Area Forecast Discussion
Issued by NWS Boston, MA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBOX 260849
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
349 AM EST FRI DEC 26 2014

.SYNOPSIS...
A LARGE HIGH PRESSURE AREA OVER THE MID ATLANTIC STATES WILL DRIFT
EASTWARD OFF THE COAST OF NORTH CAROLINA ON SATURDAY. THE WEST TO
SOUTHWEST FLOW AROUND THIS HIGH WILL BRING DRY AND ABOVE NORMAL
TEMPERATURES TO SOUTHERN NEW ENGLAND THROUGH SATURDAY. A COLD FRONT
IS EXPECTED TO BRING SCATTERED RAIN SHOWERS ON SUNDAY. EXCEPT FOR A
LOW PRESSURE SYSTEM THAT MAY GLANCE THE OUTER CAPE AND ISLANDS ON
MON....MAINLY DRY AND COLDER THAN NORMAL CONDITIONS SHOULD
PREVAIL FOR MOST OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
3 AM UPDATE...
LOW LEVEL MOISTURE AND CLOUDINESS WILL REMAIN QUITE EXTENSIVE TO
OUR WEST AND INTO THE HIGHER TERRAIN OF WESTERN MA THROUGH MUCH OF
TODAY. THE 925 MB RELATIVE HUMIDITY SEEN ON THE 00Z NAM MODEL
DEPICTS THIS WELL. AREAS WEST OF A LINE FROM WINDSOR LOCKS CT TO
BELCHERTOWN MA TO GARDNER MA SHOULD REMAIN PARTLY TO MOSTLY CLOUDY
THIS MORNING AND EARLY AFTERNOON WHILE AREAS TO THE EAST SHOULD BE
TOTALLY SUNNY. BY MID TO LATE AFTERNOON...THE CLOUDINESS IS
FORECAST TO ERODE IN THE WEST.

STRONG HIGH PRESSURE OVER THE MID ATLANTIC WILL KEEP A WESTERLY
AIR FLOW ACROSS THE REGION TODAY. THERE IS STILL SOMEWHAT OF A
GRADIENT LEFTOVER FROM LOW PRESSURE THAT HAS DEPARTED WELL TO OUR
NORTHEAST...SO WE COULD GET SOME WIND GUSTS MIXING TO AROUND 15-25
MPH AT TIMES...MAINLY THIS MORNING...AND MAINLY IN THE HIGHER
ELEVATIONS. WENT NEAR GUIDANCE FOR HIGH TEMPERATURES THIS
AFTERNOON. WITH 925 MB TEMPERATURES NEARLY STEADY IN THE +2C TO
+4C RANGE...EXPECTING HIGHS IN THE MID TO UPPER 40S... COOLER THAN
YESTERDAY BUT WARMER THAN NORMAL.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
TONIGHT... CLEAR SKIES AND LIGHT WEST-SOUTHWEST WINDS WILL ALLOW
TEMPERATURES TO DROP TO THE UPPER 20S AND LOWER 30S...EXCEPT MID
AND UPPER 30S ON CAPE COD AND THE ISLANDS.

SATURDAY...A BEAUTIFUL MARCH DAY...IN LATE DECEMBER. OUR WEATHER
WILL STILL BE DOMINATED BY A LARGE HIGH PRESSURE SYSTEM WHICH WILL
HAVE DRIFTED OFF THE NORTH CAROLINA COAST. WITH LIGHT SOUTHWEST
WINDS AND A GOOD DEAL OF SUNSHINE...AM EXPECTING HIGH TEMPERATURES
TO REBOUND SEVERAL DEGREES HIGHER THAN MODEL GUIDANCE WOULD
INDICATE. 925 MB TEMPERATURES ARE FORECAST TO BE NEAR +6C AND AM
FORECASTING HIGHS IN THE 50 TO 55 RANGE...SOME 10 TO 15 DEGREES
ABOVE THE NORMAL FOR DECEMBER 27TH. WE COULD SEE SOME INCREASE IN
HIGH CLOUDINESS DURING THE LATE AFTERNOON WELL IN ADVANCE OF A
COLD FRONT FOR SUNDAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGHLIGHTS...

* JUST A CHANCE FOR RAIN SHOWERS WITH COLD FRONT ON SUNDAY
* MOSTLY DRY AND COLDER FOR NEXT WEEK

OVERVIEW...

MEDIUM RANGE MODELS ARE IN REASONABLY GOOOD AGREEMENT FOR THIS
FORECAST PERIOD AND THEN DIVERGE FAIRLY DRAMATICALLY AFTERWARDS.
PATTERN LOOKS TO BE DOMINATED BY A NEGATIVE PNA WITH SHORTWAVE
ENERGY DIGGING IN THE WESTERN USA AND A PERSISTENT RIDGE OFF THE
SE USA COAST. SPLIT FLOW...A THEME OBSERVED QUITE A BIT LATE FALL
INTO EARLY WINTER...IS ANTICIPATED DURING MUCH OF NEXT WEEK. THE
NAO IS TRENDING NEGATIVE OVER THE NEXT WEEK WITH PREDICTIONS OF A
SWITCH BACK TO POSITIVE. THIS ALL LEADS TO A SURFACE COLD FRONT
PASSAGE SUNDAY THAT USHERS IN COLD AIR FOR NEXT WEEK BUT AT LEAST
FOR THE MOST PART DRY. THE ECMWF DEPICTION OF AN INSIDE RUNNER AND
A RETURN TO WARMER TEMPERATURES NEXT WEEKEND WOULD APPEAR TO BE
CONSISTENT WITH A CHANGE BACK TO A POSITIVE NAO AND CONTINUATION
OF A NEGATIVE PNA.

DAY TO DAY...

SUN...SURFACE COLD FRONT PASSAGE AND ASSOCIATED UPPER SHORT WAVE
TROF  HAVE JUST ENOUGH MOISTURE TO WARRANT LOW CHANCE FOR
SHOWERS. PTYPE SHOULD BE LIQUID. COLDER AIR FOLLOWS SUN NIGHT WITH
PARTIAL CLEARING NORTH BUT PROBABLY LINGERING HIGH OVERCAST SOUTH.

MON...MODELS ALL SUGGEST THE FORMATION OF A SURFACE WAVE ALONG THE FRONT
S OF NEW ENGLAND AND GENERALLY SUPPRESSED. THE 00Z ECMWF HAS TRENDED
FURTHER N...AS THE CANADIAN HAS BEEN ADVERTISING FOR SEVERAL RUNS...WHILE
THE GFS REMAINS WELL SUPPRESSED. IN LIGHT OF MODEL CONSENSUS AND SPREAD...HAVE
KEPT SLIGHT CHANCE POPS OVER SE MA AND SOUTHERN RI AND NUDGE LOW CHANCE
POPS CLOSE TO NANTUCKET.

MON NIGHT THROUGH THU...LOOKS LIKE DRY AND COLD. HAVE LOWERED TEMPS
BELOW MODEL CONSENSUS FOR SOME OF THIS PERIOD...ESPECIALLY TUE NIGHT.
MIGHT NEED TO LOWER FURTHER IN LATER FORECASTS. SUSPECT MOST OF INTERIOR
WILL DROP AT LEAST TO THE TEENS TUE NIGHT AND POSSIBLY EVEN BELOW 10
IN SOME NORMALLY COLDER SPOTS OF NW MA. ONE OR TWO SHORT WAVE TROFS
EMBEDDED IN FAST ZONAL FLOW COULD PRODUCE A ROUND OR TWO OF FLURRIES
BUT SEE LITTLE CHANCE FOR ANY MEASURABLE PRECIPITATION AT THIS POINT.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

SHORT TERM /THROUGH SATURDAY/...HIGH CONFIDENCE.

TODAY...HIGH CONFIDENCE. VFR. BROKEN TO OVERCAST CLOUDS AROUND
4000 FT IN WESTERN AND NORTH CENTRAL MA AND A SMALL PORTION OF
HARTFORD COUNTY CT BUT CLEAR SKIES FOR THE REST OF CT/RI/EASTERN
MA. W WINDS GUSTING TO 15-20 KT AT TIMES.

TONIGHT...HIGH CONFIDENCE. VFR. BECOMING MOSTLY CLEAR NW MA. CLEAR
SKIES ELSEWHERE.

SATURDAY...HIGH CONFIDENCE. VFR.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF.

KBDL TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. KBDL WILL BE
ON THE BORDER OF LOW CLOUDINESS AROUND 4000 FT TO THE NW AND
SUNSHINE TO THE SE TODAY.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

MODERATE TO HIGH CONFIDENCE.

SAT NIGHT THROUGH SUN NIGHT...GENERALLY VFR EXCEPT POCKETS OF MVFR CIGS
INVOF OF SCT SHOWERS POSSIBLE SUN.

MON...VFR EXCEPT LOW CHANCE OF MVFR CIGS ACROSS AND S OF BID-MVY-ACK
LINE.

MON NIGHT THROUGH TUE...VFR CONDITIONS EXPECTED.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

SHORT TERM /THROUGH SATURDAY/...HIGH CONFIDENCE.

TODAY...SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR ALL WATERS
EXCEPT BOSTON HARBOR AND NARRAGANSETT BAY EARLY THIS MORNING...FOR
A COMBINATION OF WIND GUSTS TO 25 KT AND SEAS NEAR 5 FT. WINDS AND
SEAS WILL SUBSIDE THROUGHOUT THE DAY BUT THE 5 FT SEAS WILL LINGER
MOST OF THE DAY OVER THE OUTER WATERS...ESPECIALLY ON THE SOUTH
COAST. HEADLINES WILL GRADUALLY COME DOWN...FIRST ON THE NEARSHORE
WATERS.

TONIGHT AND SATURDAY...WINDS AND SEAS BELOW SMALL CRAFT ADVISORY
CRITERIA. WEST WINDS TONIGHT COULD STILL GUST TO 15 TO 20 KT AT
TIMES...AND TO AROUND 15 KT SATURDAY FROM THE SOUTHWEST.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...MODERATE CONFIDENCE.

SUN...SW FLOW AHEAD OF SURFACE COLD FRONT COULD BRING GUSTS TO NEAR
25 KT AND SEAS TO NEAR 5 FT IN THE OUTER WATERS. MAY BE ENOUGH
GRADIENT BEHIND THE COLD FRONT FOR MARGINAL SCA CONDITIONS PERSISTING
SUN NIGHT.

MON...IF SURFACE WAVE ALONG THE FRONT PASSES CLOSE ENOUGH...COULD
HAVE NE WINDS 20 TO 25 KT AND WAVES 5 TO 6 FT JUST SE OF NANTUCKET.

TUE...WINDS AND SEAS ANTICIPATED TO BE BELOW SCA CONDITIONS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR
     ANZ231>235-237-251.
     SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ250.
     SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
     ANZ254>256.

&&

$$
SYNOPSIS...GAF/THOMPSON
NEAR TERM...GAF
SHORT TERM...GAF
LONG TERM...THOMPSON
AVIATION...GAF/THOMPSON
MARINE...GAF/THOMPSON


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.