Area Forecast Discussion
Issued by NWS Upton, NY

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985 FXUS61 KOKX 190320 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1120 PM EDT MON MAY 18 2015 .SYNOPSIS... A STATIONARY FRONT SOUTHWEST OF THE REGION LIFTS NORTH AS A WARM FRONT EARLY TUESDAY MORNING...AND THEN A COLD FRONT MOVES ACROSS THE REGION TUESDAY NIGHT. HIGH PRESSURE IS THEN IN CONTROL THROUGH NEXT WEEKEND...WITH THE EXCEPTION OF A DRY COLD FRONTAL PASSAGE ON FRIDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... LOW STRATUS AND FOG WAS MOVING INTO THE REGION FROM THE EAST...ADDED AREAS OF FOG WITH VISIBILITIES 1/2SM FOR OVERNIGHT. HIGH PRESSURE NEAR NOVA SCOTIA WAS EXTENDING INTO SOUTHERN NEW ENGLAND AND ACROSS LONG ISLAND..INTO NEW JERSEY. AN EASTERLY FLOW WAS WELL ESTABLISHED AS FAR WEST AS EASTERN PENNSYLVANIA. WITH A LOW LEVEL INVERSION IN PLACE AND STRATUS ACROSS THE REGION THE AREA WAS STABLE. THE HIGH SHIFTS EAST AFTER 06Z ALLOWING A STATIONARY FRONT IN EASTERN PENNSYLVANIA INTO EASTERN MARYLAND TO BEGIN TO LIFT NORTH AS A WARM FRONT. LINE OF SHOWERS AND THUNDERSTORMS HAS BEEN WEAKENING AS LINE MOVES INTO THE MORE STABLE AIRMASS. AS A RESULT HAVE REMOVED THE MENTION OF THUNDER FOR TONIGHT. POPS LOOK OKAY AND WERE NOT ADJUSTED AT THIS TIME. THE BEST CHANCE OF SHOWERS WILL BE ACROSS NJ AND THE LOWER HUDSON VALLEY. AS LOW LEVEL MOISTURE INCREASES...AREAS OF FOG WILL DEVELOP ACROSS LONG ISLAND...SOUTHERN CT...AND COASTAL AREAS...AND PATCHY FOG WILL DEVELOP ELSEWHERE...AND FOG WILL PERSIST THROUGH TUESDAY MORNING. LOWS TONIGHT WILL GENERALLY DROP INTO THE 50S...HOLDING NEARLY STEADY ACROSS SOUTHERN CONNECTICUT AND LONG ISLAND. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... THE WARM FRONT MOST LIKELY LIFTS NORTH OF THE REGION EARLY TUESDAY MORNING. A COLD FRONT THEN APPROACHES FROM THE WEST DURING THE DAY TUESDAY. A SOUTHERLY FLOW OUT AHEAD OF THE COLD FRONT WILL USHER IN A WARMER AND MILDER AIRMASS INTO THE REGION. TEMPERATURES ON TUESDAY WILL TOP OFF IN THE MID TO UPPER 60S ACROSS LONG ISLAND AND SE CT...AND IN THE MIDDLE TO UPPER 70S ACROSS NYC...INTERIOR PORTIONS OF SOUTHERN CT...AND IN THE UPPER 70S TO NEAR 80 ACROSS NE NJ AND THE LOWER HUDSON VALLEY. THE AIRMASS REMAINS CAPPED AND STABLE THROUGH MUCH OF THE MORNING...THEN WITH A WARM AND UNSTABLE AIRMASS ACROSS THE REGION BY THE AFTERNOON. SHOWERS BECOME LIKELY WITH THE WARM FRONT IN THE MORNING...THE SHOWERS WITH ISOLATED TSTMS POSSIBLE IN THE AFTERNOON AND INTO THE EVENING AS THE COLD FRONT MOVES THROUGH THE REGION. LOWS WILL DROP INTO THE LOW TO MID 50S. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGH PRESSURE BUILDS IN FOR WEDNESDAY. A SHORTWAVE AND SURFACE TROUGH PASS THROUGH...BUT THIS SHOULD DO NOTHING MORE THAN KICK UP THE WINDS AND PRODUCE A FEW CLOUDS...PARTLY CLOUDY AND BREEZY. MAV AND NAM GUIDANCE DIFFER BY ABOUT 4-5 DEGREES FOR HIGH TEMPS. SPLITTING THE DIFFERENCE LOOKS TO BE CONSISTENT WITH THE 850MB FORECAST AND A MODERATE DOWNSLOPE FLOW. HIGH PRESSURE KEEPS THURSDAY DRY...AND PROBABLY KEEPS THURSDAY NIGHT AND FRIDAY DRY AS WELL. SOME GUIDANCE BRUSHES THE COASTAL ZONES WITH RAINFALL THURSDAY NIGHT INTO FRIDAY MORNING...ASSOCIATED WITH WEAK LOW PRESSURE PASSING SE OF THE 40N/70W BENCHMARK. WILL MAINTAIN A DRY FORECAST FOR NOW. A COLD FRONT FOLLOWS FRIDAY AFTERNOON...BUT EXPECTING A DRY PASSAGE AND INCREASING WIND GUSTS WITH IT. HIGHS NEAR NORMAL ON THURSDAY...AND A LITTLE WARMER ON FRIDAY. THE COLD ADVECTION BEHIND THE FRONT LEADS TO COOLER HIGH TEMPERATURES FOR SATURDAY...BUT ONLY SLIGHTLY BELOW NORMALS AT MOST. A RETURN SW FLOW FROM HIGH PRESSURE CENTERED OFFSHORE THEN PUSHES HIGH TEMPS BACK ABOVE NORMALS ON SUNDAY...BUT STILL IN THE 70S FOR THE MOST PART. A WARM FRONT APPROACHES FROM THE SW SUNDAY NIGHT. MEANWHILE...A COLD FRONT DROPS DOWN FROM THE NORTH. SOME UNCERTAINTY REGARDING HOW FAR SOUTH IT PUSHES AND THE MAGNITUDE OF COLD ADVECTION WITH IT. WITH INCREASING MOISTURE AND LIFT SUPPLIED BY THE TWO FRONTS...HAVE GONE WITH A CHANCE OF SHOWERS SUNDAY NIGHT AND MONDAY. SOME ELEVATED INSTABILITY COULD BE PRESENT FOR A THUNDERSTORM AS WELL. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/...
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HIGH PRESSURE EXTENDING INTO THE AREA FROM THE GULF OF MAINE WILL WEAKEN TONIGHT AS ITS CENTER MOVES OUT TO SEA. A FRONTAL BOUNDARY WILL REMAIN NEARLY STATIONARY FROM CENTRAL NY TO DE OVERNIGHT...POSSIBLY DISSIPATING BEFORE MOVING INTO THE AREA TUESDAY MORNING. IFR/LIFR CONDS HAVE MADE IT INTO KGON/KISP/KJFK. VSBYS ARE SLOWER TO COME DOWN...BUT WITH ONSHORE FLOW DECREASING...EXPECT THEM TO DROP AS WELL. EXPECT THESE SAME CONDITIONS TO EXPAND ACROSS MOST IF NOT ALL TERMINALS TONIGHT WITH A SE FLOW DEVELOPING. BIGGEST UNCERTAINTY IN THE FORECASTS ARE THE TIMING OF LOWER CONDS...WHEN/WHERE RAIN DEVELOPS AND WIND SHIFTS. WINDS ARE SLOWLY BECOMING ESE/SE AS RIDGE AXIS SINKS SWD. INITIAL LINE OF SHOWERS WEAKENED AS THEY MOVED INTO THE HUDSON VALLEY AND NJ...AND HI RES MODELS INDICATE NOTHING UNTIL AROUND 07Z. HOWEVER...THERE IS UNCERTAINTY WITH HOW WIDESPREAD THE SHOWERS WILL BE SINCE THE FRONTAL BOUNDARY MAY NOT MOVE MUCH BEFORE DISSIPATING. BUT AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT TUESDAY MORNING IN ANYTHING THAT DOES MAKE IT IN. CONDS SHOULD IMPROVE TO MVFR THEN VFR AT WRN TERMINALS TUE AFTN...BUT REMAIN IFR TO MVFR AT ERN TERMINALS. COLD FRONT APPROACHES FOR THE EVE...COULD BE A FEW TSTMS DURING THE LATE AFTN PRECEDING THE FROPA. 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: TIMING OF LIFR COULD BE OFF 1-2 HOURS. DURATION OF SHOWERS/ISOLD TSTM TUE MORNING MAY BE TOO LONG AND NOT BE AS WIDESPREAD AS FORECAST. KLGA FCSTER COMMENTS: TIMING OF IFR/LIFR COULD BE OFF A FEW HOURS. DURATION OF SHOWERS/ISOLD TSTM TUE MORNING MAY BE TOO LONG AND NOT BE AS WIDESPREAD AS FORECAST. KEWR FCSTER COMMENTS: TIMING OF IFR/LIFR COULD BE OFF A FEW HOURS. DURATION OF SHOWERS/ISOLD TSTM TUE MORNING MAY BE TOO LONG AND NOT BE AS WIDESPREAD AS FORECAST. KTEB FCSTER COMMENTS: TIMING OF IFR/LIFR COULD BE OFF A FEW HOURS. DURATION OF SHOWERS/ISOLD TSTM TUE MORNING MAY BE TOO LONG AND NOT BE AS WIDESPREAD AS FORECAST. KHPN FCSTER COMMENTS: TIMING OF IFR/LIFR COULD BE OFF A FEW HOURS. DURATION OF SHOWERS/ISOLD TSTM TUE MORNING MAY BE TOO LONG AND NOT BE AS WIDESPREAD AS FORECAST. KISP FCSTER COMMENTS: TIMING OF LIFR COULD BE OFF 1-2 HOURS. DURATION OF SHOWERS/ISOLD TSTM TUE MORNING MAY BE TOO LONG AND NOT BE AS WIDESPREAD AS FORECAST. .OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY... .TUESDAY NIGHT...COLD FROPA IN THE EVE WITH LOW CHC SHRA/TSRA IN THE EVE. NW WINDS G20-25KT POSSIBLE POST FRONTAL. .WEDNESDAY...VFR. NW WINDS G20-25KT POSSIBLE. .THURSDAY-FRIDAY...VFR. NW G20KT POSSIBLE FRIDAY. .SATURDAY...VFR.
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&& .MARINE... VISIBILITIES WERE LOWERING ON THE FORECAST WATERS FROM THE EAST AS LOW STRATUS MOVES IN. ADDED AREAS OF FOG WITH VISIBILITIES A HALF NM OR LESS THROUGH THE OVERNIGHT. AS THE WARM FRONT STARTS TO LIFT NORTH THE VISIBILITIES SHOULD BEGIN TO IMPROVE TOWARD MORNING. SEAS HAVE SUBSIDED AND WERE AROUND 4 FT ON THE OCEAN WATERS AT 23 UTC. EXPECT FOG TO RE-DEVELOP TONIGHT THROUGH TUESDAY MORNING. A COLD FRONT MOVES ACROSS THE WATERS LATE TUESDAY AND TUESDAY NIGHT...AND THEN A FEW GUSTS TO 20 KT ARE LIKELY TUESDAY NIGHT AS THE GRADIENT TIGHTENS BEHIND THE DEPARTING COLD FRONT. SEAS ARE EXPECTED TO REMAIN BELOW 5 FT THROUGH THE REST OF THE FORECAST PERIOD. THERE COULD BE HOWEVER BE FREQUENT GUSTS TO SCA CRITERIA WEDNESDAY BEHIND A TROUGH OF LOW PRESSURE...AND AGAIN ON FRIDAY BEHIND A COLD FRONT. && .HYDROLOGY... BETWEEN 2/10 AND 3/10 INCH OF RAIN IS POSSIBLE FROM LATE TONIGHT THROUGH TUESDAY EVENING. LITTLE OR NO HYDROLOGIC IMPACT IS EXPECTED. THE REMAINDER OF THE WEEK LOOKS TO BE DRY WITH HIGH PRESSURE IN CONTROL. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ330-335-338- 340-345-350-353-355. && $$ SYNOPSIS...BC/JC NEAR TERM...MET SHORT TERM...BC/MET LONG TERM...JC AVIATION...24 MARINE...BC/JC/MET HYDROLOGY...BC/JC

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