Area Forecast Discussion
Issued by NWS Upton, NY

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091 FXUS61 KOKX 270250 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1050 PM EDT TUE APR 26 2016 .SYNOPSIS... HIGH PRESSURE BUILDS IN THROUGH WEDNESDAY NIGHT. LOW PRESSURE TRACKS FROM THE OHIO VALLEY TO SOUTH OF LONG ISLAND THURSDAY AND THURSDAY NIGHT...FOLLOWED BY HIGH PRESSURE BUILDING IN FRIDAY- SATURDAY NIGHT. THE HIGH SLOWLY RETREATS TO THE NORTHEAST SUNDAY THROUGH TUESDAY. MEANWHILE...A SLOW MOVING STORM SYSTEM APPROACHES FROM THE SOUTHWEST SUNDAY AND MONDAY...THEN TRACKS TO THE SOUTH OF LONG ISLAND MONDAY NIGHT AND TUESDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... MINOR UPDATES MAINLY TO TEMP AND DEWPOINT GRIDS TO ACCOUNT FOR THE LATEST OBS AND TRENDS. STRATUS WILL LIKELY BE SLOW TO ERODE OVERNIGHT DUE A STRONG LOW-LEVEL INVERSION. CLOUD COVER WILL MAKE FOR A TOUGH TEMPERATURE FORECAST TONIGHT DESPITE WEAKENING WINDS ACROSS OUTLYING AREAS. IF SKIES CLEAR...RADIATIONAL COOLING WILL LIKELY RESULT IN FROST CONDITIONS ACROSS INTERIOR VALLEYS. IF STRATUS HANGS TOUGH THOUGH...THE FROST THREAT WILL DIMINISH. DO NOT HAVE ENOUGH CONFIDENCE FOR FROST ADVISORY. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... MEAN TROUGHING ACROSS THE REGION WEDNESDAY...SLOWLY LIFTING WED NIGHT. AT THE SURFACE...CANADIAN HIGH PRESSURE GRADUALLY BUILDS IN FROM THE NW DURING THE PERIOD. WOULD EXPECT ANY MORNING LINGERING STRATUS TO CLEAR OUT WED MORNING...WITH SUNNY CONDITIONS UNDER LIGHT NORTHERLY FLOW. AFTERNOON COASTAL SEABREEZE DEVELOPMENT EXPECTED. HIGHS SLIGHTLY BELOW SEASONABLE LEVELS UNDER CANADIAN HIGH PRESSURE...GENERALLY UPPER 50S TO LOWER 60S. GOOD RADIATIONAL COOLING LIKELY WED NIGHT OUTSIDE OF URBAN CENTERS UNDER INFLUENCE OF HIGH PRESSURE. FROST FREEZE CONDITIONS POSSIBLE ACROSS INTERIOR AND PINE BARRENS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... THE REGION WILL BE UNDER MAINLY ZONAL FLOW ALOFT THURSDAY THROUGH FRIDAY. THE FIRST HALF OF THURSDAY SHOULD BE DRY...BUT A SHORTWAVE EMBEDDED IN THE FLOW WARRANTS A CHANCE OF RAIN MAINLY OVER THE SW TO S 1/2-3/4 OF THE CWA FROM THURSDAY AFTERNOON THROUGH FRIDAY. THERE ARE SOME DIFFERENCES IN THE MODELS OVER HOW FAR TO THE S THE SHORTWAVE PASSES...MAKING FOR DIFFERENCE IN AREAS IMPACTED. IT IS POSSIBLE THE SHORTWAVE COULD PASS FAR ENOUGH S...THAT THE AREA STAYS DRY THURSDAY-FRIDAY. FOR HIGHS THURSDAY...A BLEND OF MAV/MET/ECS GUIDANCE...NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 900 HPA WAS PER BUFKIT SOUNDINGS WAS USED. HIGHS SHOULD BE AROUND 5-10 DEGREES BELOW NORMAL. FOR LOWS THURSDAY NIGHT A BLEND OF ECS/MET/MAV GUIDANCE AND NAM 2-METER TEMPERATURES WAS USED...WITH VALUES FORECAST TO BE NEAR NORMAL. FOR HIGHS ON FRIDAY...A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE...NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 925-875 HPA WAS USED PER BUFKIT SOUNDINGS. HIGHS SHOULD BE AROUND 5-10 DEGREES BELOW NORMAL. THE REGION IS PROGGED TO BE ON THE NORTHERN PERIPHERY OF A DEEP LAYERED RIDGE FROM FRIDAY NIGHT INTO SUNDAY. ASSOCIATED SUBSIDENCE SHOULD KEEP THINGS DRY FRIDAY NIGHT-SATURDAY NIGHT. THERE IS SOME DIFFERENCES BETWEEN THE MODELS ON HOW QUICKLY THE RIDGE AXIS SLIDES TO THE EAST EARLY NEXT WEEK. FOR NOW SIDED WITH A BLEND OF THE SLOWER CMC/ECMWF...SO INTRODUCE SLIGHT CHANCE POPS OVER MAINLY AREAS N/W OF NYC SUNDAY AFTERNOON. A SLOW MOVING FULL LATITUDE TROUGH IMPACTS THE TRI-STATE FROM SUNDAY NIGHT-TUESDAY. CONTINUED TO SIDE WITH SLOWER ECMWF...AS THE FLOW IS FORECAST TO BECOME QUITE MERIDIONAL...WHICH TENDS TO FAVOR A SLOWER PROGRESSION IN SYSTEMS. AS A RESULT HAVE CHANCE POPS FOR RAIN SUNDAY NIGHT-TUESDAY CWA WIDE. FOR TEMPERATURES FRIDAY NIGHT-TUESDAY THE SUPER BLEND WAS USED. TEMPERATURES START OUT WITHIN A FEW DEGREES ON EITHER SIDE OF NORMAL FRIDAY NIGHT-SUNDAY NIGHT...THEN TRANSITION TO BELOW NORMAL FOR HIGHS AND NEAR TO SLIGHTLY ABOVE NORMAL FOR LOWS MONDAY-TUESDAY. NOTE...DEPENDING ON EXACTLY HOW FAST THE SYSTEM MOVES EARLY NEXT WEEK WILL PLAY A LARGE BEARING ON HOW WARM/COLD IT ACTUALLY ENDS UP BEING MONDAY/TUESDAY. THERE IS THE POTENTIAL FOR QUITE OF BIT OF CHANGE IN THE TEMPERATURE FORECAST IN THIS TIME FRAME UNTIL THIS IS RESOLVED. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... A FRONTAL BOUNDARY SOUTH OF LONG ISLAND WILL GRADUALLY CONTINUE SWD AS A WAVE OF LOW PRES RIDES ALONG IT TONIGHT. E-NE WINDS THIS EVE WILL BECOME NLY OVERNIGHT AND CONTINUE INTO WED. AFT A BRIEF SURGE IN SPEEDS THIS EVE...WINDS ARE EXPECTED TO DIMINISH BELOW 10 KT. SLY WINDS DEVELOP WED AFTN WITH TRUE SEABREEZES POSSIBLE. MVFR TO IFR CIGS ALL TERMINALS THIS EVE WILL GRADUALLY LIFT TONIGHT AS THE FRONT MOVES FURTHER S AND HIGH PRES BUILDS IN. TIMING OF VFR RETURNING IS A BIT TRICKY DUE TO A LOW LEVEL INVERSION TRAPPING MOISTURE BENEATH IT BUT EXPECT IMPROVEMENT FROM N TO S BETWEEN 06Z AND 10Z. THE EXACT TIMING IN THE TAFS COULD BE +/- 1-2 HOURS. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .WEDNESDAY NIGHT...VFR. .THURSDAY-FRIDAY...MVFR POSSIBLE IN RAIN. .FRIDAY NIGHT-SATURDAY...VFR. .SUNDAY...SUB-VFR POSSIBLE LATE IN PRECIPITATION. && .MARINE... A SCA REMAINS IN EFFECT FOR THE OCEAN THRU TONIGHT MAINLY FOR SEAS 4 TO 6 FT. SEAS ON THE OCEAN SHOULD SUBSIDE TO BELOW SCA LEVELS DURING THE FIRST HALF OF WEDS MORNING. A LIGHT TO MODERATE PRESSURE GRADIENT OVER THE REGION WEDNESDAY- SUNDAY SHOULD KEEP WINDS TO 15 KT OR LESS OVER THE WATERS AROUND LONG ISLAND DURING THIS TIME FRAME. PERSISTENT E-NE FLOW COULD BUILD SEAS ON THE COASTAL OCEAN WATERS TO SCA LEVELS ON SUNDAY. && .HYDROLOGY... NO SIGNIFICANT WIDESPREAD RAINFALL IS EXPECTED TONIGHT INTO SUNDAY. THERE IS THE POTENTIAL FOR WIDESPREAD RAINFALL EARLY NEXT WEEK...BUT AT THIS TIME THERE IS TO MUCH UNCERTAINTY TO SPECIFY AMOUNTS OR ANY POTENTIAL IMPACTS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...MALOIT/NV NEAR TERM...JC/NV SHORT TERM...NV LONG TERM...MALOIT AVIATION...24 MARINE...MALOIT/NV HYDROLOGY...MALOIT/NV

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