670  
FXUS61 KBOX 120800  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
400 AM EDT THU JUL 12 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE BRINGS DRY WEATHER WITH SEASONABLE TEMPERATURES  
AND COMFORTABLE HUMIDITY THROUGH FRIDAY. 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/
 
 
MID LEVEL TROUGH AXIS WILL BE OVER NEW ENG TODAY AND SOUNDINGS  
SHOW STEEP LOW LEVEL LAPSE RATES THIS AFTERNOON. ENOUGH MOISTURE  
IN THE 850-700 MB LAYER FOR SCT-BKN CU DEVELOPING. WHILE A  
BRIEF SHOWER IN THE INTERIOR CAN'T BE RULED OUT PER SOME OF THE  
HI-RES MODELS, EXPECTING A MAINLY DRY DAY AS ENVIRONMENT IS  
STABLE AND OVERALL MOISTURE IN THE COLUMN IS LIMITED.  
 
TEMPS ALOFT SIMILAR TO WED, SO EXPECT HIGHS IN THE LOW/MID 80S  
INTERIOR AND 70S ALONG THE COAST WHERE SEA BREEZES ARE LIKELY.  
COMFORTABLE HUMIDITY LEVELS WITH DEWPOINTS IN THE 50S.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/
 
 
TONIGHT...  
 
QUIET NIGHT WITH MOSTLY CLEAR SKIES AND LIGHT WINDS LEADING TO  
ANOTHER COOL NIGHT WITH LOWS MOSTLY IN THE 50S, WITH LOWER 60S  
URBAN CENTERS. PATCHY LATE NIGHT RADIATION FOG IS POSSIBLE IN  
THE TYPICAL PRONE LOCATIONS.  
 
FRIDAY...  
 
MID LEVEL TROUGH SHARPENS EAST OF NEW ENG AS SHORTWAVES ROTATE  
THROUGH THE FLOW. NOT MUCH CHANGE IN SENSIBLE WEATHER WITH SCT-  
BKN CU DEVELOPING BUT MAINLY DRY WEATHER AS MID LEVEL TEMPS ARE  
WARMING WITH STABLE ENVIRONMENT. NOT MUCH CHANGE IN 925 AND 850  
MB TEMPS SO EXPECT ANOTHER DAY WITH HIGHS LOW/MID 80S INTERIOR  
AND 70S ALONG THE COAST WITH SEA BREEZES.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
 
 
OVERVIEW...  
 
00Z MODEL GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT ON THE EVOLUTION  
OF THE SYNOPTIC PATTERN THROUGH NEXT WEDNESDAY. STILL SOME MINOR  
TIMING AND STRENGTHEN ISSUES. THEREFORE WILL CONTINUE TO FAVOR A  
CONSENSUS APPROACH TO SMOOTH OVER THE LESS PREDICTABLE DETAILS.  
 
FLAT HIGH PRESSURE OVER THE CENTRAL CONUS AND BUILDING NORTH  
ATLANTIC RIDGE WILL LEAD TO A TROUGH OVER NEW ENGLAND TO START THE  
MEDIUM RANGE. MODELS HAVE TRENDED TOWARDS A CUT-OFF LOW PRESSURE  
SYSTEM WHICH MEANDERS SOUTH AND EAST OF ACK/CAPE ON SATURDAY.  
APPROACHING COLD FRONT WILL BECOME MORE DIFFUSED WITH TIME AS IT  
MOVES TOWARDS THE NORTHEAST DURING THE WEEKEND. WEAK RIDGING EARLY  
NEXT WEEK AS A POTENT UPPER LEVEL LOW MOVES INTO ALBERTA. 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 OFFSHORE LOW  
PRESSURE SYSTEM. HEAT AND HUMIDITY WILL MAKE A RETURN BEGINNING ON  
SUNDAY LASTING INTO MID-WEEK DUE TO SOUTHERLY FLOW. THIS COULD BRING  
ANOTHER ROUND OF 90+ DEGREES TEMPERATURES FOR LOCATIONS ACROSS THE  
INTERIOR. HEAT AND HUMIDITY ARE ANTICIPATED TO DROP OFF BEHIND A  
COLD FRONT SOMETIME LATE WED INTO THURSDAY.  
 
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 MONDAY IN THE  
WARM, MOIST AIRMASS. BUT THESE WILL BE MAINLY AIRMASS TYPE STORMS.  
APPROACHING COLD FRONT ON TUESDAY/WEDNESDAY HAS THE BEST CHANCE TO  
BRING SOME MEASURABLE PRECIP FOR THE REGION PER LATEST GEFS AND EPS  
PROBS. PWAT VALUES ABOVE 2.3 INCHES AND INCREASING THETA-E VALUES  
COULD LEAD TO SOME WIDESPREAD RAINFALL. STILL SOME TIMING ISSUES,  
BUT CANNOT RULE OUT THE POTENTIAL FOR THUNDER AS THE REGION WILL BE  
IN A WARM, MUGGIER AIRMASS AHEAD OF THE FRONT.  
 

 
   
AVIATION /08Z THURSDAY THROUGH MONDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.  
 
VFR WITH SCT-BKN DIURNAL CU DEVELOPING EACH AFTERNOON. SEA  
BREEZES LIKELY TODAY AND FRI. SOME PATCHY LATE NIGHT FOG  
POSSIBLE IN THE TYPICAL PRONE LOCATIONS.  
 
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE DEVELOPING  
15-17Z. .  
 
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
FRIDAY NIGHT: VFR.  
 
SATURDAY THROUGH SATURDAY NIGHT: VFR. SLIGHT CHANCE SHRA,  
ISOLATED TSRA.  
 
SUNDAY: VFR. SLIGHT CHANCE SHRA.  
 
SUNDAY NIGHT THROUGH MONDAY: VFR.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.  
 
SWELL FROM HURRICANE CHRIS IS DIMINISHING. SOME 5 FT SEAS MAY  
LINGER INTO THE MORNING OVER SOUTHERN OUTER WATERS, OTHERWISE  
SEAS BELOW 5 FT THROUGH FRI. GENERALLY LIGHT WINDS TURNING  
ONSHORE OVER NEARSHORE WATERS DURING THE AFTERNOONS AS SEA  
BREEZES DEVELOP.  
 
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...  
 
FRIDAY NIGHT THROUGH SATURDAY: WINDS LESS THAN 25 KT.  
 
SATURDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING  
5 FT. SLIGHT CHANCE OF RAIN SHOWERS, ISOLATED THUNDERSTORMS.  
 
SUNDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.  
SLIGHT CHANCE OF RAIN SHOWERS, ISOLATED THUNDERSTORMS.  
 
SUNDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING  
5 FT.  
 
MONDAY: WINDS LESS THAN 25 KT.  
 

 
   
TIDES/COASTAL FLOODING
 
 
ASTRONOMICAL TIDES WILL BE RATHER HIGH DURING THE NIGHT TIME  
HIGH TIDE CYCLES TONIGHT THROUGH SAT NIGHT. FORTUNATELY WAVE  
ACTION WILL NOT BE MUCH OF A FACTOR AND SURGE IS LIMITED.  
HOWEVER, LEFTOVER SE SWELL MAY RESULT IN MINOR SPLASHOVER FOR  
VULNERABLE AREAS ALONG EAST COASTAL MA TONIGHT.  
 
TIDES ARE A SLIGHTLY HIGHER FRI NIGHT AND SAT NIGHT SO  
ADDITIONAL ROUNDS OF SPLASHOVER ARE POSSIBLE DURING THESE HIGH  
TIDE CYCLES.  
 
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  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR  
ANZ254>256.  
 

 
 

 
SYNOPSIS...KJC/DUNTEN  
NEAR TERM...KJC  
SHORT TERM...KJC  
LONG TERM...DUNTEN  
AVIATION...KJC/DUNTEN  
MARINE...KJC/DUNTEN  
TIDES/COASTAL FLOODING...STAFF  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab MA Page
The Nexlab RI Page
The Nexlab NH Page
The Nexlab CT Page Main Text Page