814  
FXUS61 KBOX 251149  
AFDBOX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TAUNTON MA  
649 AM EST SAT FEB 25 2017  
   
SYNOPSIS
 
 
MILD AIR REMAINS OVER THE REGION TODAY. A STRONG COLD FRONT  
WILL CROSS THE REGION TONIGHT, BRINGING SHOWERS AND A LOW  
CHANCE FOR THUNDERSTORMS AS THIS FRONT PASSES. BLUSTERY  
CONDITIONS WITH TEMPERATURES CLOSE TO SEASONAL NORMALS EXPECTED  
FOR SUNDAY AND ABOVE AVERAGE ON MONDAY. A COUPLE OF WEATHER  
SYSTEMS WILL BRING PERIODS OF WET WEATHER TUESDAY INTO  
THURSDAY. COLDER AIR LOOKS TO RETURN LATE NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
PATCHY DENSE FOG REMAINS OVER THE REGION THIS MORNING. WENT  
AHEAD AND CONTINUED THE ADVISORY UNTIL 10 AM AS SOUTHERLY LOW  
WILL CONTINUE TO PUMP IN HIGH MOISTURE KEEPING THE FOG AROUND.  
ALSO EXPANDED THE ADVISORY TO COASTAL PLYMOUTH COUNTY PER LATEST  
OBS AND WEBCAMS SHOWING THAT REGION PRETTY SOCKED IN. WILL  
CONTINUE TO MONITOR THE AREA FOR ANY CHANGES.  
 
ASIDE FROM THE FOG, MOST OF THE FORECAST REMAINS ON TRACK FOR  
TODAY.  
 
PREVIOUS DISCUSSION...  
 
DIGGING SHORTWAVE OVER THE GREAT LAKES WILL EJECT NORTHEAST INTO  
CANADA. THE DIGGING TURNS THE UPPER FLOW MORE NORTHERLY. A COLD  
FRONT OVER THE EASTERN GREAT LAKES WILL SWEEP EAST ACROSS NY AND  
PA DURING THE DAY. PRECIPITATION ALONG THE FRONT WILL MOSTLY  
MOVE NORTH/NORTHEAST INTO CANADA AND ONLY SLOWLY SHIFT EAST.  
BEST CHANCE OF SHOWERS FROM THIS FRONT WILL BE LATE AFTERNOON  
AND IN WESTERN MA/WESTERN CT.  
 
MODEL GUIDANCE HAS BEEN CONSISTANTLY COOL COMPARED WITH  
VERIFICATION THE PAST COUPLE OF DAYS. TEMPS AT 925 MB SUPPORT  
MAX SFC TEMPS IN THE MID TO UPPER 60S. THE WARMER GUIDANCE  
MEMBERS ALSO AIM AT THIS RANGE.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/
 
 
THE COLD FRONT ARRIVES IN THE HUDSON VALLEY AROUND 6-7 PM AND  
CROSSES INTO WESTERN NEW ENGLAND AROUND 8-9 PM...CENTRAL  
SECTIONS 9-10 PM...AND EASTERN NEW ENGLAND 10 PM TO MIDNIGHT.  
THIS FRONT WILL BE SUPPORTED BY THE SHARP UPPER SHORTWAVE.  
AIRMASS STABILITY WILL DECREASE THROUGH THE EVENING...FOR  
EXAMPLE, TOTALS WILL CLIMB INTO THE LOWER 50S. THIS SUPPORTS THE  
CONCEPT OF SUFFICIENTLY UNSTABLE CONDITIONS FOR A FEW  
THUNDERSTORMS AS THE COLD FRONT APPROACHES AND MOVES THROUGH.  
THE GREATEST RISK FOR TSTMS WOULD BE IN WESTERN MA AND WESTERN  
CT WHERE THE LOW LEVEL INFLOW IS LEAST MARITIME.  
 
LOW LEVEL SOUTHERLY WINDS WILL INCREASE DURING THE AFTERNOON, SO  
THAT BY EVENING WE EXPECT A 50-KNOT JET AT OR BELOW 5000 FEET.  
CONFIDENCE IS NOT HIGH AS TO HOW MUCH OF THAT WIND MAY BE  
BROUGHT TO THE SURFACE IN GUSTS DURING SHOWERS/TSTMS, BUT ITS  
PRESENCE SUGGEST A CHANCE OF STRONG WIND GUSTS THIS  
EVENING...POSSIBLY ISOLATED DAMAGING WIND. GREATEST RISK WOULD  
AGAIN BE IN WESTERN AREAS EARLY TONIGHT.  
 
PRECIPITABLE WATER FIELDS CONTINUE TO ADVERTISE VALUES A LITTLE  
OVER AN INCH, WHICH IS WELL ABOVE NORMAL. BUT THIS IS A NARROW  
AND FAST- MOVING ZONE, SO WHILE SHOWERS MAY BE BRIEFLY STRONG,  
TOTAL AMOUNTS SHOULD BE 0.50 INCHES OR LESS.  
 
COLDER AIR RUSHES IN BEHIND A COLD FRONT. IT WILL BE A RACE  
BETWEEN THE COLD AIR AND THE DEPARTING SHOWERS, BUT A BRIEF  
CHANGEOVER TO SNOW IS POSSIBLE AT THE END. ANY ACCUMULATIONS  
SHOULD BE LIMITED, GENERALLY LESS THAN AN INCH AND MAINLY OVER  
THE HIGHER TERRAIN OF THE BERKSHIRES AND WORCESTER HILLS.  
 
FINALLY, THE COLDER AIR ADVECTION BEHIND THE FRONT WILL BRING  
MIXING OF STRONG WNW WINDS ALOFT TO THE SURFACE LATE AT NIGHT.  
WIND GUSTS AT THAT TIME WILL HAVE A POTENTIAL OF REACHING 30-35  
KNOTS.  
 
SUNDAY...HIGH CONFIDENCE.  
 
THE SHORTWAVE TROUGH MOVES OFFSHORE SUNDAY MORNING. THE LAST OF  
ANY PCPN SHOULD END BY THAT TIME. SO SUNDAY SHAPES UP TO BE A  
DRY DAY AS HIGH PRESSURE BUILDS IN FROM THE WEST.  
 
COLD ADVECTION CONTINUES DURING THE DAY. MIXING DUE TO THIS  
ADVECTION WILL TAP WINDS ALOFT OF 25-35 KNOTS AND POSSIBLY A  
FEW AREAS OF 40 KNOTS. THESE WINDS WILL DIMINISH DURING THE  
AFTERNOON AS THE HIGH PRESSURE AREA APPROACHES.  
 
TEMPS ALOFT CHILL BEHIND THE FRONT, BUT HOVER ON SUNDAY AT  
LEVELS THAT SUPPORT SFC MAX TEMPS AROUND 40 OR THE LOWER 40S.  
GIVEN THE MORNING TEMPS STARTING IN THE 30S, WE HAVE FORECAST  
MAX TEMPS IN THE UPPER 30S TO MID 40S.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
 
 
HIGHLIGHTS...  
 
* ABOVE AVERAGE TEMPERATURES FOR NEXT WEEK  
* WIDESPREAD SHOWERS POSSIBLE WEDNESDAY/THURSDAY  
* MORE SEASONABLE CONDITIONS RETURN ON FRIDAY  
 
PATTERN OVERVIEW...  
 
THE 00Z MODELS AND THEIR ENSEMBLES HAVE BEEN IN GENERALLY FOOD  
AGREEMENT THROUGH THE PERIOD WITH THE GFS JUST A BIT DISPLACED.  
THEREFOR USED A BLEND OF THE ENSEMBLES FOR THE BULK OF THE FORECAST.  
OVERALL, ZONAL FLOW OVER THE REGION AS BERMUDA HIGH BEGINS TO BUILD  
IN THE MID-LEVELS. BY MID-WEEK THE WESTERN TROUGH IS FORECAST TO  
TRANSITION INTO THE EAST AS A SURFACE FRONT WILL MOVE FROM THE GREAT  
LAKES TOWARDS THE NORTHEAST AROUND WED/THURS. STILL SOME ISSUES WITH  
THE TIMING OF THE FRONT AS A SURFACE WAVE MAY DEVELOP ALONG IT,  
WHICH COULD SLOW IT DOWN A BIT. THIS APPEARS TO BE MORE INLINE WITH  
THE EC/GEFS AND ECENS. OTHERWISE, NORTHWEST FLOW BEHIND THE FRONT  
COULD RESULT IN SEVERAL CLIPPERS FOR NEXT WEEKEND.  
 
DETAILS...  
 
MONDAY... HIGH CONFIDENCE.  
 
WESTERLY FLOW ACROSS THE REGION AS HIGH PRESSURE BUILDS SOUTH OF THE  
REGION. DEVELOPING LLJ OF NEAR 40 KTS WILL DEVELOP WITH HIGH  
PRESSURE TO THE SOUTH AND QUICK MOVING WAVE TO THE NORTH. THIS WILL  
MAKE CONDITIONS A BIT GUSTY AT TIMES. AS SURFACE HIGH PRESSURE MOVES  
FARTHER TO THE EAST, WINDS WILL BEGIN TO BACK RESULTING IN WAA.  
SURFACE TEMPS COULD REACH INTO THE MID 50S ON MONDAY WITH FULL  
MIXING. OTHERWISE DRY WEATHER WILL PREVAIL.  
 
TUESDAY...HIGH CONFIDENCE.  
 
MORE OF A TRANSITION DAY FOR TUESDAY AS HIGH PRESSURE MOVES EASTWARD  
AS UPPER LEVEL TROUGH APPROACHES. SOUTHWEST FLOW ALOFT WILL HELP  
SATURATE THE PROFILE. GUIDANCE DOES SHOW A WEAK WAVE DEVELOPING A  
COASTAL LOW BUT APPEARS TO BE JUST TO FAR EAST TO BRING SIGNIFICANT  
RAINFALL TO THE REGION. DEPENDING ON WHEN THIS OCCURS, WE COULD SEE  
A FEW FLAKES NORTH OF THE PIKE BUT CONFIDENCE IS LOW ON THIS  
OCCURRING. FOR NOW EXPECT A FEW SHOWERS AND CLOUDS ON TUESDAY.  
 
WEDNESDAY INTO THURSDAY... MODERATE CONFIDENCE.  
 
MAIN WEATHER PRODUCE FOR THE LONG TERM WILL OCCUR WED INTO THURSDAY  
AS UPPER LEVEL TROUGH APPROACHES THE REGION. WARM FRONT AHEAD OF THE  
SYSTEM WILL BRING SOME SHOWERS TO THE AREA AS TEMPERATURES RISE WELL  
ABOVE AVERAGE.  
 
UPPER LEVEL LOW WILL MOVE FROM THE PLAINS TOWARDS NORTHERN MAINE.  
THIS WILL DRAG A POTENT COLD FRONT THROUGH THE REGION. GOOD  
AGREEMENT AMONGST THE GUIDANCE WITH THIS SYSTEM, JUST SOME ISSUE'S  
WITH THE EXACT TIMING OF THE FRONT. TRENDED TOWARDS THE SLOWER SIDE  
AS THERE IS THE POTENTIAL FOR A SECONDARY LOW TO DEVELOP ALONG THE  
FRONT. THIS IS MORE INLINE WITH THE ENSEMBLES.  
 
THIS IS AN ANOMOLOUS SYSTEM WITH PWATS 3 STD ABOVE NORMAL AS GULF  
MOISTURE IS TAPPED OUT AHEAD OF THE FRONTAL PASSAGE. HEAVY PRECIP IS  
A POSSIBILITY IF SECONDARY LOW DOES DEVELOP BRINGING THE BETTER  
DYNAMICS OVER SOUTHERN NEW ENGLAND. ALSO HAVE NOTICED THAT THERE IS  
A POTENT SOUTHERLY LLJ OUT AHEAD OF THIS SYSTEM WITH 925 MB LLJ  
INCREASING TO NEAR 50-60 KTS. IF HEAVY RAIN DOES DEVELOP THEN WE  
COULD TAP INTO THESE STRONGER WINDS AS THE SYSTEM MOVES THROUGH.  
LASTLY APPEARS THAT THERE IS SOME ELEVATED INSTABILITY SO HAVE KEPT  
WITH ISO THUNDER IN THE FORECAST. STILL A LOT OF DETAILS TO WORK  
OUT, BUT A SYSTEM TO WATCH IN THE COMING DAYS.  
 
HIGH CONFIDENCE IN ABOVE AVERAGE TEMPERATURES WITH A NON-DIURNAL  
TREND WEDNESDAY NIGHT. WENT SEVERAL DEGREES ABOVE GUIDANCE AND COULD  
STILL BE A BIT LOW.  
 
FRIDAY AND BEYOND... MODERATE CONFIDENCE.  
 
AS THE COLD FRONT PASSES THROUGH, NORTHEAST WINDS TAKE A HOLD OF THE  
REGION. MODELS APPEAR TO BE INLINE WITH A FEW SHORTWAVES/CLIPPER  
SYSTEMS MOVING THROUGH THE FLOW. SO SOME SNOW SHOWERS ARE CERTAINLY  
POSSIBLE AS TEMPS DROP BACK TO SEASONABLE.  
 

 
   
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH SUNDAY/...  
 
TODAY...MODERATE CONFIDENCE.  
 
GENERALLY VFR TO MVFR ACROSS THE AREA WITH IFR/LIFR ACROSS THE  
SOUTH COAST IN DENSE FOG. FOG AND STRATUS WILL REMAIN OVER THE  
REGION THE MORNING BEFORE LIFTING BY THE AFTERNOON. CONDITIONS  
COULD IMPROVE TO MVFR BY THIS AFTERNOON. CANNOT RULE OUT A FEW  
SHOWERS DURING THE DAY.  
 
TONIGHT...MODERATE CONFIDENCE.  
 
A COLD FRONT SWEEPS WEST TO EAST ACROSS THE REGION BETWEEN 6 PM  
AND MIDNIGHT. SHOWERS AND WIDELY SCATTERED THUNDERSTORMS ARE  
POSSIBLE. THIS MEANS CONDITIONS MAY BRIEFLY LOWER TO IFR IN ANY  
SHOWERS OR THUNDERSTORMS. WE CONTINUE TO EXPECT LOW LEVEL WIND  
SHEAR AS WELL AS A CHANCE OF STRONG WIND GUSTS WITH  
SHOWERS/STORMS AS THAT 50 KNOT LOW LEVEL JET SWEEPS ACROSS AHEAD  
OF THE COLD FRONT. THE BEST CHANCE FOR THIS WILL CONTINUE TO BE  
IN WESTERN MA AND CT EARLY IN THE NIGHT.  
 
BEHIND THE COLD FRONT, WINDS WILL SHIFT FROM THE WEST AND WEST-  
NORTHWEST. COLDER AIR MOVING IN BEHIND THE FRONT WILL ALLOW  
STRONG WNW GUSTS TO WORK IN BY LATE NIGHT, WITH SPEEDS OF 30 TO  
35 KNOTS POSSIBLE. THE COLDER AIR MAY ALSO BRING A BRIEF CHANGE  
FROM RAIN TO SNOW AT THE WESTERN EDGE OF THE PRECIPITATION.  
 
SUNDAY...HIGH CONFIDENCE.  
 
VFR. WEST-NORTHWEST WINDS WILL CONTINUE TO GUST 25-35 KNOTS.  
THERE ARE POCKETS OF 40 KNOTS SHOWN IN OUR FORECAST GUIDANCE,  
SO A FEW OF THESE STRONGER WINDS ARE POSSIBLE. WINDS WILL  
DIMINISH BY MID TO LATE AFTERNOON.  
 
KBOS TAF...MODERATE CONFIDENCE IN TAF. LOW PROBABILITY IN FOG  
DEVELOPMENT THIS MORNING.  
 
KBDL TAF...HIGH CONFIDENCE IN TRENDS, LOWER CONFIDENCE IN  
TIMING.  
 
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...  
 
MONDAY...HIGH CONFIDENCE. VFR WITH WESTERLY WIND GUSTS NEAR 20-30  
KTS.  
 
TUESDAY...MODERATE CONFIDENCE. GENERALLY VFR WITH MVFR CONDITIONS  
POSSIBLE SOUTH OF THE PIKE.  
 
WEDNESDAY...MODERATE CONFIDENCE. MVFR TO POSSIBLE IFR IN -SHRA.  
 

 
   
MARINE
 
 
FORECASTER CONFIDENCE LEVELS...  
 
LOW - LESS THAN 30 PERCENT.  
MODERATE - 30 TO 60 PERCENT.  
HIGH - GREATER THAN 60 PERCENT.  
 
SHORT TERM /THROUGH SUNDAY/...HIGH CONFIDENCE.  
 
TODAY...HIGH CONFIDENCE.  
 
INCREASING SOUTHERLY WINDS THROUGH THE DAY, WITH GUSTS TO 25  
KNOTS MID TO LATE AFTERNOON. SEAS WILL INCREASE THROUGH THE DAY  
WITH 5 TO 6 FOOT HEIGHTS ON THE SOUTHERN WATERS BY MID TO LATE  
AFTERNOON.  
 
TONIGHT...MODERATE CONFIDENCE.  
 
A COLD FRONT SWEEPS ACROSS THE WATERS THE FIRST PART OF THE  
NIGHT. THIS WILL BRING SHOWERS AND A WIDELY SCATTERED  
THUNDERSTORM. THE SHOWERS MAY TAP STRONG WINDS AT 2000 TO 4000  
FEET ABOVE THE SURFACE AND BRING THEM TO THE SURFACE IN STRONG  
SOUTHERLY WIND GUSTS. SEAS BUILD TO 5-8 FEET ON THE EXPOSED  
WATERS OF THE SOUTH AND THE OUTER WATERS OF THE EAST.  
 
BEHIND THE FRONT, WINDS SHIFT FROM THE WEST OR WEST-NORTHWEST  
AND BRING COOLER AIR. WINDS LATE TONIGHT SHOULD GUST 30 TO 35  
KNOTS. SEAS WILL CONTINUE AT 5 TO 8 FEET.  
 
SUNDAY...HIGH CONFIDENCE.  
 
WEST-NORTHWEST WINDS CONTINUE TO GUST 30 TO 35 KNOTS DURING THE  
MORNING AND EARLY AFTERNOON. WINDS MAY SLOWLY DIMINISH DURING  
THE LATER AFTERNOON. SEAS WILL LINGER AT 5 TO 8 FEET ON THE  
EXPOSED WATERS.  
 
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...  
 
MONDAY...HIGH CONFIDENCE. IMPROVING CONDITIONS ON MONDAY WITH GUSTS  
NEAR 20 KTS AND SEAS BEGINNING TO RELAX AS HIGH PRESSURE BUILDS OVER  
THE SOUTHERN WATERS.  
 
TUESDAY INTO WEDNESDAY...LOW CONFIDENCE. WIND AND SEAS WILL BE BELOW  
SCA FOR TUESDAY. APPROACHING SYSTEM TO THE WEST COULD SEE LOWER  
VSBYS IN RAIN AND FOG. SEAS BUILD LATE TUESDAY NIGHT INTO WEDNESDAY  
AS LOW PRESSURE SYSTEM APPROACHES. THERE IS THE POTENTIAL FOR  
SOUTHERLY GALES ACROSS THE WATERS.  
 

 
   
HYDROLOGY
 
 
WE WILL NEED TO MONITOR RISING WATER LEVELS ACROSS SOUTHERN NEW  
ENGLAND INTO EARLY NEXT WEEK. MUCH, IF NOT ALL, OF OUR SNOWPACK  
HAS, OR WILL HAVE, MELTED. THERE IS STILL MUCH MORE SNOWPACK  
UPSTREAM, OVER NORTHERN NEW ENGLAND, THAT WILL PUSH INTO THE  
HEADWATERS AND HEAD DOWNSTREAM. SOME RIVER LEVELS COULD APPROACH  
ACTION STAGE.  
 

 
   
CLIMATE
 
 
RECORD HIGH TEMPS FOR YESTERDAY  
BOS 73/2017 - PREVIOUS RECORD 70/1985  
PVD 72/1985 - TOPPED OFF AT 71 DEGREES (NO RECORD)  
BDL 73/1985 - TOPPED OFF AT 72 DEGREES (NO RECORD)  
ORH 69/2017 - PREVIOUS RECORD 67/1985  
 
RECORD HIGH MIN TEMPS FOR YESTERDAY  
BOS 49/1930 - BOTTOMED OUT AT 46 (NO RECORD)  
PVD 45/2017 - TIES PREVIOUS RECORD OF 45/1984  
BDL 43/1981 - BOTTOMED OUT AT 42 (NO RECORD)  
ORH 48/2017 - PREVIOUS RECORD 46/1985  
 
RECORD HIGH TEMPS FOR TODAY  
BOS 65/1930  
PVD 69/1976  
BDL 70/1976  
ORH 64/1976  
 
RECORD HIGH MIN TEMPS FOR TODAY  
BOS 46/1891  
PVD 45/1930  
BDL 45/1930  
ORH 37/1996, 1984, 1976  
 
DEW POINTS OF NOTE FOR YESTERDAY  
BOS MAX DEW POINT 54 TIES HIGHEST FOR DATE SET IN 1985  
PVD MAX DEW POINT 53 IS HIGHEST FOR DATE. PREVIOUS HIGH 50/1990  
BDL MAX DEW POINT 54 IS HIGHEST FOR DATE. PREVIOUS HIGH 49/1990  
ORH MAX DEW POINT 53 IS HIGHEST FOR DATE. PREVIOUS HIGH 48/1985  
 

 
   
BOX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
MA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR MAZ019>022.  
RI...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR RIZ002>008.  
MARINE...GALE WARNING FROM MIDNIGHT TONIGHT TO 7 PM EST SUNDAY FOR  
ANZ231>235-237-250-251-254>256.  
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 7 PM EST SUNDAY  
FOR ANZ230-236.  
 

 
 

 
SYNOPSIS...WTB/DUNTEN  
NEAR TERM...WTB/DUNTEN  
SHORT TERM...WTB  
LONG TERM...DUNTEN  
AVIATION...WTB/DUNTEN  
MARINE...WTB/DUNTEN  
HYDROLOGY...  
CLIMATE...  
 
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