Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 241800
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
200 PM EDT FRI APR 24 2015

.SYNOPSIS...
UNSEASONABLY COOL WEATHER CONTINUES THROUGH THIS WEEKEND WITH
SPOTTY SHOWERS OR SPRINKLES. UNSETTLED WEATHER AND BELOW NORMAL
TEMPERATURES WILL CONTINUE THROUGH NEXT WEEK AS WELL.

&&

.NEAR TERM /THROUGH TONIGHT/...

THROUGH 8 PM...
UPPER LOW AND COLD POOL IN PLACE OVER NEW NEW ENGLAND. A WEAK
SHORTWAVE MOVES THROUGH THE CYCLONIC FLOW AROUND THIS LOW AND
CROSSES NEW ENGLAND TOWARD 00Z. RH FORECAST PROFILES SHOW A LAYER
OF HIGH RH VALUES BETWEEN 850 AND 700 MB THROUGH 00Z...ALTHOUGH
VERTICAL MOTION IS SUBSIDENT. WE COULD SEE A FEW SPRINKLES OR
FLURRIES LATE TODAY/THIS EVENING.

TONIGHT...LINGERING CLOUD SHIELD UNDER THE UPPER LOW AND COLD
POOL...BUT THIS SHOULD START TO LIFT OUT TO THE NORTH AND EAST
SOMEWHAT. SO WE EXPECT AT LEAST PARTIAL CLEARING TONIGHT WITH THE
BEST CHANCE OVER CONNECTICUT. PRESSURE GRADIENT STAYS ENOUGH TO
KEEP THE AIR MOVING...SO FROST IS NOT LIKELY EXCEPT POSSIBLY IN
THE MOST SHELTERED OF LOCATIONS THAT CLEAR. ON THE OTHER HAND
TEMPERATURES WILL BE SIMILAR TO LAST NIGHT OR PERHAPS A DEGREE OR
TWO COOLER. EXPECTED RANGE IS IN THE UPPER 20S AND 30S...AND
FREEZING TEMPS IN PARTS OF THE ACTIVE GROWING ZONE /CT-RI-
SOUTHEAST MA/. WE PLAN ON CONVERTING THE EXISTING FREEZE WATCH TO
A FREEZE WARNING FOR NORTHERN CT AND NORTHWEST RI.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...

SATURDAY...UPPER CLOUD SHIELD AND COLD POOL WILL BE FOCUSSED OVER
NORTHERN NEW ENGLAND BUT CLOSE ENOUGH TO AFFECT US. DAYTIME
HEATING AND A SHORTWAVE CYCLING AROUND THE LOW MAY PUSH CLOUDS
BACK OUR WAY DURING THE DAY. THE SURFACE LAYER WILL BE DRIER...SO
MOST ATTEMPTS AT PRECIPITATION SHOULD EVAPORATE ON THE WAY DOWN.
TEMPS AT 850 MB ARE FORECAST AROUND -2C...WHICH SUPPORTS MAX SFC
TEMPS IN THE 50S. WINDS ALOFT IN THE MIXED LAYER REACH 20
KNOTS...SO EXPECT ANOTHER DAY OF GUSTS EITHER SIDE OF 20.

SATURDAY NIGHT...

WEAK RIDGE BUILDS OVER SOUTHERN NEW ENGLAND PROVIDING CLEARING
SKIES AND LIGHT WINDS. RADIATIONAL COOLING WITH DEW POINTS IN THE
30S...SO MIN SFC TEMPS SHOULD BE IN THE 30S.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGHLIGHTS...

* BELOW NORMAL TEMPERATURES THROUGH NEXT WEEK
* SCATTERED DIURNAL SHOWERS THIS WEEKEND INTO MID-NEXT WEEK
* LOW CONFIDENCE ON COASTAL SYSTEM THURS/FRIDAY.

OVERVIEW...

DEEP CLOSED LOW OVER THE REGION BEGINS TO GRADUALLY PIVOT EAST
OFFSHORE NOVA SCOTIA ON SAT BUT THEN BECOMES NOTABLY ELONGATED BY
SUN AS ADDITIONAL ENERGY DROPS SOUTH DOWN ACROSS THE NORTHEAST. THE
00Z GEM IS THE WEAKEST SOLUTION WHILE THE 00Z GFS/00Z NAM/00Z UKMET
AND 00Z ECMWF ARE ALL BETTER CLUSTERED WITH DEPTH AND TIMING THROUGH
SUNDAY.

BY NEXT WEEK APPEARS UNSETTLED WEATHER AND BELOW NORMAL TEMPS
CONTINUE AS BLOCKING PATTERN PERSIST...SUPPORTED BY -NAO/-AO/+PNA.
UPPER LEVEL LOW AND CONTINUED COLD POOL WILL KEEP ON SPINNING OVER
THE REGION MONDAY AND BEGIN TO EXIT LATE TUESDAY. STILL LOTS OF
QUESTIONS ABOUT THE MIGRATION OF THE DESERT CUTOFF LOW AS IT MOVES
ACROSS THE SOUTHEAST AND ITS POTENTIAL WRAP UP INTO ANOTHER CLOSED
LOW FOR NEW ENGLAND. A KEY COMPONENT OF THE SYSTEM`S INTENSIFICATION
WILL BE THE INCORPORATION OF SOUTHEASTWARD-MOVING SHORTWAVE ENERGY
AND WHERE THIS NORTHERN STREAM ENERGY WILL PHASE WITH THE CUTOFF
SYSTEM. CURRENTLY THE 00Z GFS PHASES THE SOUTHERN PLAIN WAVE FASTER
THAN THE EC WHICH IS MORE AMPLIFIED. THE EC/S NORTHERN STREAM IS
FARTHER EASTWARD THAN THE GFS...IN WHICH THE EC SEEMS TO PULL A
COASTAL LOW CLOSER TO THE REGION BY THUS/FRI. REGARDLESS APPEARS
THAT A COASTAL LOW WILL HAVE AN IMPACT ON THE REGION LATE IN THE
WORK WEEK. FELT ENSEMBLE GUIDANCE WAS BEST FOR THE WORK WEEK.

DETAILS...

* SUNDAY...HIGH CONFIDENCE.

STRONG CUTOFF LOW WILL CONTINUE TO IMPACT THE NORTHEAST DURING THIS
TIME PERIOD. UPPER LEVEL RIDGE OVER THE CENTER CONUS WILL BUILD
PUSHING THE BULK OF THE ENERGY OFFSHORE SAT NIGHT BEFORE THE LOW
MIGRATES BACK TOWARDS NEW ENGLAND BY SUNDAY. STRONG SHORTWAVE WILL
MOVE THROUGH THE REGION FROM THE NORTH INCREASING PRECIPITATION
CHANCES ON SUNDAY. TEMPS MAY REACH 60F AS COLD POOL IS STILL
OFFSHORE.

* MONDAY INTO TUESDAY...MODERATE CONFIDENCE.

THE UPPER LEVEL LOW WILL RETROGRADE INCREASING THE CHANCES OF PRECIP
AS 2 POTENT SHORTWAVES MORE THROUGH THE FLOW FROM THE NORTH. COLD
POOL ALOFT SEEMS TO SIT OVER THE REGION AS WELL. CHANCE FOR SHOWERS
WILL BE HIGHER THAN FOR THIS UPCOMING WEEKEND AS LAPSE RATES WILL BE
STEEPER AND SOME HINTS OF INSTABILITY. INCREASED POPS ESP ALONG THE
MASS COASTLINE WHERE FORCING COULD OCCUR IF SEA BREEZE DEVELOPS.
TEMPERATURES APPEAR TO BE AROUND 10 DEGREES COOLER ON MONDAY THANKS
TO THE STRONG COLD POOL OVER THE REGION.


* WEDNESDAY AND BEYOND...LOW CONFIDENCE.

STILL SOME UNCERTAINTY IN THIS PORTION OF THE FORECAST. EVERYTHING
IS DEPENDENT ON HOW THE CUT-OFF LOW IN THE DESERT SOUTHWEST AND
DIGGING NORTHERN STREAM WAVES BEHAVES. CURRENTLY BELIEVE WED IS A
TRANSITION DAY WITH MID LEVEL RIDGE BUILDING INTO THE REGION BUT
KEEPING TEMPS BELOW NORMAL. WATCHING THE DEVELOPMENT OF A COASTAL
LOW ON THURSDAY/FRIDAY. BOTH THE GFS AND EC HAVE SHOWN THE COASTAL
LOW THIS TIME AROUND...SO CONFIDENCE IS INCREASING THAT IT WILL
OCCUR. THIS IS SUPPORTED BY THE ENSEMBLES. THE GFS IS SLIGHTLY
FARTHER OFFSHORE AND FASTER COMPARED TO THE EC...REGARDLESS WET
WEATHER AND COOL TEMPS WILL CONTINUE.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...

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

.SHORT TERM /THROUGH SATURDAY/...

THIS AFTERNOON...HIGH CONFIDENCE. VFR WITH NORTHWEST WINDS GUSTING
20-22 KNOTS.

TONIGHT AND SATURDAY...HIGH CONFIDENCE. VFR. POSSIBLE BRIEF MVFR
IN SPOTTY SHOWERS DURING THE DAY SATURDAY. NORTHWEST WINDS GUSTING
AROUND 20 KNOTS.

SATURDAY NIGHT...HIGH CONFIDENCE. VFR WITH LIGHT WIND.

KBOS TAF...HIGH CONFIDENCE IN OVERALL TAF.

KBDL TAF...HIGH CONFIDENCE IN OVERALL TAF.

OUTLOOK...SUNDAY THROUGH TUESDAY...

MODERATE CONFIDENCE. VFR WITH MVFR CONDITIONS IN SCT SHOWERS. SEA
BREEZE DEVELOPMENT IS POSSIBLE ALONG THE EAST COAST EACH DAY.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TONIGHT THROUGH SATURDAY/...

TODAY...HIGH OVERALL CONFIDENCE.

1000 AM UPDATE...WINDS CONTINUE TO GUST AT OR ABOVE 25KTS ACROSS
SOME OF THE NEAR SHORE WATERS. EXPECT THESE GUSTS TO CONTINUE
UNTIL AROUND NOON...SCA REMAINS IN EFFECT UNTIL THAT TIME.

PREVIOUS DISCUSSION...WEST- NORTHWEST WINDS WILL GUST TO 20 KT.
SEAS LINGER AROUND 5 FEET ON THE SOUTHERN AND SOUTHEAST OUTER
WATERS. THERE WILL LIKELY BE A BRIEF PERIOD WHERE SMALL CRAFT
ADVISORY CONDITIONS ARE NOT MET. THOUGHT IT BEST TO KEEP SMALL
CRAFT ADVISORIES GOING CONSISTENTLY ACROSS THE OUTER COASTAL
WATERS...RATHER THAN TAKING THEM DOWN...ONLY TO HAVE TO HOIST THEM
AGAIN LATER.

OUTLOOK...SUNDAY THOUGH TUESDAY...

HIGH CONFIDENCE. UPPER LEVEL LOW WILL CONTINUE TO SPIN ACROSS THE
NORTHEAST. HIT OR MISS SHOWERS POSSIBLE DURING THE DAY. WIND AND
SEAS TO REMAINS BELOW SCA ON SUNDAY. POTENT COLD POOL WILL FILTER
IN FROM THE NORTH CREATING STRONG CAA AN INCREASE WINDS/SEAS FOR
MONDAY AND TUESDAY. SCA MAY BE NEEDED.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FREEZE WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR
     CTZ002>004.
MA...NONE.
RI...FREEZE WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR
     RIZ001-003.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ235-237.
     SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ250-
     254>256.

&&

$$
SYNOPSIS...WTB/DUNTEN
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...DUNTEN
AVIATION...WTB/DUNTEN
MARINE...BELK/DUNTEN/NMB



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