Area Forecast Discussion
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000
FXUS61 KBOX 310829
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
329 AM EST SAT JAN 31 2015

.SYNOPSIS...
BLUSTERY AND VERY COLD CONDITIONS CONTINUE THROUGH THE WEEKEND. A
MAJOR WINTER STORM WILL AFFECT THE REGION SUNDAY NIGHT INTO
MONDAY EVENING WITH POTENTIALLY HEAVY SNOW ACCUMULATION AND GUSTY
WINDS. A FRIGID AIRMASS WILL FOLLOW MONDAY NIGHT WITH DANGEROUSLY
COLD WIND CHILLS. MODERATING TEMPS WEDNESDAY THEN VERY COLD
CONDITIONS WILL RETURN TOWARD THE END OF THE WEEK. A COASTAL STORM
WILL PASS WELL SOUTH OF NEW ENG LATE IN THE WEEK BUT WILL HAVE TO
BE MONITORED.

&&

.NEAR TERM /THROUGH TODAY/...
MID LEVEL LOW CLOSING OFF NEAR CAPE COD WITH BANDS OF LIGHT
SNOW ROTATING BACK ACROSS E MA. HIGHER REFLECTIVITIES ARE
DEVELOPING ON RADAR ACROSS E COASTAL MA AND THE ADJACENT WATERS
INDICATING STEADIER SNOW. MODEL GUIDANCE SUGGEST SOME QPF
ENHANCEMENT OVER THE OUTER CAPE THROUGH THE MORNING WITHIN THE
DEVELOPING COMMA HEAD. MAIN FOCUS FOR MINOR ACCUM THROUGH MID
MORNING WILL BE ACROSS CAPE ANN AND THE OUTER CAPE WHERE 1-2
INCHES IS POSSIBLE. LOW PROB FOR ISOLD 3 INCH AMOUNTS OUTER CAPE.
ELSEWHERE ACROSS E MA...MAINLY A COATING TO ONE HALF INCH.

AREAS OF LIGHT SNOW WILL LINGER ACROSS E MA INTO THE
MORNING...EXITING THE OUTER CAPE BY MIDDAY. CLEARING SKIES
DEVELOP ACROSS E NEW ENG LATER THIS MORNING INTO THE
AFTERNOON...WITH FULL SUNSHINE ACROSS THE WEST.

STRONG NW WINDS WILL CONTINUE TODAY. GUSTS 35-45 MPH EXPECTED WITH
A FEW GUSTS NEAR 50 MPH NEAR THE COAST.

BITTER COLD WIND CHILLS DOWN TO -10 TO -20 THIS MORNING ACROSS
CENTRAL AND W NEW ENG AND -5 TO -10 IN THE COASTAL PLAIN.
AFTERNOON HIGH TEMPS ONLY IN THE TEENS MOST LOCATIONS BUT WITH THE
STRONG WINDS...WIND CHILLS WILL ONLY RECOVER TO -5 TO +5.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
TONIGHT...

WEAK SFC RIDGE MOVES INTO THE REGION AHEAD OF ARCTIC FRONT
DROPPING INTO N NEW ENG. THIS WILL RESULT IN GRADUAL DIMINISHING
WINDS TONIGHT...BUT REMAINING RATHER GUSTY OVER THE CAPE/ISLANDS
THROUGH THE NIGHT. MIN TEMPS WILL DROP INTO THE SINGLE NUMBERS
WITH TEENS ALONG THE IMMEDIATE COAST AND CAPE/ISLANDS.

SUNDAY...

ARCTIC FRONT WILL PUSH S INTO SNE REACHING THE S COAST BY EVENING.
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS IN THE AFTERNOON AS
OVERRUNNING MID/HIGH CLOUDS MOVE INTO THE REGION...ALONG WITH
DEVELOPMENT OF SOME LOWER CLOUDS AS LOW LEVEL MOISTURE INCREASES.
BUT REMAINING DRY THROUGH THE DAY. HIGH TEMPS MOSTLY IN THE
MID/UPPER 20S BUT DROPPING BACK INTO THE TEENS TOWARD EVENING
ACROSS N ZONES AS ARCTIC AIR BEGINS TO DRAIN SOUTH.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
*/ SATURDAY NIGHT THROUGH MONDAY NIGHT...

HIGHLIGHTS...

 - PLOWABLE SNOW ANTICIPATED FOR SUNDAY NIGHT INTO MONDAY NIGHT
 - IMPACTS TO TRAVEL DURING THE MONDAY MORNING/AFTERNOON COMMUTE
 - ENOUGH CONFIDENCE FROM CONSENSUS TO GO WITH A WINTER STORM WATCH
 - WINTER STORM WATCH IN EFFECT FOR LOCALES ALONG AND S OF MASS-PIKE

OVERVIEW...

MODERATE CONFIDENCE FORECAST.

AND HERE WE GO AGAIN WITH A STORM. GOING DOWN ALL THE GUIDANCE EVER
KNOWN. LIKE A DRIFTER I AM LOST ABOUT THIS STORM. SO I`VE MADE UP MY
MIND. I`M ENSEMBLE BLENDING THIS TIME. SO HERE WE GO AGAIN.

WITH THIS FORECAST AM NOT GOING TO INVEST IN ONE INDIVIDUAL STOCK OF
FORECAST GUIDANCE. WILL DIVERSIFY WITH A PORTFOLIO BLEND OF ENSEMBLE
WEIGHTED GUIDANCE...EVALUATING RISKS AND POTENTIAL IMPACTS WHICH ARE
OUTLINED IN THE DISCUSSION BELOW.

NEUTRAL-TILT OPEN-WAVE TROUGH ABOVE H85 SWEEPS ACROSS S NEW ENGLAND
SUNDAY NIGHT-MONDAY NIGHT...PROGRESSING TOWARDS A NEGATIVE-TILT LATE
IN THE PERIOD. SURFACE LOW EMERGES FROM THE OHIO RIVER VALLEY MONDAY
MORNING SWEEP S OF NEW ENGLAND MONDAY-MONDAY NIGHT AS IT INTENSIFIES
IN RESPONSE TO THE ISALLOBARIC WIND ENHANCING THE BAROCLINIC ZONE IN
OUR PROXIMITY AND THE TROUGH ALOFT UNDERGOING NEGATIVE-TILT.

FOCUS IS WITHIN THE ANTICYCLONIC BRANCH OF THE WARM-CONVEYER-BELT
/WCB/ WHERE A BAROCLINIC-LEAF SETUP IS ANTICIPATED WITH BROADSCALE
ISENTROPIC/DEEP-LAYER FORCING BENEATH RRQ/LFQ JET COUPLING OF UPPER-
LEVEL JET STREAKS. CONVERGENCE OF THE WCB ALONG N-S SLANTWISE ASCENT
AGAINST TIGHTENING ISOTHERMAL PACKING /SUBSEQUENT OF THE ENHANCEMENT
OF THE BAROCLINIC ZONE/ WILL LIKELY YIELD E-W MESOSCALE BANDING OUT
AHEAD OF THE STORM AND NOTABLY WITHIN THE NE-QUADRANT OF THE H85 LOW
IN REGIONS OF STRONG FRONTOGENESIS. NEIGHBORING -EPV /POTENTIAL
INSTABILITY/ THERE IS THE INDICATION AS SUGGESTED BY SREF MEANS OF
SNOWFALL RATES OF AROUND 1 INCH PER HOUR.

YET UNCERTAINTY...

BUT WHERE EXACTLY ALL THESE INGREDIENTS COME TOGETHER AND WHERE THE
GREATEST AMOUNT OF FORCING LIES REMAINS SUSPECT. ASSOCIATED ENERGY
IS JUST COMING ASHORE IN BRITISH COLUMBIA CANADA AND THERE IS SOME
QUESTION AS TO THE S-STREAM ENERGY THAT IS CAPTURED FROM THE LOW
CENTER OVER THE SW CONUS / MEXICO. LOTS OF UNCERTAINTY GIVEN BY THE
LATITUDINAL / ENHANCEMENT SPREAD OF FORECAST GUIDANCE UPSTREAM OVER
THE OHIO RIVER VALLEY. JUST LIKE THE RUN-UP TO THE RECENT BLIZZARD
MODELS VARY IN PLACEMENT OF BEST E-W BANDING AND THERMAL PROFILES.
SUBTLE SHIFTS EVEN ON THE ORDER OF 5 TO 10 MILES WILL RESULT IN
SIGNIFICANT SNOWFALL AMOUNTS AND PRECIP-TYPES. EVALUATING SPC SREF
PLUMES SHOW GRAPHICALLY JUST THAT EXTENT OF SPREAD OF POSSIBILITIES.

ITS INCREDIBLY DIFFICULT TO NAIL THE SPECIFICS DOWN AT THIS TIME BUT
FEEL THAT THERE IS ENOUGH WEIGHTING TO GO WITH A WINTER STORM WATCH.
WISH TO BETTER INFORM/ALERT BOTH THE PUBLIC AND STATE / LOCAL GOVTS.
FEEL MESSAGING THE THREAT PRIOR TO THE WEEKEND AND THE FACT THAT
THERE IS A TON OF SNOW ON THE GROUND GIVES EVERYONE TIME TO PREPARE
AND TO ACT ACCORDINGLY FOR THE POTENTIAL OF A SIGNIFICANT SNOWFALL.

NO TWO STORMS ARE ALIKE JUST LIKE NO TWO SNOWFLAKES ARE ALIKE. YET
WE CAN DRAW COMPARISONS FROM ANALOGS. NOTING CIPS-ANALOGS...FROM THE
60-HR NAM-FORECAST AND 72-HR GFS-FORECAST...BOTH KEY UPON A SWATH OF
E-W SNOW ACROSS THE NE-CONUS WITH AT LEAST 60% OF ANALOGS AGREEING
UPON STORM-TOTAL SNOWFALLS IN EXCESS OF 8-INCHES...AND YES NOTING
THAT THE MEAN-MEDIAN E-W SNOWFALL IS N OF THE MASS-PIKE. WHAT IS
IMPORTANT TO TAKE AWAY IS THAT IT IS THERE AND THE PROBABILITIES
SUGGEST SEEING SNOWFALLS IN EXCESS OF WATCH-WARNING CRITERIA. OTHER-
WISE ALONG THE S-FRINGE OF THE BANDING IS THE LIKELIHOOD OF SEEING
MIXING WITH A FREEZING RAIN POTENTIAL. PERHAPS SOME STRONG GUSTS
ACROSS THE CAPE / ISLANDS IN EXCESS OF 35 MPH...OTHERWISE MAJORITY
OF ANALOGS SIGNAL NO ISSUE WITH WINDS.

SNOW...

MODELS DIFFER ON N-S PLACEMENT OF E-W BANDING. JUST TOO FAR OUT AND
TOO MUCH UNCERTAINTY TO MAKE ANY SPECIFIC GUESSES. WENT WITH A BROAD
SPREAD BASED ON ENSEMBLE MEANS AND ANALOGS. WOULD VENTURE TO BELIEVE
THAT THE HEAVY SNOW POTENTIAL AND HIGHEST ACCUMULATIONS WILL EXIST
AROUND AND S OF THE MASS-PIKE IN LINE WITH WPC-THINKING. AMOUNTS UP
TO A FOOT ARE POSSIBLE...SOME OF THIS DEPENDENT ON THE FLUFF-FACTOR
OF THE SNOW. SNOW-RATIOS ANTICIPATED TO BE HIGHER S TO N WITH LESSER
INTRUSION OF WARMER AIR ALOFT AROUND H8. SO WOULD FIGURE A MORE WET-
SNOW TO THE S...FLUFFIER N. CAN NOT RULE OUT THUNDERSNOW POTENTIAL
BUT BELIEVE THE LESS CHANCES IN COMPARISON TO THE RECENT BLIZZARD.

MAIN TAKE-AWAY: TRAVEL WILL BE IMPACTED DURING BOTH THE MORNING AND
EVENING COMMUTE ON MONDAY. MOTORISTS SHOULD BE AWARE OF ADVERSE
WEATHER CONDITIONS THAT WILL BE CHANGING THROUGH THE EVENT WITH
RESPECT TO THE PACE OF SNOWFALL AND POSSIBLE NEAR-ZERO VISIBILITIES.

PRECIPITATION-TYPE

MAY ALSO CONTEND WITH A E-W MIXING LINE IN PROXIMITY TO THE S-SHORE.
WARM INTRUSION AROUND H8 PUSHED N BY WCB MAY LEND TO A TRANSITION OF
RAIN/SNOW WITH PERHAPS A WINTRY MIX BETWEEN OF FREEZING RAIN/SLEET
ALBEIT THINKING VERY THIN. FOCUS OF THE NARROW BAND OF MIXING WOULD
OCCUR WITH THE APPROACH AND PASSAGE OF THE LOW IN PROXIMITY TO S NEW
ENGLAND DURING THE AFOREMENTIONED TIMEFRAME. FORECAST GUIDANCE SPLIT
BUT QUESTION WHETHER A MICRO-CLIMATE AND THE ARCTIC AIR SPILLING S
WILL KEEP US ALL SNOW. ALTOGETHER...MAIN FOCUS FOR POTENTIAL WINTRY
MIX...IF ANY...IS ALONG THE IMMEDIATE S-SHORE.

WINDS...

BLUSTERY OUT OF THE N IN RESPONSE TO THE APPROACHING / DEEPENING LOW
PRESSURE CENTER THROUGH THE DAY MONDAY INTO MONDAY EVENING. WILL SEE
STRONG NW-WINDS IN WAKE OF THE STORM. COULD BE CONTENDING WITH GUSTS
ON THE ORDER OF AROUND 20-30 MPH FOR SOME LOCATIONS...ESPECIALLY FOR
THE SHORES. ADDING TO THE POTENTIAL FLUFF-FACTOR OF THE SNOW...THAT
ADDS TO THE POTENTIAL OF BLOWING AND DRIFTING WHICH HAS THE IMPACT
OF GENERATING NEAR-ZERO VISIBILITIES.

TAKE-AWAY: AT THIS TIME IT APPEARS WINDS WILL REMAIN BELOW WIND-ADV
CRITERIA.

COASTAL FLOODING...

MID-MORNING HIGH TIDES ARE NOT ASTRONOMICALLY HIGH AND LATE-EVENING
TIDES ARE MUCH LOWER. ESTIMATING AROUND A FOOT OF SURGE IN RESPONSE
TO THE STORM...LOW CONFIDENCE AT THIS TIME OF ANY COASTAL FLOODING.

*/ TUESDAY ONWARD...

HIGHLIGHTS...

 - ANOTHER ROUND OF SNOW POSSIBLE THURSDAY-FRIDAY; LOW CONFIDENCE

OVERVIEW...

COLD HIGH PRESSURE IS FORECAST TO MOVE OVER NEW ENGLAND ON TUESDAY
BEHIND THE DEPARTING STORM WITH HIGHS ONLY FORECAST TO MAKE IT INTO
THE TEENS MOST LOCALES.

NEXT IN THE SERIES OF SHORTWAVES IS SHOWN BY THE GLOBAL MODELS TO
MOVE ONSHORE THE NW PACIFIC COAST TUE NIGHT. THIS LOOKS TO BE THE
NEXT PIECE OF ENERGY TO WATCH IN THE LONG TERM. GFS/ECMWF SHOW
COASTAL LOW DEVELOPMENT OCCURRING WED NIGHT OR THU /SLIGHTLY DELAYED
FROM MODEL RUNS YESTERDAY/ AND THREATENING YET ANOTHER IMPACT TO
NEW ENGLAND CENTERED ON THE THU-FRI TIMEFRAME. LARGE SPREADS IN
THE MODELS/ENSEMBLES...NO SURPRISE 6-7 DAYS OUT IN TIME. THE MEAN
SHOWS A WEAKER STORM COMPARED TO THE MONDAY ONE...WITH THE LATEST
30.12Z OPERATIONAL RUNS EITHER A GLANCING BLOW OR A COMPLETE MISS.
TOO SOON THOUGH TO LEAN ON A HIT OR A MISS TO SOUTHERN NEW ENGLAND.
BITTER COLD LOOKS TO FOLLOW IN THE WAKE OF THIS POTENTIAL LATE WEEK
STORM.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...

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

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

THROUGH TODAY...N-S BAND OF -SN WITH MVFR CONDITIONS WILL BE
CONFINED TO E MA SHIFTING TO JUST CAPE COD AFT 12Z BEFORE ENDING
BY MIDDAY OVER THE OUTER CAPE. OTHERWISE...VFR WITH CLEARING SKIES
IN EASTERN NEW ENG. NW GUSTS TO 30-40 KT.

TONIGHT...VFR WITH GRADUAL DIMINISHING WIND.

SUNDAY...MAINLY VFR...BUT LOW PROB FOR AREAS OF MVFR CIGS
DEVELOPING IN THE AFTERNOON.

KBOS TAF...HIGH CONFIDENCE. MVFR VSBYS DUE TO LIGHT SNOW AND
BLOWING SNOW EARLY THIS MORNING. IMPROVING CONDITIONS AFT 12Z.

KBDL TAF...HIGH CONFIDENCE.

OUTLOOK /SUNDAY NIGHT THROUGH TUESDAY/...

SUNDAY NIGHT INTO MONDAY NIGHT...MODERATE CONFIDENCE.

DETERIORATING CONDITIONS TO IFR-VLIFR WITH SNOW. BLUSTERY N-WINDS
WITH GUSTS UP TO AROUND 30 KTS. CONDITIONS IMPROVE LATE AS WINDS
BACK NW.

TUESDAY...MODERATE CONFIDENCE. MAINLY VFR. MAY SEE GUSTY NW WINDS
EARLY.

WEDNESDAY...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 SATURDAY NIGHT/...HIGH CONFIDENCE.

TODAY...GALE CENTER LIFTS INTO THE MARITIMES WITH NW GALES
CONTINUING OVER THE WATERS. GUSTS TO 40-45 KT LIKELY WITH
MODERATE FREEZING SPRAY LIKELY. SNOW SHOWERS REDUCE VSBY OVER
EASTERN MA WATERS IN THE MORNING.

TONIGHT...GALE CENTER PULLS FARTHER AWAY WITH WINDS DIMINISHING
BELOW GALE 00-06Z...BUT GUSTS 25-30 KT WILL CONTINUE OVERNIGHT.
MODERATE FREEZING SPRAY LIKELY CONTINUING...ESPECIALLY E MA
COASTAL WATERS.

SUNDAY...WINDS AND SEAS GRADUALLY DIMINISH THROUGH THE DAY. SUB
SCA CONDITIONS DEVELOP OVER THE S COASTAL WATERS DURING THE
MORNING...BUT SCA CONDITIONS WILL CONTINUE ACROSS THE OUTER
EASTERN WATERS. LIGHT FREEZING SPRAY WILL PERSIST.

OUTLOOK /SUNDAY NIGHT THROUGH TUESDAY/...

SUNDAY NIGHT INTO MONDAY NIGHT...MODERATE CONFIDENCE.

AREA OF LOW PRESSURE SWEEPING W-E ACROSS THE S-WATERS. WILL SEE
WINDS OUT OF THE N INCREASE TO GALE-FORCE. WAVES INCREASING 10-12
FEET ON THE S/SE WATERS AS THE STORM INTENSIFIES TO THE E AND WINDS
BACK OUT OF THE NW LATE IN THE PERIOD.

TUESDAY...MODERATE CONFIDENCE.

NW WINDS RELAX AROUND DEPARTING STORM WITH SEAS SUBSIDING...
THOUGH STILL FORECAST TO REMAIN AT SMALL CRAFT ADVISORY LEVELS.

WEDNESDAY....MODERATE CONFIDENCE.

WINDS FORECAST TO TURN SW AND PICK UP WITH SEAS INTO SMALL CRAFT
ADVISORY LEVELS AGAIN. FEW SNOW SHOWERS POSSIBLE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY
     NIGHT FOR CTZ002>004.
     WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR CTZ002-003.
MA...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR MAZ022>024.
     WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR MAZ007-015-016-
     019>021.
     WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY
     NIGHT FOR MAZ009-011>013-015>022.
     WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR MAZ003-004-
     010-011.
     WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR MAZ002-
     008-009.
     WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     MAZ022.
RI...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR RIZ008.
     WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR RIZ005>007.
     WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY
     NIGHT FOR RIZ001>007.
MARINE...FREEZING SPRAY ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ231-232-
     250-251.
     GALE WARNING UNTIL 1 AM EST SUNDAY FOR ANZ231-232-250-251-
     254>256.
     FREEZING SPRAY ADVISORY UNTIL 6 PM EST THIS EVENING FOR
     ANZ233>235-237.
     GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ233>235-237.
     GALE WARNING UNTIL 9 PM EST THIS EVENING FOR ANZ230.
     GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ236.

&&

$$
SYNOPSIS...KJC
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL



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