Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 261819 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 219 PM EDT TUE MAY 26 2015 .SYNOPSIS... A BERMUDA HIGH REMAINS ANCHORED WELL OFF THE EASTERN SEABOARD THROUGH WEDNESDAY. A WEAK COLD FRONT WILL APPROACH THE AREA WEDNESDAY NIGHT...AND REACH THE TRI-STATE REGION THURSDAY. THE FRONT WILL DISSIPATE OVER THE AREA ON FRIDAY. ANOTHER COLD FRONT WILL APPROACH ON SATURDAY...AND SAG SOUTH OF THE REGION ON SUNDAY. THE FRONT WILL THEN BECOME STATIONARY FOR THE BEGINNING OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO MAJOR CHANGES MADE TO THE FORECAST DATABASE THIS UPDATE OTHER THAN TO UPDATE TEMPERATURE...DEW POINT...AND SKY GRIDS TO REFLECT LATEST OBSERVATIONAL TRENDS. THE REGION REMAINS ON N/W PERIPHERY OF DEEP LAYERED RIDGE. THE BIGGEST QUESTION FOR LATER TODAY IS IF NW ZONES FAR ENOUGH REMOVED FROM THE RIDGE TO GET ANY DIURNALLY DRIVEN CONVECTION. THE GFS/NAM ARGUE YES...THE CMC/ECMWF ARGUE NO. A TRIGGER FOR CONVECTION IS LACKING TODAY ACROSS NW ZONES...BUT EXPECT A FAIRLY STRONG SEABREEZE TO PENETRATE WELL INLAND THIS AFTERNOON. THE SEABREEZE BOUNDARY COULD SERVE AS A TRIGGER FOR CONVECTION OVER NW INTERIOR ZONES IF FORECAST CAPE OF 500-1500 J/KG CAPE IS REALIZED (NO CAPE IN ECMWF). SURFACE BASED CAPE HAS BEGUN TO INCREASE ACROSS ORANGE COUNTY...BUT BEST INSTABILITY AND LIFT ARE LIKELY TO STAY TO THE NORTH AND WEST OF OUR INTERIOR ZONES. HAVE CONTINUED WITH MAINLY SLIGHT CHANCE POPS OVER NW ZONES...WITH CHANCE POPS W ORANGE COUNTY. FOR HIGHS TODAY USED A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 975 TO 850 HPA PER BUFKIT SOUNDINGS. HIGHS SHOULD BE AROUND 10 DEGREES ABOVE NORMAL. THERE IS A MODERATE RISK FOR METEOROLOGICAL ENHANCEMENT OF RIP CURRENT DEVELOPMENT AT ATLANTIC OCEAN BEACHES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... CORE OF DEEP LAYERED RIDGE SLIDES SLIGHTLY FARTHER TO THE S/E THROUGH WEDNESDAY. FOR TONIGHT...THE CMC/ECMWF KEEP THINGS DRY...WITH NO FORCING. WHILE THE GFS/NAM BRING A WEAK 700-500 HPA SHORTWAVE OVER MAINLY N/W PORTIONS OF THE AREA. GIVEN UNCERTAINTY HAVE CAPPED POPS AT SLIGHT CHANCE. GIVEN PERSISTENT ONSHORE FLOW AND FORECAST DEVELOPMENT OF A LOW LEVEL INVERSION...EXPECT FOR LOW CLOUDS TO DEVELOP TONIGHT...TIMING IS SOMEWHAT UNCERTAIN...BUT WOULD EXPECT S SHORE LOCATIONS TO GO FIRST...AFTER SUNSET...WITH INTERIOR AREAS CLOUDING UP AROUND/AFTER MIDNIGHT. ANY LOW CLOUDS WILL BE LAST TO REACH NW ZONES...IF THEY DO AT ALL...NOTING WEAKER IF NOT NON- EXISTENT LOW LEVEL INVERSION IN BUFKIT SOUNDINGS AT KMGJ/KSWF. IN ADDITION TO THE STRATUS...HAVE THE POTENTIAL FOR FOG AS WELL. IF THE SHOWERS/TSTMS MATERIALIZE...WOULD NOT EXPECT ANY FOG UNTIL AFTER THEY PASS. AS IS ALWAYS THE CASE WHEN YOU HAVE MARINE INDUCED STRATUS...IS IT IS NEVER CERTAIN WHETHER YOU WILL GET FOG AS WELL...SO RESTRICTED FOG TO PATCHY AND AT THIS TIME WILL NOT FORECAST ANY LOCALLY DENSE FOG...THOUGH CANNOT RULE IT OUT...ESPECIALLY NEAR THE IMMEDIATE COAST. FOR LOWS TONIGHT...USED A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM 2-METER TEMPERATURES. VALUES SHOULD BE AROUND 10 DEGREES ABOVE NORMAL. ON WEDNESDAY CONVECTIVE POTENTIAL OVER WESTERN ZONES WILL BE AIDED BY FORMATION OF A LEE/THERMAL TROUGH...PASSING OF A 30-35 KT 950 HPA JET...AND MODEL AVERAGE FORECAST CAPES OF 1000-2000 J/KG. BASED ON THIS HAVE 40-50 POPS OVER NW ZONES BY AFTERNOON...WITH CHANCE POPS INTO NYC/SW CT AND SLIGHT CHANCE ELSEWHERE. AS IS ALWAYS THE QUESTION THIS TIME OF YEAR...IS HOW LONG DO STORMS STAY TOGETHER AS THEY HEAD EAST INTO THE MARINE LAYER. WITH BULK RICHARDSON NUMBER GENERALLY FORECAST TO BE MUCH GREATER THAN 40...WOULD EXPECT MAINLY ISOLATED PULSE STORMS. HOWEVER...IF THE HIGH END OF MODEL FORECAST CAPE IS REALIZED...THEN SOME LOCALIZED SEVERE STORMS CANNOT BE COMPLETELY RULED OUT...WITH THE BEST CHANCE OVER THE LOWER HUDSON VALLEY W OF THE HUDSON RIVER. FOR HIGHS WEDNESDAY USED A BLEND OF MIXING DOWN FROM 975 TO 900 HPA PER BUFKIT SOUNDINGS WITH NAM 2-METER TEMPERATURES AND A BLEND OF MAV/ECS/MET GUIDANCE. HIGHS SHOULD BE AROUND 5-10 DEGREES ABOVE NORMAL. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... RESIDUAL CONVECTION IS LIKELY TO EASE THRU THE REGION WED NIGHT. THE FRONT WILL STILL BE ACROSS UPSTATE NY AND CENTRAL PA AT THIS POINT PER THE NAM AND GFS. A DECENT RIBBON OF CAPE AHEAD OF THE FRONT ON THU. THIS INSTABILITY AXIS SHOULD RESIDE FROM ROUGHLY NORTHEASTERN NJ THRU THE HUDSON VALLEY AND INTO WRN CT. THE PERSISTENT SWLY SFC FLOW WILL KEEP THE COASTS FAIRLY STABLE. THE CITY WILL BE IN THE GRADIENT REGION...WITH THE SEA BREEZE INFLUENCE ATTEMPTING TO STABILIZE THE AREA AS WELL. THE FRONT WILL BE A FOCUS FOR TSTMS PER THE 00Z GUIDANCE. HOWEVER...THE FRONT LOOKS TO DISSIPATE AS IT ENCOUNTERS THE COOLER MARITIME INFLUENCED AIRMASS. AS A RESULT THE BOUNDARY MAY NEVER EVEN MAKE IT TO ERN AREAS. SLY FLOW DEVELOPS ON FRI AS THE PRES FALLS N OF THE REGION. THIS FALLING PRES WILL BE ASSOCIATED WITH A STRONGER COLD FRONT...WHICH WILL APPROACH ON SAT BEFORE STALLING S OF THE AREA LATE SUN INTO TUE. GOOD CHANCES FOR CONVECTION SAT. PRECIPITATION TYPE AND CHANCES WILL TIED TO THE POSITION OF THE FRONT SUN AND MON. FOR NOW IT LOOKS LIKE THE FRONT WILL BE FAR ENOUGH S TO KEEP THE CWA FIRMLY IN THE COLDER AIRMASS WITH EASTERLY WINDS AND RAIN CHANCES AS OPPOSED TO SHOWERS AND TSTMS. HOWEVER...THIS IS STILL FAR OUT AND EVEN A FRONTAL POSITION JUST S OF THE CWA COULD ALLOW FOR ELEVATED CONVECTION. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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PERSISTENT OFFSHORE HIGH PRESSURE THROUGH THE TAF PERIOD WITH VFR THROUGH TONIGHT. ONLY EXCEPTION WOULD BE KSWF THIS AFTERNOON...WHERE THERE IS A POSSIBILITY OF A SHOWER OR THUNDERSTORM BUT CONFIDENCE IN TIMING AND EXACT LOCATION IS PRETTY LOW. THE CONTINUED S-SW FLOW OF 10-15 KT GUSTING TO 20-25 KT WILL LOWER THIS EVENING AND WEDNESDAY. CONFIDENCE IS HIGH WITH THE CATEGORY FORECAST AND MODERATE WITH WINDS. HOWEVER...THE CONFIDENCE FOR CATEGORY LOWERS LATE TONIGHT AND WEDNESDAY. THERE WILL BE THE POTENTIAL FOR LOW STRATUS/FOG AS WELL AS SOME SHOWERS. THERE IS UNCERTAINTY IN TIMING WHERE THE LOWERING OF CATEGORY COULD START/END 2-3 HRS DIFFERENT FROM FORECAST AND THE CATEGORY ITSELF COULD BE 1-2 CATEGORIES DIFFERENT FROM OBSERVED AT TIMES. 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 WIND GUSTS MAY BE OFF BY AN HOUR OR TWO. PEAK WIND GUSTS MAY BE A FEW KTS HIGHER THAN FORECAST. KLGA FCSTER COMMENTS: TIMING OF WIND GUSTS MAY BE OFF BY AN HOUR OR TWO. PEAK WIND GUSTS MAY BE A FEW KTS HIGHER THAN FORECAST. KEWR FCSTER COMMENTS: TIMING OF WIND GUSTS MAY BE OFF BY AN HOUR OR TWO. PEAK WIND GUSTS MAY BE A FEW KTS HIGHER THAN FORECAST. KTEB FCSTER COMMENTS: TIMING OF WIND GUSTS MAY BE OFF BY AN HOUR OR TWO. PEAK WIND GUSTS MAY BE A FEW KTS HIGHER THAN FORECAST. KHPN FCSTER COMMENTS: TIMING OF WIND GUSTS MAY BE OFF BY AN HOUR OR TWO. PEAK WIND GUSTS MAY BE A FEW KTS HIGHER THAN FORECAST. KISP FCSTER COMMENTS: TIMING OF WIND GUSTS MAY BE OFF BY AN HOUR OR TWO. PEAK WIND GUSTS MAY BE A FEW KTS HIGHER THAN FORECAST. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... .WEDNESDAY-WEDNESDAY NIGHT...CHANCE OF AFTERNOON AND EARLY EVENING SHRA/TSTM...MAINLY NORTH AND WEST OF THE NYC METRO TERMINALS. SOUTHERLY WIND GUSTS UP TO 25 KT. .THURSDAY-SATURDAY...THIS IS A CHANCE OF LATE NIGHT AND EARLY MORNING MVFR OR LOWER STRATUS AND/OR FOG. THERE IS A SLIGHT CHANCE OF AFTERNOON AND EVENING SHRA/TSTM THU AND SAT. WIND GUSTS 15-20 KT THU AFTN AND SAT AFTN. .SATURDAY NIGHT...MVFR OR LOWER POSSIBLE WITH CHANCE OF SHRA/TSTM. .SUNDAY...MVFR OR LOWER POSSIBLE WITH CHANCE OF SHRA/ISOLATED TSRA.
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&& .MARINE... HAVE CONTINUED WITH SCA ON THE COASTAL OCEAN WATERS THROUGH TONIGHT...WITH GUSTS AGAIN THIS AFTERNOON TO AROUND 25 KT HELPING TO KEEP SEAS AT AROUND 5 FT. HAVE ALSO ISSUED AN SCA FOR NY HARBOR AND THE S SHORE BAYS OF LONG ISLAND FROM 16Z TODAY THROUGH 4Z TONIGHT FOR GUSTS TO AROUND 25 KT WITH THE SEABREEZE. ON THE REMAINDER OF THE WATERS FOR TODAY AND TONIGHT..EXPECT GUSTS TO TOP OUT AT 20 KT THIS AFTERNOON/EVENING. THERE IS THE POTENTIAL FOR AREAS OF DENSE FOG TO FORM OVER THE WATERS LATE TONIGHT AND LINGER INTO WEDNESDAY MORNING...WHAT FORMS COULD ALSO JUST END UP BEING AN AREA OF LOW CLOUDS. TO SOON TO TELL...SO WENT WITH PATCHY FOG LOWERING VISIBILITIES TO 1-3NM. FOR WINDS AND WAVES ON WEDNESDAY...ITS LIKELY WILL BE SIMILAR TO YESTERDAY/TODAY WITH SCA SEAS ON THE COASTAL OCEAN WATERS ALL DAY...AND GUSTS TO 25 KT ON THE COASTAL OCEAN ZONES/NY HARBOR/S SHORE BAYS OF LONG ISLAND IN THE AFTERNOON. HOWEVER...CONFIDENCE IS NOT QUITE HIGH ENOUGH TO EXTEND THE SCA INTO WEDNESDAY AT THIS TIME. SCA SEAS REMAIN ON THE OCEAN WED NIGHT THEN GRADUALLY SUBSIDE THRU THE DAY ON THU. WINDS WILL BE MARGINAL ON THE OCEAN AND S SHORE BAYS...AND BELOW SCA LEVELS ELSEWHERE. LIGHTER FLOW THU THRU FRI NIGHT WITH CONDITIONS BELOW SCA LEVELS. WINDS AND SEAS BUILD ON SAT AHEAD OF A COLD FRONT WITH SCA CONDITIONS POSSIBLE BY SUNSET...ESPECIALLY THE OCEAN. AS THE FRONT STALLS S OF THE WATERS SUN AND MON...NE FLOW WOULD DRIVE SEAS TO 5 FT OR MORE ON THE OCEAN...WITH WIND SPEEDS IN THE 15-25KT RANGE ALL WATERS. && .HYDROLOGY... GENERALLY LESS THAN 1/10 OF AN INCH OF BASIN AVERAGE RAINFALL IS EXPECTED THROUGH WEDNESDAY. HOWEVER ANY STRONGER CONVECTION THAT FORMS...ESPECIALLY IF THERE IS ANY TRAINING OF STORMS...COULD LEAD TO MINOR FLOODING OF URBAN AND/OR POOR DRAINAGE AREAS. LOCALLY HEAVY RAINFALL IS POSSIBLE DURING THE FIRST HALF OF THE WEEKEND AS A COLD FRONT IMPACTS THE AREA. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ350-353- 355. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ338-345. && $$ SYNOPSIS...JMC/MALOIT NEAR TERM...JMC/MALOIT/DS SHORT TERM...MALOIT LONG TERM...JMC AVIATION...JM MARINE...JMC/MALOIT HYDROLOGY...JMC/MALOIT

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