Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 121229 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 729 AM EST FRI FEB 12 2016 .SYNOPSIS... HIGH PRESSURE SLIDES OFFSHORE TODAY. A LOW PRESSURE SYSTEM WILL TRACK SOUTHEAST OF THE REGION TONIGHT. IN ITS WAKE AN ARCTIC COLD FRONT WILL APPROACH TONIGHT...AND PASS THROUGH TOWARDS DAYBREAK SATURDAY. ARCTIC HIGH PRESSURE THEN BUILDS IN FROM THE WEST...SETTLING RIGHT ACROSS THE REGION SUNDAY NIGHT. HIGH PRESSURE OVER THE REGION SLIDES EAST ON MONDAY AS A DEVELOPING LOW PRESSURE SYSTEM WELL WEST OF THE REGION APPROACHING. THIS NEXT LOW MOVES ACROSS THE AREA TUESDAY AND TUESDAY NIGHT. ANOTHER COLD FRONT MOVES ACROSS WEDNESDAY WITH HIGH PRESSURE STARTING TO BUILD THEREAFTER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... POLAR UPPER LOW SLOWLY DROPS SE FROM THE CANADA...WITH A SHORTWAVE ROUNDING ITS BASE TOWARDS THE REGION IN THE EVENING. AT THE SURFACE...HIGH PRESSURE SLOWLY MOVES OFFSHORE OF THE MID ATLANTIC. A TRANQUIL BUT COLD DAY...WITH HIGHS IN THE LOWER TO MID 20S. INCREASING HIGH CLOUDS THIS AFTERNOON AHEAD OF APPROACHING SHORTWAVE. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... POLAR LOW CONTINUES TO DESCEND INTO THE NORTHEAST THROUGH SATURDAY NIGHT WITH A SHORT LIVED BUT DANGEROUS TO POTENTIALLY LIFE THREATENING ARCTIC INTRUSION SAT INTO SUN. LEADING UP TO THIS...SHORTWAVE ENERGY ROUNDING THE BASE OF THE POLAR LOW WILL APPROACH THE REGION THIS EVENING AND CROSS TONIGHT INTO EARLY SATURDAY MORNING. THIS WILL COINCIDE WITH THE APPROACH OF THE ARCTIC FRONT LATE TONIGHT AND CROSSING EARLY SAT MORNING. MEANWHILE A PAC SHORTWAVE DIVES TO THE SOUTHERN MID ATLANTIC COAST THIS EVENING...SPAWNING LOW PRESSURE THAT WILL TRACK WELL SE OF THE REGION TONIGHT. SCATTERED SNOW SHOWERS/FLURRIES EXPECTED AHEAD OF APPROACHING SHORTWAVE ENERGY THIS EVENING...WITH POTENTIAL FOR EVEN A PERIOD OF LIGHT SNOW ACROSS EASTERN LI/SE CT WITH INITIAL ONSHORE FLOW AND THEN FRINGE IMPACTS FROM OFFSHORE LOW. SCATTERED SNOW SHOWERS EXPECTED ONCE AGAIN AHEAD OF/ALONG ARCTIC FRONTAL PASSAGE LATE TONIGHT INTO SAT MORNING. OVERALL POTENTIAL FOR A DUSTING IN MOST SPOTS...WITH UP TO AN INCH OR TWO ACROSS FAR EASTERN LI AND POSSIBLE SE CT. ARCTIC INTRUSION BEGINS EARLY SAT MORNING IN WAKE OF ARCTIC FRONT WITH NW OF 20 TO 30 MPH WITH GUSTS TO 45 MPH. POTENTIAL FOR A FEW GUSTS TO 50 MPH SAT AFT/EVE BASED ON MORE FAVORABLE MOMENTUM TRANSFER. THERE IS POTENTIAL FOR WIND ADVISORY CONDITIONS TO BE MET FOR BOTH MARGINAL SUSTAINED WINDS AND GUSTS ALONG THE NJ/NYC METRO...COAST AND HIGHER ELEVATIONS. WINDS WILL BE SLOW TO SUBSIDE SAT NIGHT WITH STRONG GRADIENT BETWEEN ARCTIC HIGH AND CANADIAN MARITIMES LOW. DANGEROUSLY COLD AIR MASS ADVECTS INTO THE REGION SAT MORNING IN THE WAKE OF ARCTIC FRONT. HIGHS WILL LIKELY BE REACHED AHEAD OF THE FRONT IN THE MORNING IN THE TEENS. THEN TEMPS SHOULD STEADILY FALLING INTO THE SINGLE DIGITS AND LOWER TEENS THROUGH THE AFTERNOON...WITH WIND CHILLS FALLING TO 10 TO 20 DEGREES BELOW ZERO. HEART OF COLD ENTERS SAT NIGHT INTO SUNDAY MORNING...WITH TEMPS LIKELY TO FALL TO AROUND ZERO FOR NYC/NJ METRO AND COAST...AND 5 TO 10 BELOW ZERO ACROSS INTERIOR PORTIONS OF THE TRI-STATE. COMBINED WITH SLOW TO DIMINISH WINDS...DANGEROUS TO POTENTIALLY LIFE THREATENING WIND CHILLS OF 20 TO 30 BELOW EXPECTED. HIGH ENOUGH CONFIDENCE FOR A RARE WINDCHILL WARNING ACROSS NORTHERN ZONES...AND WINDCHILL ADVISORY FOR CITY/COAST. WINDCHILL WATCH REMAINS FOR COASTAL CT...WITH TEMPS ON BORDERLINE FOR ADVISORY VS WARNING. WITH UPPER LOW APPROACHING IN THE AFT/EVE AND RESIDUAL LAKE STREAMER MOISTURE...SCT INSTABILITY CU AND SCT FLURRIES POSSIBLE FROM LATE MORNING INTO EVENING. ACROSS TWIN FORKS OF LI...MAYBE ENOUGH OF A FETCH OVER LONG ISLAND SOUND AND INSTABILITY FOR SCATTERED SNOW SHOWERS/FLURRIES SAT AFT INTO SAT EVE. CLEARING SKIES LATE SAT NIGHT ON BACKSIDE OF UPPER LOW. && .LONG TERM /SUNDAY THROUGH THURSDAY/... ONE OF THE COLDEST DAYS OF THE SEASON WILL OCCUR ON SUNDAY AS THE POLAR VORTEX REMAINS OVER THE REGION. EARLY MORNING TEMPERATURES WILL BE IN THE SINGLE DIGITS ACROSS NORTHEAST NJ...NYC...AND LONG ISLAND. ACROSS THE INTERIOR...TEMPERATURES WILL START THE MORNING IN THE 0 TO -10 DEGREE RANGE. WITH MOSTLY SUNNY SKIES ON SUNDAY...EXPECT TEMPERATURES TO RISE INTO THE TEENS FOR DAYTIME HIGHS. WITH WINDY CONDITIONS EARLY SUNDAY MORNING...EXPECT WIND CHILLS IN THE -15 TO -25 RANGE. THESE WIND CHILLS LIKELY DO NOT RISE ABOVE 0 UNTIL THE EARLY TO MID AFTERNOON. THE UPPER LEVEL TROUGH...AND COLD SURFACE HIGH PRESSURE OVER THE REGION WILL SLIDE EAST LATE SUNDAY INTO SUNDAY NIGHT...ALLOWING TEMPERATURES TO MODERATE THROUGH THE FIRST PART OF THE NEW WEEK. EXPECT TEMPERATURES SUNDAY NIGHT TO REMAIN SOMEWHAT STEADY WITH TEMPERATURES IN THE TEENS. BY MONDAY...TEMPERATURES SLOWLY RISE THROUGH THE 20S AND INTO THE LOWER 30S. A TROUGH MOVING OUT OF THE MIDDLE OF THE COUNTRY WILL APPROACH ON MONDAY. EXPECT CLOUDS TO THICKEN AND LOWER THROUGH THE DAY...WITH POPS GRADUALLY INCREASING THROUGH THE AFTERNOON. WITH TEMPERATURES STILL BELOW FREEZING...EXPECT PRECIPITATION TO START AS SNOW. SOUTHERLY FLOW OUT AHEAD OF THE LOW PRESSURE SYSTEM WILL RESULT IN WARM AIR ADVECTION CONTINUING MONDAY NIGHT AND TUESDAY. AS TEMPERATURES RISE THROUGH THIS PERIOD...EXPECT PRECIPITATION TO GRADUALLY CHANGE FROM SNOW TO RAIN. THE TRANSITION FROM SNOW TO RAIN WILL OCCUR FROM THE SOUTHEASTERN PORTION OF THE CWA...TO THE NORTHWESTERN. BY MID MORNING ON TUESDAY...IT IS EXPECTED THAT TEMPERATURES WARM ENOUGH EVERYWHERE FOR JUST PLAIN RAIN ACROSS THE ENTIRE CWA. HIGHS ON TUESDAY CLIMB INTO THE UPPER 40S AND LOWER 50S. 00Z FORECAST GUIDANCE IN DECENT AGREEMENT WITH THE LOW PRESSURE SYSTEM...AND ASSOCIATED COLD FRONT MOVING ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY MORNING...WITH MOST OF THE PRECIPITATION ENDING EARLY WEDNESDAY. THE MODELS DO HOWEVER DIFFER ON THE EXACT PLACEMENT OF THE LOW...AND THE TRACK IT TAKES ACROSS THE REGION. FOR NOW...EXPECTING RAINFALL AMOUNTS BETWEEN 1 AND 2 INCHES...WITH AT LEAST SOME OF THAT QPF...STARTING AS A PERIOD OF SNOW. SEE ADDITIONAL DETAILS ON QPF IN THE HYDROLOGY SECTION. HIGH PRESSURE BUILDS INTO THE REGION BEHIND THE COLD FRONT WEDNESDAY NIGHT THROUGH FRIDAY...WITH MOSTLY DRY CONDITIONS. HIGHS ON THURSDAY WILL BE IN THE LOWER 40S...WITH 30S EXPECTED ON FRIDAY. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... WEAK HIGH PRESSURE WILL MOVE ACROSS TODAY. LOW PRESSURE WILL PASS WELL TO THE SOUTH TONIGHT. AN ARCTIC COLD FRONT WILL MOVE THROUGH JUST BEFORE DAYBREAK ON SAT. VFR. MEDIUM TO HIGH CONFIDENCE IN WIND FORECAST. WINDS GENERALLY WNW 5-10 KT WILL BACK SW THIS AFTERNOON. OCNL G15-20KT POSSIBLE AT THE NYC METRO TERMINALS THIS AFTERNOON...ESPECIALLY KEWR. WINDS SHIFT NW AND BECOME GUSTY AFTER ARCTIC FROPA LATE TONIGHT. SCT SNOW SHOWERS WITH BRIEF LOCAL IFR VSBY ARE POSSIBLE TONIGHT AS THE ARCTIC FRONT APPROACHES AND AS THE OFFSHORE LOW MAKES ITS CLOSEST APPROACH...WHICH COULD LEAVE A COATING OF ACCUMULATION ON RUNWAYS. PROBABILITIES ARE STILL LOW AND AS SUCH ARE HANDLED VIA PROB30 THIS FAR OUT IN TIME. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: OCNL G15-20KT POSSIBLE THIS AFTERNOON. KLGA FCSTER COMMENTS: OCNL G15-20KT POSSIBLE THIS AFTERNOON. KEWR FCSTER COMMENTS: HIGH CONFIDENCE IN WINDS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: OCNL G15-20KT POSSIBLE THIS AFTERNOON. KHPN FCSTER COMMENTS: OCNL G15-20KT POSSIBLE THIS AFTERNOON. KISP FCSTER COMMENTS: HIGH CONFIDENCE IN WINDS. .OUTLOOK FOR 12Z SAT THROUGH TUE... .SAT...SCT EARLY MORNING SNOW SHOWERS WITH BRIEF MVFR VSBY STILL POSSIBLE MAINLY KISP/KGON...OTHERWISE VFR. NW WINDS 20-25 KT WITH GUSTS 35-40 KT...HIGHEST AT THE NYC METROS AND KISP. .SUNDAY...VFR. NW WINDS 15-20G25KT IN THE MORNING. .MON...VFR. .MON NIGHT...IFR CONDS LIKELY. SNOW CHANGING TO RAIN BY LATE EVENING NYC METROS/KISP...AND AROUND/SHORTLY AFTER MIDNIGHT KHPN/KBDR/KGON...AND COLD GROUND COULD MAKE FOR A PD OF FREEZING RAIN ON RUNWAYS DESPITE AIR TEMPS RISING ABOVE FREEZING. SNOW MIXING WITH OR CHANGING TO FREEZING RAIN AROUND MIDNIGHT AT KSWF. .TUE...RAIN LIKELY WITH IFR CONDS. SE-S WINDS G30-35KT AND LLWS. && .MARINE... WINDS WILL CONTINUE TO SUBSIDE AS HIGH PRESSURE BUILDS IN THIS MORNING. SEAS WILL TAKE UNTIL MID MORNING HOURS TO SUBSIDE ACROSS EASTERN OCEAN. THEREAFTER...SUB SCA CONDITIONS EXPECTED TODAY AS SW WINDS DEVELOP AHEAD OF AN APPROACHING ARCTIC COLD FRONT. A FEW GUSTS TO AROUND 20 KT LIKELY ON THE OCEAN THIS AFTERNOON/EVENING. THE RELATIVELY TRANQUIL CONDITIONS WILL BE SHORT LIVED...WITH ARCTIC FRONTAL PASSAGE FORECAST AROUND DAYBREAK SAT WITH NW GALES DEVELOPING SOON THEREAFTER. GALES EXPECTED ON THE OCEAN...AND LIKELY FOR REST OF THE WATERS SATURDAY AND SATURDAY NIGHT. GALES PREVAIL INTO EARLY SUNDAY BEFORE DECREASING TO 20-30 KT DURING THE DAY. THESE WINDS SHOULD BUILD OCEAN SEAS TO 7 TO 11 FT...AND 3 TO 6 FT ON CENTRAL AND EASTERN LI SOUND. WITH ARCTIC AIR MASS OVERSPREADING THE WATERS...MODERATE TO HEAVY FREEZING SPRAY EXPECTED SATURDAY INTO SATURDAY NIGHT FOR MOST OF THE WATERS. SOME LEFT OVER GALES MAY PREVAIL INTO EARLY SUNDAY BEFORE DECREASING TO 20-30 KT DURING THE DAY. FREEZING SPRAY IS ALSO POSSIBLE ON SUNDAY AT LEAST THE OCEAN WATERS. WEAK PRESSURE GRADIENT SUNDAY NIGHT THROUGH MONDAY NIGHT WILL LEAD TO BELOW SCA CONDITIONS. CONDITIONS BUILD BACK TO SCA LEVELS AHEAD OF THE NEXT LOW PRESSURE SYSTEM TUESDAY AND WEDNESDAY. && .HYDROLOGY... LIQUID EQUIVALENT OF LESS THAN A TENTH OF AN INCH IS FORECAST TONIGHT INTO SATURDAY MORNING IN THE FORM OF SNOW SHOWERS. LOW PRESSURE MOVING UP THE COAST HAS POTENTIAL TO PRODUCE LIQUID EQUIVALENT QPF AT LEAST 1 TO 2 INCHES. PART OF THIS WILL FALL AS SNOW INITIALLY...BUT THEN RUNOFF VIA MELTING SNOW AND HEAVY RAIN TUESDAY INTO TUESDAY NIGHT COULD CAUSE AT LEAST URBAN AND SMALL STREAM FLOODING PROBLEMS. IT IS TOO EARLY TO SAY IF MAIN STEM RIVERS WOULD BE AFFECTED. && .CLIMATE... WITH THE EXTREMELY COLD AIR MASS FORECAST SATURDAY INTO SUNDAY...RECORD MINIMUMS AND RECORD LOW MAXIMUMS MAY BE REACHED. HERE ARE THE RECORDS AND FORECASTS... STATION......RECORD/FORECAST MINIMUM FOR 2/14 NYC...........2 (1916) / 1 LGA...........1 (1979) / 2 JFK...........4 (1979) / 1 ISP...........7 (2015) / 1 EWR...........0 (1979) / 0 BDR...........3 (2015*) / -1 STATION......RECORD LOW MAXIMUM/FORECAST HIGH FOR 2/14 NYC.............17 (1979) / 17 LGA.............15 (1979) / 17 JFK.............17 (1979) / 18 ISP.............26 (1987) / 15 EWR.............15 (1979) / 17 BDR.............18 (1979) / 16 *IN 1979 AS WELL && .OKX WATCHES/WARNINGS/ADVISORIES... CT...WIND CHILL WARNING FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR CTZ005>008. WIND CHILL WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR CTZ009>012. NY...WIND CHILL ADVISORY FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NYZ072>075-078>081-176>179. WIND CHILL WARNING FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NYZ067>070. WIND CHILL WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR NYZ071. NJ...WIND CHILL ADVISORY FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NJZ004-006-104>108. WIND CHILL WARNING FROM 4 PM SATURDAY TO NOON EST SUNDAY FOR NJZ002. WIND CHILL WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR NJZ103. MARINE...GALE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR ANZ330- 335-338-340-345. HEAVY FREEZING SPRAY WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR ANZ330-335-338-340-350-353-355. FREEZING SPRAY ADVISORY FROM 4 AM TO 6 PM EST SATURDAY FOR ANZ330-335-338-340-350-353-355. GALE WARNING FROM 4 AM SATURDAY TO 7 AM EST SUNDAY FOR ANZ350- 353-355. SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR ANZ350. && $$ SYNOPSIS...BC/NV NEAR TERM...NV SHORT TERM...NV LONG TERM...BC AVIATION...GOODMAN MARINE...BC/NV HYDROLOGY...BC/NV CLIMATE...

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