480  
FXUS61 KBOX 192041  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
341 PM EST TUE NOV 19 2019  
   
SYNOPSIS
 
 
LOW PRESSURE PASSING SOUTH AND EAST OF THE REGION MAY BRING  
SOME LIGHT RAIN/SNOW SHOWERS OVERNIGHT TONIGHT THROUGH  
WEDNESDAY. HIGH PRESSURE BUILDING IN FROM THE WEST THU YIELDS  
DRY CONDITIONS AND SEASONABLE TEMPERATURES. MILDER AND BREEZY  
FRIDAY AHEAD OF AN APPROACHING COLD FRONT THAT MAY BE  
ACCOMPANIED BY SCATTERED SHOWERS LATE FRIDAY/FRI EVENING. COOL  
DRY WEATHER LINGERS MUCH OF SATURDAY, FOLLOWED BY COASTAL LOW  
PRESSURE BRINGING A RISK OF RAIN/SNOW SAT NIGHT INTO SUNDAY  
MORNING. AS THIS LOW EXITS, A DRYING TREND WITH SEASONABLE  
TEMPERATURES SHOULD FOLLOW EARLY NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
 
 
DRIER AIR WORKING IN AT THE MID LEVELS HAS ALLOWED FOR SOME  
BREAKS OF SUN THIS AFTERNOON ACROSS SOUTHERN NEW ENGLAND, BUT  
THEY ARE FEW AND FAR BETWEEN. AHEAD OF THE APPROACHING UPPER  
TROUGH WE STILL HAVE PRETTY SATURATED LOWER AND UPPER LEVELS,  
LEADING TO A RATHER THICK DECK OF LOW CLOUDS. THESE WILL HANG  
AROUND AND FURTHER THICKEN THIS EVENING INTO THE OVERNIGHT HOURS  
AS THE SHORTWAVE APPROACHES. THE LOW PASSES OFF THE NEW JERSEY  
COAST BY SUNRISE TOMORROW AND HELPS TO SPIN UP A COASTAL LOW  
WELL SOUTH AND EAST OF THE BENCHMARK WHICH WILL LIMIT ITS  
IMPACT.  
 
NW WINDS BECOME MORE NORTHERLY OVERNIGHT BUT SHOULD REMAIN LIGHT.  
THE SATURATED LOW LEVELS WILL ALLOW FOR SOME LIGHT SHOWERS TO  
WRAP AROUND THE LOW REACHING INTO SOUTHERN NEW ENGLAND, BUT  
AMOUNTS LOOK LIGHT. GIVEN THE SHALLOW LOW SATURATED LAYER  
INITIALLY BELOW 5 KFT MUCH OF IT MAY BE DRIZZLE, AT LEAST UNTIL  
THE DRY MID LEVELS SATURATE BY MID-LATE WEDNESDAY MORNING. THAT  
BEING SAID, THE SECOND NEARLY SATURATED LAYER RESIDES UP NEAR  
THE -12 TO 18C LAYER, SO SOME SNOW IS POSSIBLE. IN FACT, WITH A  
COOLING COLUMN SOME LOCATIONS MAY SEE LIGHT SNOW SHOWERS BEFORE  
SUNRISE AND LASTING INTO WEDNESDAY, MAINLY IN THE HIGHER  
ELEVATIONS OF CENTRAL AND WESTERN MA.  
 

 
   
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/
 
 
BY MID MORNING WEDNESDAY THE LOW MOVES FURTHER TOWARD THE  
CANADIAN MARITIMES ALL THE WHILE CONTINUING TO WRAP MOISTURE  
AROUND THE BACK EDGE BRINGING LIGHT RAIN AND SNOW SHOWER CHANCES  
TO THE REGION THROUGH MUCH OF THE DAY WEDNESDAY. THE BEST  
CHANCE FOR SNOW WILL AGAIN BE THE HIGHER ELEVATIONS OF THE  
WORCESTER HILLS AND SLOPES OF THE BERKSHIRES. MODEL SOUNDINGS  
SHOW SUB FREEZING TEMPS ALOFT BUT WITH SURFACE TEMPS IN THE  
UPPER 30S BY MID-LATE MORNING, ANY SNOW THAT FALLS WILL STRUGGLE  
TO AMOUNT TO MUCH. GENERALLY EXPECTING UP TO A COATING FOR  
THOSE HIGHEST ELEVATIONS. FOR EVERYONE ELSE ANOTHER COLD RAIN IS  
EXPECTED, WITH HIGH TEMPERATURES IN THE UPPER 30S INLAND, MID  
TO UPPER 40S CLOSER TO THE COAST. OVERALL ANOTHER CLOUDY, DAMP  
DAY ON TAP WITH BREEZY WINDS ALONG THE SOUTHEAST COAST.  
 
WEDNESDAY NIGHT IS A TRANSITION PERIOD AS THE LOW EXITS TO THE  
EAST, REPLACED BY SURFACE HIGH PRESSURE AND DRIER AIR BY  
THURSDAY MORNING. ANY LINGERING SHOWERS EXIT OFFSHORE IN THE  
EVENING. HOWEVER, THE CAPE AND NANTUCKET MAY DEAL WITH A FEW  
LINGERING OCEAN EFFECT SHOWERS GIVEN THE COLD NORTHERLY FLOW  
OVER THE STILL "WARM" WATER. BREEZY WINDS CONTINUE, MAINLY ALONG  
THE IMMEDIATE COAST AND OVER THE WATERS.  
 

 
   
LONG TERM /THURSDAY THROUGH TUESDAY/
 
 
HIGHLIGHTS...  
 
* HIGH PRESSURE BUILDS IN THURSDAY INTO THURSDAY NIGHT  
 
* LOW PRESSURE MOVES INTO THE GREAT LAKES FRIDAY, PUSHING A WARM  
FRONT THROUGH FRIDAY, WITH A COLD FRONT FRIDAY NIGHT  
 
* RAIN/WET SNOW POSSIBLE SATURDAY NIGHT INTO EARLY SUNDAY  
 
* HIGH PRESSURE EXPECTED EARLY NEXT WEEK  
 
THURSDAY...  
 
LOW PRESSURE NEAR MARITIMES CONTINUES TO MOVE OUT TO SEA. HIGH  
PRESSURE IN THE CENTRAL APPALACHIANS WILL ALSO MOVE EAST, AND  
EXERT ITS INFLUENCE TOWARDS DRIER WEATHER DURING THIS TIME.  
WINDS SHOULD DIMINISH, TOO. BELOW NORMAL TEMPERATURES EXPECTED  
THURSDAY, BUT NEAR NORMAL THURSDAY NIGHT.  
 
FRIDAY...  
 
STILL MONITORING THE PROGRESS OF A POTENT MID-LEVEL SHORTWAVE  
AND LONGWAVE TROUGH LATE FRIDAY INTO FRIDAY NIGHT. THIS SHOULD  
PROVIDE A DECENT AMOUNT OF LIFT, AND STEER A LOW PRESSURE  
THROUGH THE GREAT LAKES INTO THE SAINT LAWRENCE VALLEY.  
EXPECTING A WARM FRONT TO ARRIVE FAIRLY EARLY IN THE DAY,  
RESULTING IN NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES. ANY  
SHOWERS ASSOCIATED WITH THIS FRONT WILL BE RAIN.  
 
THE COLD FRONT ASSOCIATED WITH THIS LOW PRESSURE SHOULD ARRIVE  
SOMETIME FRIDAY NIGHT. DEPENDING UPON THE TIMING, PRECIPITATION  
COULD END AS A BRIEF PERIOD OF LIGHT SNOW. THIS WILL BE MAINLY  
ACROSS THE HIGHER TERRAIN WITHIN INTERIOR SOUTHERN NEW ENGLAND.  
ALL SHOWERS SHOULD END BY LATE FRIDAY NIGHT.  
 
THIS WEEKEND...  
 
THINKING DRIER AND COOLER WEATHER TO START OUT SATURDAY, WITH  
AN INCREASING RISK FOR PRECIPITATION SATURDAY AFTERNOON INTO  
SATURDAY NIGHT. IT REMAINS POSSIBLE FOR MOST OF SATURDAY TO  
REMAIN DRY. SUBTLE TIMING DIFFERENCES IN THE LATEST GLOBAL  
MODELS MAY LEAD TO LATER FORECAST CHANGES.  
 
THE PRIMARY PERIOD FOR A RAIN/SNOW MIX LOOKS TO BE SATURDAY  
NIGHT INTO SUNDAY, AS A LOW PRESSURE PASSES BY TO OUR SOUTH.  
THIS IS LOOKING MORE LIKE A CLIPPER, THAN A BIG COASTAL STORM.  
THIS STORM MAY ALSO PASS SO FAR SOUTH AS TO HAVE LITTLE IMPACT  
ON OUR REGION. WILL KEEP AT LEAST A CHANCE FOR RAIN/SNOW IN THE  
FORECAST FOR NOW. THERE ARE ENOUGH DETAIL DIFFERENCES IN THE  
GUIDANCE WHERE ADDITIONAL FORECAST CHANGES ARE LIKELY OVER THE  
COMING DAYS.  
 
EARLY NEXT WEEK...  
 
BEHIND DEPARTING COASTAL WAVE A TREND TOWARD DRY WEATHER ALONG  
WITH NEAR NORMAL TEMPERATURES.  
 

 
   
AVIATION /20Z TUESDAY THROUGH SUNDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH WEDNESDAY NIGHT/...MODERATE CONFIDENCE.  
 
18Z TAF UPDATE:  
 
THIS AFTERNOON...  
 
IFR/MVFR CONDITIONS CURRENTLY WILL IMPROVE A BIT TOWARD MAINLY  
MVFR TO EVEN LOW END VFR TOWARDS THE SOUTH COAST, CAPE COD AND  
ISLANDS. MAINLY DRY CONDITIONS. LIGHT WINDS BECOME W/NW.  
 
TONIGHT:  
 
CEILINGS LOWER TO MVFR-IFR FROM NE TO SW. LATE OVERNIGHT,  
SHALLOW MOISTURE FROM A DISTANT COASTAL LOW COULD BRING A  
POTENTIAL FOR UNRESTRICTED RAIN/DRIZZLE OR VERY LIGHT SNOW, WITH  
LOW PROB OF LIGHT FREEZING DRIZZLE. BEST CHANCE OF FROZEN  
PRECIP MAINLY NW OF BED/ORH. LIGHT WNW/W WINDS INITIALLY, THOUGH  
BECOME NORTHWEST 3-8 KTS, HIGHEST TOWARDS THE CAPE/ACK.  
 
WEDNESDAY:  
 
LOW PRESSURE AND NORTHERLY FLOW RESULTS IN CONTINUED OVC MVFR-  
IFR CEILINGS WITH SPOTTY/UNRESTRICTED LIGHT PRECIP EARLY  
BECOMING MORE CONFINED TO THE CAPE AND ISLANDS. N/NW WINDS  
INCREASE TO 6-10 KTS, 10-15 KTS WITH GUSTS TO 20 KTS ACROSS  
CAPE COD TERMINALS.  
 
WEDNESDAY NIGHT:  
 
MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY ON CAPE COD AND THE  
ISLANDS.  
 
KBOS TAF...HIGH CONFIDENCE IN TAF AND TRENDS.  
 
KBDL TAF...HIGH CONFIDENCE IN TAF AND TRENDS. RAIN MAY BRIEFLY  
MIX WITH SNOW SHOWERS EARLY TUESDAY AM.  
 
OUTLOOK /THURSDAY THROUGH SUNDAY/...  
 
THURSDAY: VFR. BREEZY.  
 
THURSDAY NIGHT: VFR. BREEZY. SLIGHT CHANCE SHRA.  
 
FRIDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY. SLIGHT  
CHANCE SHRA.  
 
FRIDAY NIGHT: VFR. WINDY WITH GUSTS UP TO 30 KT. SLIGHT CHANCE  
SHRA AND SHSN.  
 
SATURDAY: VFR. BREEZY. SLIGHT CHANCE RA.  
 
SATURDAY NIGHT: VFR. CHANCE SN AND RA.  
 
SUNDAY: VFR. SLIGHT CHANCE RA AND SN.  
 

 
   
MARINE
 
 
SHORT TERM /THROUGH WEDNESDAY NIGHT/...MODERATE CONFIDENCE.  
 
TONIGHT: SMALL CRAFT ADVISORIES CONTINUE. DISTANT COASTAL LOW  
PASSING SOUTH OF THE REGION WILL INCREASE WIND SPEEDS. NW WINDS  
BECOME N AND INCREASE TO 10-15 KTS, GUSTS 20-25 KTS. SEAS 4-6  
FEET OFFSHORE WATERS. LIGHT SHOWERS OVERNIGHT.  
 
WEDNESDAY: WINDS CONTINUE TO INCREASE TO 10-15 KTS WITH GUSTS  
NEARING OR AT SCA LEVELS ESPECIALLY EASTERN/SOUTHEASTERN  
OFFSHORE WATERS. SEAS OFFSHORE WATERS 4-6 FT, HIGHEST WITH  
EASTERN EXTENT. BETTER CHANCES FOR SHOWERS AND REDUCED  
VISIBILITIES LATE WEDNESDAY.  
 
WEDNESDAY NIGHT: SMALL CRAFT ADVISORY CONTINUES WITH GUSTS UP  
TO 25 KT. AREAS OF ROUGH SEAS. SLIGHT CHANCE OF RAIN SHOWERS.  
 
OUTLOOK /THURSDAY THROUGH SUNDAY/...  
 
THURSDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 25 KT. AREAS OF ROUGH SEAS.  
 
THURSDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS  
APPROACHING 5 FT. SLIGHT CHANCE OF RAIN SHOWERS.  
 
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH AREAS  
OF GUSTS UP TO 30 KT. AREAS OF ROUGH SEAS. CHANCE OF RAIN  
SHOWERS.  
 
FRIDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS  
UP TO 11 FT. CHANCE OF RAIN SHOWERS.  
 
SATURDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP  
TO 30 KT. AREAS OF ROUGH SEAS. SLIGHT CHANCE OF RAIN.  
 
SATURDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING  
5 FT. CHANCE OF RAIN.  
 
SUNDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.  
CHANCE OF RAIN.  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ250-251-  
254>256.  
 

 
 

 
SYNOPSIS...BELK/BW  
NEAR TERM...BW  
SHORT TERM...BW  
LONG TERM...BELK  
AVIATION...BELK/BW  
MARINE...BELK/BW  
 
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