Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 270842 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 442 AM EDT MON OCT 27 2014 .SYNOPSIS... A HIGH PRES RIDGE BUILDS OVER THE TRI-STATE REGION TODAY...AND OFFSHORE ON TUE. A COLD FRONT MOVES ACROSS LATE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE FOLLOWS THROUGH THURSDAY WITH LOW PRESSURE DEVELOPMENT SOUTHEAST OF THE REGION FRIDAY...SWINGING INTO THE CANADIAN MARITIMES AND DEEPENING FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/...
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LOW CLOUDS ENHANCED BY MOISTURE OFF LAKE ONTARIO HAVE BEEN SLOW TO ERODE...PARTICULARLY ACROSS THE HUDSON VALLEY TO CT AND ERN LI. THE CLOUDS ARE LIKELY TRAPPED BELOW THE SUBSIDENCE INVERSION...THE 12Z RAOB SHOULD VERIFY THIS. THIS SETUP WOULD LIMIT THE CLOUD DISSIPATION TIL A FEW HOURS AFT SUNRISE UPPER RIDGE BUILDS IN TODAY SO DRY WX. TEMPS ALOFT WARM BUT LGT WINDS WILL NOT BE CONDUCIVE TO DEEP MIXING. MIXING TO H75 WOULD YIELD LOWER 80S...BUT THE CWA WILL ONLY MAX OUT AROUND 60. HIGH CLOUDS FROM SUBTROPICAL PACIFIC TAP AND MIDWEST CONVECTIVE DEBRIS SPREADS INTO THE REGION LATE THIS AFTERNOON AND TONIGHT. OUTSIDE OF THAT...WINDS WILL BE LGT AND ATTEMPT TO VEER THE SW BY TUE MORNING. EXPECT THE CLOUDS TO KEEP TEMPS FROM COMPLETELY BOTTOMING OUT...SO BLENDED IN THE WARMER GMOS25 WITH THE MET.
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&& .SHORT TERM /TUESDAY/...
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A WARMING TREND AS WINDS VEER TO THE SW AND PICK UP ON THE BACKSIDE OF THE HIGH. HIGH CLOUDS BKN-OVC AT TIMES...BUT BECAUSE OF OPACITY FCST INDICATES MOSTLY SUNNY. UPSTREAM COLD FRONT WILL BE APPROACHING...SO THIS COULD ALLOW FOR A LITTLE COMPRESSIONAL HEATING WHICH COULD BOOST TEMPS A FEW DEGREES ABOVE FCST...ESPECIALLY ACROSS NJ AND THE INTERIOR. MOISTURE AND FORCING IN THE VICINITY OF THE FRONTAL BOUNDARY STILL W OF THE CWA SO CONTINUED DRY WEATHER.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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TUESDAY NIGHT INTO WEDNESDAY...SHORTWAVE AND SFC LOW MOVE NORTHEAST THROUGH ONTARIO AND QUEBEC. AN ASSOCIATED COLD FRONT MOVES ACROSS LATE TUESDAY NIGHT INTO WEDNESDAY. THE JET STREAM MOVES INTO THE REGION AND EVENTUALLY JUST SOUTH OF THE REGION WEDNESDAY NIGHT AS SHORTWAVE EXITS NORTHEAST INTO CANADIAN MARITIMES AND SFC LOW SLOWLY MOVES NORTH IN SOUTHEAST CANADA AND WEAKENS. THE COLD FRONT MOVES FARTHER EAST OF THE AREA AND OFFSHORE. THE RAIN SHOWERS ASSOCIATED WITH THE FRONT START TO MOVE IN LATE TUESDAY NIGHT INTO WEDNESDAY MORNING...THOUGH COULD DISSIPATE WITH EASTWARD PROGRESS DURING WEDNESDAY AS THE FRONT MOVES ACROSS THE REGION. THIS WILL BE ANOTHER MOISTURE LIMITED FRONT. THE GFS AND NAM MODELS HAVE PRETTY GOOD AGREEMENT REGARDING THIS. HOWEVER...THE CANADIAN AND ECMWF SHOW ENHANCEMENT OF PRECIP ALONG THE FRONT FROM THE DELMARVA THROUGH LONG ISLAND AND SOUTHERN CONNECTICUT WEDNESDAY NIGHT WITH THESE MODELS ALREADY SHOWING SOME WEAK LOW DEVELOPMENT ALONG THE SOUTHERN END OF THE FRONT. THEREFORE...KEPT SHOWERS IN THE FORECAST THROUGH WEDNESDAY NIGHT...MAINLY NYC...LONG ISLAND...AND SOUTHEAST CONNECTICUT. WEAK SFC HIGH PRESSURE MOVES IN PLACE THURSDAY AND THURSDAY NIGHT BUT FLOW ALOFT WILL BECOME AMPLIFIED WITH A TROUGH SHARPENING AND APPROACHING THE REGION AS JET STREAM REMAINS SOUTH OF THE REGION. COLD FRONT WILL BE WELL OFFSHORE WITH WEAK LOW PRESSURE DEVELOPING ALONG SOUTHERN END OF FRONT SOUTHEAST OF THE CAROLINAS. DRY WEATHER WILL BE IN PLACE. MODELS HAVE GOOD AGREEMENT WITH TROUGH TO WEST OF REGION FRIDAY AND SFC HIGH PRESSURE IN CENTRAL U.S. BUT THE GFS IS DISTINGUISHED IN THAT IT SHOWS A LOW IN THE NORTHEAST SO SFC FEATURES HAVE GREATER UNCERTAINTY. THE UNCERTAINTY HAS RIPPLE EFFECTS AS THE TROUGH APPROACHING CAN BE TRACED BACK TO UPSTREAM RIDGE AND WEST OF THERE...YET ANOTHER TROUGH. SO OVER THE NEXT FEW DAYS...THERE WILL LIKELY BE SOME TIMING CHANGES OF PRECIP AND TEMPERATURE VARIANCES FROM FORECAST TO FORECAST AS THERE ARE MANY FACTORS THAT HAVE TO BECOME BETTER RESOLVED WITH UPSTREAM FEATURES IN ADDITION TO ONES NEAR THE REGION. THE SHORTWAVE AND JET STREAM FEED MOISTURE INTO THE OFFSHORE FRONT AND LOW DEVELOPING ALONG THE SOUTHERN END OF IT. WITHOUT MUCH SIGNIFICANT EASTWARD PROGRESS OF SFC HIGH PRESSURE...A BLOCKING PATTERN WILL EMERGE AND SHOWERS COULD DEVELOP IN WESTERN PERIPHERY OF CYCLONIC FLOW ALL IN ASSOCIATION WITH DEEP LOW PRESSURE DEVELOPING EAST OF NOVA SCOTIA IN THE PERIOD OF MAINLY FRIDAY NIGHT THROUGH SATURDAY NIGHT. AT NIGHT...TEMPERATURES ARE FORECAST TO BE COLD ENOUGH FOR SOME SNOW SHOWERS NORTH AND WEST OF NYC. THE SOURCES OF THE LOW PRESSURE WILL BE FROM THE CAROLINAS AND ALSO ANOTHER FROM SOUTHEAST CANADA. A STEEP PRESSURE GRADIENT WILL BE ESTABLISHED BETWEEN THE HIGH TO THE WEST OF THE REGION AND LOW PRESSURE EAST OF NOVA SCOTIA FOR NEXT WEEKEND. THEREFORE...MORE GUSTY NORTHERLY FLOW FOR NEXT WEEKEND. THE UPPER LEVEL PATTERN REMAINS CONSISTENT WITH AMPLIFICATION WITH SHORTENING WAVELENGTH OF UPPER LEVEL TROUGH AND JET STREAM STILL SOUTH OF REGION. THE FEATURES TRANSLATE EAST SUNDAY INTO EARLY NEXT WEEK WITH A HIGH PRESSURE RIDGE MOVING IN FROM THE WEST. CONCERNING TEMPERATURES...WARMING TREND COMES TO A CLOSE WEDNESDAY NIGHT...WITH A COLDER AIRMASS MOVING IN BEHIND THE COLD FRONT. TEMPERATURES WILL BE CLOSE TO NORMAL THURSDAY AND THURSDAY NIGHT WITH LOWER THAN NORMAL TEMPERATURES THROUGH THE REMAINDER OF THE FORECAST PERIOD.
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&& .AVIATION /09Z MONDAY THROUGH FRIDAY/...
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HIGH PRESSURE BUILDS OF THE SOUTHEAST AND MID ATLANTIC COASTS INTO FRIDAY EVENING. VFR. CEILINGS AROUND 5000 FT LINGER ON/OFF AT KGON THROUGH POSSIBLY 10Z. WNW WINDS AROUND 10 KT EARLY THIS MORNING. EXCEPTION IS AT KSWF/KISP WHERE WINDS LIGHT AND VARIABLE AND KGON WHERE WINDS LESS THAN 10 KT. WINDS BECOME WNW-NW THROUGHOUT AROUND 10 KT BY MID MORNING...WITH OCCASIONAL GUSTS TO 15-20KT POSSIBLE 12-18Z AT ALL TERMINALS. HOWEVER RELATIVELY LOW CONFIDENCE IN OCCURRENCE AND LIMITED DURATION AT ANY GIVEN POINT DO NOT WARRANT PLACING IN TAFS AT THIS TIME. WINDS BACK TO THE W-WSW BY EARLY EVENING...THEN BECOME LIGHT AND VARIABLE THROUGH THE EVENING. ...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: WINDS MAINLY JUST TO THE LEFT OF 300 TRUE/310 MAGNETIC. HOWEVER...THERE WILL BE OCCASIONS WHERE WINDS REACH OR GO 10 TO 20 DEGREES TO THE RIGHT OF 300 TRUE/310 MAGNETIC. LOW-MODERATE CHANCE OF OCCASIONAL GUSTS TO 15-20KT FROM LATE MORNING INTO MID AFTERNOON. TIMING OF CHANGES IN WIND DIRECTION AND SPEED COULD BE OFF +/- 1-3 HOURS. KLGA FCSTER COMMENTS: WINDS MAINLY JUST TO THE LEFT OF 300 TRUE/310 MAGNETIC. HOWEVER...THERE WILL BE OCCASIONS WHERE WINDS REACH OR GO 10 TO 20 DEGREES TO THE RIGHT OF 300 TRUE/310 MAGNETIC. LOW-MODERATE CHANCE OF OCCASIONAL GUSTS TO 15-20KT FROM LATE MORNING INTO MID AFTERNOON. TIMING OF CHANGES IN WIND DIRECTION AND SPEED COULD BE OFF +/- 1-3 HOURS. KEWR FCSTER COMMENTS: WINDS MAINLY TO THE LEFT OF 300 TRUE/310 MAGNETIC. HOWEVER...THERE WILL BE BRIEF OCCASIONS WHERE WINDS REACH OR GO 10 TO POSSIBLY 20 DEGREES TO THE RIGHT OF 300 TRUE/310 MAGNETIC. LOW-MODERATE CHANCE OF OCCASIONAL GUSTS TO 15-20KT FROM LATE MORNING INTO MID AFTERNOON. TIMING OF CHANGES IN WIND DIRECTION AND SPEED COULD BE OFF +/- 1-3 HOURS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: LOW-MODERATE CHANCE OF OCCASIONAL GUSTS TO 15-20KT FROM LATE MORNING INTO MID AFTERNOON. TIMING OF CHANGES IN WIND DIRECTION AND SPEED COULD BE OFF +/- 1-3 HOURS. KHPN FCSTER COMMENTS: LOW-MODERATE CHANCE OF OCCASIONAL GUSTS TO 15-20KT FROM LATE MORNING INTO MID AFTERNOON. TIMING OF CHANGES IN WIND DIRECTION AND SPEED COULD BE OFF +/- 1-3 HOURS. KISP FCSTER COMMENTS: LOW-MODERATE CHANCE OF OCCASIONAL GUSTS TO 15-20KT FROM LATE MORNING INTO MID AFTERNOON. TIMING OF CHANGES IN WIND DIRECTION AND SPEED COULD BE OFF +/- 1-3 HOURS. .OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY. .LATE MONDAY NIGHT-TUESDAY...VFR. .TUESDAY NIGHT...MAINLY VFR. LLWS POSSIBLE SOUTHERN TERMINALS. BRIEF PERIOD MVFR POSSIBLE IN ANY STRONGER -SHRA - MAINLY AFTER MIDNIGHT. .WEDNESDAY-WEDNESDAY NIGHT...MAINLY VFR. HOWEVER BRIEF PERIOD OF MVFR OR LOWER POSSIBLE IN ANY STRONGER -SHRA. WINDS VEER WSW TO NW WITH PASSAGE OF COLD FRONT. G15-20KT POSSIBLE. .THURSDAY-FRIDAY...VFR.
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&& .MARINE...
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WINS AND SEAS HAVE FALLEN BELOW SCA LEVELS...SO THE SCA HAS BEEN CANCELLED. CONDITIONS BELOW SCA LEVELS THROUGH TONIGHT WITH HIGH PRESSURE OVER THE WATERS. RETURN FLOW ON TUE AS THE HIGH DRIFTS E OVER THE ATLANTIC...BUT WINDS AND SEAS LIKELY REMAIN BELOW SCA LEVELS. SOUTHERLY FETCH AHEAD OF COLD FRONT WILL KEEP SCA SEAS ON OCEAN TUE NIGHT THROUGH MUCH OF WED NIGHT WITH SEAS FALLING BELOW SCA BEFORE DAYBREAK THU. SEAS ARE FORECAST TO STAY BELOW SCA THEREAFTER UNTIL SAT WHEN OCEAN SEAS OF AT LEAST 5-7 FT WILL BE POSSIBLE. REGARDING WINDS...THERE COULD BE SOME SCA WIND GUSTS RIGHT AHEAD OF THE COLD FRONT LATE TUE NIGHT. OTHER WATERS WILL BE BELOW SCA FOR WINDS. THE OCEAN WILL REMAIN MARGINAL FOR SCA WINDS WITH GUSTS 20-25 KT WED AND WED NIGHT. OTHER WATERS CLOSER TO 20 KT. SUB SCA THEREAFTER UNTIL FRIDAY NIGHT AND THE WEEKEND...WHICH LOOKS TO BE A ROUGH PERIOD FOR THE AREA WATERS. GALES WILL BE POSSIBLE FOR THE WEEKEND.
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&& .HYDROLOGY...
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NO SIGNIFICANT WIDESPREAD PRECIPITATION EXPECTED.
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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...MALOIT MARINE...JMC/JM HYDROLOGY...JM

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