Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 261834 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 134 PM EST MON JAN 26 2015 .SYNOPSIS... A NOR`EASTER DEVELOPS OFF THE DELMARVA COAST THIS AFTERNOON AND TRACKS SLOWLY NORTH TONIGHT AS IT INTENSIFIES REACHING JUST EAST OF MONTAUK POINT BY TUESDAY NIGHT. THE STORM WEAKENS AS IT MOVES EAST TO THE GULF OF MAINE ON WEDNESDAY. HIGH PRESSURE ON THURSDAY IS FOLLOWED BY A CLIPPER LOW PASSING ACROSS THURSDAY NIGHT INTO EARLY FRIDAY. COLD HIGH PRESSURE BUILDS IN FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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SURFACE LOW WAS REDEVELOPING N OR CAPE HATTERAS AT 1 PM. SNOW WAS BEGINNING TO INTENSIFY FROM NJ INTO THE CITY AND LONG ISLAND. ELSEWHERE THE SNOW WAS LGT. UP TO 4 INCHES BY DARK EXPECTED FOR THE SRN TIER OF THE CWA WITH UP TO 2 ACROSS THE NRN TIER ATTM. WINDS ARE ALREADY AROUND 30KT AT 44017...WITH MID 20S AT KFOK. THE STORM APPEARS ON TRACK. THE 12Z GFS IS AN OUTLIER FROM THE 12Z NAM AND 12Z ECMWF. HAVE UPPED SNOWFALL TOTALS ACCORDINGLY WITH MOST AREAS IN THE 20-30 RANGE FOR THIS EVENT. TEMPS ARE RUNNING WELL BLW GUIDANCE...SO MANUAL ADJUSTMENTS WERE MADE TO THE GRIDS.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
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A LIFE THREATENING...POTENTIALLY HISTORIC WINTER STORM EXPECTED FROM LATE TODAY INTO TUESDAY... STILL ANTICIPATE THE LOW TO UNDERGO RAPID INTENSIFICATION AS THE PARENT UPPER LOW CUTS OFF ALOFT NEAR THE MID ATLANTIC COAST TONIGHT. THE LOW STALLS SE OF MONTAUK LATE TONIGHT INTO TUESDAY. A PROLONGED PERIOD OF MODERATE TO HEAVY SNOW IS EXPECTED ON THE NW FLANK OF THE LOW...IN THE DEFORMATION ZONE. THE MID LEVEL LOW CENTERS AND INTENSE MID LEVEL FRONTOGENESIS WILL PROMOTE HEAVY SNOW BANDS...BUT IT IS IMPOSSIBLE TO PREDICT THEIR LOCATION THIS FAR OUT. MODELS ALSO HAVE A TENDENCY TO NOT SPREAD THE BEST LIFT FAR ENOUGH NW IN INTENSE CYCLONES. SNOWFALL RATES OF 2-4 INCHES PER HOUR EXPECTED LATE TONIGHT INTO TUE MORNING. SNOWFALL TOTALS WERE INCREASED SLIGHTLY PER THE 12Z DATA TO A GENERAL 20-30 E OF THE HUDSON. IN ADDITION...THE DEEP LOW PRESSURE COMBINED WITH STRONG HIGH PRESSURE TO THE NORTH AND WEST AND HEAVY FALLING/BLOWING SNOW WILL CREATE BLIZZARD CONDITIONS ACROSS THE ENTIRE REGION. A BLIZZARD WARNING REMAINS IN EFFECT...WITH POTENTIAL FOR SUSTAINED WINDS UP TO 35 MPH ON LONG ISLAND...AND WIND GUSTS RANGING FROM 40 MPH INLAND...TO 45-50 MPH MOST ELSEWHERE. GUSTS UP TO 60 MPH CANNOT BE RULED OUT ACROSS FAR EASTERN LONG ISLAND. WITH THE LOW NEARLY STALLING NEAR CAPE COD ON TUESDAY...LIGHT TO OCCASIONALLY MODERATE SNOW IS POSSIBLE IN MESOSCALE BANDS...ESPECIALLY LATE TUESDAY MORNING INTO EARLY AFTERNOON. TEMPS DURING THE STORM WILL GENERALLY BE IN THE 20S...EXCEPT FALLING TO 15-20 TONIGHT INLAND. WIND CHILLS WILL BE MOSTLY IN THE SINGLE DIGITS TO MID TEENS...BUT COULD GET CLOSE TO ZERO ACROSS SOUTHERN CT. TEMPERATURES ON TUESDAY WILL ONLY BE IN THE LOWER TO MIDDLE 20S.
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&& .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... THE NOR`EASTER BEGINS TO FILL AND PULL AWAY TUESDAY NIGHT. LIGHT SNOW ENDS FROM WEST TO EAST WITH AN INCH OR LESS OF ADDITIONAL ACCUMULATION. WINDS ALSO DIMINISHING AND HAVE REMOVED MENTION OF BLOWING SNOW. BECOMING SUNNY ON WEDNESDAY WITH 15-20 MPH WINDS. TEMPS FCST BELOW MOS WITH SNOW COVER. WIND CHILLS ON WEDNESDAY ARE IN THE LOWER TEENS. CONTINUE TO UNDERCUT MOS THROUGH THE PERIOD WITH THE NEW SNOW COVER. CLIPPER SYSTEM STILL ON TAP FOR THURSDAY NIGHT INTO FRIDAY MORNING. THIS LOOKS LIKE A "TYPICAL" CLIPPER WITH 1-3" IN AN ALL SNOW EVENT. HIGH PRESSURE BUILDS BACK IN ON SATURDAY WITH BELOW NORMAL TEMPERATURES CONTINUING. THE ACTIVE PATTERN REACHING THE LIMITS OF PREDICTABILITY BY SUNDAY. SUGGESTION OF A SOUTHERN STREAM SYSTEM SOMETIME LATE THIS WEEKEND INTO EARLY NEXT WEEK. WITH GEFS LOOKING VERY CHAOTIC...HARD TO SAY MUCH AS TO WHAT MIGHT HAPPEN WITH THIS NEXT SYSTEM. && .AVIATION /18Z MONDAY THROUGH SATURDAY/...
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** HIGH IMPACT SNOW AND WIND EVENT EXPECTED FROM LATE TODAY INTO TUESDAY NIGHT ** LOW PRESSURE DEVELOPING OFF THE MID ATLANTIC COAST IS EXPECTED TO TRACK SOUTH AND EAST OF THE REGION TONIGHT. MAINLY IFR CONDITIONS IN SNOW THROUGH 18Z...THEN LIFR CONDITIONS GRADUALLY DEVELOPING BY 21Z FROM S TO N. BLIZZARD CONDITIONS EXPECTED AT KJFK/KLGA/KISP/KGON BY LATE THIS EVENING. 1-3" OF SNOW EXPECTED BY 00Z...THEN 2-4 INCH AN HOUR RATES DEVELOP FROM SE TO NW STARTING AROUND MIDNIGHT. NE WINDS STRENGTHEN WITH GUSTS 25-30KT BY MID-LATE AFTERNOON. WINDS BACK TO THE NNE LATE TONIGHT...WITH GUSTS INCREASING TO 25-40KT...LOWEST FAR W TERMINALS AND STRONGEST FAR E TERMINALS. MODERATE ICING IS LIKELY BELOW FL180. MODERATE TURBULENCE BETWEEN SFC-FL390 WITH LOCAL SEVERE POSSIBLE FL200-310. REFER TO ZNY MIS AND SIGMET VICTOR FOR MORE INFORMATION. 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: CONDITIONS MAY BRIEFLY DROP TO LIFR IN SNOW BANDS THIS AFTERNOON. 1-3 INCHES OF SNOW EXPECTED THROUGH 00Z. AFTER 00Z...HEAVY SNOW WITH RATES OF 2-4 INCHES PER HOUR LIKELY. KLGA FCSTER COMMENTS: CONDITIONS MAY BRIEFLY DROP TO LIFR IN SNOW BANDS THIS AFTERNOON. 1-3 INCHES OF SNOW EXPECTED THROUGH 00Z. AFTER 00Z...HEAVY SNOW WITH RATES OF 2-4 INCHES PER HOUR LIKELY. KEWR FCSTER COMMENTS: CONDITIONS MAY BRIEFLY DROP TO LIFR IN SNOW BANDS THIS AFTERNOON. 1-3 INCHES OF SNOW EXPECTED THROUGH 00Z. AFTER 00Z...HEAVY SNOW WITH RATES OF 2-4 INCHES PER HOUR LIKELY. KTEB FCSTER COMMENTS: CONDITIONS MAY BRIEFLY DROP TO LIFR IN SNOW BANDS THIS AFTERNOON. 1-3 INCHES OF SNOW EXPECTED THROUGH 00Z. AFTER 00Z...HEAVY SNOW WITH RATES OF 2-4 INCHES PER HOUR LIKELY. KHPN FCSTER COMMENTS: TIMING OF GUSTS MAY BE OFF BY AN HOUR OR TWO. CONDITIONS MAY BRIEFLY DROP TO LIFR IN SNOW BANDS THIS AFTERNOON. 1-3 INCHES OF SNOW EXPECTED THROUGH 00Z. AFTER 00Z...HEAVY SNOW WITH RATES OF 2-4 INCHES PER HOUR LIKELY. KISP FCSTER COMMENTS: CONDITIONS MAY BRIEFLY DROP TO LIFR IN SNOW BANDS THIS AFTERNOON. 2-3 INCHES OF SNOW EXPECTED THROUGH 00Z. AFTER 00Z...HEAVY SNOW WITH RATES OF 2-4 INCHES PER HOUR LIKELY. .OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... .TUESDAY AND TUESDAY EVENING...LIFR OR LOWER CONDITIONS WITH BLIZZARD CONDITIONS. NE-N WINDS G35-50 KT. .LATE TUESDAY NIGHT...GRADUALLY BECOMING VFR. NW WINDS G25-35KT. .WEDNESDAY...VFR. NW WINDS G25-30KT POSSIBLE. .WEDNESDAY NIGHT-THURSDAY...VFR. .THU NGT...MVFR OR LOWER CONDITIONS IN LGT SN. .FRI...CHC MVFR IN LGT SN IN THE AM. VFR WITH NW WNDS G25-30KT IN THE AFTN.
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&& .MARINE... NO CHANGES TO THE MARINE HEADLINES WITH THIS FORECAST PACKAGE. HAVE MADE MINOR ADJUSTMENTS TO WINDS AND SEAS. WINDS AND SEAS INCREASE ACROSS ALL WATERS ON TODAY AHEAD OF APPROACHING LOW PRESSURE. GALE FORCE EASTERLY WIND GUSTS EXPECTED ON THE OCEAN WATERS DURING THE DAY...RAMPING UP TONIGHT AS WINDS BACK NORTHERLY TO MINIMAL HURRICANE FORCE ON THE EASTERN OCEAN WATERS LATE MON NIGHT INTO TUE MORNING...AND STORM FORCE ELSEWHERE AND ALSO ON EASTERN LONG ISLAND SOUND AND THE BAYS OF LONG ISLAND. THE EASTERN OCEAN WATERS MAY ALSO SEE SUSTAINED STORM FORCE WINDS DURING THIS TIME. WINDS AND SEAS START SUBSIDING TUESDAY NIGHT. EXPECT TO BE BELOW GALES BEFORE MORNING AND BELOW SCA LEVELS IN THE EARLY EVENING TUESDAY. SUB SCA ON THURSDAY INTO EARLY FRIDAY MORNING. THEN SCA WINDS RETURN AS A CLIPPER SYSTEM DEEPENS WELL OFF SHORE. && .HYDROLOGY... A MAJOR SNOWSTORM EXPECTED FROM MON INTO TUE NIGHT...WITH LIQUID EQUIVALENT AMOUNTS OF 1.5 TO 2.25 INCHES. LIQUID EQUIVALENT PRECIPITATION AMOUNTS FOR THE SYSTEM MOVING THROUGH THURSDAY NIGHT INTO FRIDAY IS CURRENTLY FORECAST TO BE LIGHT...MOSTLY IN THE FORM OF SNOW. ICE ON THE WALLKILL AND YANTIC RIVERS IS CAUSING MINOR FLUCTUATIONS IN RIVER LEVELS AT THIS TIME. && .TIDES/COASTAL FLOODING...
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A COASTAL FLOOD WARNING IS IN EFFECT FOR NORTHERN LONG ISLAND AND WESTERN NY COAST WITHIN THE WESTERN LONG ISLAND SOUND. FOR THE TWIN FORKS OF LONG ISLAND...COASTAL FLOOD WARNING IS IN EFFECT. A COASTAL FLOOD WARNING FOR THE SOUTH SHORE BAYS OF LONG ISLAND. COASTAL FLOOD ADVISORY IS IN EFFECT FOR NY HARBOR...AND THE CT COASTS. THE NOR`EASTER IS EXPECTED TO PRODUCE MODERATE COASTAL IMPACTS FOR PARTS OF THE REGION OVERNIGHT INTO EARLY TUESDAY MORNING HIGH TIDE. THERE`S THE POTENTIAL FOR FLOODING OF VULNERABLE SHORE ROADS AND/OR ADJACENT PROPERTIES DUE TO HEIGHT OF STORM TIDE AND/OR WAVE ACTION. THE UNCERTAINTY WITH THE SURGE IS IN HOW QUICKLY WINDS TURN FROM THE NE TO N. AN EARLIER VEERING OF WINDS TO THE N AHEAD OF HIGH TIDE TYPICALLY REDUCES SURGE IN OUR REGION. THE MOST LIKELY SURGE FOR COASTAL AREAS IS: - WESTERN LONG ISLAND SOUND (NY ZONES)...3 TO 4 FT OF SURGE WITH POTENTIAL FOR UP TO 4 1/2 FT. - LONG ISLAND SOUND CT COAST...2 TO 2 1/2 FT OF SURGE WITH POTENTIAL FOR UP TO 3 FT. - THE TWIN FORKS OF LONG ISLAND WHERE 3 TO 4 FT OF SURGE IS POSSIBLE AS WATER GETS PILED UP AROUND THE FORKS. - NEW YORK HARBOR AND THE SOUTH SHORE BAYS...2 TO 3 FT OF SURGE. BEACH EROSION AND WASHOVERS ARE EXPECTED ALONG OCEAN FACING BARRIER BEACHES OF LONG ISLAND DUE TO 7 TO 12 FT WAVES AND THE HIGH STORM TIDE. A FEW EXPOSED WATERFRONT STRUCTURES MAY BE DAMAGED. HIGH WAVES AND HIGH STORM TIDE WILL ALSO CAUSE BEACH EROSION ALONG NORTH FACING SHORELINES OF LONG ISLAND SOUND AND ALONG THE TWIN FORKS. A FEW EXPOSED WATERFRONT STRUCTURES MAY BE DAMAGED.
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&& .CLIMATE... THIS BLIZZARD HAS THE POTENTIAL TO PRODUCE THE LARGEST SINGLE- STORM SNOWFALL IN NYC HISTORY. HERE ARE THE CURRENT TOP TEN SNOWFALLS FOR THE CITY... AMOUNT DATES 26.9 FEB 11-12 2006 25.8 DEC 26-27 1947 21.0 MAR 12-13 1888 20.9 FEB 25-26 2010 20.2 JAN 7-8 1996 20.0 DEC 26-27 2010 19.8 FEB 16-17 2003 19.0 JAN 26-27 2011 18.1 JAN 22-24 1935 AND MARCH 7-8 1941 18.0 DEC 26 1872 && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...BLIZZARD WARNING UNTIL MIDNIGHT EST TUESDAY NIGHT FOR CTZ005>012. COASTAL FLOOD ADVISORY FROM 1 AM TO 7 AM EST TUESDAY FOR CTZ009>012. NY...COASTAL FLOOD WARNING FROM 1 AM TO 7 AM EST TUESDAY FOR NYZ079- 081. BLIZZARD WARNING UNTIL MIDNIGHT EST TUESDAY NIGHT FOR NYZ067>075-078>081-176>179. COASTAL FLOOD WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST TUESDAY FOR NYZ075-080-178-179. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 4 AM EST TUESDAY FOR NYZ072-074. COASTAL FLOOD WARNING FROM 3 AM TO 7 AM EST TUESDAY FOR NYZ071- 073-078-176-177. NJ...BLIZZARD WARNING UNTIL MIDNIGHT EST TUESDAY NIGHT FOR NJZ002- 004-006-103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ345. STORM WARNING FROM 6 PM THIS EVENING TO 6 PM EST TUESDAY FOR ANZ330-340-345-353-355. GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EST TUESDAY FOR ANZ335-338. GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ350-353-355. HURRICANE FORCE WIND WARNING FROM 6 PM THIS EVENING TO NOON EST TUESDAY FOR ANZ350.
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&& $$ SYNOPSIS...DS/JST NEAR TERM...JMC SHORT TERM...JMC/DS LONG TERM...JST AVIATION...MMD MARINE...DS/JST HYDROLOGY...DS/JST TIDES/COASTAL FLOODING...PW CLIMATE...

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