532  
FXUS61 KBOX 092148  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAUNTON MA  
ISSUED BY NATIONAL WEATHER SERVICE UPTON NY  
448 PM EST TUE JAN 9 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL BUILD ACROSS THROUGH WEDNESDAY, THEN PASS  
EAST WEDNESDAY NIGHT. A WARM FRONT WILL THEN PASS TO THE NORTH  
WEDNESDAY NIGHT INTO THURSDAY. STRENGTHENING LOW PRESSURE WILL  
THE MOVE OUT OF THE SOUTHERN STATES AND BRING RAINY WEATHER  
THURSDAY NIGHT INTO SATURDAY, AND COULD END WITH SOME WINTRY  
PRECIPITATION ACROSS THE INTERIOR DEPENDING ON HOW MUCH COLD AIR  
WORKS BACK INTO THE REGION. DRY AND COLD WEATHER IS FAVORED FOR  
EARLY NEXT WEEK. SUNDAY INTO MONDAY.  
 

 
   
NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
 
 
STRATOCU MAINLY ACROSS THE INTERIOR WILL DISSIPATE TONIGHT AS  
WINDS DIMINISH. GIVEN THE DEEP SNOW PACK STILL IN PLACE ALONG  
WITH IDEAL RADIATIONAL COOLING CONDITIONS, MANY LOCATIONS SHOULD  
BOTTOM OUT IN THE SINGLE DIGITS TO MIDDLE TEENS. THE MILDER  
SPOTS WILL BE THE URBAN HEAT ISLANDS OF DOWNTOWN  
BOSTON/PROVIDENCE WHERE LOW TEMPS SHOULD MAINLY BE IN THE UPPER  
TEENS AND THE LOWER 20S.  
 

 
   
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/
 
 
WED: HIGH PRESSURE SLIDING ACROSS WILL PRODUCE LIGHT WINDS AND  
PLENTY OF SUNSHINE, WITH SOME LATE DAY MID/HIGH LEVEL  
CLOUDINESS. DESPITE WARMING MID LEVEL TEMPERATURES, THE LOW  
JANUARY SUN ANGLE AND WEAK MIXING SHOULD HOLD AFTERNOON HIGH  
TEMPERATURES IN THE 30S AND LOWER 40S.  
 
WED NIGHT: INITIALLY, WITH HIGH PRES IN PLACE, (OUTSIDE OF A  
FEW CLOUDS) CONDITIONS SUPPORT SOME RADIATIONAL COOLING WHICH  
WILL ALLOW TEMPS TO DROP FROM THE MID 20S TO LOWER 30S. BY EARLY  
AM, WITH CONTINUED LOW LVL MOISTURE INCREASE AS A WARM FRONT  
PASSES TO THE NW, AND DRYING/WARMING ALOFT, MAY NEED TO WATCH  
FOR PATCHY LIGHT FREEZING RAIN/DRIZZLE WELL INLAND OR ICING DUE  
TO CONDENSATION.  
 

 
   
LONG TERM /THURSDAY THROUGH TUESDAY/
 
 
FLOW ALOFT SHOULD AMPLIFY OVER THE LOWER 48, WITH A BUILDING  
UPPER RIDGE IN THE EAST AND A TROUGH OVER THE CENTRAL STATES.  
THE SOUTHERN EXTENSION OF THIS TROUGH SHOULD CUT OFF OVER THE  
LOWER MISSISSIPPI VALLEY LATE THU NIGHT AND THEN LIFT NW, WITH  
ATTENDANT SFC LOW PRESSURE RIDING FROM THE TN VALLEY UP THE  
APPALACHIANS. THIS LOW WILL TAP INTO GULF AND ATLANTIC MOISTURE  
AND HAS POTENTIAL TO BRING MULTIPLE ROUNDS OF LOCALLY HEAVY RAIN  
FRI INTO SAT, THE FIRST WITH A LEADING AREA OF LOW LEVEL  
WAA/ISENTROPIC LIFT DAYTIME FRI, THEN ANOTHER JUST AHEAD OF THE  
SFC LOW AND ANOTHER WARM FRONTAL APPROACH LATE FRI NIGHT AND  
POSSIBLY INTO SAT MORNING. TEMPS SHOULD REMAIN ON THE MILD  
SIDE, FALLING ONLY TO THE MID 40S THU NIGHT, THEN RISING TO THE  
MID 50S ON FRI PER BLEND OF MOS AND MODEL RAW 2M TEMPS.  
 
AFTER THE LOW PASSES, PRECIP COULD CHANGE BACK TO SNOW MAINLY  
ACROSS INTERIOR MASSACHUSETTS ON SAT BEFORE ENDING SOME TIME  
LATE DAY SAT INTO SAT EVENING. COLDER WX EXPECTED TO FOLLOW FOR  
EARLY NEXT WEEK, WITH AN ALBERTA CLIPPER LOW POSSIBLY BRINGING  
SOME SNOW SHOWERS ON TUE.  
 

 
   
AVIATION /21Z 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/...  
 
TONIGHT...MODERATE CONFIDENCE. REMNANT LOWER BROKEN VFR  
CLOUDS FOR WESTERN MA TERMINALS WITH OTHERWISE FEW-SCT VFR  
CLOUDS. W-NW WINDS WITH GUSTS 20-25 KT THROUGH THE EARLY  
EVENING. GUST END TIMING COULD VARY 1-2 HOURS FROM FORECAST.  
 
WEDNESDAY...HIGH CONFIDENCE. VFR CONDITIONS WITH WINDS BECOMING  
S-SW 5-10 KT.  
 
KBOS TERMINAL...HIGH CONFIDENCE IN TAF CATEGORY FORECAST.  
MODERATE CONFIDENCE IN TAF WIND FORECAST.  
 
KBDL TERMINAL...HIGH CONFIDENCE IN TAF CATEGORY FORECAST.  
MODERATE CONFIDENCE IN TAF WIND FORECAST.  
 
OUTLOOK /THURSDAY THROUGH SUNDAY/...  
 
WEDNESDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.  
SLIGHT CHANCE RADZ/FZDZ IN THE INTERIOR.  
 
THURSDAY: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY. SLIGHT  
CHANCE FZRA EARLY FOR INTERIOR. OTHERWISE SLIGHT CHANCE OF RA  
FOR NEAR KBOS AND INTERIOR.  
 
THURSDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE. BREEZY TOWARDS  
SOUTHEAST COAST WITH GUSTS 15-20 KT. INCREASING CHANCES OF RA,  
PATCHY BR.  
 
FRIDAY: MVFR/IFR CONDITIONS POSSIBLE. WIND GUSTS 20-30 KT. RA,  
OCCASIONAL +RA, PATCHY BR.  
 
FRIDAY NIGHT: MAINLY IFR, WITH LOCAL MVFR POSSIBLE. BREEZY. RA,  
OCCASIONAL +RA, PATCHY BR.  
 
SATURDAY: MAINLY MVFR, WITH AREAS IFR POSSIBLE. WIND GUSTS  
15-25 KT. OCCASIONAL +RA EARLY. RA MIXING WITH SN TOWARDS  
INTERIOR DURING DAY. CHANCE OF SNOW SHOWERS AT NIGHT WITH  
MVFR/IFR POSSIBLE.  
 
SUNDAY: MAINLY VFR. WIND GUSTS 15-20 KT.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH WEDNESDAY NIGHT/...  
 
TONIGHT...HIGH CONFIDENCE. HIGH PRESSURE BUILDS IN FROM THE  
WEST TONIGHT ALLOWING WINDS/SEAS TO GRADUALLY DIMINISH BELOW  
SMALL CRAFT THRESHOLDS FROM CLOSE TO COAST TO FARTHER AWAY FROM  
COAST. SCA EXTENDED FOR SOME WATERS A FEW HOURS LATER THAN  
PREVIOUS FORECAST. WAVEWATCH ADJUSTED UP 1 FOOT. HIGHER SEAS  
MEETING LOW END SCA LINGER ON OUTER OCEAN WATERS OVERNIGHT.  
 
WEDNESDAY...HIGH CONFIDENCE. BELOW SCA CONDITIONS EXPECTED.  
 
OUTLOOK /THURSDAY THROUGH SUNDAY/...  
 
WEDNESDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 30 KT. SEAS LOCALLY APPROACHING 5 FT.  
 
THURSDAY: WINDS MAINLY LESS THAN 25 KT. SEAS LOCALLY  
APPROACHING 5 FT.  
 
THURSDAY NIGHT: WIND GUST TO 25 KT FOR SOME PARTS OF LI SOUND  
AND OUTER OCEAN WATERS. AREAS OF SEAS APPROACHING 5 FT. RAIN.  
 
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH LOCAL  
GUSTS UP TO 30 KT. LOW RISK FOR GALE FORCE WINDS UP TO 35 KT FOR  
SOME WATERS. ROUGH SEAS APPROACHING UP TO 10 FT. RAIN,  
OCCASIONALLY HEAVY.  
 
FRIDAY NIGHT: WIND GUSTS 25-30 KT. ROUGH SEAS UP TO 11-13 FT.  
RAIN, OCCASIONALLY HEAVY.  
 
SATURDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 30 KT. LOCALIZED GALE FORCE GUSTS UP TO 35 KT  
POSSIBLE. ROUGH SEAS UP TO 13 FT. RAIN, OCCASIONALLY HEAVY  
EARLY.  
 
SUNDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH  
GUSTS UP TO 25 KT. OCEAN SEAS UP TO 9 FT EARLY.  
 

 
   
HYDROLOGY
 
 
POTENTIAL FOR HEAVY RAIN, WITH WIDESPREAD AMOUNTS 1.50-3.00"  
AND LOCALLY UP TO 4", EXISTS FROM LATE THU NIGHT INTO SAT  
MORNING. THE HEAVIEST RAIN SHOULD COME IN MULTIPLE ROUNDS, ONE  
MAINLY DAYTIME FRI, AND ANOTHER LATE FRI NIGHT INTO SAT MORNING.  
THIS COULD LEAD TO AREAS OF URBAN AND POOR DRAINAGE FLOODING  
FRIDAY AND SATURDAY, WITH SNOW MELT EXACERBATING THE FLOOD RISK.  
THE RELATIVELY LONG DURATION SHOULD MAKE THIS MORE OF AN AREAL  
VS. FLASH FLOOD THREAT, BUT THAT SAID WE MAY HAVE TO WATCH FOR  
ICE JAMS AND RELATED FLOODING ON INTERIOR STREAMS AND RIVERS.  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...NONE.  
RI...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ232-233-  
235-237.  
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ230-  
236.  
SMALL CRAFT ADVISORY UNTIL 2 AM EST WEDNESDAY FOR ANZ231-251.  
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ234.  
SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ250-  
254>256.  
 

 
 

 
 
BG/JM  
 
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