608  
FXUS61 KBOX 111046  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
646 AM EDT WED JUL 11 2018  
   
SYNOPSIS
 
 
A COLD FRONT WILL MOVE SOUTH OF THE COAST TODAY. HURRICANE  
CHRIS WILL PASS WELL SOUTHEAST OF NANTUCKET. 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 PM THIS EVENING/
 
 
0700 AM UPDATE...  
 
TRENDS IN THE FORECAST REMAIN ON TRACK THIS MORNING. SLOWED DOWN  
THE TIMING OF THE PRECIP CHANCES AS CAM MODELS KEEP ISOLATED  
SHOWERS AROUND TIL AT LEAST 10 AM. CONTINUE TO MONITOR THUNDER  
POTENTIAL ESP ACROSS RI AND SOUTHEAST MA WHERE CONDITIONS ARE  
MORE FAVORABLE THANKS TO HIGH K VALUES AND APPROACHING  
SHORTWAVE. IN FACT THE GOES-16 LL WV TRULY SHOWS THE DRY AIR  
PUSHING ITS WAY INTO SOUTHERN NEW ENGLAND.  
 
PREVIOUS DISCUSSION...  
 
SCATTERED SHOWERS AND ISOLATED T-STORMS CONTINUE TO DEVELOP  
ACROSS SNE AS MID LEVEL TROUGH APPROACHES. DEEPER MOISTURE AXIS  
WITH HIGH KI VALUES SOUTH OF THE PIKE AND MOVING TOWARD THE  
SOUTH COAST, SO MAIN FOCUS FOR SCATTERED SHOWERS AND AN ISOLD  
T-STORM THROUGH DAYBREAK WILL BE CONFINED TO RI AND SE MA TO THE  
SOUTH COAST. EXPECT SHOWERS TO CONTINUE TO DEVELOP IN THIS  
REGION EARLY THIS MORNING.  
 
COLD FRONT MOVES SOUTH OF THE COAST THIS MORNING AND CAN'T RULE  
OUT A FEW LINGERING SHOWERS THROUGH MID MORNING ALONG THE  
IMMEDIATE SOUTH COAST AND CAPE/ISLANDS. OTHERWISE A MAINLY DRY  
DAY, BUT AS MID LEVEL TROUGH AXIS MOVES INTO THE REGION A WEAK  
INVERTED TROUGH DEVELOPS OVER THE INTERIOR. ENOUGH MOISTURE IN  
THE COLUMN FOR THE RISK OF A FEW LIGHT SHOWERS DEVELOPING IN  
THE AFTERNOON ACROSS WESTERN HALF MA AND NORTHERN CT WHERE  
DEEPER MOISTURE AXIS IS LOCATED.  
 
HURRICANE CHRIS PASSES OVER 300 MILES SE OF ACK LATER TODAY 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.  
 
N/NE FLOW TODAY WILL RESULT IN COOLER TEMPS, ESPECIALLY ACROSS  
EASTERN MA. HIGH WILL RANGE FROM THE MID 70S EAST COASTAL MA TO  
THE LOW/MID 80S IN THE CT VALLEY.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/
 
 
TONIGHT...  
QUIET NIGHT TONIGHT WITH CLEARING SKIES AND DIMINISHING WIND.  
DECENT RADIATIONAL COOLING WILL RESULT IN LOW TEMPS DROPPING  
INTO THE 50S REGION WIDE, EXCEPT LOWER 60S FOR BOSTON.  
 
THURSDAY...  
WEAK HIGH PRESSURE IN CONTROL WILL BRING SUNSHINE AND LIGHT  
WINDS WHICH WILL PROMOTE COASTAL SEA BREEZES DEVELOPING. TEMPS  
SLIGHTLY BELOW NORMAL WITH HIGHS MOSTLY UPPER 70S TO LOWER 80S,  
A BIT COOLER CAPE/ISLANDS.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
 
 
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 /12Z 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 14Z...  
MAINLY VFR. SCATTERED SHOWERS AND ISOLATED T-STORMS FOCUSED  
ACROSS THE SOUTH COAST AND CAPE COD.  
 
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: 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/...HIGH CONFIDENCE.  
 
NE FLOW AVERAGING 10-20 KTS TODAY INTO THIS EVENING WITH  
DIMINISHING WIND LATE TONIGHT INTO THURSDAY. WINDS BECOMING  
ONSHORE OVER NEARSHORE WATERS ON THU AS SEABREEZES DEVELOP.  
MAIN ISSUE FOR THE SOUTHERN WATERS WILL BE INCREASING LONG  
PERIOD SOUTHERLY SWELL FROM DISTANT HURRICANE CHRIS. SEAS WILL  
BUILD TO 5-7 FT LATE TODAY AND THIS EVENING OVER OUTER SOUTHERN  
WATER BEFORE SUBSIDING LATE TONIGHT AND THU.  
 
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...  
 
THURSDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING  
5 FT.  
 
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 AT BOSTON WILL BE ABOVE 12.0 FEET BEGINNING ON  
THURSDAY NIGHT LASTING INTO SUNDAY MORNING AS WE APPROACH  
ASTRONOMICAL HIGH TIDE. WINDS WILL BE GENERALLY LIGHT AND  
EITHER FROM THE SOUTH OR SOUTHEAST DURING THIS TIME-FRAME.  
 
HOWEVER, STILL EXPECT A SLIGHT SURGE EACH NIGHT, NEAR 0.2 FEET,  
AS SOUTHEAST SWELL REMAINS FROM HURRICANE CHRIS. THIS SWELL WILL  
BE ENOUGH TO RESULT IN SOME MINOR COASTAL FLOODING ESPECIALLY  
BOSTON POINTS NORTHWARD AS WELL AS NANTUCKET FOR THURSDAY AND  
ESPECIALLY ON FRIDAY. ON SATURDAY, BOTH SEAS AND SWELL ARE ON  
THE INCREASE SO EXPECT MINOR COASTAL FLOODING FOR PERHAPS THE  
ENTIRE MA EAST COASTLINE.  
 
BOSTON HIGH TIDE...  
 
12.06 FEET THURSDAY 11:22 PM  
12.25 FEET SATURDAY 12:16 AM  
12.23 FEET SUNDAY 1:11 AM  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 8 AM EDT  
THURSDAY FOR ANZ254>256.  
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM EDT  
THURSDAY FOR ANZ235-237.  
 

 
 

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