Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 280801 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 401 AM EDT THU MAY 28 2015 .SYNOPSIS...
-- Changed Discussion --
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.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
REMNANTS OF THE FIRST FRONT SHOW UP ON IR FROM ERN ME THRU THE CWA AND INTO THE CAROLINAS. THIS WILL PROVIDE SOME LLVL CONVERGENCE THRU THIS MRNG...AND COULD PRODUCE A FEW SHWRS OR AN ISOLD TSTM. THE LIMITING FACTOR IS A LACK OF INSTABILITY. THE MARINE INFLUENCE RESULTS IN MINUSCULE SBCAPE INVOF THE BOUNDARY...HOWEVER THERE IS A FEW HUNDRED J/KG OF ELEVATED CAPE. AS A RESULT HAVE AROUND A 30 POP FOR ACTIVITY THIS MRNG. THE SECOND FRONT DRAWS CLOSER THIS AFTN. MORE IMPORTANTLY...A MID LVL SHRTWV SHOWING UP ON STLT 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 SBCAPE INCREASES...THE WAVE SHOULD SERVE AS A TRIGGER...PARTICULARLY WHERE CIN IS SUFFICIENTLY ERODED. ANYWHERE FROM NERN NJ THRU THE CITY INTO INTERIOR CT AND THE LWR HUDSON VALLEY WILL BE IN THIS ZONE PER THE LATEST DATA. LI AND ERN CT SHOULD BE TOO STABLE FOR MUCH INITIATION...AND THE FOCUS WILL LIKELY BE ON ACTIVITY SUSTAINING WITH STORM MOTION SELY 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 BRN 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 ATTM WHERE THE EHI IS HIGHER. ANY CONVECTION SHOULD DECLINE TNGT WITH THE PASSAGE OF THE BOUNDARY...SUBSIDENCE AND STABLE NE FLOW. THERE IS A MDT RISK FOR RIPS AT THE OCEAN TODAY.
-- End Changed Discussion --
&& .SHORT TERM /FRIDAY/...
-- Changed Discussion --
THE REMNANTS OF THE COLD FRONT WILL FIZZLE OFFSHORE...ALLOWING EARLY NE WINDS TO VEER THRU THE DAY BECOMING S BY AFTN. WITH A STABLE AIRMASS OVER THE REGION...HAVE MAINTAINED THE DRY FCST. MODEL TIME HEIGHTS REVEAL A BIT OF A CHALLENGE WRT 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 LLVL MOISTURE BIAS. TEMPS WILL BE COOLER AND A BLEND OF THE GUIDANCE WAS USED.
-- End Changed Discussion --
&& .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --
&& .AVIATION /08Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE REMAINS ACROSS THE NORTH ATLANTIC. MEANWHILE...AN AREA OF LOW PRESSURE WILL MOVE THROUGH EASTERN CANADA OVERNIGHT THROUGH THURSDAY BRINGING A WEAKENING COLD FRONT TOWARD THE AREA THURSDAY 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 LOW CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS WITH THE FRONT. VFR UNTIL LATE TONIGHT WHEN MARGINAL CEILINGS IN STRATUS ARE EXPECTED WITH CEILINGS 1000 TO 2000 FT. LOCAL MARGINAL VFR FOG IS ALSO POSSIBLE. ANY MARGINAL VFR CEILINGS BECOME VFR AFTER 15Z THURSDAY. MODERATE CONFIDENCE IN THE FORECAST OF STRATUS AND FOG. .OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY... .THU NIGHT...COLD FRONT MOVES THROUGH EARLY IN THE EVENING WITH THE WIND SHIFTING TO NW TO N. VFR. .FRI...VFR. LGT NE WINDS VEERING THRU THE DAY. .SAT...MRNG MVFR OR LOWER POSSIBLE. CHC SHWRS AND TSTMS IN THE AFTN 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...
-- Changed Discussion --
THE SCA WAS EXTENDED ON THE OCEAN TODAY WITH SEAS IN THE 3-5FT RANGE AND SOME GUSTS TO 25KT POSSIBLE...ESPECIALLY IN THE AFTN. SEAS MAY REMAIN CLOSE TO THE 5FT THRESHOLD TNGT...BUT IT WAS TOO MRGNL TO EXTEND THE SCA AT THIS POINT. ALL AREAS BLW SCA LVLS 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.
-- End Changed Discussion --
&& .HYDROLOGY...
-- Changed Discussion --
WIDESPREAD SIGNIFICANT RAINFALL IS NOT EXPECTED TODAY...HOWEVER ANY TSTMS THAT DEVELOP WILL BE CAPABLE OF PRODUCING LOCALLY HVY 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.
-- End Changed Discussion --
&& .OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ350- 353-355.
-- End Changed Discussion --
&& $$ SYNOPSIS...JMC/MALOIT NEAR TERM...JMC SHORT TERM...JMC LONG TERM...MALOIT AVIATION...BC MARINE...JMC/MALOIT HYDROLOGY...JMC/MALOIT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.