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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