Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 280241
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
940 PM EST FRI FEB 27 2015

.SYNOPSIS...
HIGH PRESSURE SLOWLY BUILDING IN FROM THE WEST WILL BRING DRY BUT
UNSEASONABLY COLD WEATHER INTO SUNDAY MORNING. A LOW PRESSURE SYSTEM
WILL BRING A PLOWABLE SNOW LATE SUNDAY AND SUNDAY NIGHT. ANOTHER
STORM IS LIKELY TUESDAY NIGHT INTO WEDNESDAY...WITH SNOW AND MIXED
PRECIPITATION LIKELY CHANGING TO RAIN. COLD AND DRY CONDITIONS
RETURN FOR THE END OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...

940 PM UPDATE...

LARGE HIGH PRESSURE BUILDING IN FROM THE WEST IS RESULTING IN CLEAR
SKIES AND LIGHT WIND.  THIS COMBINED WITH THE DEEP SNOW PACK WILL
RESULT IN AN IDEAL NIGHT OF RADIATIONAL COOLING AND A WIDE RANGE IN
OVERNIGHT LOW TEMPERATURES.  LOW TEMPS SHOULD BOTTOM OUT BETWEEN 5
AND 15 BELOW ZERO ACROSS THE NORMAL COLDEST OUTLYING LOCATIONS!
MEANWHILE...OTHER AREAS THAT TYPICALLY DO NOT RADIATE AS WELL WILL
SEE LOW TEMPS IN THE SINGLE DIGITS TO AROUND 10 ABOVE.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SATURDAY AND SATURDAY NIGHT...HIGH PRESSURE REMAINS IN CONTROL OF
THE REGION. DESPITE A FRIGID START TO THE DAY...TEMPERATURES WILL
REBOUND INTO THE MID TO UPPER 20S SATURDAY AFTERNOON. LIGHT WINDS
AND THE HIGHER SUN ANGLE WILL AID IN IT FEELING A BIT MORE
TOLERABLE DESPITE TEMPS REMAINING WELL BELOW NORMAL. ANOTHER COLD
NIGHT IS EXPECTED SATURDAY NIGHT WITH EXCELLENT RADIATIONAL
COOLING.

&&

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

*  PLOWABLE SNOW LIKELY LATE SUN/SUN NIGHT...CLEARING MONDAY
*  ANOTHER STORM POSSIBLE TUE NIGHT INTO WED...WITH SNOW OR
   MIXED PRECIP LIKELY CHANGING TO RAIN
*  COLD AND DRY TOWARD THE END OF THE WEEK

SUNDAY...
HIGH PRES MOVES OFF THE COAST DURING THE AFTERNOON WITH DEVELOPING
WARM ADVECTION PATTERN RESULTING IN SUNSHINE QUICKLY GIVING WAY TO
INCREASING CLOUDS. SOME UNCERTAINTY ON TIMING OF LEADING EDGE OF
SNOW AND HOW QUICKLY THE COLUMN MOISTENS.  SOME LIGHT SNOW MAY
DEVELOP BY LATE AFTERNOON. MAX TEMPS UPPER 20S TO LOWER 30S.

SUNDAY NIGHT...
MODELS SIMILAR WITH LOW PRES TRACKING ACROSS CENTRAL NEW ENG LATE
SUN NIGHT...WITH SOME HINT OF A WEAK LOW LEVEL CIRCULATION
DEVELOPING SOUTH OF THE COAST. GOOD OVERRUNNING SIGNATURE WITH A
PERIOD OF MID LEVEL FGEN AND DECENT PWATS WILL BRING A SLUG OF
PRECIP INTO SNE SUN NIGHT. THERMAL PROFILES COLD ENOUGH FOR ALL
SNOW...EXCEPT PERHAPS FOR THE ISLANDS WHERE BOUNDARY LAYER WARMING
MAY EVENTUALLY FORCE A CHANGE TO RAIN.

MODELS IN GOOD AGREEMENT ON QPF WITH 0.25"-0.50"+ FROM NORTH TO
SOUTH...HEAVIEST ALONG THE SOUTH COAST.  CROSS SECTIONS DO SHOW A
PERIOD OF DECENT SNOW GROWTH WITH MAX OMEGA NUDGING INTO -10C LAYER.
GENERALLY EXPECTING A GOOD ADVISORY EVENT WITH 3 TO 6 INCHES WITH
MAX SNOW ALIGNED ALONG AND SOUTH OF THE MASS PIKE BUT INLAND FROM
THE S COAST WHERE SLR MAY BE LOWER DUE TO BL WARMING. A FEW LOCALLY
HIGHER AMOUNTS CANT BE RULED OUT ACROSS N CT...N RI AND ADJACENT SE
MA.  THE SYSTEM IS PROGRESSIVE AND BULK OF SNOW SHOULD BE MOVING OUT
BEFORE THE MONDAY MORNING COMMUTE.

MONDAY...
SOME LINGERING LIGHT SNOW POSSIBLE IN THE MORNING...OTHERWISE MAINLY
DRY AS DEEPENING LOW PRES MOVES INTO THE GULF OF MAINE WITH GOOD MID
LEVEL DRYING MOVING INTO THE REGION.  EXPECT CLEARING SKIES IN THE
AFTERNOON BUT BECOMING BLUSTERY WITH NW WINDS GUSTING TO 35 MPH. MAX
TEMPS IN THE 30S.

MONDAY NIGHT INTO TUE...
HIGH PRES BUILDS IN FROM THE WEST. GUSTY  WINDS MON EVENING WILL
GRADUALLY DIMINISH LATER MON NIGHT INTO TUE AS THE RIDGE CRESTS OVER
NEW ENG. TEMPS BELOW NORMAL.

TUESDAY NIGHT INTO WEDNESDAY NIGHT...
MODELS IN AGREEMENT ON DEEPENING LOW PRES MOVING UP THROUGH THE
LAKES WITH NOT MUCH HINT OF SECONDARY LOW DEVELOPMENT. WITH LOW
LEVEL S/SW FLOW IT WILL BE VERY DIFFICULT TO LOCK IN THE COLD AIR SO
AN EVENTUAL CHANGE TO RAIN IS EXPECTED...QUICKEST ALONG THE COAST
TUE NIGHT...BUT ECMWF IS QUITE A BIT COLDER THAN GFS ON THE FRONT
END OF THE STORM TUE NIGHT AND WOULD SUGGEST A DECENT ACCUM OF
SNOW/ICE IN THE INTERIOR BEFORE GOING TO RAIN WED.  GFS WOULD
SUGGEST A FAIRLY RAPID TRANSITION FROM SNOW TO RAIN TUE NIGHT. DUE
TO UNCERTAINTY WE BLENDED THE GFS/ECMWF PARTIAL THICKNESSES AND HAVE
PRECIP STARTING AS SNOW EVERYWHERE TUE NIGHT THEN TRANSITIONING TO A
MIX/ICE OVERNIGHT IN THE INTERIOR WITH RAIN ALONG THE COAST...THEN
ALL RAIN WED. SNOWPACK WILL BE ABLE TO ABSORB THE RAINFALL AND OTHER
THAN AREAS OF POOR DRAINAGE FLOODING DUE TO CLOGGED
DRAINS...FLOODING IS NOT ANTICIPATED.

THE OTHER ITEM OF UNCERTAINTY IS HOW QUICKLY THE RAIN EXITS.  GFS IS
MOST PROGRESSIVE AND DRIES IT OUT WED NIGHT...WHILE ECMWF HAS MORE
AMPLIFIED UPSTREAM TROF WHICH SLOWS THE FRONT DOWN WITH POTENTIAL
FRONTAL WAVE BRINGING ANOTHER PERIOD OF RAIN WED NIGHT INTO EARLY
THU. CONSENSUS OF THE GUIDANCE FAVORS ECMWF SOLUTION. STILL LOTS OF
UNCERTAINTY THIS FAR OUT AND HOW THIS PLAYS OUT WILL AFFECT FORECAST
POPS/TEMPS/PTYPE. A SOLUTION CLOSER TO ECMWF WOULD RESULT IN MILDER
TEMPS WED NIGHT WITH MORE RAIN.

THURSDAY AND FRIDAY...
PRECIP COULD LINGER INTO THU MORNING IF ECMWF SOLUTION IS
CORRECT...BUT TREND THROUGH THE END OF THE WEEK WILL BE FOR COLDER
AND DRY CONDITIONS WITH TEMPS DROPPING WELL BELOW
NORMAL...ESPECIALLY THU NIGHT AND FRI.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...

TONIGHT THROUGH SATURDAY NIGHT...HIGH CONFIDENCE. VFR

KBOS TAF...HIGH CONFIDENCE. VFR.

KBDL TAF...HIGH CONFIDENCE. VFR.

OUTLOOK...SUNDAY THROUGH WEDNESDAY...

SUNDAY...HIGH CONFIDENCE. VFR...THEN CIGS/VSBYS LOWERING TO MVFR
LATER IN THE AFTERNOON FROM WEST TO EAST AS LIGHT SNOW OVERSPREADS
THE REGION.

SUNDAY NIGHT...HIGH CONFIDENCE. IFR IN PERIODS OF SNOW. EXPECTING 3
TO 6 INCHES AT AREA TERMINALS...LESS ON THE ISLANDS.

MONDAY...MODERATE CONFIDENCE. MVFR/IFR POSSIBLE EARLY...THEN
IMPROVING TO VFR. NW WIND GUSTS TO 30 KT DEVELOPING IN THE
AFTERNOON.

TUESDAY...HIGH CONFIDENCE. MAINLY VFR.

TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS LOWERING TO IFR WITH SNOW
CHANGING TO ICE THEN RAIN...QUICKEST ALONG THE COAST.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

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

HIGH PRESSURE BUILDS OVER THE WATERS FROM THE WEST ALLOWING WINDS
AND SEAS TO SUBSIDE GRADUALLY. SEAS REMAIN ABOVE 5 FEET ON THE
OUTER WATERS SO AM ALLOWING THE SMALL CRAFT ADVISORY TO CONTINUE
ON THOSE WATERS THROUGH TONIGHT.

OUTLOOK...SUNDAY THROUGH WEDNESDAY...HIGH CONFIDENCE.

SUNDAY...LIGHT WINDS AND SEAS SUN...THEN SW INCREASING TO 10-20 KT
SUN NIGHT. VSBYS REDUCED IN RAIN/SNOW SUN NIGHT.

MONDAY...INCREASING NW WINDS DEVELOP WITH GALE FORCE GUSTS POSSIBLE
IN THE AFTERNOON AND EVENING BEFORE DIMINISHING OVERNIGHT.

TUESDAY...WINDS BELOW SCA WITH SUBSIDING SEAS AS HIGH PRES CRESTS
OVER THE WATERS.

LATE TUE NIGHT INTO WEDNESDAY...INCREASING SW WINDS WITH GUSTS TO
SCA THRESHOLDS. LOWERING VSBYS IN SNOW CHANGING TO RAIN.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ250-
     254>256.

&&

$$
SYNOPSIS...KJC/RLG
NEAR TERM...FRANK
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...KJC/RLG
MARINE...KJC/RLG


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