Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 290603 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 203 AM EDT FRI MAY 29 2015 .SYNOPSIS... HIGH PRESSURE BUILDS DOWN FROM SOUTHEASTERN CANADA THIS MORNING...THEN MERGES WITH THE BERMUDA HIGH THIS AFTERNOON. THE BERMUDA HIGH THEN SLOWLY RETREATS TO THE EAST INTO THE WEEKEND. A SLOW MOVING COLD FRONT APPROACHES FROM THE WEST SATURDAY...EVENTUALLY MOVES IN SATURDAY NIGHT...THEN STALLS NEAR THE REGION INTO EARLY NEXT WEEK. HIGH PRESSURE BUILDS IN FROM THE NORTH LATE TUESDAY INTO MID NEXT WEEK AND ONCE AGAIN BECOMES ESTABLISHED OFFSHORE IN THE WESTERN ATLANTIC. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... COLD FRONT IS THRU THE CWA WITH NLY COMPONENT FLOW. MAINLY CLR SKIES FOR THE REST OF THE NGT WITH SOME PATCHY RADIATION FOG. FORECAST LOWS ARE EXPECTED TO RANGE FROM MID 50S TO MID 60S. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... DEEP-LAYERED RIDGING WILL PROVIDE THE SUBSIDENCE AND DRYING FOR A SUNNY DAY ON FRIDAY. MAV/NAM MOS BLEND IN GOOD AGREEMENT...AND WAS USED FOR HIGH TEMPS. HIGH TEMPS ABOVE AVERAGE...EVEN ACROSS THE COASTAL ZONES IN SPITE OF A LIGHT ONSHORE FLOW. CLOUDS AND MOISTURE THEN INCREASE FRIDAY NIGHT. REMAINING DRY...BUT PATCHY FOG DEVELOPING LATE AT NIGHT. STRATUS DEVELOPMENT ALSO POSSIBLE FOR THE COASTAL ZONES. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THE JET STREAM STAYS NORTH OF THE REGION UNTIL EARLY NEXT WEEK WHEN IT WILL MOVE SOUTH FROM NEW ENGLAND AND THEN WITH RIDGING...THE JET PUSHES BACK NORTH OF THE AREA MID TO LATE NEXT WEEK. IN THE MID LEVELS...THE OFFSHORE RIDGE BECOMES LESS AMPLIFIED SATURDAY. THERE WILL BE A SHORTWAVE MOVING THROUGH SOUTHEAST CANADA FOR THE REST OF THE WEEKEND...RESULTING IN A BROADENING QUASI ZONAL FLOW ACROSS THE LOCAL REGION. ANOTHER SHORTWAVE APPROACHES CLOSER TO THE AREA MONDAY NIGHT AND MOVES ACROSS TUESDAY INTO TUESDAY NIGHT. UPPER LEVEL RIDGING BUILDS IN THEREAFTER. A SLOW MOVING COLD FRONT APPROACHES FROM THE WEST SATURDAY. THE PARENT LOW ATTACHED TO THIS FRONT WILL NOT BE THAT STRONG...SLOWLY DEEPENING WITH EASTWARD PROGRESS THROUGH SATURDAY AND THEN DEEPENING MORE WITHIN THE CANADIAN MARITIMES SUNDAY THROUGH SUNDAY NIGHT. THE COLD FRONT WILL BE MOVING WITHIN INTO THE REGION THROUGH THIS TIME. THE FRONT WILL THEN STALL NEAR THE REGION WITH LOW PRESSURE AND INVERTED TROUGH DEVELOPING AT THE SURFACE TO THE SOUTHWEST OF THE REGION ALONG THE FRONT MONDAY AND MONDAY NIGHT. HIGH PRESSURE GRADUALLY RETURNS TUESDAY FROM THE CANADIAN MARITIMES...BUT WEAKENS AND MOVES INTO THE WESTERN ATLANTIC MID TO LATE IN THE WEEK. IN TERMS OF WEATHER...THERE WILL BE A GRADUAL INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS FIRST NORTH AND WEST OF NYC SATURDAY AHEAD OF THE COLD FRONT. FARTHER EAST ACROSS LONG ISLAND...CONDITIONS LIKELY REMAIN DRY THROUGH SATURDAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE SATURDAY NIGHT ACROSS THE WHOLE FORECAST REGION AND FURTHERMORE ON SUNDAY. THUNDERSTORMS WILL BE MORE LIMITED SUNDAY AND SUNDAY NIGHT WITH DECREASING INSTABILITY WITH A MORE NORTHERLY AND EASTERLY FLOW DEVELOPING DURING THE DAY. THE INSTABILITY WILL BE LOCATED FARTHER SOUTH OF THE REGION. WITH THE FRONT STALLING NEAR THE REGION...SHOWERS REMAIN INTO EARLY NEXT WEEK...BEFORE BECOMING MORE MINIMAL TUESDAY AS THE FRONT PUSHES FARTHER SOUTH OF THE AREA WITH MAINLY DRY CONDITIONS RETURNING LATE TUESDAY NIGHT THROUGH NEXT THURSDAY. THE AIRMASS WILL STAY MOSTLY AS MARITIME TROPICAL THROUGH THE LONG TERM BUT COOLER FOR MONDAY AND TUESDAY NEXT WEEK. HIGHS WELL INTO 70S AND INTO LOWER 80S SATURDAY BUT UPPER 60S TO LOWER 70S SUNDAY. HIGHS LOWER INTO MAINLY THE 60S EARLY NEXT WEEK TRENDING BACK TO NEAR NORMAL VALUES. LOWS WITHIN THE 60S SATURDAY NIGHT AND WITHIN THE 50S ON AVERAGE SUNDAY NIGHT THROUGH EARLY NEXT WEEK. THEN THEY TREND BACK TO NORMAL AS WELL MID TO LATE NEXT WEEK. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... HIGH PRESSURE BUILDS DOWN FROM SOUTHEASTERN CANADA THIS MORNING...THEN MERGES WITH HIGH PRESSURE OFFSHORE THIS AFTERNOON. THIS HIGH THEN SLOWLY RETREATS TO THE EAST TONIGHT. VFR THROUGH THE TAF PERIOD. WINDS BECOME LIGHT AND VARIABLE THROUGHOUT EARLY THIS MORNING...THEN BECOME NE AT UNDER 10 KT DURING THE MORNING PUSH. THE WINDS AGAIN BECOME LIGHT AND VARIABLE LATE THIS MORNING/EARLY THIS AFTERNOON...BEFORE SE-SSE WINDS SETS UP AT AROUND 10 KT FOR COASTAL TERMINALS AND AT UNDER 10 KT INLAND. WINDS BECOME LIGHT AND VARIABLE AGAIN THROUGHOUT THIS EVENING. .OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY... .LATE FRIDAY NIGHT-SATURDAY MORNING...MVFR OR LOWER POSSIBLE. .SATURDAY AFTERNOON...MOST LIKELY VFR. CHANCE OF MVFR IN SHOWERS/THUNDERSTORMS MAINLY TO THE N/W OF CITY TERMINALS. GUSTS TO 20-25KT POSSIBLE WITH SEABREEZE. .SATURDAY NIGHT-TUESDAY MORNING...MVFR OR LOWER AT TIMES. THUNDERSTORMS POSSIBLE SATURDAY NIGHT-SUNDAY NIGHT. .TUESDAY AFTERNOON/NIGHT...BECOMING VFR. && .MARINE... COLD FRONT MOVES ACROSS THE WATERS TONIGHT. SEAS WILL REMAIN BELOW 5 FT...AND WINDS WILL BECOME 5 KT OR LESS ON LONG ISLAND SOUND/NY HARBOR/LONG ISLAND BAYS AND 5-10 KT ON THE OCEAN. SUB-SCA CONDITIONS THEN CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH WINDS REMAINING BELOW 15 KT. SOUTHERLY FLOW INCREASES SATURDAY AND SATURDAY NIGHT WITH HIGH PRESSURE MOVING FARTHER OFFSHORE. THE SOUTHERLY FETCH WILL BUILD SEAS ON THE OCEAN TO 5 FT SATURDAY LATE IN THE DAY. THE OCEAN SEAS REMAIN WITHIN SCA RANGE...MAINLY 5 TO 7 FT...FOR THE REST OF THE MARINE FORECAST PERIOD WITH WINDS BEING MORE MARGINAL EXCEPT FOR WESTERN OCEAN SATURDAY WITH AMBROSE JET LIKELY ENHANCING WINDS AND THEN AGAIN ON MONDAY...WHEN GUSTS WILL REACH NEAR 25 KT. THE FLOW SWITCHES TO MORE EASTERLY SUNDAY INTO EARLY NEXT WEEK WHICH WILL HELP KEEP SWELLS AND HIGHER SEAS WITHIN THE OCEAN FORECAST WATERS. && .HYDROLOGY... THERE WILL BE POTENTIAL FOR AN EXTENDED SIGNIFICANT WIDESPREAD RAINFALL...MAINLY SUNDAY THROUGH MONDAY WITH A COLD FRONT STALLING NEAR THE REGION. IT IS DIFFICULT TO SPECIFY EXACT RAINFALL AMOUNTS...BUT THERE WILL BE POTENTIAL FOR HEAVY RAINFALL ESPECIALLY SUNDAY AND SUNDAY NIGHT INTO EARLY MONDAY MORNING WHEN PRECIPITABLE WATERS REACH 1.5 TO 1.75 INCHES. ANY SHOWERS AND THUNDERSTORMS COULD PRODUCE LOCALLY HEAVY RAINFALL AND THEREFORE AT LEAST MINOR FLOODING OF URBAN/POOR DRAINAGE AREAS WILL BE A POSSIBILITY. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JC/JM NEAR TERM...JMC/MPS SHORT TERM...JC LONG TERM...JM AVIATION...MALOIT MARINE...MPS HYDROLOGY...JC/JM

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