Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 091756 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1256 PM EST TUE FEB 9 2016 .SYNOPSIS... WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY AS LOW PRESSURE DEVELOPS OFF THE MID ATLANTIC COAST AND MOVES EAST OUT TO SEA. ANOTHER LOW WILL DEVELOP JUST SOUTH OF LONG ISLAND TONIGHT AND PASS EAST ON WEDNESDAY. A WEAK LOW PRESSURE TROUGH WILL REMAIN OVER THE WATERS FROM WEDNESDAY NIGHT INTO FRIDAY. LOW PRESSURE AND A STRONG ARCTIC COLD FRONT WILL MOVE THROUGH FRIDAY NIGHT INTO SATURDAY NIGHT. AN ARCTIC AIR MASS WILL BUILD IN SATURDAY NIGHT THROUGH MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SOME LIGHT SNOW MAY MOVE INTO WESTERN ZONES LATER IN THE AFTERNOON...BUT FOR THE MOST PART...DRY CONDS IN PLACE AS WEAK SFC HIGH PRESSURE WILL OTHERWISE PREVAIL AS DEVELOPING LOW PRESSURE PASSES WELL TO THE SOUTH. A LINGERING LOW PRESSURE TROUGH IN THE WAKE OF THE LOW WILL START TO LIFT NORTH LATE IN THE AFTERNOON. HIGH TEMPS TODAY SHOULD BE 30-35 PER MOS GUIDANCE BLEND. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... AS A DEEP LONGWAVE TROUGH MOVES TOWARD THE NORTHEAST...THE ASSOCIATED MID LEVEL CLOSED LOW WILL OPEN UP...WITH A STRONG MID LEVEL VORT MAX ROUNDING THE BASE OF THE TROUGH AND SWING ACROSS WED MORNING. MEANWHILE AT THE SURFACE...THE INVERTED TROUGH IN THE WAKE OF THE FIRST LOW WILL CONTINUE TO LIFT SLOWLY NORTH CLOSER TO THE AREA...WITH A WEAK LOW CENTER ALSO DEVELOPING OFFSHORE IN RESPONSE TO THE APPROACHING SHORTWAVE. THESE WILL BOTH HELP TO FOCUS BANDS OF LIGHT TO MODERATE SNOW MAINLY OVER NYC METRO...LONG ISLAND AND COASTAL SECTIONS TONIGHT INTO WED MORNING. SIDED MOSTLY WITH A BLEND OF THE 00Z NAM/GFS...WITH THE NAM MOSTLY HAVING HELD COURSE OVER THE PAST 24 HR AND THE GFS TRENDING NORTH TOWARD A SIMILAR FCST SOLUTION. FCST SOUNDINGS SHOW BEST LIFT AT TEMPS IDEAL FOR DENDRITIC SNOW GROWTH...AND ALSO SHOW VERY WEAK STATIC STABILITY...WITH A DEEP SATURATED LAYER AND MOIST ADIABATIC LAPSE RATES. SNOWFALL RATES SHOULD BE ENHANCED AS A RESULT LATE TONIGHT INTO WED MORNING...AND WOULD NOT RULE OUT A RUMBLE OF THUNDER DURING PERIODS OF HEAVIER SNOW. AS A RESULT...ISSUED A WINTER WX ADVY FOR NYC METRO...LONG ISLAND AND COASTAL CT FOR TONIGHT INTO WED MORNING. THESE INVERTED TROUGHS OFTEN OUT-PERFORM MODEL GUIDANCE AND SOMETIMES ALSO END UP NORTH OF MODEL FCST...SO THE SITUATION TONIGHT WILL HAVE TO BE WATCHED CLOSELY. HAD EVEN BRIEFLY CONSIDERED A WINTER STORM WATCH FOR NYC METRO AND LONG ISLAND BECAUSE OF THIS...BUT WITH SREF STAYING TO THE SOUTH AND CAM GUIDANCE NOT PRODUCING APPRECIABLE QPF CONSIDERING THE CONVECTIVE ASPECT...DECIDED ON THE ADVY AS THE BEST COURSE OF ACTION. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... A LONGWAVE EASTERN TROUGH WILL REMAIN INTO SATURDAY WITH A SERIES OF SHORTWAVES ROTATING THROUGH THE FLOW. THE UPPER TROUGH AXIS FINALLY MOVES TO THE EAST SATURDAY NIGHT INTO SUNDAY AS A SURGE OF ARCTIC AIR...THE COLDEST OF THE SEASON...PUSHES INTO THE NORTHEAST SATURDAY NIGHT INTO MONDAY. FORECAST AND MODEL GUIDANCE REMAINS VERY CONSISTENT THROUGH THE EXTENDED PERIOD. CYCLONIC FLOW REMAINS...AND COLD AIR WILL BE IN PLACE...WITH A CHANCE OF LIGHT SNOW OR SNOW SHOWERS CONTINUING INTO THURSDAY. SNOWFALL AMOUNTS ARE EXPECTED TO BE LIGHT...PROBABLY AN INCH OR SO...MAINLY NORTH AND WEST OF NYC. THE FIRST PUSH OF COLDER AIR INTO THE AREA MOVES IN FOR THURSDAY BEHIND THE DEPARTING LOW. THE AREA WILL BE BETWEEN SHORTWAVES THURSDAY NIGHT INTO FRIDAY AS WEAK SURFACE RIDGING BUILDS IN. THE NEXT SHORTWAVE ROTATES THROUGH FRIDAY NIGHT INTO SATURDAY NIGHT WITH A SURFACE LOW TRACKS NORTH OF THE REGION. THIS LOW WILL BRING AN ARCTIC FRONT THROUGH THE AREA WITH THE COLDEST AIR OF THE SEASON MOVING IN FOR SATURDAY NIGHT AND REMAINING INTO SUNDAY. THIS LOW BRINGS ANOTHER CHANCE OF LIGHT SNOW ACROSS THE REGION. ARCTIC HIGH PRESSURE BUILDS IN SATURDAY NIGHT AND REMAINS INTO THE BEGINNING OF NEXT WEEK. RIGHT NOW THE CORE OF THE COLDEST AIR LOOKS TO TRACK WEST OF THE REGION...MOVING THROUGH WESTERN NEW YORK STATE...WESTERN PENNSYLVANIA AND INTO THE CENTRAL APPALACHIANS. REGARDLESS...TEMPERATURES WILL BE RUNNING 15 TO AS MUCH AS 25 DEGREES BELOW NORMAL. THERE WILL BE A SLIGHT MODIFICATION TO THE AIR MASS MONDAY. CURRENTLY WIDESPREAD RECORD LOWS ARE NOT EXPECTED WITH THE ARCTIC OUTBREAK. THE BEST CHANCE WILL BE SATURDAY NIGHT/SUNDAY MORNING...SEE THE CLIMATE SECTION FOR DETAILS. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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A LOW PRESSURE TROUGH WILL APPROACH FROM THE SOUTH TODAY AND ENTER THE REGION TONIGHT. MOSTLY MVFR...BUT SOME VFR NORTH OF THE CITY THRU MID-LATE AFTERNOON. FLIGHT CATS LOWER THIS EVENING WITH SNOW. SNOW ACCUMS IN THE 2-5 INCH RANGE EXPECTED OVERNIGHT INTO WEDS MORNING. NE WINDS 10KT OR LESS TO START...THEN BECOMING E 5-10KT LATE THIS AFTN. LIGHT AND VARIABLE WINDS STARTING AROUND THE ONSET OF SNOW. ...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: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2 HOURS. KLGA FCSTER COMMENTS: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2 HOURS. KEWR FCSTER COMMENTS: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2 HOURS. KTEB FCSTER COMMENTS: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2 HOURS. KHPN FCSTER COMMENTS: TIMING OF SUB-VFR COULD BE OFF BY 1-2 HOURS. ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2 HOURS. KISP FCSTER COMMENTS: TEMPO VFR POSSIBLE THIS AFTERNOON. ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2H OURS. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... .WEDS PM...VFR. W GUSTS 20-25KT. .THU...SLIGHT CHC -SHSN...OTHERWISE VFR. WNW GUSTS 25-30KT. .FRI...VFR. .SAT...SLIGHT CHC -SHSN...OTHERWISE VFR. NW GUSTS 25-30KT. .SUN...VFR. NW GUSTS 20-25KT.
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&& .MARINE... SCA CONTINUES FOR THE OCEAN WATERS...AND WILL CONTINUE INTO WEDNESDAY. SEAS 8-10 FT TODAY SHOULD ONLY SLOWLY SUBSIDE BEFORE STRONG WESTERLY FLOW IN THE WAKE OF DEPARTING LOW PRESSURE BEGINS LATE DAY WED INTO WED NIGHT...WITH GUSTS UP TO 30 KT ON ALL WATERS...POSSIBLY REACHING MINIMAL GALE FORCE ON THE OUTER OCEAN WATERS. SCA CONDITIONS WILL CONTINUE ON THE OCEAN WATERS THU INTO FRI AS LOW PRESSURE SLOWLY DEPARTS TO THE EAST. GUSTS THURSDAY ON THE REMAINDER OF THE FORECAST WATERS MAY REACH SMALL CRAFT LEVELS AS THE FIRST PUSH OF ARCTIC AIR MOVES IN. THERE MAY BE A BRIEF LULL IN SMALL CRAFT CONDITIONS LATER FRIDAY INTO FRIDAY NIGHT. ANOTHER LOW AND AN ARCTIC FRONT MOVE THROUGH THE WATERS LATE FRIDAY NIGHT INTO SATURDAY WITH SMALL CRAFT CONDITIONS LIKELY ONCE AGAIN. && .HYDROLOGY... LIQUID EQUIVALENT QPF TONIGHT INTO WED MORNING SHOULD BE LESS THAN 1/2 INCH...ALL IN THE FORM OF SNOW. NO HYDROLOGIC PROBLEMS. LITTLE PRECIPITATION EXPECTED WED AFTERNOON THROUGH SAT NIGHT...THEN DRY EARLY NEXT WEEK. && .TIDES/COASTAL FLOODING... FOR THE HIGH TIDE CYCLE THIS MORNING...SPRING ASTRONOMICAL TIDES WILL PEAKING. IN ADDITION...WINDS SHOULD VEER MORE TO THE NE AS ADDITIONAL WAVES OF LOW PRESSURE TRACK TO THE SOUTH OF THE REGION. WIDESPREAD MINOR COASTAL FLOODING IS EXPECTED FOR MOST OF THE REGION...WITH MODERATE COASTAL FLOODING FOR THE SOUTH SHORE BAYS OF LONG ISLAND AND NYC. THE HIGH END OF THE FORECAST RANGE COULD COME CLOSE TO THE WATER LEVELS REACHED DURING YESTERDAYS MORNING FOR THE BAYS OF NYC AND WESTERN LONG ISLAND. THEREAFTER...WE ARE GENERALLY LOOKING MINOR TO LOCALLY MODERATE COASTAL FLOODING CONCERNS WITH TUESDAY EVENINGS HIGH TIDE CYCLE. ASTRONOMICAL TIDES WILL GRADUALLY CONTINUE TO LOWER...WITH SOME ADDITIONAL COASTAL FLOODING POSSIBLE INTO THE WED MORNING HIGH TIDE CYCLE. HIGH SURF OF 6 TO 10 FT WILL CONTINUE TODAY A MODERATE THREAT FOR DUNE TOE EROSION ALONG THE ATLANTIC OCEAN BEACHES...AND A LOCALIZED POTENTIAL FOR OVERWASHES ON FIRE ISLAND. THIS IS BASED ON MODELED IMPACTS OF GALE CENTER FROM THE USGS COASTAL CHANGE HAZARDS PORTAL. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST WEDNESDAY FOR CTZ009>012. COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR CTZ009-010. COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 2 AM EST WEDNESDAY FOR CTZ009. NY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST WEDNESDAY FOR NYZ069>075-078>081-176>179. COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NYZ071-073-078-079-081-177. COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR NYZ074-075-080-178-179. COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 2 AM EST WEDNESDAY FOR NYZ071-078-177. COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO 2 AM EST WEDNESDAY FOR NYZ081. NJ...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST WEDNESDAY FOR NJZ002-004-006-103>108. COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR NJZ006-106-108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR ANZ350-353- 355.
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&& $$ SYNOPSIS...MET NEAR TERM...GOODMAN/MPS SHORT TERM...GOODMAN LONG TERM...MET AVIATION...JC MARINE...GOODMAN/MET HYDROLOGY...GOODMAN/MET TIDES/COASTAL FLOODING...

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