Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 021925 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 325 PM EDT MON MAY 2 2016 .SYNOPSIS...
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AN AREA OF LOW PRESSURE OVER THE TENNESSEE VALLEY TONIGHT WILL TRACK NORTHEAST...PASSING TO THE SOUTH AND EAST OF LONG ISLAND ON TUESDAY. HIGH PRESSURE WILL THEN BRIEFLY FOLLOW FOR TUESDAY NIGHT. A COMPLEX AND SLOW MOVING STORM SYSTEM WILL IMPACT THE TRI-STATE FROM WEDNESDAY THROUGH SATURDAY. A COLD FRONT CROSSES THE AREA ON SUNDAY.
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&& .NEAR TERM /THROUGH TONIGHT/...
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A PROLONGED PERIOD OF INCLEMENT WEATHER IS ON TAP AS AN UPPER TROF AMPLIFIES ACROSS THE EASTERN HALF OF THE COUNTRY THROUGH MID WEEK. PRECEDING THIS TROF...WILL BE SEVERAL WAVES OF LOW PRESSURE...THE FIRST OF WHICH EJECTS FROM THE TN VALLEY TONIGHT TO JUST SOUTH OF THE AREA BY MORNING. 12Z GUIDANCE HAS COME INTO BETTER AGREEMENT..ALBEIT THERE ARE SOME SMALL TIMING ISSUES...FOR A DECENT BANDED RAIN EVENT LATE TONIGHT INTO TUE MORNING. MID LEVEL FRONTOGENESIS COUPLED WITH A VORT APPROACHING FROM THE MID ATLANTIC WILL PRODUCE ABOUT HALF TO ONE INCH OF RAINFALL. THE HIGHEST AMOUNTS ARE FORECAST ACROSS LI. THE RAIN WILL DEVELOP AFTER MIDNIGHT FROM SW TO NE WITH ABOUT A 3 TO 5 HOUR PERIOD OF MODERATE TO OCCASIONALLY HEAVY RAINFALL. MOST OF THE NIGHT WILL BE OVERCAST...BUT THERE MAY BE ENOUGH DRYING IN THE BOUNDARY LAYER EARLY THIS EVE FOR SOME PARTIAL CLEARING AHEAD OF THE APPROACHING FRONTAL WAVE. DIURNAL TEMP RANGES WILL BE SMALL THE NEXT COUPLE OF DAYS DUE TO THE CLOUD OVER AND NE FLOW. LOWS TONIGHT WILL BE IN THE UPPER 40S TO LOWER 50S...WHICH IS A FEW DEGREES ABOVE NORMAL.
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&& .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
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MODERATE RAIN WILL QUICKLY EXIT THE AREA DURING THE MORNING HOURS...MAINLY IMPACTING AREAS EAST OF THE HUDSON RIVER. THERE IS THE POSSIBILITY THAT SOME LIGHT RAIN COULD LINGER INTO THE AFTERNOON WITH THE EXIT REGION OF THE UPPER LEVEL JET IN CLOSE PROXIMITY. GENERALLY THOUGH LOOKING AT LOW RAIN CHANCES BY AFTERNOON WITH THE DEEP MOISTURE AND LIFT PASSING WELL TO THE EAST AND ONLY LOW-LEVEL MOISTURE ON THE BACKSIDE OF THE LOW. AN OVERRUNNING PATTERN IN THE LOW-LEVELS WILL MAINTAIN CLOUDY CONDITIONS THROUGH TUE NIGHT WITH A EVEN A CHANCE OF SOME LIGHT RAIN DEVELOPING OVERNIGHT. ONCE AGAIN...DIURNAL TEMP RANGES WILL BE SMALL...WITH HIGHS TUE IN THE 50S...WITH LOWS TUE NIGHT ABOUT 5 DEGREES COOLER. THIS WILL EQUATE TO WELL BELOW NORMAL HIGHS AND LOWS JUST A FEW DEGREES ABOVE NORMAL.
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&& .LONG TERM /WEDNESDAY THROUGH MONDAY/...
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GOOD AGREEMENT AMONG THE MODELS THE REGARDING CUTOFF LOW THAT MOVES THROUGH THE GREAT LAKES WEDNESDAY AND THEN SLOWLY TRACKS SE TOWARDS THE MIDDLE ATLANTIC COAST BY FRIDAY. THE LOW IS THEN PROGGED TO SLOWLY LIFT AWAY FROM THE COAST ON SATURDAY AS A NEW NORTHERN STREAM TROUGH DIGS INTO THE GREAT LAKES REGION. THIS WILL SEND A COLD FRONT ACROSS ON SUNDAY. FOR WEDNESDAY...MUCH OF THE GUIDANCE IS HINTING AT SOME SHOWER ACTIVITY AS THERE IS SOME SHORTWAVE ENERGY IN THE MID TO UPPER LEVEL. HOWEVER...DIFFERENCES EXIST IN ANY WAVE OF LOW PRESSURE THAT DEVELOPS ON A STALLED BOUNDARY JUST OFFSHORE. TIMING DIFFERENCES ARE DEPICTED WITH THE LATEST MODELS WHICH LEADS TO A LOW CONFIDENCE FORECAST. HAVE CAPPED POPS AT CHANCE CATEGORY THROUGH THE DAY...HIGHEST IN THE AFTERNOON AND EVENING. FOR THURSDAY INTO FRIDAY...HAVE ALSO ELECTED TO REMAIN PERSISTENT WITH THE PREVIOUS FORECAST WITH GENERALLY CHANCE POPS. TIMING ENERGY WITHING THE CUTOFF LOW REMAINS DIFFICULT. IT WILL NOT BE A COMPLETE WASH OUT...BUT PERIODS OF SHOWERS MAY OCCUR AT ANY TIME. THE LATEST DETERMINISTIC AND ENSEMBLE GUIDANCE ARE SIGNALING THAT FRIDAY MAY BE THE DAY WITH BETTER CHANCES FOR SHOWERS. THIS IS WHEN THE CUTOFF LOW SLOWLY LIFTS NE TOWARDS THE AREA AND A WAVE OF LOW PRESSURE COULD DEVELOP OFF THE DELMARVA. THE CUTOFF LOW SHOULD PULL AWAY ON SATURDAY...SO WILL SHOW A DOWNWARD TREND IN POPS. AS THE COLD FRONT MOVES THROUGH ON SUNDAY...POPS INCREASE BACK TO CHANCE. AS NOTED ABOVE...THERE REMAINS A GREAT DEAL OF UNCERTAINTY INTO THE WEEKEND. THERE WILL PERIOD OF DRY CONDITIONS AND PERIODS OF SHOWERS...BUT TIMING OF THESE FEATURES IS STILL DIFFICULT TO PINPOINT AT THIS TIME. BELOW NORMAL TEMPERATURES ARE FORECAST WEDNESDAY THROUGH FRIDAY. TEMPERATURES COULD COME CLOSE TO SEASONABLE LEVELS FOR THE WEEKEND.
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&& .AVIATION /19Z MONDAY THROUGH SATURDAY/...
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LOW PRES SLOWLY APPROACHES NY AIRSPACE TONIGHT...AND WILL PASS SOUTH OF LONG ISLAND LATE TONIGHT THROUGH TUESDAY. MVFR/IFR FORECAST WITH CIGS GENERALLY 700-1200 FT THROUGH THIS EVENING. CIGS LOWER TO AROUND 500 FT THIS EVENING...AND VSBYS WILL DROP AS WELL AS FOG DEVELOPS. RAIN DEVELOPS BY DAYBREAK TUESDAY. THE HEAVIEST RAIN WILL IMPACT KNYC/KISP. VSBYS WILL DROP TO 1SM...AND CIGS WILL BE 500 FT OR LESS THROUGH TUESDAY MORNING. CONDS IMPROVE SLIGHTLY BY TUESDAY AFTERNOON. SE WINDS 10 KT OR LESS...BCMG LGT/VRB THIS EVENING. E-NE WINDS THEN INCREASE TO 5-10 KT EARLY TUESDAY MORNING. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.WEATHER.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: AMDS POSSIBLE FOR FLIGHT CATEGORY CHANGES. KLGA FCSTER COMMENTS: CIGS AROUND 1000 FT THROUGH LATE AFTERNOON. KEWR FCSTER COMMENTS: CIGS AROUND 1000 FT THROUGH LATE AFTERNOON. KTEB FCSTER COMMENTS: AMDS POSSIBLE FOR FLIGHT CATEGORY CHANGES. KHPN FCSTER COMMENTS: AMDS POSSIBLE FOR FLIGHT CATEGORY CHANGES. KISP FCSTER COMMENTS: AMDS POSSIBLE FOR TIMING OF FLIGHT CATEGORY CHANGES. .OUTLOOK FOR 20Z TUESDAY THROUGH SATURDAY... .TUESDAY AFTERNOON...GRADUAL IMPROVEMENTS IN THE AFTERNOON. .TUESDAY NIGHT...IFR CONDS IN FOG/STRATUS POSSIBLE. .WEDNESDAY THROUGH SATURDAY...PERIODS OF MVFR OR LOWER CONDS IN RAIN/FOG/STRATUS.
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&& .MARINE...
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SUB-SCA CONDS ARE FORECAST THROUGH TUE WITH THE POSSIBILITY OF A BRIEF PERIOD OF SEAS AROUND 5 FT LATE TUE AFT/EARLY EVE. CONFIDENCE IS LOW ENOUGH AT THIS TIME TO HOLD OFF ON THE ISSUANCE OF AN SCA. NE WINDS INCREASE TO 10-15 KT ON THE OCEAN WATERS TUE MORNING WITH GUSTS UP TO 20 KT...BEFORE SUBSIDING IN THE EVENING. A RELAXED PRESSURE GRADIENT ON ALL COASTAL WATERS WILL LEAD TO WINDS BELOW SCA LEVELS WEDNESDAY THROUGH SATURDAY. OCEAN SEAS MAY COME CLOSE TO 5 FT AT TIMES WITH A PERSISTENT SE SWELL...MAINLY ON THE WATERS EAST OF MORICHES INLET.
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&& .HYDROLOGY...
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TOTAL RAINFALL AMOUNTS OF A QUARTER TO AN INCH IS FORECAST LATE TONIGHT THROUGH TUESDAY MORNING. THE HIGHER AMOUNTS WILL LIKELY FALL ACROSS NYC METRO AND LONG ISLAND...WITH THE LOWER END BEING ACROSS NORTHERN PORTIONS OF THE LOWER HUDSON VALLEY. MINOR NUISANCE FLOODING IN URBAN AREAS IS POSSIBLE. PERIODS OF SHOWERS ARE POSSIBLE WEDNESDAY INTO THE WEEKEND. CONFIDENCE ON THE TIMING AND AMOUNTS REMAIN LOW AT THIS TIME.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...DS/DW NEAR TERM...DW SHORT TERM...DW LONG TERM...DS AVIATION...MPS MARINE...DS/DW HYDROLOGY...DS/DW

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