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Area Forecast Discussion
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000
FXUS61 KBOX 131443
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1043 AM EDT FRI MAR 13 2015

.SYNOPSIS...
DRY BUT CHILLY WEATHER PREVAILS TODAY AND THIS EVENING. LOW PRESSURE 
WILL BRING A COLD SOAKING RAIN SATURDAY...PROBABLY STARTING AS A 
BRIEF PERIOD OF FREEZING RAIN INLAND EARLY SATURDAY MORNING. LEFT 
OVER RAIN SHOWERS WILL CHANGE TO SCATTERED SNOW SHOWERS LATE 
SATURDAY NIGHT INTO SUNDAY WITH A MINOR ACCUMULATION POSSIBLE IN 
NORTHEAST MA. DRY WEATHER RETURNS MONDAY FOLLOWED BY RAIN SHOWERS 
MONDAY NIGHT INTO EARLY TUESDAY. THEN A BLAST OF UNSEASONABLY COLD 
WEATHER LATE TUESDAY INTO WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1045 AM UPDATE...NO SIGNIFICANT CHANGES MADE TO CURRENT FORECAST.
MADE A FEW MINOR UPDATES TO TRY AND CAPTURE CURRENT TRENDS.
OTHERWISE...FORECAST IS ON TRACK.

PREVIOUS DISCUSSION...

TODAY...

CONFLUENT FLOW PROVIDES DRY WEATHER TODAY ALONG WITH LIGHT WINDS AS 
SURFACE HIGH CREST OVER THE REGION. THIS SUBSIDENCE INVERSION WILL 
LIMIT MIXING/BLYR DEPTH AND WILL PRECLUDE COLD/DRY AIRMASS OVER THE 
AREA FROM WARMING MUCH TODAY. IN ADDITION SOLAR HEATING WILL BE 
DIMMED BY MID AND HIGH CLOUDINESS STREAMING ACROSS THE REGION FROM 
THE GREAT LAKES...WITH MORE CLOUDS ACROSS NORTHERN MA AND MORE 
SUNSHINE ALONG THE SOUTH COAST OF MA AND RI. NEVERTHELESS THIS WILL 
LIMIT HIGHS TODAY TO 35 TO 40...ABOUT 5 TO 10 DEGS COLDER THAN 
NORMAL. THE LIGHT PGRAD WILL LIKELY YIELD TO AFTERNOON SEABREEZES.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
*** A FEW HOURS OF FREEZING RAIN POSSIBLE EARLY SATURDAY MORNING ***

TONIGHT...

MOISTURE/PRECIP OVER THE GULF STATES AND TN VLY TODAY WILL BEGIN 
ADVECTING NORTHWARD UP THE EASTERN SEABOARD TONIGHT. DRY WEATHER 
PREVAILS THIS EVENING BUT PRECIP BEGINS TO OVERSPREAD THE AREA 
TOWARD SUNRISE FROM SOUTH TO NORTH. STRONG LOW LEVEL WARM ADVECTION 
WILL RESULT IN PTYPE BEING RAIN. HOWEVER THE CAVEAT IS THE COLD/DRY 
AIRMASS CURRENTLY OVER THE REGION WILL TAKE SOME TIME TO
ERODE/SCOUR OUT ESPECIALLY ACROSS THE INTERIOR VALLEYS...
SPECIFICALLY THE I-91 CORRIDOR OF MA. WEAK PGRAD WILL LIKELY
RESULT IN SURFACE WINDS DECOUPLING FROM THE BLYR...CUTTING OFF
WARM AIR ADVECTION AT THE SURFACE. NAM SOUNDINGS ACROSS INTERIOR
MA SUPPORT THIS IDEA WITH A DISTINCT FREEZING RAIN SIGNATURE.

THE DILEMMA THEN BECOMES WILL THE PRECIP ARRIVE IN TIME BEFORE TEMPS 
BEGIN TO RISE SAT MORNING. A BLEND OF ALL GUID SOURCES YIELDS LIKELY 
POPS BY 8 AM SAT ACROSS THE ENTIRE REGION WITH CATEGORICAL POPS OVER 
CT AND RI. IN ADDITION A MODEL BLEND OF QPF OFFERS 0.01 TO 0.05 
INCHES OF PRECIP ENDING AT 8 AM. THUS AN INCREASED RISK FOR FREEZING 
RAIN 09Z-14Z SAT ACROSS NORTHERN CT/NW RI INTO THE I495 CORRIDOR 
/POSSIBLY THE RT-128 CORRIDOR TOO/ AND WESTWARD INTO CENTRAL AND 
WESTERN MA.  WHILE ANY ICING SHOULD BE QUITE LIGHT...GIVEN THAT 
PRECIP MAY BEGIN AS STRAIGHT FREEZING RAIN ROADS CONDITIONS MAY 
BECOME QUITE HAZARDOUS.
 
SATURDAY...

BY 15Z OR SO THE RISK OF ANY FREEZING RAIN INLAND WILL DIMINISH AS 
SHALLOW COLD AIR ERODES. RAIN WILL BE MODERATE TO HEAVY AT TIMES SAT 
ESPECIALLY ACROSS EASTERN CT/RI AND EASTERN MA WITH SECONDARY WAVE 
TRAVERSES. A MODEL BLEND SUPPORTS 0.50 TO 1.00 INCHES OF RAINFALL 
ACROSS THIS REGION WITH LESS OVER WESTERN MA. DEW PTS ONLY EXPECTING 
TO RISE INTO THE 30S TO PERHAPS 40 AS WARM SECTOR LIKELY REMAINS 
SOUTH OF THE REGION OR JUST CLIPS SOUTHEAST MA. GIVEN THE ABSENCE OF 
WARM SECTOR AIRMASS NOT EXPECTING MUCH WATER RELEASE FROM THE 
SNOWPACK. HOWEVER RAINFALL OF 0.50 TO 1.00 COMBINED WITH SNOW 
CLOGGED STORM DRAINS WILL LIKELY BE SUFFICIENT FOR AT LEAST SOME 
NUISANCE URBAN/STREET FLOODING.

&&

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

* A PERIOD OF SNOW SHOWERS IS POSSIBLE SUNDAY...PARTICULARLY ON THE 
  EAST COAST
* RAIN SHOWERS LIKELY AHEAD OF A COLD FRONT MONDAY NIGHT AND TUESDAY
* UNSEASONABLY COLD WEATHER LATE TUESDAY AND WEDNESDAY

MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGHOUT THE LONG TERM PORTION 
OF THE FORECAST.  THERE ARE SOME TIMING DISCREPANCIES WITH A COLD 
FRONT AT THE START OF NEXT WEEK AND THESE DISCREPANCIES CONTINUE 
THROUGH THE REMAINDER OF THE FORECAST.  BY THURSDAY...THE ECMWF AND 
GFS SOLUTIONS ARE QUITE DIFFERENT.  OVERALL...FAVORED A BLEND OF 
AVAILABLE MODEL GUIDANCE FOR THE LONG TERM.

SATURDAY NIGHT AND SUNDAY...A MID LEVEL TROUGH AND ITS ATTENDANT LOW 
PRESSURE SYSTEM MOVES OVER NEW ENGLAND.  RAIN SHOWERS SHOULD COME TO 
AN END ACROSS MUCH OF THE AREA AS THE ASSOCIATED DRY SLOT MOVES
INTO SOUTHERN NEW ENGLAND SATURDAY NIGHT. ANY LINGERING RAIN
SHOWERS WILL CHANGE TO SNOW BY EARLY SUNDAY MORNING AS MUCH COLDER
AIR WORKS INTO THE REGION FROM THE NORTH. THESE SHOWERS WILL BRING
ANYWHERE FROM A COATING UP TO AN INCH OR TWO OF SNOW...WITH THE
MOST ACROSS NORTHEASTERN MASSACHUSETTS.

MONDAY AND TUESDAY...SEASONABLE TEMPERATURES WILL GIVE WAY TO A MUCH 
COLDER AIRMASS AS A COLD FRONT MOVES THROUGH SOUTHERN NEW ENGLAND 
SOMETIME MONDAY NIGHT OR TUESDAY.  A MIX OF RAIN AND SNOW SHOWERS 
WILL ACCOMPANY THE FRONT.  THERE ARE SOME DISCREPANCIES IN THE 
TIMING OF THIS FRONT.  THESE DISCREPANCIES WILL HAVE THE BIGGEST 
IMPACT ON TUESDAYS HIGH TEMPERATURES.  IF THE FRONT MOVES THROUGH 
MONDAY NIGHT...TEMPERATURES TUESDAY WILL BE MUCH COOLER AND WELL 
BELOW NORMAL.  IF THE FRONT IS SLOWER THEN TUESDAYS HIGHS MAY BE 
REACHED EARLY ON AND STILL BE IN THE NORMAL RANGE FOR MID MARCH 
BEFORE COLDER AIR SURGES IN.

WEDNESDAY AND THURSDAY...THE MODELS START TO DIVERGE IN THIS TIME 
FRAME.  AN UPPER LEVEL TROUGH IN SOUTHEASTERN CANADA MAY DEEPEN INTO 
SOUTHERN NEW ENGLAND OR MAY STAY TO THE NORTHEAST.  THIS WILL MEAN A 
DIFFERENCE AT THE SURFACE BETWEEN LOW PRESSURE AND A COLD FRONT AND 
HIGH PRESSURE.  TEMPERATURES WILL BE UNSEASONABLY COLD WEDNESDAY AND 
POSSIBLY THURSDAY AS WELL.

&&

.AVIATION /15Z 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 INTO THIS
EVENING...THEN LOWER CONFIDENCE ON EXACT TIMING THEREAFTER.

TODAY...VFR/FAIRLY LIGHT WINDS AND DRY WEATHER. LOW PROBABILITY
OF A SEABREEZE DEVELOPING AT KBOS.

TONIGHT...VFR WITH MVFR TOWARD SUNRISE. LIGHT RAIN LIKELY TOWARD
MORNING ESPECIALLY ACROSS CT/RI AND SOUTHEAST MA. INLAND /BAF-
BDL-ORH/ PRECIP LIKELY -FRZA.

SAT...IFR AND LIFR IN RAIN...HEAVY AT TIMES ACROSS EASTERN CT/RI
AND SOUTHEAST MA. -FZRA POSSIBLE UNTIL ABOUT 15Z ACROSS THE
INTERIOR.
 
KBOS TAF...HIGH FORECAST CONFIDENCE. MODERATE PROBABILITY OF A
SEABREEZE DEVELOPING.

KBDL TAF...HIGH FORECAST CONFIDENCE EXCEPT LOWER CONFIDENCE ON
TIMING AND DURATION OF -FZRA LATE TONIGHT INTO EARLY SAT AM.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT...MODERATE CONFIDENCE.  -SHRA SHOULD COME TO AN END 
AS DRIER AIR MOVES IN.  LOW CLOUDS LIKELY TO REMAIN SO MOST 
LOCATIONS MVFR/IFR.

SUNDAY...HIGH CONFIDENCE.  MAINLY VFR.  BRIEF MVFR/IFR CONDITIONS IN 
SCT -SHSN.

MONDAY AND TUESDAY...MODERATE CONFIDENCE.  MAINLY VFR.  BRIEF 
MVFR CONDITIONS POSSIBLE IN SCT -SHSN OR -SHRA.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

TODAY...DIMINISHING WNW WINDS THIS MORNING BECOMING LIGHT AND 
VARIABLE THIS AFTERNOON. DRY WEATHER AND GOOD VSBY.

TONIGHT...LIGHT SOUTH WINDS WITH RAIN LIKELY BY SUNRISE OVER THE 
SOUTHERN WATERS.  CHANCE OF RAIN NORTHERN WATERS.

SAT...SSW WINDS BECOME LIGHT AND VARIABLE LATE AS SECONDARY LOW 
TRACKS OVER SOUTHEAST MA.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT AND SUNDAY...HIGH CONFIDENCE.  SEAS INCREASE AS LOW 
PRESSURE MOVES OVER THE GULF OF MAINE AND A COLD FRONT MOVES ACROSS 
THE WATERS.  SMALL CRAFT ADVISORIES LIKELY NEEDED FOR MUCH OF THIS 
TIME.

MONDAY AND TUESDAY...WINDS AND SEAS DIMINISH BRIEFLY MONDAY AS HIGH 
PRESSURE BUILDS OVER THE WATERS.  THEN THEY INCREASE AS ANOTHER COLD 
FRONT APPROACHES THE WATERS MONDAY NIGHT OR TUESDAY.  SMALL CRAFT 
ADVISORIES WILL BE NECESSARY FOR THIS PERIOD...WITH GALES POSSIBLE 
TUESDAY.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EDT THIS AFTERNOON FOR ANZ254.

&&

$$
SYNOPSIS...NOCERA/RLG
NEAR TERM...BELK/NOCERA/RLG
SHORT TERM...NOCERA
LONG TERM...RLG
AVIATION...BELK/NOCERA/RLG
MARINE...BELK/NOCERA/RLG



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