Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 260535 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1235 AM EST MON JAN 26 2015 .SYNOPSIS... LOW PRESSURE TRACKS INTO THE CENTRAL APPALACHIANS OVERNIGHT...THEN TRANSITIONS TO A COASTAL LOW OFF THE MID ATLANTIC COAST BY MONDAY EVENING. THIS COASTAL LOW WILL RAPIDLY DEEPEN...BECOMING A DANGEROUS WINTER STORM AS IT TRACKS SLOWLY NORTH FROM THE MID ATLANTIC COAST AND STALLS SOUTHEAST OF MONTAUK POINT LATE MONDAY NIGHT INTO TUESDAY...THEN WEAKENS AND MOVES SLOWLY EAST TUESDAY NIGHT. A WEAKER SYSTEM WILL PASS THROUGH THURSDAY NIGHT INTO FRIDAY. HIGH PRESSURE WILL FOLLOW FOR SATURDAY...THEN A COLD FRONT WILL MOVE THROUGH ON SUNDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... MADE MINOR CHANGES TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. UPPER TROUGH SLIDES EAST OF NEW ENGLAND OVERNIGHT WITH POLAR HIGH SLIDING INTO NEW ENGLAND IN WAKE OF A WEAKENING ARCTIC FRONTAL PASSAGE. LOWS GENERALLY DROPPING INTO THE TEENS INTERIOR AND 20S COAST. THESE LOWS MAY BE TOO COLD DEPENDING ON HOW QUICKLY HIGH CLOUDS STREAM IN. TEMPS SHOULD STABILIZE OVERNIGHT WITH INCREASING CLOUDS AND INCREASING NE FLOW. THEREAFTER...ALL EYES ON STRONG SHORTWAVE ENERGY DIVING THROUGH THE MID MISSISSIPPI RIVER VALLEY THIS AFTERNOON AND INTO THE SE US TONIGHT. THIS WILL HAVE LOW PRESSURE TRACKING ALONG THE SOUTHEASTERN US TONIGHT...AND REACHING THE COAST BY MONDAY MORNING...WITH POTENTIAL FOR LIGHT SNOW TO DEVELOP LATE SUN NIGHT INTO MONDAY MORNING ACROSS AT LEAST FAR SW PORTIONS OF THE TRI- STATE. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... A LIFE THREATENING...HISTORIC WINTER STORM EXPECTED FROM LATE MONDAY INTO TUESDAY... NWP GUIDANCE CONTINUES TO BRING THE INGREDIENTS TOGETHER FOR A DANGEROUS...HISTORIC BLIZZARD AS A SECONDARY LOW FORMS OFF THE MID ATLANTIC COAST ON MON. THIS LOW WILL UNDERGO RAPID INTENSIFICATION AS THE PARENT UPPER LOW CUTS OFF ALOFT NEAR THE MID ATLANTIC MON NIGHT...STALLING SE OF MONTAUK LATE MON NIGHT INTO TUE. MSLP DROPS NEARLY 30 MB IN 24 HR FROM MON AM TO TUE AM... BEFORE GRADUALLY FILLING. THIS WILL PLACE THE FORECAST AREA ON THE NW FLANK OF THE LOW. AFTER LIGHT WARM ADVECTION SNOWFALL OF 1-3 INCHES DURING THE DAYTIME HOURS MON IN ADVANCE OF THE SECONDARY LOW...A PROLONGED PERIOD OF MDT-HEAVY SNOW EXPECTED IN THE DEFORMATION ZONE. FOLLOWED 12Z NAM/ECMWF CLOSELY...WITH BOTH MODELS SUPPORTING QPF UPWARDS OF 2 INCHES LIQUID EQUIVALENT...WITH THE HIGHEST AMOUNTS NOW EXPECTED NOT ONLY ACROSS EASTERN LONG ISLAND/CT BUT ALSO FARTHER WEST INTO SW CT AND THE NYC METRO AREA/WESTERN LONG ISLAND...AS MODELS OFTEN DO NOT PLACE THE AREA OF MOST INTENSE MID LEVEL FRONTOGENESIS FAR ENOUGH WEST. SNOWFALL RATES OF 2-4 INCHES PER HOUR EXPECTED LATE MON NIGHT INTO TUE MORNING. MUCH OF THE AREA SHOULD SEE AMOUNTS OF 20-30 INCHES...LOCALLY HIGHER WHERE BEST MESOSCALE SNOW BANDING SETS UP. 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 IS NOW IN EFFECT...WITH POTENTIAL FOR SUSTAINED WINDS UP TO 40 MPH ON LONG ISLAND...AND WIND GUSTS RANGING FROM 40 MPH INLAND...TO 50-55 MPH MOST ELSEWHERE...TO 65 MPH ACROSS EASTERN LONG ISLAND...WHERE A BRIEF HURRICANE FORCE GUST CANNOT BE RULED OUT. TEMPS DURING THE STORM WILL GENERALLY BE IN THE 20S...EXCEPT FALLING TO 15-20 MON NIGHT INLAND. WIND CHILLS WILL BE MOSTLY IN THE SINGLE DIGITS TO MID TEENS...BUT AS LOW AS ZERO TO 5 BELOW ACROSS SOUTHERN CT. THANKS TO ALL NEIGHBORING WFOS...ERH AND WPC FOR COLLABORATION THIS AFTERNOON. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... A LINGERING SNOW SHOWER COULD OCCUR OVER FAR EASTERN AREAS WEDNESDAY MORNING...OTHERWISE DRY WEATHER...CLEARING AND COLD WITH DIMINISHING WINDS. WENT BELOW GUIDANCE FOR HIGHS TEMPS AS WELL AS OVERNIGHT LOWS...CONSIDERING A DEEP SNOW PACK IN PLACE. A HIGH PRESSURE RIDGE IS PROGGED TO BE RIGHT OVER US THURSDAY MORNING. THE HIGH SHIFTS OFFSHORE...THEN LOW PRESSURE APPROACHING FROM THE WEST COULD BRING LIGHT SNOW BY LATE IN THE DAY TO THE FAR NW ZONES. THE CENTER OF THIS LOW IS FORECAST TO PASS NEAR OR THROUGH THE CWA AT SOME POINT THURSDAY NIGHT INTO FRIDAY. WILL CONTINUE TO CAP POPS AT CHANCE FOR THE ENTIRE AREA DURING THIS PERIOD...BUT MAY NEED TO EVENTUALLY BUMP POPS UP. PRECIPITATION TYPE PROBABLY SNOW FOR MOST OF THE AREA...BUT MIXED PRECIPITATION WOULD BE POSSIBLE FOR SOME COASTAL AREAS. HIGH PRESSURE BUILDS BACK IN ON SATURDAY WITH BELOW NORMAL TEMPERATURES. A COLD FRONT OR TROUGH THEN MOVES THROUGH DURING SUNDAY. MOISTURE LOOKS LIMITED...BUT WILL GO WITH SLIGHT CHANCE POPS IN THE GRIDS FOR SNOW SHOWERS. TEMPS REMAINING BELOW NORMAL. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... ** HIGH IMPACT SNOW AND WIND EVENT EXPECTED FROM LATE TODAY INTO TUESDAY NIGHT ** LOW PRESSURE DEVELOPS EAST OF THE MID ATLANTIC COAST THIS MORNING AND...THEN TRACKS TO A POSITION AROUND 175 MILES SOUTHEAST OF MONTAUK POINT BY AROUND 6Z TUESDAY. VFR...LOWERING TO MVFR BY AROUND 12-14Z FROM W TO E. IFR IN SNOW BY 15-18Z AND LIFR BY 18-21Z FROM W TO E. BLIZZARD CONDITIONS EXPECTED AT KJFK/KLGA/KISP/KGON BY LATE THIS EVENING. 1-4" OF SNOW EXPECTED BY 00Z...THEN 2-4 INCH AN HOUR RATES DEVELOP FROM SE TO NW STARTING AROUND MIDNIGHT. N WINDS VEER TO THE NE EARLY THIS MORNING. WINDS BECOME GUSTY BY LATE MORNING WITH GUSTS UP TO 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. .OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY... .LATE MONDAY NIGHT-TUESDAY EVENING...LIFR OR LOWER CONDITIONS WITH BLIZZARD CONDITIONS. NE-N WINDS G40-55 KT. .LATE TUESDAY NIGHT...BECOMING VFR. NW WINDS G25-35KT. .WEDNESDAY...VFR. NW WINDS G25-30KT POSSIBLE. .WEDNESDAY NIGHT-THURSDAY...VFR. .THURSDAY NIGHT-FRIDAY...MVFR OR LOWER CONDITIONS IN SNOW. SW WINDS G25-40KT POSSIBLE. && .MARINE... MAIN CHANGE THIS PACKAGE WAS TO ISSUE STORM WARNING FOR THE SOUTH SHORE BAYS FOR MONDAY NIGHT AND TUESDAY. WITH STORM FORCE GUSTS FORECAST FOR THE COASTAL OCEAN WATERS AND FOR AT LEAST A PORTION OF ADJACENT SUFFOLK COUNTY...IT MAKES SENSE THAT SIMILAR GUSTS WILL OCCUR IN THE BODY OF WATER IN BETWEEN THE TWO. OTHERWISE...ONLY MINOR ADJUSTMENTS MADE WITH THIS UPDATE...WITH THE FORECAST AS A WHOLE APPEARING ON TRACK OUTSIDE OF THE ADJUSTMENT NOTED ABOVE. WINDS AND SEAS INCREASE ACROSS ALL WATERS ON MON AHEAD OF APPROACHING LOW PRESSURE. GALE FORCE EASTERLY WIND GUSTS EXPECTED ON THE OCEAN WATERS DURING THE DAY ON MON...RAMPING UP MON NIGHT 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. WIND GUSTS SHOULD SUBSIDE BELOW GALE FORCE ON THE OCEAN WATERS DURING WED...WITH ALL WATERS BELOW ADVISORY CRITERIA BY LATE WED NIGHT. RELATIVELY TRANQUIL CONDITIONS WILL FOLLOW FOR THU INTO THU NIGHT AS A HIGH PRESSURE RIDGE SHIFTS THROUGH. SCA CONDITIONS ARE POSSIBLE AGAIN ON FRI...WITH A LOW PRESSURE SYSTEM AFFECTING THE REGION. && .HYDROLOGY... A MAJOR SNOWSTORM EXPECTED FROM MON INTO TUE NIGHT...WITH LIQUID EQUIVALENT AMOUNTS OF 1.5 TO 3 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... AN INTENSE COASTAL STORM WILL LIKELY BRING MODERATE COASTAL IMPACTS TO PARTS OF THE COASTAL REGION WITH THE LATE MONDAY NIGHT INTO EARLY TUESDAY MORNING HIGH TIDE. THIS WILL BRING POTENTIAL FOR FLOODING OF VULNERABLE SHORE ROADS AND/OR ADJACENT PROPERTIES DUE TO HEIGHT OF STORM TIDE AND/OR WAVE ACTION. SEVERAL SHORE ROAD CLOSURES MAY BE NEEDED. 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 ALONG WESTERN LONG ISLAND SOUND IS 3 TO 4 FT OF SURGE ABOVE ASTRONOMICAL TIDE. A LOW PROBABILITY OF 4 TO 4 1/2 FT SURGE ABOVE ASTRONOMICAL TIDE EXISTS. THE MOST LIKELY SURGE FOR COASTAL AREAS ALONG EASTERN LONG ISLAND SOUND AND EASTERN LONG ISLAND SOUND IS 2 1/2 TO 3 1/2 FT OF SURGE ABOVE ASTRONOMICAL TIDE. A LOW PROBABILITY OF 3 1/2 TO 4 FT SURGE ABOVE ASTRONOMICAL TIDE EXISTS. THE MOST LIKELY SURGE FOR NY/NJ COASTAL AREAS ALONG NEW YORK HARBOR AND THE SOUTH SHORE BAYS OF LI/NYC IS 2 1/2 TO 3 1/2 FT OF SURGE ABOVE ASTRONOMICAL TIDE. A LOW PROBABILITY OF 3 TO 4 FT SURGE ABOVE ASTRONOMICAL TIDE EXISTS. SIGNIFICANT BEACH EROSION AND WASHOVERS ARE EXPECTED ALONG OCEAN FACING BARRIER BEACHES OF LONG ISLAND DUE TO 10 TO 15 FT WAVES AND HIGH STORM TIDE. A FEW EXPOSED WATER FRONT 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 WATER FRONT STRUCTURES MAY BE DAMAGED. && .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... CT...COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR CTZ011-012. BLIZZARD WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TUESDAY NIGHT FOR CTZ005>012. COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR CTZ009-010. NY...COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR NYZ079-081. BLIZZARD WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TUESDAY NIGHT FOR NYZ067>075-078>081-176>179. COASTAL FLOOD WATCH LATE TONIGHT FOR NYZ074-075-080-178-179. COASTAL FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR NYZ071-073-078-176-177. NJ...BLIZZARD WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TUESDAY NIGHT FOR NJZ002-004-006-103>108. COASTAL FLOOD WATCH LATE TONIGHT FOR NJZ006-106-108. MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 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. SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ350-353-355. GALE WARNING FROM 6 AM THIS MORNING TO 6 PM EST THIS EVENING FOR ANZ350-353-355. HURRICANE FORCE WIND WARNING FROM 6 PM THIS EVENING TO NOON EST TUESDAY FOR ANZ350. && $$ SYNOPSIS...JC/GOODMAN/NV NEAR TERM...MALOIT/NV SHORT TERM...GOODMAN LONG TERM...JC AVIATION...BC/MALOIT MARINE...JC/GOODMAN/MALOIT HYDROLOGY...JC/GOODMAN TIDES/COASTAL FLOODING... CLIMATE...

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