Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 281808 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 208 PM EDT TUE JUL 28 2015 .SYNOPSIS... HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST AND INTO THE AREA THROUGH MID WEEK. A COLD FRONT APPROACHES FROM THE WEST WEDNESDAY NIGHT AND THURSDAY MORNING...THEN SLOWLY CROSSES THE TRI-STATE THROUGH THURSDAY NIGHT. HIGH PRESSURE THEN BUILDS IN FROM THE WEST INTO THE WEEKEND. THE BERMUDA HIGH RIDGES IN FROM THE WEST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FORECAST REMAIN ON TRACK THIS AFTERNOON. A HIGH AMPLITUDE RIDGE OVER THE MID MS VALLEY EXTENDING NORTH INTO SOUTH CENTRAL CANADA BUILDS EAST TOWARD THE EASTERN SEABOARD THROUGH MID WEEK. THE COMBINATION OF THE WARMING ALOFT AND S/SW FLOW AT THE SFC WILL RESULT IN VERY WARM TO HOT AND MUGGY CONDITIONS ACROSS THE TRI- STATE AREA. WITH THE LACK OF A SFC TRIGGER...AND A DEVELOPING SUBSIDENCE INVERSION...CONVECTION IS UNLIKELY. THERE WILL BE SOME INSTABILITY CLOUDS ACROSS THE AREA DUE TO DAYTIME HEATING...BUT MAINLY LOOKING AT MOSTLY SUNNY SKIES WITH HIGHS IN THE LOWER 90S INLAND AND ACROSS PORTIONS OF THE NYC METRO...BUT A BIT COOLER ACROSS LONG ISLAND/CT. DUE TO THE COMBINATION OF THE HIGH HEAT AND HUMIDITY...HEAT INDICES WILL IN THE LOWER TO MID 90S FOR MOST LOCATIONS. PER LOCAL CRITERIA...A HEAT ADVISORY WILL BE ISSUED FOR NYC FOR HEAT INDEX VALUES IN THE MID AND UPPER 90S TODAY AND TOMORROW. THERE IS A MODERATE RISK FOR RIP CURRENTS AT THE OCEAN BEACHES TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... CONDITIONS CONTINUE TO WARM WITH RIDGING BUILDING IN BOTH ALOFT AND AT THE SFC. A THERMAL TROF WILL REDEVELOP ON WED WHICH WILL KEEP THE AREA IN S/SW FLOW...WITH A CONTINUATION OF HIGH DEW POINT AIR ACROSS THE REGION. HIGHS ON WED LOOK TO BE A COUPLE OF DEGREES WARMER THAN TUE WITH HEAT INDICES IN THE MID AND UPPER 90S FOR MOST LOCATIONS. ONCE AGAIN...A LOWERING SUBSIDENCE INVERSION AND LACK OF A TRIGGER WILL KEEP A LID ON ANY CONVECTION. THE OVERNIGHT PERIOD WILL BE VERY MUGGY WITH LOWS CLOSE TO DEW POINTS AROUND 70. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE AXIS OF A NORTHERN STREAM DEEP LAYERED RIDGE BUILDS OVER THE AREA WEDNESDAY NIGHT...WITH ASSOCIATED SUBSIDENCE KEEPING THINGS DRY AND RELATIVELY CLOUD FREE. IT APPEARS THE SOUTHERN PART OF THE RIDGE MAYBE UNDERCUT BY A 700-500 HPA SHORTWAVE LATE WEDNESDAY NIGHT. THIS SHOULD ALLOW FOR JUST ENOUGH MIXING FOR TEMPERATURES TO FALL A FEW DEGREES LOWER THAN PREVIOUSLY FORECAST. LOWS WEDNESDAY NIGHT ARE BASED ON A BLEND OF NAM 2-METER TEMPERATURES WITH A MIXTURE OF ECS/MET/MAV GUIDANCE. VALUES SHOULD BE 5-10 DEGREES ABOVE NORMAL. THERE COULD BE SOME MAINLY ISOLATED SHOWERS/THUNDERSTORMS TO THE NW OF NYC THURSDAY MORNING AS A PRE-FRONTAL TROUGH DEVELOPS. MOST OF THE PRECIPITATION THOUGH IS ASSOCIATED WITH A NORTHERN STREAM TROUGH THAT WILL PASS TO THE N THURSDAY NIGHT...ALONG WITH ITS ASSOCIATED SURFACE COLD FRONT. AS A RESULT THE BULK OF ANY SHOWERS AND THUNDERSTORMS SHOULD OCCUR THURSDAY AFTERNOON MAINLY TO THE NW OF NYC AND OVER THE REMAINDER OF THE CWA THURSDAY NIGHT. THE 00Z GFS/ECMWF/CMC ALL HAVE NO PRECIPITATION FROM 12Z FRIDAY ON AND A REASONABLE INTERPRETATION HAS THINGS DRY BY 12Z FRIDAY...SO BRING ALL PRECIPITATION TO AN END THURSDAY NIGHT FROM NW TO SE AS THE FRONT PASSES. MODEL BUFKIT SOUNDINGS STILL SHOWING A SMALL CAP AROUND 650 HPA...BUT MUCH WEAKER THAN THE PAST COUPLE OF DAYS. MOST MODELS ALSO TEND TO LIMIT ANY SIGNIFICANT CAPE TO OVER NE NJ/LOWER HUDSON VALLEY/SW CT AND MAYBE NYC THURSDAY AFTERNOON. SO THE TWO LIMIT THE RISK OF ANY STRONGER TO POSSIBLY SEVERE STORMS TO THIS AREA. WITH 30 KT OF BULK SHEAR COULD SEE A MIXTURE OF PULSE STORMS AND SOME BOWING SEGMENTS. GIVEN THE POTENTIAL FOR ORGANIZED CONVECTION...AND 1000- 1500 J/KG OF CAPE...SPC HAS PLACED NE NJ/LOWER HUDSON VALLEY/SW CT AND NYC UNDER A MARGINAL RISK FOR SEVERE THUNDERSTORMS. WILL HIGHLIGHT THIS THREAT IN THE HWO. HIGHS ON THU ARE NOW FORECAST TO BE SEVERAL DEGREES COOLER...MAINLY IN THE MID AND UPPER 80S. HOWEVER A FEW 90 DEGREE READINGS IN URBAN NE NJ CANNOT BE RULED OUT. HEAT INDICES AS A RESULT ARE NOW FORECAST TO BE BELOW 95 DEGREES AREA-WIDE ON THURSDAY. LOWS THURSDAY NIGHT SHOULD BE AROUND 5 DEGREES ABOVE NORMAL. FOR NOW HAVE GONE WITH A DRY FORECAST FRIDAY-SATURDAY...WITH THE REGION ON THE SOUTHERN EDGE OF A NORTHERN STREAM TROUGH SETTING UP TO THE N. AS A RESULT...MOST IF NOT ALL ASSOCIATED FORCING SHOULD STAY TO THE N OF THE AREA. ANOTHER COMPLICATION IS THE COLD FRONT IS FORECAST TO STALL OUT OFF THE MID ATLANTIC STATES INTO THE WEEKEND. THERE IS SOME VARIETY IN EXACTLY HOW FAR TO THE S THE FRONT STALLS...WITH SOLUTIONS CREEPING NORTH OVER THE PAST FEW DAYS. IF THIS TREND CONTINUES...MIGHT NEED TO REVISIT POPS OVER S ZONES. THE MODELS THEN BEGIN TO DIFFER WITH HOW FAR S/HOW LONG THE TROUGH DIGS INTO THE NE U.S. WITH THE GFS SHARPER WITH THE TROUGH...DIGGING IT IN INTO MONDAY. THE ECMWF HOWEVER...KEEPS THE BULK OF THE TROUGH TO THE N AND IN FACT BUILDS IN A WESTWARD EXTENSION OF THE SUB- TROPICAL RIDGE BY EARLY NEXT WEEK. NOTING THAT WE ARE CURRENTLY IN A FAIRLY CLIMATOLOGICAL PATTERN RIGHT NOW...HAVE FAVORED THE MORE CLIMATOLOGICAL SOLUTION OF THE ECMWF RIGHT NOW SATURDAY NIGHT- MONDAY. SO ANTICIPATE HOT AND HUMID CONDITIONS EARLY NEXT WEEK. HOWEVER...DO HAVE SLIGHT CHANCE POPS IN FOR NOW MONDAY IN CASE THE GFS ENDS UP BEING MORE CORRECT. TEMPERATURES FRIDAY-MONDAY SHOULD BE ABOVE NORMAL. HOWEVER...GIVEN THE LARGE DIFFERENCES IN PATTERNS FORECAST BY THE GFS AND ECMWF...THERE IS QUITE A BIT OF UNCERTAINTY IN TEMPERATURES FOR THE WEEKEND AND EARLY NEXT WEEK. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... A WEAK LOW PRESSURE TROUGH WILL REMAIN OVER THE AREA...WHILE HIGH PRESSURE REMAINS TO THE WEST. VFR THROUGH THIS EVENING...THOUGH AN ISOLD TSTM MAY BE POSSIBLE INVOF KGON TOWARD EVENING. KSWF/KHPN/KISP/KGON COULD SEE AT LEAST MVFR CONDS LATE TONIGHT...AND KGON COULD GO IFR OR LOWER AS WAS THE CASE LAST NIGHT. EXPECT ANY MVFR OR LOWER CONDS TO QUICKLY IMPROVE TO VFR BY 13Z-14Z. WINDS TRICKY AROUND THE NYC METRO THIS AFTERNOON. KEWR/KLGA MAINLY LIGHT ENE UNTIL ABOUT 20-21Z...WHEN A SOUTHERLY OCEAN SEA BREEZE SHOULD ARRIVE. OTHERWISE...S-SW FLOW AT OR JUST OVER 10 KT RIGHT ALONG THE COAST...HIGHEST AT KJFK...AND LESS THAN 10 KT INLAND...SHOULD VEER SW AND GO LIGHT/VARIABLE TONIGHT...THEN PICK UP AGAIN TO 5-10 KT BY ABOUT 15Z WED. ...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: NO UNSCHEDULED AMD EXPECTED. KLGA FCSTER COMMENTS: TIMING OF ARRIVAL OF SOUTHERLY SEA BREEZE COULD VARY UP TO AN HOUR FROM FCST. KEWR FCSTER COMMENTS: TIMING OF ARRIVAL OF SOUTHERLY SEA BREEZE COULD VARY UP TO AN HOUR FROM FCST. KTEB FCSTER COMMENTS: TIMING OF ARRIVAL OF SOUTHERLY SEA BREEZE COULD VARY UP TO AN HOUR FROM FCST. KHPN FCSTER COMMENTS: TIMING OF ARRIVAL OF SOUTHERLY SEA BREEZE COULD VARY UP TO AN HOUR FROM FCST. KISP FCSTER COMMENTS: NO UNSCHEDULED AMD EXPECTED. .OUTLOOK FOR 18Z WED THROUGH SUNDAY... .WED AFTERNOON...VFR. .WED NIGHT...MVFR VSBY POSSIBLE LATE. .THU...EARLY MORNING HAZE WITH MVFR CONDS...THEN SCT AFTERNOON/EVENING TSTMS WITH MVFR OR LOWER CONDS. .FRI-SUNDAY...VFR. && .MARINE... MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK. A WEAK PRESSURE GRADIENT ACROSS THE FORECAST WATERS TODAY INTO TONIGHT WILL KEEP WINDS AND SEAS BELOW SMALL CRAFT LEVELS. GRADIENT WIND FROM THE SOUTH STRENGTHENS WED WITH THE POSSIBLE DEVELOPMENT OF A COASTAL JET. STILL THOUGH...GUSTS SHOULD REMAIN BELOW 25 KT...STRONGEST WEST OF FIRE ISLAND INLET. EVEN FACTORING IN THE SEABREEZE AND THE PASSAGE OF A COLD FRONT LATE THURSDAY...WINDS SHOULD BE 15 KT OR LESS ON THE WATERS WEDNESDAY NIGHT-SATURDAY. AT THIS TIME...THERE IS NO RELIABLE PREDICTION OF ANY SIGNIFICANT SWELL MOVING INTO THE COASTAL OCEAN WATERS IN THIS TIME FRAME...SO SEAS SHOULD REMAIN BELOW SCA LEVELS WEDNESDAY NIGHT-SATURDAY CONSISTENT WITH THE FORECAST WINDS. && .HYDROLOGY... DRY CONDITIONS ARE FORECAST THROUGH MID WEEK. WHILE WIDESPREAD SIGNIFICANT RAINFALL IS NOT EXPECTED WITH ANY SHOWERS/THUNDERSTORMS THURSDAY/THURSDAY NIGHT...THERE IS THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH ANY STRONGER CONVECTION. IF THIS WERE TO OCCUR...THAN LOCALIZED MINOR URBAN/POOR DRAINAGE FLOODING WOULD BE POSSIBLE. IT SHOULD THEN BE DRY FROM FRIDAY INTO THE WEEKEND. && .CLIMATE... RECORD HIGHS FOR WEDNESDAY JULY 29 2015... LOCATION..........RECORD HIGH/YEAR.........FORECAST HIGH NEWARK....................100/1949.................94 BRIDGEPORT.................96/2002.................91 CENTRAL PARK...............99/1949.................92 LA GUARDIA.................97/1949.................94 J F KENNEDY................99/2002.................89 ISLIP......................96/2002.................89 && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...HEAT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR NYZ072>075-176-178. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MALOIT/DW NEAR TERM...BC/MALOIT/DW SHORT TERM...DW LONG TERM...MALOIT AVIATION...JE/GOODMAN/JM MARINE...JE/GOODMAN HYDROLOGY...MALOIT/DW CLIMATE...

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