AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1020 AM EDT MON JUN 27 2011 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH TONIGHT. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA TUESDAY. A COLD FRONT WILL CROSS THE TRI-STATE TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE BUILDING IN FROM THE GREAT LAKES THROUGH FRIDAY...THAT THEN SLIDES OFFSHORE FRIDAY NIGHT. A WARM FRONT LIFTS TO OUR NORTH SATURDAY...WITH HIGH PRESSURE BUILDING IN TO OUR SOUTHEAST THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1420Z UPDATE...GENERALLY A SUNNY MORNING. SATELLITE IMAGES INDICATE DIURNAL CU STARTING TO DEVELOP OVER THE LOWER HUDSON VALLEY AND NORTHEAST NJ. COULD ALSO SEE FEW-SCT CUMULUS ALONG THE SEABREEZE FRONT THIS AFTERNOON. NAM INDICATES SOME -SHRA ALONG THE BOUNDARY IN CT THIS AFTERNOON. WITH THE BOUNDARY ENDING UP JUST N OF THE CWA AND SYNOPTIC SUBSIDENCE...FCST WILL BE KEPT DRY. TEMPS WARMED A LITTLE MORE QUICKLY THAN FORECAST THIS MORNING DUE TO ABUNDANT SUNSHINE. HOURLY ADJUSTMENTS MADE FOR LATE MORNING- EARLY AFTERNOON. AFTERNOON HIGHS WILL DEPEND ON EFFECTS FROM SEA BREEZES AND ANY CU...WHICH MAY KEEP TEMPS FROM INCREASING IN SPOTS DURING THE MID-AFTERNOON. ALL THINGS CONSIDERED...MADE NO CHANGES TO AFTERNOON HIGHS AT THIS TIME. HIGHS ARE A BLEND OF MAV/MET AND ARE RIGHT AROUND NORMAL FOR THIS TIME OF YEAR. SE SWELL CONTINUES TODAY. ALTHOUGH WIND COMPONENT IS NOT STRONG...OBSERVATIONS OF RIP CURRENTS WERE MODERATE-STRONG YESTERDAY. BECAUSE OF THE SIMILAR SWELL TODAY...WILL INDICATE A MODERATE THREAT FOR RIPS IN THE SURF FCST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... MAIN FCST CONCERN FOR TONIGHT WILL BE THE AMOUNT OF HIGH CLOUDS THAT OVERSPREAD THE CWA FROM MIDWEST CONVECTION. CLOUDS ARE CURRENTLY OUTRUNNING THE MODEL DATA SLIGHTLY...SO IF THIS TREND CONTINUES...AN INCREASE IN THE CLOUD FCST CAN BE EXPECTED. THE RESULT WOULD BE A SLIGHTLY LOWER POTENTIAL FOR SHALLOW FOG INTO TUE MORNING ACROSS THE OUTLYING AREAS. FOR NOW...FOG IS INCLUDED IN THE FCST WITH CALM WINDS AND NO MID/LOW CLOUDS EXPECTED. WARM FRONT CURRENTLY OVER THE VA/NC BORDER WILL LIFT N ON TUE. THE FRONT LOOKS TO PASS BY LATE AFTERNOON. MEANWHILE...H5 TROUGH RACING ACROSS CANADA WILL APPROACH FROM THE W. AT THIS TIME...TIMING IS NOT IN PHASE WITH THE LATE AFTERNOON PRIME TIME FOR CONVECTION. ALTHOUGH TSTMS ARE INCLUDED IN THE FCST FOR THE AFTERNOON...THE THREAT WILL BE ENHANCED IF THE FEATURE ARRIVES A FEW HOURS FASTER THAN CURRENTLY PROGGED BY THE NAM/GFS...AND CLOSER TO THE 00Z ECMWF. INCREASED HEIGHTS WILL LEAD TO WARMER TEMPS THAN TODAY ACROSS THE INTERIOR...WHILE ONSHORE FLOW WILL MEAN SLIGHTLY LOWER TEMPS THAN TODAY FOR SOME SPOTS ALONG THE IMMEDIATE COASTS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE GFS IS THE SLOWEST OF THE MODELS WITH THE COLD FRONT TUESDAY NIGHT AND HAS BEEN DISCARDED AS A SLOW OUTLIER. HAVE MAINTAINED LIKELY POPS TUESDAY NIGHT...THOUGH WITH INSTABILITY LIMITED TO ALOFT HAVE RESTRICTED THE PROBABILITY OF THUNDERSTORMS TO CHANCE. THERE ARE SOME SIGNS THE FRONT COULD BECOME ANAFRONTAL IN NATURE...SO DO HAVE SOME POPS IN FOR SHOWERS THE FIRST PART OF WEDNESDAY MORNING - SLIGHT CHANCE TO CHANCE TAPERING OFF FROM W TO E. THE 00Z ECMWF IS ALONE IN BRINGING THE 500 HPA LOW AS FAR S/E AS IT DOES DURING THE DAY ON WED - AND WITH IT AN ASSOCIATED CHANCE OF INSTABILITY SHRA/TSRA - SO HAVE OPTED NOT TO INCLUDE THIS IN THE FORECAST FOR NOW. FOR LOWS TUESDAY NIGHT USED A 2/3 MAV/MET BLEND WITH 1/3 NAM 2-METER TEMPERATURES...AND FOR HIGHS WEDNESDAY BLENDED A MAV/MET BLEND WITH A MIXING DOWN FROM 825 HPA - PER BUFKIT SOUNDINGS. THE RESULT IS TEMPERATURES A FEW DEGREES ABOVE NORMAL. FOR THE WEDNESDAY NIGHT-THURSDAY NIGHT PERIOD FAVORED THE CMC-GLOBAL AS IT IS IN BETWEEN THE DEEPER/SLOWER 500 HPA LOW IN THE ECMWF AND THE MORE OPEN/PROGRESSIVE LOW IN THE GFS. WITH 20-30KT OF DOWN SLOPING LOW LEVEL BOUNDARY LAYER FLOW WORKING TO HELP DRY OUT THE LOWER LEVELS OF THE ATMOSPHERE...DO NOT FEEL THERE WILL BE ENOUGH MOISTURE AVAILABLE FOR ANY SHORTWAVES ROTATING AROUND THE BASE OF THE UPPER LEVEL LOW TO TRIGGER ANY SHRA/TSRA...SO WENT WITH A DRY FORECAST. ECMWF AND GFS ARE IN GOOD AGREEMENT THAT 500 HPA RIDGING BUILDS IN FRIDAY-SATURDAY - THE QUESTION IS HOW FAR EAST DOES ITS CORE GET...THE GFS IS MORE BULLISH THAN THE ECMWF. SO FOR NOW TOOK TO BLENDING THEIR LOW LEVEL MASS AND THERMAL FIELDS. INTRODUCE SLIGHT CHANCE POPS LATE FRIDAY NIGHT AND SATURDAY TO REFLECT APPROACHING WARM FRONT THAT LIFTS TO THE N SATURDAY. THE GFS AND ECMWF DIFFER SATURDAY NIGHT-SUNDAY ON HOW FAR S A NORTHERN STREAM SHORTWAVE GETS. THE GFS MOVES IT TO THE EAST NEAR THE US/CANADIAN BORDER...WHILE THE ECMWF HAS IT FURTHER N. FOR NOW LEANING MORE TOWARDS THE ECMWF WITH THIS FEATURE...LEAVING THE REGION UNDER THE INFLUENCE OF WEAK TROUGHING AT THE SURFACE AND ON THE NE PERIPHERY OF THE UPPER RIDGE ALOFT. GIVEN THE FAVORABLE LOCATION ON THE /RING OF FIRE/ AND THE PRESENCE OF THE SURFACE TROUGH...HAVE GONE WITH SLIGHT CHANCE POPS FOR DIURNAL SHRA/TSRA. FOR TEMPERATURES WEDNESDAY NIGHT-SUNDAY USED A MEX/MEX ENSEMBLE MEAN BLEND...ADJUSTED TOWARDS CMC-GLOBAL LOW LEVEL THERMAL FIELDS WEDNESDAY NIGHT-THURSDAY NIGHT AND A BLEND OF ECMWF/GFS LOW LEVEL THERMAL FIELDS FRIDAY-SUNDAY. EXPECT TEMPERATURES TO START OUT SLIGHTLY BELOW NORMAL WEDNESDAY NIGHT/THURSDAY...THEN GRADUALLY WARM TO ABOVE NORMAL BY FRIDAY NIGHT...AND CONTINUE ABOVE NORMAL THROUGH THE WEEKEND. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL BUILD INTO THE AREA TODAY. A WARM FRONT WILL APPROACH FROM THE SW TONIGHT. VFR THROUGH 06Z TUE. SKC GIVING WAY TO FEW-SCT FAIR WEATHER CUMULUS THIS AFTERNOON. LIGHT N-NE WINDS THIS MORNING WITH SEABREEZE DEVELOPMENT AT THE COAST LATE THIS MORNING/EARLY AFTERNOON...TIMED FOR 15Z AT CT TERMINALS. WINDS BECOME LIGHT AND VRB THIS EVENING AND OVERNIGHT. THERE IS SOME UNCERTAINTY ON FOG DEVELOPMENT WITH LIGHT WINDS AND LOW TEMP/DEWPOINT SPREAD AS A WARM FRONT APPROACHES LATE TONIGHT. MAY BE TOO MUCH MID/HIGH CLOUDS AROUND FOR FOG...BUT HAVE NOTICED THAT GUIDANCE IS HINTING AT PATCHY MVFR VSBY OUTSIDE OF NYC TERMINALS. LOW CONFIDENCE...THEREFORE HAVE LEFT OUT OF TAFS. COULD ALSO BE A FEW LOW CLOUDS AS WELL. 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: HIGH CONFIDENCE OF SEABREEZE. TIMING OF WIND SHIFT BETWEEN 16Z AND 18Z. WIND SPEEDS COULD INCREASE TO AROUND 15KT AFT 20Z. KLGA FCSTER COMMENTS: LIGHT SOUND BREEZE THIS MORNING. HIGH CONFIDENCE OF SEABREEZE. TIMING OF WIND SHIFT BETWEEN 17Z AND 19Z. KEWR FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE OF SEABREEZE. TIMING OF WIND SHIFT BETWEEN 17Z AND 19Z. KTEB FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE OF SEABREEZE. TIMING OF WIND SHIFT BETWEEN 17Z AND 19Z. KHPN FCSTER COMMENTS: HIGH CONFIDENCE OF SEABREEZE. TIMING OF WIND SHIFT BETWEEN 17Z AND 19Z. KISP FCSTER COMMENTS: HIGH CONFIDENCE OF SEABREEZE. TIMING OF WIND SHIFT BETWEEN 17Z AND 19Z. OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... TUE...WARM FROPA. EARLY PATCHY MVFR FOG POSSIBLE...OTHERWISE VFR. TUE EVE/NIGHT...SHRA/TSRA. SUB-VFR POSSIBLE AT TIMES. WED-FRI...CHANCE SUB-VFR EARLY AM WED...OTHERWISE VFR. && .MARINE... 1130Z UPDATE...MINOR CHANGES TO WINDS/WAVES TO REFLECT LATEST OBSERVATION TRENDS. LIGHT FLOW THROUGH TUE WILL RESULT IN WINDS/SEAS BELOW SCA LEVELS. THE STRONGEST WINDS TODAY WILL BE NEARSHORE DUE TO SEABREEZE FLOW. WINDS WILL VEER TO THE S BEHIND THE WARM FRONT TUE. SUB-SMALL CRAFT CONDITIONS ARE EXPECTED TUESDAY NIGHT-FRIDAY. OUTSIDE OF SOME STRONGER WINDS WEDNESDAY NIGHT AS 15-20 KT WINDS MIX DOWN FROM 950 HPA...WINDS SHOULD BE 10 KT OR LESS THROUGH THE PERIOD DUE TO A RELAXED PRESSURE GRADIENT OVER THE REGION. && .HYDROLOGY... UP TO AROUND A HALF AN INCH OF BASIN AVERAGE RAINFALL IS POSSIBLE AHEAD OF A FRONTAL SYSTEM TUESDAY AFTERNOON AND NIGHT...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IN ANY STRONGER CONVECTION. DRY CONDITIONS ARE THEN EXPECTED WEDNESDAY-FRIDAY. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JMC/MALOIT