Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 240914 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 514 AM EDT THU JUL 24 2014 .SYNOPSIS... A COLD FRONT MOVES SLOWLY EAST TODAY. HIGH PRESSURE BUILDS TONIGHT AND FRIDAY. HIGH PRESSURE MOVES FARTHER OFFSHORE ON SATURDAY. A FRONTAL SYSTEM APPROACHES SATURDAY NIGHT INTO SUNDAY...WITH AN ASSOCIATED AREA OF LOW PRESSURE PASSING TO THE NORTHWEST ON MONDAY. FOLLOWING THE COLD FRONT PASSAGE...HIGH PRESSURE BUILDS IN TOWARDS MID-WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE COLD FRONT MOVES SLOWLY EAST TODAY AS UPPER TROUGH APPROACHES FROM THE WEST. DRIER AIR MOVES IN FROM THE NW...WITH WEAK COLD AIR ADVECTION NOTED BEHIND THE FRONT AND WITH THE APPROACH OF THE TROUGH. CANNOT RULE OUT ISOLATED SHOWERS...MAINLY EASTERN LOCALES PER 12KM WRF...WRF-NMM...WRF-ARW...HRRR AND CANADIAN. DEVELOPMENT OF SHOWERS REMAINS POSSIBLE DUE TO EXPECTED WEAK CAPE...AND VORTICITY ADVECTION IN THE MID LEVELS. IN GENERAL THOUGH...DRY WEATHER IS EXPECTED FOR MOST LOCATIONS. ASSUMING MIXING UP TO ABOUT H8...HIGH TEMPS IN THE LOWER 80S SEEM REASONABLE BASED ON H8 TEMPS SETTLING AROUND 12C PER NAM AND GFS. MOS NUMBERS CLOSE AND ACCEPTED. CANNOT RULE OUT LATE DAY SEA BREEZES IF WINDS REMAIN SUFFICIENTLY WEAK. A MODERATE RISK OF RIP CURRENTS EXISTS FOR EASTERN LONG ISLAND BEACHES TODAY WITH RESIDUAL SOUTHERLY SWELLS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... UPPER TROUGH MOVES ACROSS THE AREA AND LIFTS TO THE NORTH THROUGH THIS TIME FRAME. AT THE SFC...HIGH PRESSURE BUILDS FROM THE WEST. ANY EVENING SHOWERS GIVE WAY TO DRY WEATHER WITH LOWER HUMIDITY. A LIGHT NORTHERLY WIND TONIGHT WILL GIVE WAY TO ONSHORE FLOW FRIDAY AS THE HIGH MOVES OVERHEAD. MOS TEMPS ARE CLOSE...WITH 50S ACROSS THE INTERIOR...AND 60S NEAR THE COAST TONIGHT...AND UPPER 70S TO LOWER 80S FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... AS HIGH PRESSURE SHIFTS FARTHER OFFSHORE ON SATURDAY...RETURN FLOW WILL HELP INCREASE MOISTURE ACROSS THE TRI-STATE. ADDITIONALLY...WEAK H5 SHORTWAVES PASSING NEAR/JUST NORTH OF THE AREA IN ZONAL FLOW RESULT IN SLIGHT/LOW CHC POPS ACROSS THE AREA. LATE SATURDAY NIGHT INTO SUNDAY MORNING...A WARM FRONT WILL LIFT ACROSS THE AREA AS A STRONGER SHORTWAVE PROGRESSES TO THE EAST ACROSS SOUTHERN ONTARIO/QUEBEC. AS A RESULT...CHANCES FOR SHOWERS AND STORMS WILL BE ON THE INCREASE...AS SW FLOW ALOFT INCREASES OVER THE FRONTAL SURFACE. AS THE WARM FRONT LIFTS NORTH AND EAST OF THE REGION DURING THE FIRST HALF OF SUNDAY...THERE MAY BE SOMEWHAT OF A LULL IN ACTIVITY ACROSS THE AREA. HOWEVER...WITH SEVERAL SHORTWAVES EMBEDDED IN THE FLOW ALOFT AND THE INCREASING MOISTURE PRESENT...TIMING OF MORE WIDESPREAD ACTIVITY IS FAIRLY UNCERTAIN. 24/00Z GFS IS MORE ROBUST/QUICKER THAN 24/00Z CMC/ECMWF WITH A WAVE APPROACHING FROM THE WEST ON SUNDAY. BELIEVE IT IS A LITTLE TOO FAST...THEREFORE DID NOT GO WITH LIKELY POPS EVERYWHERE UNTIL SUNDAY NIGHT. DURING THIS TIME...THE CMC SOLUTION INDICATES THE POTENTIAL FOR WIDESPREAD HEAVY RAIN...AS SOMEWHAT STRUNG-OUT CYCLOGENESIS TAKES PLACE ACROSS THE AREA...AND A STRONG LLJ DEVELOPS ALONG AN AXIS OF HIGHER H5 THETA-E. ECMWF APPEARS TO KEEP THE UPPER-LEVEL JET DYNAMICS A LITTLE FARTHER NW/WEAKER...RESULTING IN HIGHER QPF BYPASSING THE AREA TO THE NW. REGARDLESS...PRECIP APPEARS LIKELY BY SUNDAY NIGHT. CHANCES FOR RAIN GRADUALLY DIMINISH MONDAY INTO MONDAY NIGHT AND TUESDAY...AS THE ASSOCIATED SURFACE COLD FRONT MOVES THROUGH THE AREA AND OFF TO THE EAST. NONETHELESS...WITH THE DEEP UPPER-LEVEL TROUGH TAKING HOLD AND CYCLONIC FLOW ACROSS THE REGION...SOME DIURNAL ACTIVITY IS POSSIBLE TUESDAY. FOLLOWING THE FRONTAL PASSAGE...TEMPS LOOK TO BE A FEW DEGREES BELOW NORMAL TUESDAY INTO WEDNESDAY. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... COLD FRONT HAS PUSHED EAST OF ALL TERMINALS...MARKED BY A WIND SHIFT TO THE NW. AN UPPER TROUGH WILL PASS THROUGH TODAY...BRINGING THE CHC OF ISOLD SHRA/TSTMS MAINLY E OF NYC. LOW LEVEL MOISTURE IS STILL FAIRLY HIGH...WHICH HAS RESULTED IN THE FORMATION OF MVFR CIGS IN THE NYC METRO. MODELS INDICATE THAT THIS WILL PERSIST THROUGH 12Z OR SO...BUT MAY BEGIN TO LIFT TO LOW END VFR AFT 10Z. HAVE NOT EXPANDED THESE CIGS INTO EASTERN TERMINALS AS THERE IS NO INDICATION OF DEVELOPMENT AND MAY ONLY BE SCT AS MODELS INDICATE. THERE COULD ALSO BE PATCHY MVFR FOG THROUGH 12Z WHERE WINDS ARE BELOW 5 KT. VFR CONDS THEN EXPECTED ALL TERMINALS THROUGH 06Z FRI...EXCEPT IN ANY ISOLD SHRA/TSTMS LATER TODAY WHERE THEY COULD BRIEFLY DROP OF MVFR. MODERATE TO HIGH CONFIDENCE IN WIND FORECASTS. LOW LEVEL WINDS IN THE MODEL GUIDANCE HAS TRENDED LOWER DURING THE DAY...THEREFORE DO NOT THINK THERE WILL BE MUCH IN THE WAY OF GUSTS. IN LIGHT OF THIS...THE POTENTIAL FOR SEABREEZE DEVELOPMENT IS POSSIBLE ALTHOUGH HIGHEST CHC IS AT KGON/KBDR AND POSSIBLY KJFK LATE IN THE DAY. DUE TO LACK OF CONFIDENCE AT KJFK...HAVE ONLY TEMPO`ED FOR NOW. OTHERWISE...THERE IS SOME GUIDANCE INDICATING THAT WIND DIRECTIONS MAY BACK 30-40 DEGREES AT COASTAL TERMINALS AFT 18Z. ...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: MVFR CIGS MAY LIFT EARLIER THAN FORECAST. SLY WINDS POSSIBLE AFT 19Z...OTHERWISE...MODERATE TO HIGH CONFIDENCE WINDS REMAIN RIGHT OF 310 MAGNETIC. ISOLD GUSTS UP TO 20 KT BETWEEN 11Z AND 14Z. KLGA FCSTER COMMENTS: MVFR CIGS MAY LIFT EARLIER THAN FORECAST. MODERATE TO HIGH CONFIDENCE WINDS REMAIN RIGHT OF 310 MAGNETIC. ISOLD GUSTS UP TO 20 KT BETWEEN 11Z AND 14Z. KEWR FCSTER COMMENTS: MVFR CIGS MAY LIFT EARLIER THAN FORECAST. MODERATE TO HIGH CONFIDENCE WINDS REMAIN RIGHT OF 310 MAGNETIC. ISOLD GUSTS UP TO 20 KT BETWEEN 11Z AND 14Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: MVFR CIGS MAY LIFT EARLIER THAN FORECAST. ISOLD GUSTS UP TO 20 KT BETWEEN 11Z AND 14Z. KHPN FCSTER COMMENTS: MVFR CIGS POSSIBLE THROUGH 13Z. ISOLD GUSTS UP TO 20 KT BETWEEN 12Z AND 14Z. KISP FCSTER COMMENTS: MVFR CIGS POSSIBLE THROUGH 13Z. WLY WINDS POSSIBLE AFT 18Z. LOW CHC OF SLY WINDS AFT 20Z. ISOLD GUSTS UP TO 20 KT BETWEEN 12Z AND 15Z. .OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY... .THURSDAY NIGHT-SATURDAY...VFR. .SATURDAY NIGHT-MONDAY...VFR WITH A CHANCE OF SHRA/TSTMS WITH MVFR OR LOWER POSSIBLE. && .MARINE... A COLD FRONT SLOWLY MOVES EAST OF THE WATERS TODAY AND TONIGHT. HIGH PRESSURE BUILDS IN FRIDAY. SUB SCA CONDITIONS ARE ANTICIPATED TODAY THROUGH FRIDAY. RELATIVELY TRANQUIL CONDITIONS LOOK TO EXIST ON THE OCEAN WATERS THROUGH SATURDAY. WITH STRENGTHENING S/SW WINDS SATURDAY NIGHT INTO SUNDAY...SEAS LOOK TO REACH SCA CRITERIA DURING THE SECOND HALF OF THE WEEKEND INTO EARLY NEXT WEEK. && .HYDROLOGY... AREAS OF LOW PRESSURE PASSING NEAR THE AREA SUNDAY INTO MONDAY HAVE THE POTENTIAL TO PRODUCE SHOWERS AND STORMS CAPABLE OF HEAVY RAIN. SIGNIFICANT UNCERTAINTY STILL EXISTS WITH TIMING/AMOUNTS THOUGH...SO WILL NOT OUTLOOK IN HWO AT THIS TIME. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...PICCA/PW NEAR TERM...PW SHORT TERM...PW LONG TERM...PICCA AVIATION... MARINE...PICCA/PW HYDROLOGY...PICCA/PW

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