Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 130216
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1016 PM EDT SAT APR 12 2014

.SYNOPSIS...
HIGH PRESSURE IS SHIFTING OFFSHORE. A WARM FRONT WILL LIFT NORTH
ACROSS THE REGION SUNDAY BRINGING EVEN MILDER TEMPERATURES INTO
MONDAY. A SLOW MOVING FRONT WILL BRING A SOAKING RAIN TUESDAY INTO
TUESDAY NIGHT FOLLOWED BY DRY AND MUCH COOLER CONDITIONS FOR THE
MIDDLE AND END OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
PATCHY HIGH CLOUDS OVER SOUTHEAST MASS/RI AT 10 PM...ALSO PATCHES
OVER EASTERN NEW YORK. A MORE SOLID AREA OF CLOUDS IS E-W ACROS
NORTHERN NY AND NORTHERN VT/NH. UPPER AIR OBSERVATIONS AT 00Z SHOW
40-45 KNOT SOUTHERLIES AT 850 MB OVER MICHIGAN/CENTRAL GREAT
LAKES...WHICH IS NOTICEABLY WEST OF THE OBSERVED CLOUDS. BUT MID
LEVEL WINDS ARE MORE WEST-SOUTHWEST AND FEED NORTHEAST ACROSS
SOUTHERN ONTARIO...ADVECTING THE CLOUDS TO THEIR POSITION FARTHER
EAST. IN ANY EVENT...THE ISENTROPIC LIFT IS FORECAST TO MOVE INTO
THE CURRENT CLOUD AREA OVERNIGHT.

NEW ENGLAND REMAINS SOUTH OF THIS THROUGH THE NIGHT. BUT WITH THE
WARM ADVECTION ALOFT ONE WOULD EXPECT SOME AMOUNT OF LIFT WORKING
ON THE AIRMASS. WE WILL CONTINUE WITH MOSTLY CLEAR SKIES...BUT
POTENTIAL FOR A FEW MID AND HIGH CLOUDS OVERNIGHT ESPECIALLY OVER
WESTERN MASS AND SOUTHERN NH. A DRY FORECAST WITH NO SIGNIFICANT
CHANGES TO TEMPERATURES...MINS IN THE UPPER 30S AND 40S.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...SFC WARM FRONT LIFTS NORTH ACROSS THE REGION. BEST
MOISTURE AND LIFT REMAINS TO THE NORTH...BUT LOW LEVELS MOISTEN UP
AND THERE COULD BE A FEW SHOWERS IN THE MORNING MAINLY ACROSS N MA
AND S NH. ECMWF IS MOST AGGRESSIVE WITH THE SHOWERS BUT WE
FOLLOWED NAM/GFS SOLUTION WHICH KEEP BULK OF RAIN TO THE NORTH.
MOST CLOUD COVER WILL BE ACROSS NORTHERN AREAS...OTHERWISE PTSUNNY
SKIES EXPECTED.

SW LOW LEVEL JET STRENGTHENS ACROSS THE REGION AND IT WILL BECOME
BREEZY WITH WIND GUSTS TO 30 MPH. MIXING DEPTH IS SHALLOW BUT MAX
TEMPS EXPECTED TO REACH INTO THE LOWER 70S IN THE INTERIOR
VALLEYS. COOLEST TEMPS NEAR THE S COAST WITH READINGS IN THE
UPPER 50S TO LOWER 60S.

SUNDAY NIGHT...
WARM FRONT LIFTS TO THE NORTH AND REGION WILL BE IN THE WARM
SECTOR LEADING TO A MILD NIGHT WITH MINS IN THE UPPER 40S TO
LOWER 50S. HIGHER DEWPOINT AIR MOVING OVER THE COLDER OCEAN WILL
LEAD TO DEVELOPMENT OF STRATUS AND FOG WHICH IS EXPECTED TO MOVE
INLAND ACROSS THE SOUTH COAST.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGHLIGHTS...

* ABOVE AVERAGE TEMPERATURES ARE EXPECTED MONDAY
* STRONG COLD FRONTAL PASSAGE NEXT TUES/WED
* BELOW AVERAGE TEMPERATURES RETURN FOR THE REMAINDER OF THE WORK
  WEEK

MODELS AND CONFIDENCE...

HAVE HIGH CONFIDENCE IN THE WARMING TREND IN THE FORECAST OVER
THIS WEEKEND...WITH MODERATE CONFIDENCE FOR THE TIMING OF A LOW
PRESSURE TOWARD THE MIDDLE OF NEXT WEEK. INCREASING CONFIDENCE
THAT PRECIP WILL OCCUR DURING THE MID-WEEK...BUT THE EXACT TIMING
AND LOCATION OF MODERATE RAINFALL ARE STILL UNCERTAIN. IN FACT
GUIDANCE IS TRYING TO STALL A FRONT JUST SOUTH OF THE AREA. HAVE
LOW CONFIDENCE THAT THIS WILL OCCUR. FINALLY...BELIEVE TEMPS WILL
DROP BELOW AVERAGE BY WEDNESDAY.

OVERALL 12/12Z MODEL GUIDANCE IS GENERALLY IN GOOD AGREEMENT. FOR
EARLY NEXT WEEK...THE UPPER PATTERN WILL BEGIN TO FAVOR A DIGGING
TROUGH ACROSS THE CENTRAL CONUS AS UPPER LEVEL RIDGING BUILDS OVER
BOTH COASTLINES. THIS WILL PUSH A WAVY COLD FRONT ACROSS THE CONUS
AND INTO SOUTHERN NEW ENGLAND BY TUES/WED. THE UPPER LEVEL FLOW
APPEARS TO RAPIDLY FLATTEN...LEAVING THIS FRONT OVER THE WESTERN
ATLANTIC FOR THE REST OF THIS FORECAST PERIOD.

THE DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUE TO SHOW BETTER
AGREEMENT ON THE EVOLUTION OF THIS SYSTEM. THE 12/12Z ECMWF
SHOWED A COASTAL LOW DEVELOPING ALONG THIS STALLED FRONT AND
MOVING CLOSER TO SOUTHERN NEW ENGLAND. THIS STILL APPEARS TO BE AN
OUTLIER SOLUTION. WILL CONTINUE TO FAVOR A STRONG HIGH PRESSURE
DOMINATING OUR WEATHER THROUGH THE END OF NEXT WEEK BEHIND A COLD
FRONT.

DETAILS...

MONDAY...

AS A WARM FRONT MOVES THROUGH NEW ENGLAND...EXCELLENT WARM AIR
ADVECTION WILL DEVELOP. SOUNDINGS SHOW BOUNDARY LAYER MIXING TO
ABOUT 900 MB. WITH 925 MB TEMPS AROUND 14-16C...HIGH TEMPERATURES
WILL FLIRT INTO THE MID TO PERHAPS UPPER 70S. IF THE ATMOSPHERE
IS SUPER ADIABATIC AND CLOUD COVER AHEAD OF THE FRONT BREAKS UP...
THEN TEMPERATURES MAY REACH 80F...ESPECIALLY NORTH OF THE MA
PIKE. HOWEVER IF YOU ARE ALONG THE SOUTH COASTLINE...SOUTHERLY
WINDS WILL BRING THE COOL MARITIME AIR ONSHORE...KEEPING TEMPS IN
THE LOWER 60S. 925 MB LOW LEVEL JET WILL BE INCREASING THROUGHOUT
THE DAY AS AN ANOMALOUS COLD FRONT APPROACHES FROM THE WEST. THIS
LOW LEVEL JET WILL INCREASE TO ABOUT 40-50 KT. WITH EXCELLENT
MIXING IN PLACE...WE COULD SEE GUSTS BETWEEN 25-35 MPH...AND
POSSIBLY FLIRT WITH WIND ADVISORY CRITERIA.

MONDAY NIGHT INTO WEDNESDAY....

GUIDANCE IS BEGINNING TO CLUSTER MORE ON THE TIMING AND INTENSITY
OF AN APPROACHING COLD FRONTAL SYSTEM. THE LATEST GUIDANCE
CONTINUE TO INDICATE SEVERAL WAVES WILL DEVELOP ALONG THIS SLOW
MOVING COLD FRONT...ALLOWING FOR MULTIPLE CHANCES FOR MODERATE TO
HEAVY RAINFALL.

ANTICIPATING A FEW SHOWERS TO DEVELOP AHEAD OF THE FRONT MONDAY
NIGHT INTO TUESDAY EARLY MORNING. BUT AS SOON AS THE FRONT
APPROACHES EXPECT MODERATE TO HEAVY RAINFALL TO FALL. THIS PRECIP
MAY CAUSE URBAN AND POOR DRAINAGE FLOODING...AND IT MAY ALSO HELP
ELEVATE THE RIVER LEVELS IF EVERYTHING LINES UP. GUIDANCE IS
SHOWING EXCELLENT MOISTURE TRANSPORT...AND PRECIPITABLE WATER
VALUES ARE OVER 1.5 INCHES...WHICH IS 4 STANDARD DEVIATIONS ABOVE
NORMAL.

VERY STRONG COLD AIR ADVECTION WILL OCCUR AS THIS FRONT PASSES
THROUGH BY WEDNESDAY. THIS WILL LIKELY RESULT IN AN INCREASE OF
WIND SPEEDS IMMEDIATELY BEHIND THIS FRONT. TEMPERATURES ARE
EXPECTED TO DROP VERY QUICKLY BEHIND THIS FRONT TUESDAY NIGHT. IF
ANY PRECIP LINGERS BEHIND THE MAIN FRONT...WE COULD HAVE SOME
MIXED PRECIPITATION...ESPECIALLY ACROSS THE BERKSHIRES AND IN
SOUTHERN NEW HAMPSHIRE. CURRENT THINKING IS DRIER AIR ARRIVES
QUICKLY TUESDAY EVENING...MAKING THIS MORE OF A MINOR RISK.

LASTLY WITH THE STRONG ONSHORE FLOW FROM THE SOUTH...WE WILL NEED
TO WATCH FOR THE POTENTIAL FOR SOME MINOR SPLASHOVER ALONG THE
SOUTH SHORE AND INTO NARRAGANSETT BAY. TIDES ARE SLOWLY INCREASING
WITH HIGH ASTRONOMICAL TIDE PEAKING NEXT FRIDAY/SATURDAY. HOWEVER
WE WOULD NEED CLOSE TO A 2 FT SURGE INTO NARRAGANSETT BAY AND A 5
FT SURGE ALONG THE SOUTH COAST TO RESULT IN COASTAL ISSUES. YET
THE BIGGEST CONCERN ACROSS THE SOUTH COASTLINE WOULD BE THE
POTENTIAL WAVE ACTION AHEAD OF A COLD FRONT.

THURSDAY THROUGH SATURDAY...

STRONG HIGH PRESSURE WILL QUICKLY USHER INTO THE REGION BEHIND A
STALLED FRONT TO OUR SOUTH. TEMPERATURES WILL DROP WELL BELOW
NORMAL. WE WILL NEED TO MONITOR THE FRONT FOR ANY POTENTIAL WAVES
THAT COULD DEVELOP ALONG IT ON THURSDAY OR FRIDAY. RIGHT NOW
BELIEVE THAT THE HIGH PRESSURE WILL WIN OUT...OVERALL HAVE
MODERATE CONFIDENCE IN THE CURRENT FORECAST.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

SHORT TERM /THROUGH SUNDAY NIGHT/...

TONIGHT...HIGH CONFIDENCE. VFR.

SUNDAY...MODERATE CONFIDENCE. MAINLY VFR WITH LOW PROB OF A FEW
SHOWERS NORTH OF ROUTE 2. BRIEF MVFR CIGS MAY DEVELOP AROUND
MIDDAY NEAR THE SOUTH COAST BUT CONFIDENCE IS LOW. GUSTY SW WINDS
DEVELOPING WITH GUSTS TO 25 KT.

SUNDAY NIGHT...IFR STRATUS AND FOG DEVELOP MAY DEVELOP NEAR THE S
COAST BUT LOW CONFIDENCE ON AREAL EXTENT. INCREASING LOW LEVEL JET
WILL LEAD TO AREAS OF LLWS.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. WE LEFT A SEABREEZE OUT OF
THE TAF AS THERE SHOULD BE ENOUGH MIXING TO KEEP IT OFFSHORE.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF.

OUTLOOK...MONDAY THROUGH THURSDAY...

MONDAY...MODERATE CONFIDENCE.
LOCAL MVFR-IFR CIGS/VSBYS ALONG S COAST EARLY MON SHOULD
IMPROVE...OTHERWISE VFR. S-SW WINDS GUSTING UP 25-35 KTS.

TUESDAY-WEDNESDAY...LOW CONFIDENCE.
EXPECT MVFR CONDITIONS TO DEVELOP FROM W-E DURING TUE IN RAIN
SHOWERS. PERIODS OF HEAVY RAIN POSSIBLE TUE AFTERNOON/EVENING
ACROSS CENTRAL AND WESTERN AREAS WITH AREAS OF IFR. PRECIP MAY
MIX WITH LIGHT SNOW AND/OR SLEET ACROSS S NH/W MA BEFORE ENDING
LATE TUE NIGHT OR WED MORNING. CONDITIONS SHOULD IMPROVE TO VFR
FROM W-E DURING WED.

THURSDAY...MODERATE CONFIDENCE. VFR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.

DIMINISHING SEAS OVERNIGHT. STILL A REPORT OF 5 FOOT SEAS
SOUTHEAST OF BLOCK ISLAND...A 9 SECOND SWELL. WE WILL ALLOW THE
EXISTING SMALL CRAFT ADVISORY TO EXPIRE. WITH INCREASING WINDS
AND SEAS EXPECTED ON SUNDAY AFTERNOON...WE EXPECT TO BE ISSUING A
NEW SET OF SMALL CRAFTS AT THE 4 AM FORECAST ISSUANCE.

PREVIOUS DISCUSSION...
INCREASING SW FLOW DEVELOPING SUNDAY AFTERNOON INTO SUN NIGHT AS
LOW LEVEL JET STRENGTHENS OVER THE WATERS. HOWEVER...STRONG
INVERSION WILL LIMIT GUSTS AND BEST CHANCE FOR GUSTS TO 25 KT WILL
BE OVER NEARSHORE WATERS AND ESPECIALLY BOS HARBOR AND
NARRAGANSETT BAY. SEAS WILL BE BUILDING TO 5-7 FT OVER THE OUTER
WATERS SUN AFTERNOON INTO SUN NIGHT. SMALL CRAFT ADVISORIES WILL
LIKELY BE NEEDED. AREAS OF FOG LIKELY SUN NIGHT WHICH WILL REDUCE
VSBYS.

OUTLOOK...MONDAY THROUGH THURSDAY...

MONDAY...HIGH CONFIDENCE.

AREAS OF FOG MAY LINGER INTO MID-MORNING. DURING THE DAY...EXPECT
S-SW WINDS TO GUST UP TO 25 KTS DURING THE DAY. FOG WILL DEVELOP
AGAIN MONDAY NIGHT. SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED.

TUESDAY INTO THURSDAY...MODERATE CONFIDENCE.

STRONG COLD FRONT WILL MOVE ACROSS THE WATERS TUESDAY INTO
WEDNESDAY. EXPECTING GUSTY WINDS AROUND THIS FRONT DUE TO STRONG
COLD AIR ADVECTION. SEAS WILL BUILD IN RESPONSE AND MAY START
RELAXING LATE WEDNESDAY INTO THURSDAY. THERE IS A LOW PROBABILITY
OF GALES TUESDAY EVENING INTO THE OVERNIGHT HOURS. SMALL CRAFT
ADVISORIES WILL LIKELY BE NEEDED...ESPECIALLY ACROSS THE OUTER
COASTAL WATERS.

&&

.HYDROLOGY...
NERFC FORECASTS BRING LOWER CT RIVER FROM HARTFORD THROUGH MIDDLE
HADDAM INTO MINOR FLOOD STARTING DURING SUNDAY...BASED ON WATER
BEING ROUTED DOWNSTREAM FROM THE UPPER CT BASIN. FLOOD WARNINGS
ISSUED FOR THE CT RIVER AT HARTFORD AND AT MIDDLE HADDAM. THOSE
WITH INTERESTS ALONG LOWER REACHES OF CT RIVER SHOULD PAY
ATTENTION TO THE LATEST FORECASTS AND CURRENT WATER LEVELS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM EDT THIS
     EVENING FOR ANZ254>256.

&&

$$
SYNOPSIS...BELK/KJC
NEAR TERM...WTB/BELK/KJC
SHORT TERM...KJC
LONG TERM...BELK/99
AVIATION...BELK/KJC/99
MARINE...BELK/KJC/WTB
HYDROLOGY...



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