Area Forecast Discussion
Issued by NWS Upton, NY

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319 FXUS61 KOKX 270554 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 154 AM EDT WED APR 27 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 THIS MORNING/...
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OVERCAST CONDITIONS REMAIN AS HIGH PRESSURE BUILDS IN SLOWLY FROM THE NORTH AND MOISTURE REMAINS...SO INCREASED CLOUD COVER OVERNIGHT INTO WEDNESDAY MORNING. OTHERWISE FORECAST TEMPERATURES AND DEW POINTS...ALONG WITH OVERNIGHT LOWS ARE ON TRACK. 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.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... 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 NIGHT 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 /06Z WEDNESDAY THROUGH SUNDAY/...
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A FRONTAL BOUNDARY SOUTH OF LONG ISLAND WILL GRADUALLY CONTINUE MOVING SOUTH AS A WAVE OF LOW PRES RIDES ALONG IT TONIGHT. HIGH PRES BUILDS IN WED. WINDS BECOME NLY OVERNIGHT AND CONTINUE INTO WED AT AROUND 10 KT OR LESS. SLY WINDS DEVELOP WED AFTN WITH THE SEA BREEZE DEVELOPMENT. MVFR IMPROVES TO VFR BEFORE 10Z. THE EXACT TIMING OF IMPROVEMENT TO VFR IN THE TAFS COULD BE +/- 1-3 HOURS. ONCE VFR RETURNS...IT IS EXPECTED TO LAST THROUGH THE REST OF THE TAF PERIOD. .OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .LATE WEDNESDAY NIGHT...VFR. .THURSDAY-FRIDAY...MVFR POSSIBLE IN RAIN. .FRIDAY NIGHT-SATURDAY NIGHT...VFR. .SUNDAY...MVFR OR LOWER POSSIBLE LATE IN RAIN.
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&& .MARINE...
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SMALL CRAFT SEAS REMAIN ON THE OCEAN WATERS OVERNIGHT AND INTO EARLY WEDNESDAY MORNING...WITH A LIGHT NORTH TO NORTHEAST FLOW. AN ADVISORY REMAINS IN EFFECT THROUGH 800 AM WEDNESDAY. WINDS AND SEAS REMAIN BELOW SMALL CRAFT LEVELS ON ALL THE FORECAST WATERS LATER WEDNESDAY THROUGH THURSDAY AS HIGH PRESSURE BUILDS IN THROUGH EARLY THURSDAY...AND A WEAK WAVE OF LOW PRESSURE APPROACHES LATER THURSDAY AS THE HIGH MOVES OFF THE COAST. A LIGHT TO MODERATE PRESSURE GRADIENT OVER THE REGION THURSDAY NIGHT THROUGH 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.
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&& .HYDROLOGY...
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NO SIGNIFICANT WIDESPREAD RAINFALL IS EXPECTED 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.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ350- 353-355.
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&& $$ SYNOPSIS...MALOIT/NV NEAR TERM...MET SHORT TERM...NV LONG TERM...MALOIT AVIATION...JM MARINE...MET HYDROLOGY...MET

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