Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 292000 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 400 PM EDT FRI AUG 29 2014 .SYNOPSIS...
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HIGH PRESSURE SLIDES OFFSHORE SATURDAY INTO SUNDAY. A COLD FRONT SLOWLY APPROACHES FROM THE WEST SUNDAY NIGHT AND DISSIPATES AS IT MOVES WITHIN THE AREA BY MONDAY. WEAK HIGH PRESSURE BRIEFLY RETURNS BEFORE ANOTHER COLD FRONT APPROACHES TUESDAY. THIS FRONT MOVES ACROSS LATE TUESDAY NIGHT WITH HIGH PRESSURE BUILDING BACK IN FROM THE WEST FROM MID TO LATE NEXT WEEK. ANOTHER COLD FRONT APPROACHES LATE NEXT FRIDAY.
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&& .NEAR TERM /THROUGH SATURDAY/...
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HIPRES CENTERED OVER THE NERN CONUS WILL TRANSLATE EWD TNGT...ENDING UP OFFSHORE SAT. THIS WILL ALLOW FOR LGT RETURN FLOW TO PRODUCE INCREASING LLVL MOISTURE. THERE WAS SOME FOG ON THE BACK SIDE OF THE HI OVER THE OH VALLEY FRI MRNG...SO HAVE INCLUDED PATCHY FOG FOR LATE TNGT ACROSS THE OUTLYING AREAS. THE NAM AND GFS TIME HEIGHTS SUGGEST SOME STRATUS DEVELOPS SAT. WITH SIGNIFICANT DRY AIR IN THE MID LVLS...WILL PREFER A MORE MIXED SCENARIO AND AS A RESULT HAVE GONE WITH A PTCLDY FCST. THE RIP RISK WILL CONTINUE TO SUBSIDE THRU THIS EVE. LOW RISK SAT MRNG THEN INCREASING SLY FLOW WILL RESULT IN A MDT RISK BY AFTN/EVE. TEMPS A BLEND OF THE GMOS25 AND MET...50/50 DURING THE DAY AND 70/30 MET AT NGT.
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&& .SHORT TERM /SATURDAY NIGHT/...
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THE ONSHORE FLOW CONTINUES. THIS SHOULD BE SUFFICIENT FOR AREAS OF STRATUS AND AT LEAST PATCHY FOG DEVELOPMENT. ALL MODELS KEEP SHRTWV ENERGY W OF THE CWA THRU THE PERIOD. AS A RESULT...HAVE KEPT THE FCST DRY DUE TO A LACK OF LIFT. TEMPS A BLEND OF THE GMOS25 AND MET...WEIGHTED TOWARDS THE MET.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/...
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LOOKING AT THE LARGE SCALE...THE OVERALL PATTERN IN THE MID LEVELS IS A QUASI-ZONAL FLOW THROUGH THE REMAINDER OF THE FORECAST...SUNDAY THROUGH NEXT FRIDAY. THE GEOPOTENTIAL HEIGHT AT 500MB STAYS MAINLY BETWEEN 582 AND 590DM THROUGHOUT THE PERIOD. THE JET STREAM WILL BE STAYING NORTH OF THE REGION MUCH OF THE TIME AS WELL. ONE DEPARTURE FROM THESE AFOREMENTIONED PARAMETERS IS ON SUNDAY INTO MONDAY. THERE WILL BE A PIECE OF THE JET POSITIONED NORTH OF THE AREA...BUT CLOSE ENOUGH TO PLACE OUR REGION WITHIN THE RIGHT REAR QUAD...ESPECIALLY SUNDAY NIGHT INTO EARLY MONDAY. THIS WILL BE A TIMEFRAME FOR ENHANCED LIFT. LOOKING AT HEIGHT FIELDS...A SMALLER SHORTWAVE...EVIDENT AS A SLIGHT UNDULATION COMPARED TO THE OVERALL PATTERN...MOVES NEAR SUNDAY AND EAST OF THE AREA ON MONDAY. AT THE SURFACE...HIGH PRESSURE WILL BE DISPLACED WELL OFFSHORE STARTING ON SUNDAY. THEN A COLD FRONT WILL BE SLOWLY APPROACHING FROM THE WEST. THE FRONT WILL BE LOSING STRENGTH WITH TIME AS IT MOVES IN...WITHOUT A STRONG PARENT LOW ASSOCIATED WITH IT AND THE SLIGHT AMPLIFICATIONS OF HEIGHT FIELDS ALOFT. THE FRONT MOVES IN MONDAY AND EVENTUALLY DISSIPATES WITHOUT A REAL SIGNIFICANT CHANGE OF WIND DIRECTION AND THEREBY AIRMASS. WE WILL STILL HAVE OFFSHORE HIGH PRESSURE...NOT TOO STRONG OVER THE LOCAL REGION. SO THE AREA WILL BE SUSCEPTIBLE TO DIURNALLY INDUCED CONVECTION. A LITTLE STRONGER PARENT LOW IN SOUTHEAST CANADA NEAR THE GREAT LAKES MOVES INTO THE NORTHEAST TUESDAY NIGHT WITH AN ASSOCIATED COLD FRONT MOVING IN OVERNIGHT INTO WEDNESDAY MORNING. THE FRONT PUSHES EAST OF THE REGION WEDNESDAY WITH A WEAK HIGH BUILDING IN FROM THE WEST THEREAFTER THROUGH EARLY FRIDAY. ANOTHER FRONT MAY APPROACH FOR LATER NEXT FRIDAY.` IN TERMS OF WEATHER...INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS SUNDAY...CONTINUING THROUGH MONDAY. CONVECTION TAPERS DOWN MONDAY NIGHT BEFORE ANOTHER CHANCE TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. IN TERMS OF THUNDERSTORM CHARACTERISTICS...30-35 KT BULK 0-6KM SHEAR FOR SUNDAY CONVEYED BY FORECAST MODELS. MODELS FORECAST MUCAPE OF 1000-2000 J/KG SUNDAY AND MONDAY WITH DAYTIME HEATING. LESS SHEAR MONDAY BUT NEARLY THE SAME MUCAPE DEVELOPMENT. A REMARKABLE WARMING TREND SETTING UP FOR THE END OF THE WEEKEND INTO THE NEW WEEK. TEMPERATURES AVERAGING ABOVE NORMAL. FOR HIGHS...AROUND 4-7 DEGREES ABOVE NORMAL WITH VALUES WELL INTO THE 80S FOR THE LONG TERM PERIOD. LOWS GENERALLY 5-10 DEGREES ABOVE NORMAL SUNDAY NIGHT THROUGH TUESDAY NIGHT AND A FEW DEGREES ABOVE NORMAL WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.
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&& .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... HIGH PRESSURE WILL MOVE SLOWLY EAST ACROSS THE AREA TODAY THEN OFFSHORE ON SATURDAY. VFR WEATHER WILL PREVAIL THROUGH SATURDAY. WINDS UNTIL SUNSET...WEAK SEA BREEZES WILL CONTINUE MOVING NORTH ACROSS NYC / LONG ISLAND / SOUTHERN CT THROUGH THIS EVENING. S WINDS OF 5-10 KT WILL PREVAIL. WINDS TONIGHT...BECOME LIGHT AND VARIABLE SHORTLY AFTER SUNSET AND LAST A FEW HOURS PAST SUNRISE ON SATURDAY. WINDS SATURDAY...INCREASING S WINDS REACHING 15-20 KT AT KJFK 18Z- 00Z...10-15 KT EVERYWHERE ELSE DURING THIS TIME. POTENTIAL FOR MVFR FOG TONIGHT AT KSWF AND KGON 08Z-12Z. .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: LOW CHANCE OF FEW 2 THSD -3 THSD FT CLOUDS 09Z- 14Z SAT. KLGA FCSTER COMMENTS: TIMING OF SEA BREEZE MAY BE OFF BY +/- 1-2 HOURS FROM FORECAST. LOW CHANCE OF FEW 2 THSD -3 THSD FT CLOUDS 09Z- 14Z SAT. KEWR FCSTER COMMENTS: TIMING OF SEA BREEZE MAY BE OFF BY +/- 1-2 HOURS FROM FORECAST. LOW CHANCE OF FEW 2 THSD -3 THSD FT CLOUDS 09Z- 14Z SAT. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: TIMING OF SEA BREEZE MAY BE OFF BY +/- 1-2 HOURS FROM FORECAST. LOW CHANCE OF FEW 2 THSD -3 THSD FT CLOUDS 09Z- 14Z SAT. KHPN FCSTER COMMENTS: LOW CHANCE OF FEW 2 THSD -3 THSD FT CLOUDS 09Z- 14Z SAT. KISP FCSTER COMMENTS: LOW CHANCE OF FEW 2 THSD -3 THSD FT CLOUDS 09Z- 14Z SAT. .OUTLOOK FOR 12Z SAT THROUGH TUE... .SAT NIGHT-TUE NIGHT...MAINLY MVFR CIGS AND VSBY WITH MULTIPLE ROUNDS OF SHOWERS AND TSTMS STARTING DURING THE DAY SUNDAY. .WED-THU...MAINLY VFR. && .MARINE...
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WINDS AND WAVES BLW SCA LVLS THRU SAT NGT. WITH INCREASING SOUTHERLY FETCH SUNDAY AND SUNDAY NIGHT...SCA CONDITIONS MAINLY FOR SEAS ARE FORECAST AS SEAS ARE FORECAST TO REACH 5 FT ON THE OCEAN. WIND GUSTS WILL BE LIMITED TO AROUND 20 KT. HOWEVER...PRESSURE GRADIENT WILL WEAKEN AGAIN FOR NEXT WEEK SO CONDITIONS ARE FORECAST TO RETURN TO SUB SCA LEVELS BY LATER MONDAY MORNING AND THEREAFTER.
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&& .HYDROLOGY...
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NO RAINFALL THROUGH SAT. LAYER PW OF AROUND 2 INCHES WITH FRONT APPROACHING SUNDAY AND INTO THE REGION SUNDAY NIGHT AND MONDAY...SO ANY SHOWERS AND THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LOCAL HEAVY DOWNPOURS. LOCALIZED FLOODING THREAT WILL REMAIN WHICH WOULD VARY FROM MINOR AND POOR DRAINAGE TO POSSIBLY FLASH FLOODING. ANY FLASH FLOODING IS EXPECTED TO BE ISOLATED.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JMC/JM NEAR TERM...JMC SHORT TERM...JMC LONG TERM...JM AVIATION...GC MARINE...JMC/JM HYDROLOGY...JMC/JM

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