Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 140648
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
145 AM EST SUN FEB 14 2016

.SYNOPSIS...

DANGEROUSLY COLD WIND CHILLS OF 25 TO 40 BELOW ZERO INTO THIS
MORNING. A PERIOD OF ACCUMULATING SNOW IS THEN LIKELY FOR MUCH OF
REGION ESPECIALLY AWAY FROM THE COAST LATE MONDAY AFTERNOON AND
EVENING...CHANGING TO RAIN BY TUESDAY MORNING. A POWERFUL STORM
SYSTEM WILL LIKELY TRACK WEST OF NEW ENGLAND TUESDAY INTO TUESDAY
NIGHT BRINGING HEAVY RAIN...STRONG WINDS AND WARM TEMPERATURES TO
THE REGION. A TREND TOWARD DRIER AND COLDER WEATHER FOLLOWS ON
WEDNESDAY AND THURSDAY. ANOTHER WEATHER SYSTEM WILL BRING SNOW AND
RAIN TOWARD THE END OF THE WEEK.

&&

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

***DANGEROUS WIND CHILLS OF 25 TO 40 BELOW ZERO CONTINUE THROUGH
  DAYBREAK***

***COLDEST LOW TEMPERATURES RECORDED IN BOSTON/WORCESTER SINCE 2004
  AND NOW NOT FAR AWAY FROM IT BEING THE COLDEST SINCE 1957***

EXTREME ARCTIC OUTBREAK FOR SOUTHERN NEW ENGLAND STANDARDS CONTINUES
WITH TEMPS DOWN TO -12 IN WORCESTER AND -6 IN BOSTON AS OF 1 AM.
THESE ARE THE COLDEST READINGS RECORDED AT BOTH LOCATIONS SINCE
2004.  IF BOS/ORH DROP TWO MORE DEGREES IT WILL BE THE COLDEST
TEMPS RECORDED IN THESE LOCATIONS SINCE 1957.  SO ITS FAIR TO SAY
THAT THIS IS A HISTORIC ARCTIC OUTBREAK FOR THE MODERN ERA.  A NEW
RECORD WAS ALSO BROKEN WITH THE FEB 14/00Z UPPER AIR
SOUNDING AT ALBANY. THE H850 TEMP WAS - 30.8 C. THE PREVIOUS RECORD
COLD 850 MB TEMPERATURE WAS -30.5 C SET BACK ON 4 JANUARY 1981 AND ON
18 JANUARY 1982.

PUTTING THE RECORDS ASIDE...MAIN STORY THIS MORNING IS THE
DANGEROUS WIND CHILLS OF 25 TO 40 BELOW ZERO INTO THE MORNING
HOURS.  FROSTBITE CAN OCCUR ON EXPOSED FLESH IN JUST 10 MINUTES.
ACTUAL LOW TEMPS WILL RANGE FROM 5 TO 15 BELOW ZERO UNDER CLEAR
SKIES.

OCEAN EFFECT SNOW SHOWERS FOR THE OUTER-CAPE...

WHILE THE REST OF THE REGION WAS CLEAR AND BITTERLY
COLD...SCATTERED OCEAN EFFECT SNOW SHOWERS HAVE DEVELOPED ACROSS
THE OUTER-CAPE.  DESPITE LIMITED FETCH WITH WINDS AT 310 TO 320
DEGREES...MID LEVEL TROUGH SINKING SOUTH IS LIKELY AIDING
IN SEEDER FEEDER PROCESSES.  ALSO...EXTREME INSTABILITY WITH NEARLY
1500 J/KG OF OCEAN INDUCED CAPE IS LIKELY OVERCOMING THE VERY
LIMITED FETCH.  NO CHANGE TO SNOW ACCUMS AT THIS TIME...WILL STICK
WITH 1 TO 2 INCHES POSSIBLE WITH A LOW RISK OF 3 TO 4 INCHES.  SNOW
AMOUNTS WILL VARY CONSIDERABLY OVER SHORT DISTANCES AND WILL BE
TOUGH TO MEASURE WITH THE STRONG WINDS.  THE BIGGEST CONCERN WILL
PROBABLY BE THE STRONG WINDS/BITTERLY COLD TEMPS WHICH WILL RESULT
IN LOCALIZED POOR VISIBILITY AT TIMES.  WILL MONITOR THIS CLOSELY
EARLY THIS MORNING.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...

WIND CHILLS 25 TO 35 BELOW-ZERO PERSIST TOWARDS MID-MORNING. BUT THE
THREAT WILL DIMINISH AS WINDS RELAX THROUGH THE DAY AS HIGH PRESSURE
BUILDS INTO THE AREA. ABUNDANT SUNSHINE BUT BENEATH A CONTINUED
ARCTIC AIRMASS ALOFT. A DRY SUBSIDENCE INVERSION BUILDING ACROSS
THE REGION IN TANDEM WITH HIGH PRESSURE WILL LIMIT MIXING THROUGH
THE DAY PER SINKING AIR. HIGHS AROUND THE SINGLE DIGITS TO TEENS.
ANY OCEAN- EFFECT SNOW SHOWERS SHOULD HAVE DIMINISHED TO FLURRIES
IF ANYTHING AT ALL.

SUNDAY NIGHT...

HIGH PRESSURE. LIGHT WINDS. MOSTLY CLEAR CONDITIONS PRIOR TO CLOUDS
INCREASING MONDAY MORNING. A GOOD RADIATIONAL COOLING SETUP. WILL
SEE LOWS DROP BELOW-ZERO ACROSS MUCH OF S NEW ENGLAND. COLDEST SPOTS
WHEREVER DEEP SNOW PACK RESIDES...NAMELY N/W MASS WHERE LOWS ARE
FORECAST TO BOTTOM OUT AROUND 10 BELOW-ZERO.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
BIG PICTURE...

LARGE SCALE PATTERN REMAINS RIDGE WEST/TROUGH EAST THROUGH THE WEEK.
SEVERAL SHORTWAVES IN THIS FLOW MOVE THROUGH NEW ENGLAND...MOST
NOTABLY ON TUESDAY...WEDNESDAY NIGHT...AND SATURDAY.  MODEL MASS
FIELDS REMAIN IN GENERAL AGREEMENT THROUGH WEDNESDAY...THEN DIVERGE
WITH THE GFS BEING THE FASTER SOLUTION.

THE DAILIES...

MONDAY-TUESDAY...

HIGH PRESSURE OVER THE REGION MONDAY MORNING MOVES OFF TO THE EAST.
MIDWEST SHORTWAVE WITH SURFACE REFLECTION APPROACHES DURING THE DAY.
MOISTURE FIELDS AT ALL LEVELS INCREASE AROUND MIDDAY WITH WEAK LIFT
DURING THE AFTERNOON. WE WILL SHOW INCREASING POPS THROUGH THE
AFTERNOON. THERMAL PROFILES FAVOR SNOW AT THE ONSET EXCEPT POSSIBLY
SOME RAIN ALONG THE SOUTH COAST/ISLANDS.

SOUTHWEST LOW LEVEL JET INCREASES TO 45 TO 55 KTS MONDAY NIGHT AND
GENERATES A FAIR AMOUNT OF LIFT AS THE WARMER AIR MOVES OVER THE
COLDER SURFACE AIR. THIS WILL GENERATE STRONGER PCPN...BUT ALSO
CHANGE THE THERMAL PROFILE WHICH WILL CHANGE PTYPE FROM SNOW TO
RAIN. WE EXPECT SURFACE TEMPERATURES TO BE COLDEST EARLY AT NIGHT
AND THEN SLOWLY RISE OVERNIGHT. LINGERING QUESTIONS INCLUDE HOW FAST
THE SURFACE LAYER WILL WARM ABOVE FREEZING...IS OUR DATABASE
FORECASTING TOO RAPID A WARMUP? WILL THERE BE MORE FREEZING RAIN IN
THE TRANSITION THAN IS CURRENTLY FORECAST...ESPECIALLY OVER WESTERN
AND CENTRAL MASS? THESE CONCERNS WILL NEED TO BE MONITORED.

TUESDAY WILL FIND THE UPPER JET MOVING INTO PLACE WITH SOUTHERN NEW
ENGLAND UNDER THE RIGHT ENTRANCE REGION. THIS WILL FURTHER ENHANCE
LIFT THROUGH THE COLUMN. FORECAST TRACKS ON THE SURFACE LOW TAKE IT
THROUGH EITHER THE HUDSON VALLEY OR WESTERN CT/MASS. THIS IS A PATH
THAT WOULD BRING WARMER TEMPERATURES TO OUR AREA.  THE STRONG LOW
LEVEL FLOW WILL INCREASE TO 60-70 KNOTS BY MIDDAY WHICH WILL ALSO
BRING IN HIGHER PRECIPITABLE WATER VALUES...AT LEAST 2 STD
DEVIATIONS ABOVE NORMAL. THIS WILL MEAN PERIODS OF RAIN WITH QPF OF
1 TO 1.5 INCHES. TEMPERATURES WILL WARM INTO THE 40S AND LOWER 50S
WHICH WILL AID IN SNOWMELT. THE RAIN AND SNOWMELT WILL BRING
POTENTIAL FOR POOR DRAINAGE FLOODING ESPECIALLY WHERE DRAINS ARE
BLOCKED.  THE PASSING SURFACE LOW WILL SWING A COLD FRONT THROUGH
THE REGION EARLY SATURDAY NIGHT WITH WINDS SHIFTING WEST AND PCPN
DIMINISHING AT THAT TIME.

WEDNESDAY-THURSDAY...

A SECOND SHORTWAVE ALOFT WILL SWEEP OVERHEAD WEDNESDAY AND WEDNESDAY
NIGHT. THIS WILL BRING LINGERING CLOUDS AND A CHANCE OF RAIN OR SNOW
SHOWERS. TEMPERATURES WILL COOL A LITTLE FROM TUESDAY WITH -7C TO
-10C ALOFT SUPPORTING MAX SFC TEMPS IN THE UPPER 30S AND LOWER 40S.
SURFACE HIGH PRESSURE THEN BUILDS IN FOR THURSDAY AND BRINGS COLDER
AIR. TEMPS ALOFT THURSDAY WILL SUPPORT MAX SFC TEMPS IN THE UPPER
20S AND LOWER 30S.

FRIDAY-SATURDAY...

NORTHERN STREAM SHORTWAVE RACES ACROSS THE GREAT LAKES AND ACROSS
NEW ENGLAND...WITH THE STORM CENTER PASSING TO OUR NORTH. THIS WILL
BRING A PERIOD OF RAIN OR SNOW LATE FRIDAY THROUGH SATURDAY.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TODAY AND TONIGHT/...

TODAY AND TONIGHT...HIGH CONFIDENCE.  VFR CONDITIONS WITH
CLEAR SKIES.  NORTHWEST WIND GUSTS OF 20 TO 30 KNOTS GRADUALLY
DIMINISH THIS AFTERNOON AND ESPECIALLY BY EARLY THIS EVENING.
THE EXCEPTION TO THE CLEAR SKIES WILL BE THE OUTER-CAPE/NANTUCKET
WHERE OCEAN EFFECT CLOUDS BETWEEN 2500 TO 4000 FEET WILL PERSIST INTO
THE AFTERNOON.  SCATTERED BANDS OF OCEAN EFFECT SNOW SHOWERS WILL
ALSO AFFECT THE OUTER CAPE THIS MORNING...BUT SHOULD DISSIPATE THIS
AFTERNOON.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF.

OUTLOOK /MONDAY THROUGH THURSDAY/...MODERATE CONFIDENCE.

MONDAY-TUESDAY... VFR DURING THE DAY BUT TRENDING TO IFR DURING
MONDAY NIGHT IN SNOW. THE SNOW WILL CHANGE TO RAIN FROM SOUTHEAST TO
NORTHWEST OVERNIGHT WITH RAIN ON TUESDAY. STRONG LOW LEVEL WINDS OFF
THE DECK...SOUTHWEST 45-50 KNOTS MONDAY NIGHT AND SOUTH 60-70 KNOTS
TUESDAY AFTERNOON. THIS WILL BRING LOW LEVEL WIND SHEAR ESPECIALLY
ON TUESDAY. LINGERING CONCERN OF A PERIOD OF FREEZING RAIN DURING
THE TRANSITION FROM SNOW TO RAIN...THIS WILL NEED TO BE MONITORED.

WEDNESDAY-THURSDAY... CONDITIONS IMPROVING TO VFR WEDNESDAY MORNING.
AREAS OF MVFR CIGS/VSBYS IN RAIN/SNOW SHOWERS WEDNESDAY
AFTERNOON/EVENING. VFR THURSDAY.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

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

*/ HIGHLIGHTS...

* GALE FORCE WIND GUSTS AND HEAVY FREEZING SPRAY EXPECTED THIS
  AFTERNOON INTO SUNDAY MORNING

TONIGHT...HIGH CONFIDENCE.

ARCTIC AIRMASS BUILDING S. INCREASING TEMPERATURE DIFFERENTIAL
BETWEEN SEA-SURFACE TEMPERATURES IN THE LOW-40S AND AIR TEMPERATURES
DROPPING TO LOWS IN THE SINGLE DIGITS TO BELOW-ZERO ALONG THE
SHORES. MIX DOWN OF 40 KT GUSTS THIS EVENING RESULTING IN WAVES
BUILDING 8-10 FEET. LIKELY THREATS OF MODERATE TO HEAVY FREEZING
SPRAY AS WELL AS ARCTIC SEA SMOKE. HAVE INCLUDED BOTH BOSTON
HARBOR AND NARRAGANSETT BAY IN THE FREEZING SPRAY WARNING. GALE
WARNINGS CONTINUE. OTHER CONCERN IS PERIODS OF OCEAN EFFECT SNOW
ACROSS THE E-WATERS AND OUTER. EXPECT POOR VISIBILITY WITH ANY
SNOW.

SUNDAY INTO SUNDAY NIGHT...HIGH CONFIDENCE.

NW-WINDS TAPERING ALONG WITH SEAS. GALES CONCLUDING...SMALL CRAFT
HEADLINES WILL LIKELY HOLD FOR A MAJORITY OF THE FORECAST PERIOD.
HIGH PRESSURE BUILDING ACROSS THE WATERS.

OUTLOOK /MONDAY THROUGH THURSDAY/...MODERATE CONFIDENCE...

MONDAY...WINDS AND SEAS BELOW SMALL CRAFT THRESHOLDS.

MONDAY NIGHT AND TUESDAY...SURFACE LOW PRESSURE WILL MOVE UP THROUGH
WESTERN NEW ENGLAND. INCREASING SOUTHEAST WINDS BECOMING SOUTH. WIND
SPEEDS WILL REACH 25 TO 32 KNOTS...SOME GUSTS TO 35 KNOTS ARE
POSSIBLE. SEAS WILL BUILD 5-6 FEET BY TUESDAY MORNING AND 8 TO 12
FEET BY LATE TUESDAY. A SMALL CRAFT ADVISORY WILL BE NEEDED...WITH A
LOWER POTENTIAL FOR A GALE WARNING. WINDS WINDS WILL BECOME WEST AND
DIMINISH DURING TUESDAY NIGHT.

WEDNESDAY...WINDS BELOW 25 KNOTS WITH 5 TO 9 FOOT SEAS. A SMALL
CRAFT ADVISORY MAY STILL BE NEEDED.

THURSDAY...NORTHWEST WINDS WILL INCREASE WITH GUSTS NEAR 25 KNOTS.
SEAS WILL SLOWLY SUBSIDE WITH 5 TO 7 FOOT HEIGHTS LINGERING ON THE
OUTER WATERS.

&&

.CLIMATE...

BEFORE MIDNIGHT...BOSTON FELL TO -4 DEGREES. THIS BROKE THE OLD
RECORD LOW FOR FEBRUARY 13TH OF -3 SET IN 1967.  AS OF 1 AM...BOSTON
HAS DROPPED TO -6 WHICH BROKE THE OLD RECORD OF -3 IN 1934.  THESE
ARE THE FIRST RECORD LOWS SET IN BOSTON SINCE 1967!

AS OF 1 AM...WORCESTER DROPPED TO -12 DEGREES BREAKING THEIR OLD
RECORD OF -11 SET IN 1967.


RECORD COLD LOWS FOR FEB 13TH - 14TH...

BOSTON...... -3/2015 -  -3/1934
HARTFORD.... -7/1967 -  -9/1979
PROVIDENCE.. -5/1967 -  -7/1979
WORCESTER...-12/1967 - -11/1979
BLUE HILL...-10/1967 -  -9/1979

RECORD COLD HIGHS FOR FEB 14TH...

BOSTON.......14/1916
HARTFORD.....11/1979
PROVIDENCE...10/1979
WORCESTER....7/1979
BLUE HILL....10/1979


&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WIND CHILL WARNING UNTIL NOON EST SUNDAY FOR CTZ002>004.
MA...WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR MAZ022>024.
     WIND CHILL WARNING UNTIL NOON EST SUNDAY FOR MAZ002>021-026.
RI...WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR RIZ008.
     WIND CHILL WARNING UNTIL NOON EST SUNDAY FOR RIZ001>007.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST SUNDAY FOR
     ANZ230>237-250-251-254>256.
     GALE WARNING UNTIL 10 AM EST SUNDAY FOR ANZ231>235-237-251-255-
     256.
     GALE WARNING UNTIL 7 AM EST SUNDAY FOR ANZ230-236.
     GALE WARNING UNTIL 2 PM EST SUNDAY FOR ANZ250-254.

&&

$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...FRANK
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...FRANK/SIPPRELL
MARINE...WTB/SIPPRELL
CLIMATE...STAFF


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