Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 281225
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
725 AM EST WED JAN 28 2015

.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE ACROSS NOVA SCOTIA TODAY. SCATTERED
OCEAN EFFECT SNOW SHOWERS WILL LINGER ACROSS CAPE COD AND
NANTUCKET INTO THIS AFTERNOON. OTHERWISE...IT WILL BE DRY AND
COLD AS THE CLEANUP CONTINUES. A CLIPPER TYPE SYSTEM WILL MOVE OUT
OF THE PLAINS STATES...BRINGING ANOTHER CHANCE FOR SNOW THURSDAY
NIGHT INTO FRIDAY NIGHT. DRY...BLUSTERY AND FRIGID CONDITIONS MOVE
IN FOR THIS WEEKEND. A THIRD STORM MAY AFFECT THE REGION SUNDAY
NIGHT AND MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
LOWER CLOUDS CONTINUE ACROSS CENTRAL AND EASTERN AREAS AT
12Z...BUT NOTING BREAKS IN THOSE CLOUDS ACROSS W MA/N CENTRAL CT.
IR SATELLITE ALSO SHOWING THESE BREAKS WITH CLEARING MOVING INTO E
NY AND THE BERKSHIRES. HOWEVER...WITH H5 TROUGH AXIS LINGERING
ACROSS THE REGION...WILL LIKELY SEE CLOUDS POP UP AGAIN THROUGH
MIDDAY.

STILL NOTING LEFTOVER SNOW SHOWERS REACHING INTO COASTAL PLYMOUTH
COUNTY AS WELL AS THE CAPE AND ISLANDS. COLD AIR ACROSS THE MILDER
OCEAN WATERS WILL KEEP SCT OCEAN EFFECT SNOW SHOWERS MOVING ACROSS
THE MID AND OUTER CAPE AND INTO NANTUCKET WITH A FEW POSSIBLE
MOVING ACROSS THE VINEYARD.

HAVE UPDATED NEAR TERM FORECAST TO BRING CONDITIONS CURRENT.

PREVIOUS DISCUSSION...
SCT OCEAN EFFECT SNOW SHOWERS WILL LIKELY CONTINUE INTO THE
AFTERNOON OVER THE OUTER CAPE. STEEP LOW LEVEL LAPSE RATES OVER
THE WATER WITH DELTA T FROM SST TO TOP OF THE MIXED LAYER
EXCEEDING 20C WHICH IS QUITE UNSTABLE. HOWEVER...NW TRAJECTORY AND
SHALLOW MIXED LAYER WILL LIMIT AREAL EXTENT SOMEWHAT. COULD SEE AN
ADDITIONAL COATING TO AN INCH OVER THE OUTER CAPE.

OTHERWISE...CLOUDS WILL GRADUALLY GIVE WAY TO PTSUNNY SKIES FROM
WEST TO EAST DURING THE AFTERNOON...EXCEPT FOR THE CAPE/ISLANDS
WHERE CLEARING WILL BE DELAYED UNTIL EVENING. HIGH TEMPS WILL
REACH LOW/MID 20S...EXCEPT UPPER TEENS HIGHER TERRAIN IN NORTHERN
AND WESTERN MA. NW WINDS GUSTING TO 20-25 MPH WILL RESULT IN WIND
CHILLS IN THE SINGLE NUMBERS AND TEENS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
HIGH PRES BUILDS IN FROM THE WEST TONIGHT WITH CLEARING SKIES AND
LIGHT WINDS DEVELOPING. WITH DEEP FRESH SNOWPACK...THE STAGE WILL
BE SET FOR IDEAL RADIATIONAL COOLING AND A VERY COLD NIGHT. LEANED
TOWARD COLDER MOS GUIDANCE AND UNDERCUT BY 2-3F WHICH YIELDS MINS
IN THE SINGLE NUMBERS ABOVE AND BELOW ZERO...EXCEPT TEENS
CAPE/ISLANDS. COLDEST MINS WILL BE ACROSS W MA.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
OVERVIEW...
ACTIVE BUT PROGRESSIVE NORTHERN AND SOUTHERN STREAMS ACROSS THE
LOWER 48 THROUGH THIS LONG TERM PERIOD. FIRST NORTHERN STREAM
SHORT WAVE WORKS OUT OF THE NORTHERN ROCKIES TODAY...CROSSING INTO
THE REGION THURSDAY NIGHT AND FRIDAY...POSSIBLY LINGERING ALONG
THE E COAST FRIDAY NIGHT. THIS WILL USHER IN ARCTIC AIR FOR THIS
WEEKEND ALONG WITH BLUSTERY WINDS AND FRIGID WIND CHILLS. A PAIR
OF H5 SHORT WAVES MAY MERGE AS THEY APPROACH THE E COAST SUNDAY
NIGHT AND MONDAY.

WHILE OPERATIONAL MODELS DID SHOW TIMING AND TRACK DIFFERENCES
ESPECIALLY WITH THE POSSIBLE LATE WEEKEND SYSTEM...USED AN OVERALL
MODEL BLEND INCLUDING ENSEMBLES. THIS GAVE GOOD CONTINUITY WITH
THE PREVIOUS FORECAST.

DETAILS...

THURSDAY...
HIGH PRES RIDGE BUILDS ACROSS IN FAST UPPER FLOW. WILL SEE MOSTLY
CLEAR SKIES AND LIGHT WINDS. THE RIDGE WILL PUSH OFFSHORE DURING
THE AFTERNOON WITH A LIGHT S-SW WIND FLOW SETTING UP. CLOUDS WILL
ALSO INCREASE AHEAD OF NEXT APPROACHING SYSTEM. EXPECT HIGHS
MAINLY IN THE UPPER 20S TO MID 30S.

THURSDAY NIGHT-FRIDAY NIGHT...
PRETTY VIGOROUS H5 SHORT WAVE WITH CLIPPER TYPE SYSTEM WORKING E
OUT OF THE EASTERN GREAT LAKES/OHIO VALLEY. LOOKS LIKE THIS SYSTEM
WILL REDEVELOP OFF THE NEW ENGLAND COAST AS THE SHORT WAVE BEGINS
TO NEGATIVE TILT AND CUTOFF...BUT THIS LOOKS LIKE IT WILL HAPPEN
ACROSS CENTRAL NEW ENGLAND. THE LOW DOES NOT DEEPEN UNTIL LATER
FRIDAY...WHICH WILL BE INTO THE GULF OF MAINE BY THEN. HOWEVER...
THE LOW LOOKS TO SPIN THERE FRI NIGHT AS IT DEEPENS...WHICH MAY
KEEP MOISTURE ACROSS EASTERN AREAS.

WITH MILDER AIR WORKING INTO THE DEVELOPING LOW FRIDAY...LOOKS
LIKE THERE MAY BE A PERIOD OF MIXED RAIN/SNOW OR EVEN A BRIEF
CHANGE TO RAIN ALONG THE S COAST...CAPE COD AND THE ISLANDS.
OTHERWISE...LOOKS LIKE ANOTHER SHOT OF SNOWFALL FOR THE REGION
THOUGH NOT NEARLY AS HIGH AS THE BLIZZARD. TOTAL QPF LOOKS TO BE
FROM 0.15 TO 0.25 INCHES ACROSS MOST AREAS...BUT WILL SEE SOME
ENHANCEMENT ACROSS E COASTAL AREAS AS THE LOW FORMS WITH QPF
POSSIBLY UP TO 0.40 INCHES. WITH THE COLD AIR IN PLACE...WILL
LIKELY SEE SNOWFALL TOTALS FROM 2-4 INCHES BUT COULD SEE A BIT
MORE ACROSS NE MA CLOSER TO THE DEVELOPING LOW WITH SOME SNOW
LINGERING FRI NIGHT.

WITH STRONG PRESSURE FALLS AS THE LOW DEVELOPS OFFSHORE...EXPECT
TIGHTENING PRES GRADIENT BRINGING INCREASING NW WINDS BEHIND THE
STORM LATER FRIDAY NIGHT. WILL LIKELY SEE GUSTS UP TO 25-35 KT
AROUND OR AFTER MIDNIGHT...BRINGING IN ARCTIC AIR AS WELL AS LOW
WIND CHILL READINGS. LOWS FRIDAY NIGHT PLUNGE TO BELOW ZERO ACROSS
THE HIGHER INLAND TERRAIN AS WELL AS THE E SLOPES OF THE
BERKSHIRES TO 10-15 ALONG THE S COAST...CAPE COD AND THE ISLANDS.
THE COMBINATION OF THE LOW TEMPS AND BLUSTERY WINDS MAY MEAN VERY
LOW WIND CHILL READINGS. ADVISORIES MAY BE NEEDED FOR PORTIONS OF
THE INTERIOR.

SATURDAY-SUNDAY...
HIGH PRES BEGINS TO SHIFT E DURING SAT...BUT THE DEPARTING STORM
INTO THE MARITIMES WILL CAUSE BLUSTERY CONDITIONS TO CONTINUE.
ARCTIC AIRMASS ENTRENCHES ITSELF ACROSS THE REGION WITH H85 TEMPS
DROPPING TO -11C TO -16C. THIS TRANSLATES TO TEMPS ONLY RECOVERING
TO THE TEENS TO AROUND 20 ON SAT...THOUGH WIND CHILLS WILL MAKE
IT FEEL MUCH COLDER.

WINDS WILL DIMINISH SAT NIGHT...BUT MAY REMAIN HIGH ENOUGH WITH
THE DROPPING TEMPS TO SEE POSSIBLE WIND CHILL ADVISORIES. LOWS
WILL BOTTOM OUT FROM ZERO TO 5 BELOW WELL INLAND TO THE MID TEENS
ON THE OUTER CAPE AND NANTUCKET.

ANOTHER LOW BEGINS TO MOVE NE ACROSS THE MISSISSIPPI VALLEY DURING
SUNDAY AS HIGH PRES CRESTS ACROSS THE REGION. NW WINDS DIMINISH
AND BEGIN TO BACK TO W LATE IN THE DAY. CLOUDS WILL ALSO INCREASE
DURING THE AFTERNOON.

SUNDAY NIGHT-MONDAY...
PAIR OF UPPER LEVEL SYSTEMS BEGIN TO APPROACH. LOW CONFIDENCE ON
THE TIMING AND TRACK OF THESE SYSTEMS...AS WELL AS HOW SURFACE LOW
PRES FORMS AS IT APPROACHES. OF CONCERN IS THE TRACK OF THIS LOW
ON THE 00Z ECMWF...WHICH TAKES THE LOW S OF THE REGION MEANING
ANOTHER SHOT FOR MORE SNOW. THE 00Z GFS AND GGEM MODELS KEEP THE
LOW FURTHER INLAND...WITH POSSIBLE MIXTURE OR A CHANGE TO RAIN FOR
SOME LOCATIONS. MAY ALSO SEE DECENT RAINFALL WITH SOME INFUSION
OF SOUTHERN STREAM MOISTURE WITH THIS LOW. SOMETHING TO KEEP A
CLOSE EYE ON...THOUGH AGAIN CONFIDENCE REMAINS LOW.

TUESDAY...DEPENDING UPON THE DEPARTURE OF THE LOW...LOOKS LIKE
MORE COLD AIR WORKS IN AS ANOTHER HIGH APPROACHES.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM...THROUGH TONIGHT...HIGH CONFIDENCE.

TODAY...VFR CIGS MOST AREAS. EXPECT MVFR CIGS ALONG WITH SCT SNOW
SHOWERS ACROSS OUTER CAPE COD AND ACK. NW GUSTS TO 20-25 KT MAINLY
ALONG COAST AND ACROSS HIGHER TERRAIN.

TONIGHT...VFR. WINDS BECOMING LIGHT.

KBOS TAF...HIGH CONFIDENCE IN TAF.

KBDL TAF...HIGH CONFIDENCE IN TAF.

OUTLOOK /THURSDAY THROUGH SUNDAY/...

THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. WINDS BECOMING LIGHT
S. MID AND HIGH CLOUDS APPROACH DURING THE AFTERNOON.

THURSDAY NIGHT-FRIDAY NIGHT...LOW TO MODERATE CONFIDENCE.
EXPECT CIGS LOWER TO MVFR WITH MVFR-IFR VSBYS IN SNOW. CONDITIONS
IMPROVE TO VFR FRIDAY AFTERNOON BUT NW WINDS INCREASE WITH GUSTS
UP TO 25-30 KT...POSSIBLY HIGHER ALONG THE E COAST.

SATURDAY-SUNDAY...LOW TO MODERATE CONFIDENCE. VFR. GUSTY
NORTHWEST WINDS 25-35 KNOTS SATURDAY...LIGHTER WINDS SUNDAY.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TONIGHT/...HIGH CONFIDENCE.

GALE FORCE GUSTS HAVE DIMINISHED OVER E WATERS AND SCA IN EFFECT
FOR ALL WATERS. WINDS WILL CONTINUE TO DIMINISH BELOW SCA LATER
THIS MORNING INTO THE AFTERNOON...WITH GRADUAL SUBSIDING SEAS.
FREEZING SPRAY DIMINISHING.

DIMINISHING NW WINDS THROUGH TONIGHT. SEAS MOSTLY BELOW SCA
THRESHOLDS...EXCEPT SUBSIDING TO NEAR 5 FT OVER E WATERS TOWARD
DAYBREAK THU.

OUTLOOK /THURSDAY THROUGH SUNDAY/...MODERATE CONFIDENCE.

THURSDAY...
CONDITIONS REMAIN BELOW SMALL CRAFT THRESHOLDS ON THURSDAY...
THOUGH S WINDS MAY GUST UP TO 20 KT THU NIGHT.

FRIDAY...
LOW PRES WILL CROSS THE WATERS. EXPECT REDUCED VSBYS IN SNOW.
EXPECT WINDS TO SHIFT TO NW BY FRI NIGHT...INCREASING TO 25-35
KT...SO GALES WILL LIKELY BE NEEDED. SEAS ALSO BUILD UP TO 6-8 FT
OVER THE OPEN WATERS. FREEZING SPRAY WILL LIKELY DEVELOP FRI
NIGHT.

SATURDAY...NW GALES EXPECTED WITH POTENTIAL FOR A LIGHT FREEZING
SPRAY. SEAS REMAIN HIGH...POSSIBLY UP TO 7-9 FT ON THE EXPOSED
WATERS. WINDS WILL BEGIN TO DIMINISH SAT NIGHT.

SUNDAY...WINDS AND SEAS AT SMALL CRAFT ADVISORY LEVELS EARLY
SUNDAY...BUT WILL DIMINISH THROUGH THE DAY.

&&

.TIDES/COASTAL FLOODING...
EARLY MORNING HIGH TIDE CYCLE HAS PASSED. NO REPORTS OF
SIGNIFICANT ISSUES WITH SPLASHOVER OR MINOR FLOODING THIS MORNING
SO FAR. HAVE ALLOWED THE COASTAL FLOOD ADVISORY TO EXPIRE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
     ANZ232>235-237.
     FREEZING SPRAY ADVISORY UNTIL 8 AM EST THIS MORNING FOR
     ANZ231>235-237-251.
     SMALL CRAFT ADVISORY UNTIL 9 AM EST THIS MORNING FOR ANZ230.
     SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ231-
     251-255-256.
     SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ250-254.

&&

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



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