Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 281142 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 742 AM EDT THU MAY 28 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH TODAY...PASS TONIGHT AND DISSIPATE OFFSHORE ON FRIDAY. THE BERMUDA HIGH BUILDS BACK TOWARDS THE REGION FRIDAY NIGHT AND SATURDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST SATURDAY NIGHT...THEN CROSSES THE AREA ON SUNDAY. THIS FRONT STALLS TO OUR SOUTH INTO TUESDAY WITH WAVES OF LOW PRESSURE RIDING ALONG IT...AS HIGH PRESSURE BUILDS ACROSS SOUTHEASTERN CANADA. THIS HIGH THEN BUILDS DOWN INTO THE TRI-STATE FROM LATE TUESDAY INTO WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... MADE MINOR CHANGES TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK. CONVECTION HAS DEVELOPED ALONG THE REMNANTS OF AN OLD FRONTAL BOUNDARY STRETCHING FROM EASTERN ME THRU THE CWA AND INTO THE CAROLINAS. THIS WILL PROVIDE SOME LOW LEVEL CONVERGENCE THIS MORNING...AND COULD PRODUCE A FEW SHOWERS/ISOLATED THUNDERSTORM. THE LIMITING FACTOR IS A LACK OF INSTABILITY...WITH ALMOST NO SURFACE BASED CAPE...AND A FEW HUNDRED J/KG OF ELEVATED CAPE. AS A RESULT HAVE AROUND A 30 POP FOR ACTIVITY THIS MORNING. A COLD FRONT DRAWS CLOSER THIS AFTERNOON. MORE IMPORTANTLY...A MID LEVEL SHORTWAVE SHOWING UP ON SATELLITE ACROSS WRN NY STATE IS ON THE DOORSTEP AT 18Z AND CLEARS THE CWA BY AROUND 3Z. BOTH THE 00Z NAM AND GFS SUPPORT THIS TIMING AT H5. AS SURFACE BASED CAPEINCREASES...THE WAVE SHOULD SERVE AS A TRIGGER...PARTICULARLY WHERE CIN IS SUFFICIENTLY ERODED. ANYWHERE FROM NORTHEASTERN NJ THRU THE CITY INTO INTERIOR CT AND THE LOWER HUDSON VALLEY WILL BE IN THIS ZONE PER THE LATEST DATA. LONG ISLAND AND ERN CT SHOULD BE TOO STABLE FOR MUCH INITIATION...AND THE FOCUS WILL LIKELY BE ON ACTIVITY SUSTAINING WITH STORM MOTION SOUTHEASTERLY AROUND 10KT. AMT OF DESTABILIZATION INLAND WILL NEED TO BE FOLLOWED ON A MESOSCALE BASIS THRU THE DAY AS CLOUD COVER AND PENETRATION OF THE MARINE LAYER WILL DICTATE WHERE THE ZONE OF LIKELY INITIATION IS. 0-6KM SHEAR DECREASES THRU THE DAY. THE BEST WINDOW FOR ORGANIZED CELLS MAY THEREFORE BE EARLIER IN THE DAY WITH A BULK RICHARDSON NUMBER AROUND 45 AT 18Z. BY 00Z...MULTICELLULAR DEVELOPMENT BECOMES FAVORED WITH LESS CAPE/SHEAR BALANCE. POTENTIAL FOR ANY WEAK TORS LOOKS TO REMAIN N OF THE CWA AT THIS TIME WHERE THE EHI IS HIGHER. ANY CONVECTION SHOULD DECLINE TONIGHT WITH THE PASSAGE OF THE BOUNDARY...SUBSIDENCE AND STABLE NE FLOW. THERE IS A MDT RISK FOR RIPS AT THE OCEAN TODAY. && .SHORT TERM /FRIDAY/... THE REMNANTS OF THE COLD FRONT WILL FIZZLE OFFSHORE...ALLOWING EARLY NE WINDS TO VEER THRU THE DAY BECOMING S BY AFTERNOON. WITH A STABLE AIRMASS OVER THE REGION...HAVE MAINTAINED THE DRY FORECAST. MODEL TIME HEIGHTS REVEAL A BIT OF A CHALLENGE WITH RESPECT TO TO CLOUD COVER...AS THE NAM HAS SIGNIFICANTLY MORE MOISTURE IN THE LOWEST 3-4K FT THAN THE GFS. HAVE GONE CLOSER TO THE GFS FOR NOW BASED ON THE AMT OF SUBSIDENCE EXPECTED AND THE NAM LOW LEVEL MOISTURE BIAS. TEMPS WILL BE COOLER AND A BLEND OF THE GUIDANCE WAS USED. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A PROTRUSION OF THE DEEP LAYERED RIDGE OFFSHORE BUILDS OVER THE AREA FRIDAY NIGHT...THEN SLIDES OFF TO THE EAST ON SATURDAY WITH SW FLOW SETTING UP ALOFT. IT SHOULD BE DRY FRIDAY NIGHT DUE TO SUBSIDENCE UNDER THE RIDGE...THEN SHOULD HAVE ENOUGH FORCING OVER NW 1/2 OF THE CWA DUE TO LEE/THERMAL DURING THE DAY TO WARRANT SLIGHT CHANCE TO CHANCE POPS. WITH CAPE FORECAST TO 500-1500 J/KG OVER MOST OF THIS AREA SATURDAY AFTERNOON A FEW STRONG STORMS CANNOT BE RULED OUT. A PASSING SHORTWAVE IN THE SW FLOW ALOFT SATURDAY NIGHT TO WARRANT LIKELY POPS OVER FAR NW ZONES AND SLIGHT CHANCE TO CHANCE POPS FOR SHOWERS/THUNDERSTORMS OVER THE REMAINDER OF THE NW 3/4 OF THE CWA. INCREASE POPS ON SUNDAY TO LIKELY THROUGHOUT FOR SHOWERS WITH A SLIGHT CHANCE OF THUNDERSTORMS - CURRENT FORECAST CAPES ARE LESS THAN 500 J/KG - WITH THE PASSAGE OF A COLD FRONT AND A COUPLE OF SHORTWAVES IN SW FLOW ALOFT. FOR SUNDAY NIGHT CONTINUE WITH LIKELY POPS FOR SHOWERS WITH A WAVE OF LOW PRESSURE RIDING ALONG THE FRONT TO THE SOUTH AND THE PASSAGE OF A 700-500 HPA SHORTWAVE IN WSW FLOW ALOFT. CONTINUE WITH CHANCE POPS FOR SHOWERS MONDAY/MONDAY NIGHT WITH MORE SHORTWAVES PASSING ALOFT AND ADDITIONAL WEAK WAVES OF LOW PRESSURE PASSING TO THE SOUTH. ON TUESDAY HAVE COMPETITION BETWEEN NORTHERN STREAM SHORTWAVE (INTENSITY VARIES BETWEEN THE MODELS)...AND SUBSIDENCE FROM HIGH PRESSURE BUILDING DOWN FROM SE CANADA. NOTING GFS IS WEAKER WITH SHORTWAVE THAN ECMWF OR CMC - HAVE CHANCE POPS FOR SHOWERS ON TUESDAY OVER S ZONES AND SLIGHT CHANCE POPS OVER N ZONES. A DEEP LAYERED RIDGE BEGINS TO BUILD IN FROM THE MS RIVER VALLEY TUESDAY NIGHT/WEDNESDAY WITH ASSOCIATED SUBSIDENCE KEEPING THINGS DRY. FOR TEMPERATURES FRIDAY NIGHT-WEDNESDAY... A BLEND OF MAV/ECS/MET GUIDANCE AND NAM 2-METER TEMPERATURES WAS USED FOR LOWS FRIDAY NIGHT...WITH VALUES FORECAST TO BE AROUND 5-10 DEGREES ABOVE NORMAL. FOR HIGHS SATURDAY A MIX DOWN FROM 975 TO 875 HPA PER BUFKIT SOUNDINGS WAS BLENDED WITH A MIX OF MET/ECS/MAV GUIDANCE AND NAM 2- METER TEMPERATURES...WITH HIGHS FORECAST TO BE AROUND 5 DEGREES ABOVE NORMAL. A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED FOR TEMPERATURES FROM SATURDAY NIGHT-WEDNESDAY...WITH NAM 2-METER TEMPERATURES BLENDED IN SATURDAY NIGHT AS WELL. TEMPERATURES SHOULD BE ABOVE NORMAL SATURDAY NIGHT...NEAR NORMAL SUNDAY AND SUNDAY NIGHT THEN BELOW NORMAL MONDAY-TUESDAY. NEAR NORMAL TEMPERATURES ARE CURRENTLY FORECAST TUESDAY NIGHT AND WEDNESDAY. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE REMAINS ACROSS THE NORTH ATLANTIC. MEANWHILE...AN AREA OF LOW PRESSURE WILL MOVE THROUGH EASTERN CANADA TODAY BRINGING A WEAKENING COLD FRONT TOWARD THE AREA THIS AFTERNOON. THE FRONT IS EXPECTED TO CROSS THE LOWER HUDSON VALLEY DURING THE LATE AFTERNOON/EVENING...AND MOVE THROUGH THE NYC AREA TERMINALS SHORTLY AFTER 00Z FRIDAY. THERE IS A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS WITH THE FRONT...HOWEVER IT APPEARS AT THIS TIME THAT COVERAGE IS TOO LOW TO INCLUDE IN THE TAF. STRATUS THIS MORNING WITH MVFR/IFR CEILINGS BETWEEN 800 FT AND 2000 FT. LOCAL MVFR FOG IS ALSO POSSIBLE. CEILINGS BECOME VFR AFTER 15Z. MODERATE CONFIDENCE IN THE FORECAST OF STRATUS AND FOG. WINDS REMAIN SOUTHERLY FOR MUCH OF THE DAY WITH SPEEDS AROUND 10 KT WITH SOME GUSTS INTO THE TEENS THIS AFTERNOON. WINDS WILL BECOME WESTERLY...THEN NORTHERLY AS THE FRONT MOVES ACROSS THE AREA. AS THE WINDS BECOME MORE NORTHERLY LATE THIS EVENING...SPEED DIMINISH TO LESS THAN 10 KT. ...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: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY LIKELY EXPECTED BETWEEN 14Z AND 15Z. KLGA FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY LIKELY EXPECTED BETWEEN 14Z AND 15Z. KEWR FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY LIKELY EXPECTED BETWEEN 14Z AND 15Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY LIKELY EXPECTED BETWEEN 14Z AND 15Z. KHPN FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY LIKELY EXPECTED BETWEEN 14Z AND 15Z. KISP FCSTER COMMENTS: AMENDMENTS LIKELY THIS MORNING FOR TIMING OF IMPROVING CEILINGS TO VFR WITH LOW STRATUS. VFR CIGS MOSTLY LIKELY EXPECTED BETWEEN 14Z AND 15Z. .OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY... .FRI...VFR. LIGHT NE WINDS VEERING THRU THE DAY. .SAT...MORNING MVFR OR LOWER POSSIBLE. CHANCE SHOWERS AND TSTMS IN THE AFTERNOON AND OVERNIGHT WITH MVFR OR LOWER. STRONG SLY FLOW. .SUN...MVFR OR LOWER IN SHOWERS/TSTMS POSSIBLE. SHIFTING WINDS TO THE E/NE. .MON...POSSIBLE IMPROVEMENT TO VFR IF SHOWERS/TSTMS MOVE TO THE SOUTH. E/NE FLOW. && .MARINE... MADE MINOR CHANGES TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK. THE SCA WAS EXTENDED ON THE OCEAN TODAY WITH SEAS IN THE 3-5FT RANGE AND SOME GUSTS TO 25KT POSSIBLE...ESPECIALLY IN THE AFTERNOON. SEAS MAY REMAIN CLOSE TO THE 5FT THRESHOLD TONIGHT...BUT IT WAS TOO MARGINAL TO EXTEND THE SCA AT THIS POINT. ALL AREAS BELOW SCA LEVELS ON FRI. SUB-SMALL CRAFT CONDITIONS ARE EXPECTED ON ALL WATERS FRIDAY NIGHT. S FLOW INCREASES SATURDAY AFTERNOON WITH GUSTS UP TO 20 KT POSSIBLE ON ALL WATERS. THIS COULD BE SUFFICIENT TO BRING SEAS ON THE COASTAL OCEAN WATERS TO AROUND 5 FT. SEAS COULD THEN REMAIN AT SCA LEVELS ON THE COASTAL OCEAN WATERS SATURDAY NIGHT-MONDAY. AT THIS TIME SUB- SMALL CRAFT CONDITIONS ARE EXPECTED FOR LONG ISLAND SOUND/NEW YORK HARBOR/THE BAYS OF LONG ISLAND SATURDAY NIGHT-MONDAY. && .HYDROLOGY... WIDESPREAD SIGNIFICANT RAINFALL IS NOT EXPECTED TODAY...HOWEVER ANY TSTMS THAT DEVELOP WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN. IT SHOULD BE DRY FRIDAY NIGHT AND SATURDAY MORNING. THERE IS THE POTENTIAL FOR A WIDESPREAD SIGNIFICANT RAINFALL FROM LATE SATURDAY THROUGH TUESDAY ACROSS THE TRI-STATE. AT THIS TIME IT IS TOO EARLY TO SPECIFY ANY AMOUNTS. IN ADDITION...FROM LATE SATURDAY THROUGH SUNDAY...ANY STRONGER CONVECTION COULD PRODUCE LOCALLY HEAVY RAINFALL...WHICH COULD RESULT IN AT LEAST THE MINOR FLOODING OF URBAN/POOR DRAINAGE AREAS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ350- 353-355. && $$ SYNOPSIS...JMC/MALOIT NEAR TERM...MALOIT/JMC SHORT TERM...JMC LONG TERM...MALOIT AVIATION...BC MARINE...MALOIT/JMC HYDROLOGY...JMC/MALOIT

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