SOUTHERLY SWELL  
FROM DISTANT HURRICANE CHRIS. A 5 TO 6 FOOT SWELL HAS BUILT  
INTO THE WATERS SOUTH OF NEW ENGLAND, AND WILL SLOWLY SUBSIDE  
LATE TONIGHT THROUGH THURSDAY NIGHT.  
 
OUTLOOK /FRIDAY THROUGH MONDAY/...  
 
FRIDAY THROUGH SATURDAY: WINDS LESS THAN 25 KT.  
 
SATURDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING  
5 FT. SLIGHT CHANCE OF RAIN SHOWERS.  
 
SUNDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.  
 

 
   
TIDES/COASTAL FLOODING
 
 
HIGH TIDE WILL BE ELEVATED AT SEVERAL LOCATIONS ALONG THE  
MASSACHUSETTS EAST COAST THURSDAY NIGHT THROUGH SUNDAY MORNING.  
THERE ARE INDICATIONS THAT PARTS OF THE SOUTH COAST, SUCH AS  
NANTUCKET HARBOR AND NARRAGANSETT BAY, WILL ALSO HAVE ELEVATED  
TIDES.  
 
THE JULY ASTRONOMICAL HIGH TIDE OCCURS LATE THIS WEEK, WITH  
HIGHEST VALUES FRIDAY NIGHT. IN ADDITION TO THE ASTRONOMICAL  
TIDE, THERE WILL BE A LEFTOVER 0.2 TO 0.4 FOOT SURGE FROM  
THE DISTANT AND DEPARTING HURRICANE CHRIS. THE COMBINATION OF  
THESE ELEMENTS MAY RESULT IN SOME MINOR COASTAL FLOODING, WITH  
THE BEST CHANCE FRIDAY NIGHT.  
 
BOSTON ASTRO HIGH TIDE...  
 
12.06 FEET THURSDAY 11:22 PM  
12.25 FEET SATURDAY 12:16 AM  
12.23 FEET SUNDAY 1:11 AM  
 
NANTUCKET ASTRO HIGH TIDE...  
 
4.33 FEET FRIDAY 12:21 AM  
4.38 FEET SATURDAY 1:18 AM  
4.34 FEET SUNDAY 2:15 AM  
 
NEWPORT ASTRO HIGH TIDE...  
 
4.91 FEET THURSDAY 8:05 PM  
4.99 FEET FRIDAY 8:58 PM  
4.92 FEET SATURDAY 9:51 PM  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THURSDAY FOR  
ANZ254>256.  
SMALL CRAFT ADVISORY UNTIL 4 AM EDT THURSDAY FOR ANZ235-237.  
 

 
 

 
SYNOPSIS...WTB/DUNTEN  
NEAR TERM...WTB/DUNTEN  
SHORT TERM...WTB  
LONG TERM...DUNTEN  
AVIATION...WTB/DUNTEN  
MARINE...WTB/DUNTEN  
TIDES/COASTAL FLOODING...  
 
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