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Area Forecast Discussion
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000
FXUS61 KBOX 250257
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
957 PM EST SAT JAN 24 2015

.SYNOPSIS...
A RAPIDLY INTENSIFYING COASTAL STORM WILL QUICKLY MOVE TO THE
CANADIAN MARITIMES TONIGHT. DRY AND SEASONABLE WEATHER EXPECTED ON
SUNDAY. A SEVERE AND LONG DURATION WINTER STORM MAY IMPACT
SOUTHERN NEW ENGLAND MONDAY NIGHT THROUGH TUESDAY INTO EARLY
WEDNESDAY MORNING. GREATER CLARITY ON DETAILS SHOULD EMERGE AS WE
DRAW CLOSER TO THIS POTENTIAL EVENT. TEMPERATURES WILL LIKELY BE
QUITE COLD FOR THE FIRST HALF OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
10 PM UPDATE...
A LOOK AT AVAILABLE SFC DATA OUT OVER THE GULF OF MAINE SUGGESTS
THAT THE LOW IS CONTINUING TO MAKE RAPID PROGRESS TOWARD NOVA
SCOTIA THIS EVENING. AS SUCH...CONTINUE TO NOTE THE BACK EDGE OF
THE PRECIP SHIELD RAPIDLY MAKING ITS WAY ACROSS THE REGION...SUCH
THAT...AT THE TIME OF THIS WRITING...ONLY CAPE COD...ACK AND MVY
CONTINUE TO SHOW SNOW. EXTRAPOLATING SPEED SUGGETS IT SHOULD BE
DONE BY MIDNIGHT IN ALL LOCATIONS.

HAVE HOISTED AN SPS ACROSS ALL OF SRN NEW ENGLAND THROUGH
1330Z...FOR LEFTOVER WET ROADWAYS AND FALLING TEMPS...LEADING TO
SLIPPERY CONDITIONS AND BLACK ICE. WOULD RATHER HAVE THIS WORD OUT
EARLY THAN WAIT UNTIL MORNING TO DO SO...THAT WAY ACTION COULD BE
TAKEN IN ADVANCE.

OTHERWISE...GRIDS ALL ADJUSTED TOWARD CURRENT TRENDS.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
ANTICIPATE LOTS OF SUNSHINE SUNDAY BUT COLD ADVECTION SHOULD CAP
HIGH TEMPERATURES UPPER 20S TO MID 30S ACROSS MOST OF THE AREA.
WIND GUSTS OVER LAND GENERALLY BETWEEN 15 AND 20 MPH.

&&

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

* DRY AND COLD SUNDAY NIGHT
* CONFIDENCE INCREASING FOR LONG DURATION WINTER STORM AFFECTING
  THE REGION LATE MONDAY INTO TUESDAY NIGHT
* VERY COLD MON-WED WITH MODERATING TEMPS THU/FRI

DETAILS...

SUNDAY NIGHT...
BLUSTERY NW WIND FLOW IN PLACE BRINGING COLD AIR ACROSS THE
REGION. WILL SEE DRY CONDITIONS AS WINDS DIMINISH SOMEWHAT AFTER
MIDNIGHT. MAY START TO SEE CLOUDS APPROACH AHEAD OF NEXT SYSTEM.
OVERNIGHT LOWS WILL BE COLD...ESPECIALLY INLAND...FALLING TO THE
SINGLE DIGITS ACROSS N CENTRAL AND W MA RANGING TO 20-25 ACROSS
THE OUTER CAPE AND NANTUCKET.

MONDAY...
NOTING VIGOROUS H5 SHORT WAVE DIVING SE TO THE SE U.S. STATES
FROM SASKATCHEWAN. THIS WILL CAUSE LOW PRES TO FORM OFF THE MID
ATLC COAST BY MON EVENING. LIGHT N WINDS ACROSS THE REGION EARLY
MON WILL VEER TO NE AND INCREASE DURING THE AFTERNOON...
ESPECIALLY ALONG THE S COAST NEAR OR AFTER SUNSET.

SOME MOISTURE WELL AHEAD OF THIS LOW MAY BRING SOME LIGHT SNOW TO
THE REGION DURING THE AFTERNOON. CARRIED MAINLY SLIGHT CHANCE TO
LOW CHANCE POPS FROM MIDDAY ONWARD. EXPECT TEMPS TO REMAIN WELL
BELOW SEASONAL NORMALS...RANGING FROM THE UPPER TEENS ACROSS THE
HIGHER INLAND TERRAIN TO NEAR FREEZING ALONG THE IMMEDIATE S
COAST.

MONDAY NIGHT THROUGH TUESDAY NIGHT...
MOST OF THE 12Z OPERATIONAL MODELS AND ENSEMBLE MEMBERS HAVE COME
MORE IN LINE TO THE 00Z OP ECMWF RUN...SIGNALING VERY STRONG
CYCLOGENESIS TAKING PLACE S OF NEW ENGLAND DURING THIS TIMEFRAME.
H5 LONG WAVE TROUGH CONTINUES TO AMPLIFY AS IT BECOMES NEGATIVELY
TILTED...WHICH MEANS THE SURFACE SYSTEM WILL LIKELY HUG CLOSER TO
THE COAST. BIG QUESTION AT THIS POINT IS HOW MUCH THE LOW WILL
DEEPEN AND WHERE IT WILL TRACK. THIS IS WHERE THE UNCERTAINTY
LIES. IT DOES LOOK LIKE THERE WILL BE A SIGNIFICANT AND LONG
DURATION WINTER STORM AFFECTING THE REGION...BUT HOW LONG IS ALSO
STILL IN QUESTION. OVERALL...MODELS IN PRETTY GOOD AGREEMENT IN
GENERAL BUT DETAILS IN QUESTION. ONE MODEL IN PARTICULAR THAT IS
IN QUESTION IS THE 12Z ECMWF...WHICH ACTUALLY HUGS THE LOW CLOSER
TO THE COAST AS IT BECOMES CAPTURED BY DEVELOPING H5 CUTOFF LOW.
ALL OP MODELS DO THE PRES DOWN TO SUB 980 HPA BY LATE TUE/TUE
NIGHT...SO ALSO EXPECT VERY STRONG NE WINDS. HIGH PRES IS ALSO
SET UP N OF THE REGION...ACROSS EASTERN QUEBEC INTO THE MARITIMES
KEEPING COLD AIR IN PLACE.

SO...IT DOES LOOK LIKE THE SEASON/S FIRST MAJOR WINTER STORM WILL
BRING HEAVY SNOWFALL AND STRONG...POSSIBLY DAMAGING WINDS
ESPECIALLY ACROSS CENTRAL AND EASTERN AREAS. HAVE CARRIED LIKELY
TO CATEGORICAL POPS...HIGHEST ACROSS E MA INTO E RI. THE NEXT BIG
QUESTION IS...WHETHER THERE WILL BE BLIZZARD CONDITIONS FOR A TIME
WITH THIS STORM. NOTE THAT THE DEFINITION OF A BLIZZARD IS SUSTAINED
WINDS OR FREQUENT GUSTS OF 35 MPH OR GREATER AND VSBYS LESS THAN
1/4 MILE FOR AT LEAST 3 CONSECUTIVE HOURS. LOOKS LIKE WINDS WILL
BE THERE...BUT VSBYS ARE ANOTHER MATTER. WILL ALSO LIKELY SEE
HEAVY SNOWFALL...WITH SOME PERIODS OF 1 INCH/HOUR SNOWFALL RATES
AND POSSIBLY HIGHER.

WITH THE VERY STRONG E-NE FETCH IN PLACE...COULD SEE PROBLEMS
WITH THE TUESDAY MORNING HIGH TIDE WITH MINOR SPLASHOVER OR
POSSIBLY EVEN SOME MINOR COASTAL FLOODING.

WE HAVE HELD OFF ON WATCHES AT THIS TIME SINCE WE ARE STILL IN AN
EVENT. ONCE THIS ONE MOVES OFF...AND THE 00Z MODELS COME IN...
DECISIONS CAN BE MADE ON HEADLINES FOR THIS UPCOMING EVENT.

WEDNESDAY...
LOW PRESSURE EXITS TO THE CANADIAN MARITIMES...BUT TIMING OF ITS
EXIT STILL IN QUESTION. AT THIS POINT...DO HAVE IMPROVING
CONDITIONS FROM W-E...BUT WILL STILL SEE COLD AND BLUSTERY
CONDITIONS.

THURSDAY THROUGH SATURDAY...
HIGH PRES LOOKS TO BUILD ACROSS DURING THURSDAY. MAY SEE ANOTHER
LOW MOVE ACROSS EITHER THU NIGHT OR FRI AS THE UPPER PATTERN
BECOMES LESS AMPLIFIED. TIMING OF THIS FEATURE IS IN QUESTION SO
LOW CONFIDENCE CONTINUES. MODELS AND ENSEMBLES INDICATE THAT WEAK
HIGH PRES BUILDS IN FOR NEXT SATURDAY.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH SUNDAY/...

THIS EVENING...MODERATE CONFIDENCE.
WESTERN MA/N CENTRAL CT...MAINLY VFR THOUGH LEFTOVER MVFR VSBYS IN
PATCHY FOG. SHOULD IMPROVE TO VFR BY 02Z. 

CENTRAL-E MA/NE CT/RI...MVFR-IFR CIGS/VSBYS IN BANDS OF LIGHT
SNOW. CONDITIONS SHOULD IMPROVE FROM W-E THROUGH 02Z-04Z. MAY SEE
ICY SURFACES DEVELOPING AT AIRPORT TARMACS AS TEMPS DROP BELOW
FREEZING. NW WINDS GUSTING TO 30-35 KT OVER THE CAPE AND ISLANDS.

OVERNIGHT...HIGH CONFIDENCE. CONDITIONS IMPROVE RAPIDLY TO VFR W
TO E THROUGH 04Z-05Z. NW WIND GUSTING TO AROUND 30 KT OVER THE
CAPE AND ISLANDS.

SUNDAY...HIGH CONFIDENCE OF VFR CONDITIONS. NW GUSTS 20 TO 25 KT
ALONG THE COASTAL PLAIN.

KBOS TAF...HIGH CONFIDENCE IN TAF TRENDS...LOWER CONFIDENCE IN
EXACT TIMING. RAIN SHOULD MIX WITH AND CHANGE TO SNOW 20Z TO 22Z
WITH UP TO AN ADDITIONAL INCH OR SO OF ACCUMULATION POSSIBLE.
TEMPERATURES DROPPING BELOW FREEZING WILL CAUSE UNTREATED SURFACES
TO BECOME ICY. BECOMING VFR AFTER ABOUT 01Z.

KBDL TAF...MODERATE CONFIDENCE. SNOW ENDING BY AROUND 23Z.
BECOMING VFR AFTER 00Z OR 01Z. TEMPERATURES WILL DROP BELOW
FREEZING AFTER 22Z.

OUTLOOK /SUNDAY NIGHT THROUGH THURSDAY/...

SUNDAY NIGHT...HIGH CONFIDENCE. VFR. 

MONDAY...MODERATE CONFIDENCE. VFR TO START...THEN CONDITIONS LOWER
TO MVFR-IFR AS LIGHT SNOW DEVELOPS MAINLY DURING THE AFTERNOON.

MONDAY NIGHT THROUGH TUESDAY NIGHT...LOW CONFIDENCE. MVFR-IFR
CONDITIONS WILL LIKELY DEVELOP AS COASTAL LOW PRESSURE TRACKS SE
OF NANTUCKET. MAY SEE PERIODS OF LIFR ACROSS E MA LATE MON NIGHT
INTO TUE MORNING. NE WINDS LIKELY GUSTING TO 30-40 KT AT LEAST
ACROSS COASTAL AREAS. 

WEDNESDAY...LOW TO MODERATE CONFIDENCE. CONDITIONS TO IMPROVE TO
VFR FROM WEST TO EAST...BUT TIMING IN QUESTION. N-NW WIND GUSTS
UP TO 25-30 KT POSSIBLE EARLY ALONG THE COAST.

THURSDAY...LOW CONFIDENCE. TIMING OF LOW PRES AND POSSIBLE SNOW
SHOWERS IN QUESTION.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

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

TONIGHT...COASTAL LOW WILL CONTINUE TO RAPIDLY STRENGTHEN AND
MOVE TO THE CANADIAN MARITIMES TONIGHT. STRONG GALE FORCE WINDS
FROM THE N AND NW LIKELY THIS EVENING AND THEN VERY GRADUALLY
DIMINISHING OVERNIGHT. SEAS WILL CONTINUE TO BUILD TO 15 FT ON
THE OUTER SE WATERS TONIGHT. NOTING SEAS AT 20 FT AT BUOY 44008 AT
00Z AND 13 FT AT 44097.

SUNDAY...NW GUSTS TO 25 TO 30 KT MAY PERSIST ACROSS MOST OF THE
WATERS UNTIL MID TO LATE SUNDAY AFTERNOON.
 
OUTLOOK /SUNDAY NIGHT THROUGH THURSDAY/...

SUNDAY NIGHT...HIGH CONFIDENCE. SMALL CRAFT WIND GUSTS TO 25 KNOTS
EARLY IN THE EVENING ACROSS THE EASTERN OUTER COASTAL WATERS
SHOULD DIMINISH DURING THE NIGHT.

MONDAY...MODERATE CONFIDENCE. EXPECT WINDS TO SHIFT TO E-NE WITH
GUSTS INCREASING TO 30 KT. LOW PROB FOR GALE FORCE GUSTS LATE MON. 

MONDAY NIGHT THROUGH TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE.
RAPIDLY INTENSIFYING LOW PRES WILL LIKELY CROSS THE COASTAL
WATERS. LOW PROB OF STORM FORCE NE GUSTS LATE MON NIGHT INTO TUE
ACROSS THE OUTER WATERS...MODERATE PROB OF GALE FORCE WINDS
ELSEWHERE. VSBYS REDUCED IN PERIODS OF MODERATE TO HEAVY SNOW AT
TIMES. SEAS BUILDING TO 20 FEET OR GREATER ESPECIALLY ACROSS THE
EASTERN WATERS. 

WEDNESDAY...LOW CONFIDENCE. SHOULD SEE AT LEAST LEFTOVER N-NW WIND
GUSTS UP TO SMALL CRAFT CRITERIA DURING WED...THEN SHOULD DIMINISH
WED NIGHT.

THURSDAY...LOW CONFIDENCE. WINDS SHOULD REMAIN BELOW SMALL CRAFT
CRITERIA. SEAS MAY LINGER AT AROUND 5 FT.

&&

.TIDES/COASTAL FLOODING...
OFFSHORE WINDS AND A LOWER ASTRONOMICAL HIGH TIDE SHOULD PRECLUDE
ANY NEED FOR COASTAL FLOOD HEADLINES OVERNIGHT. ONLY LOCATIONS
THAT MIGHT GET CLOSE TO A FLOOD STAGE WOULD BE THE NORTH SIDE OF
CAPE COD AND THE NANTUCKET HARBOR AREA. 

COASTAL FLOODING MAY BE AN ISSUE DURING THE TUESDAY MORNING TIME
FRAME.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ022-024.
RI...NONE.
MARINE...GALE WARNING UNTIL 7 AM EST SUNDAY FOR ANZ231>235-237-250-251-
     254>256.
     SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR ANZ230-236.

&&

$$
SYNOPSIS...EVT/THOMPSON
NEAR TERM...DOODY
SHORT TERM...THOMPSON
LONG TERM...EVT
AVIATION...EVT/THOMPSON
MARINE...EVT/THOMPSON
TIDES/COASTAL FLOODING...



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