Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 300151 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 951 PM EDT SAT AUG 29 2015 .SYNOPSIS... HIGH PRESSURE SLIDES OFFSHORE AND MERGES WITH THE BERMUDA HIGH INTO SUNDAY. A TROUGH OF LOW PRESSURE CROSSES THE AREA LATE SUNDAY...AS THE BERMUDA HIGH REMAINS OFFSHORE INTO EARLY NEXT WEEK. A BACK DOOR COLD FRONT MOVES INTO THE WATERS ON TUESDAY...BEFORE LIFTING BACK NORTH AS A WARM FRONT BY WEDNESDAY. HIGH PRESSURE THEN REMAINS IN CONTROL THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH SUNDAY/... A NORTHERN STREAM SHORTWAVE PASSES TO THE NORTH INTO THE OVERNIGHT HOURS...FOLLOWED BY WEAK NORTHERN STREAM RIDGING BUILDING IN LATE TONIGHT INTO FAR W ZONES. GIVEN THAT THE BEST FORCING WILL BE CONFINED TO NEAR THE U.S.-CANADIAN BORDER...EXPECT MAINLY HIGH AND SOME MID CLOUDS WITH THE PASSAGE OF THE SHORTWAVE...LIMITED TO MAINLY NW ZONES. FORECAST IS GENERALLY ON TRACK. MAINLY PARTLY CLOUDY CONDITIONS EXPECTED. OTHERWISE...MINOR CHANGES TO T/TD/WINDS TO BETTER REFLECT CURRENT CONDS AND TRENDS. LOWS SHOULD BE A FEW DEGREES ABOVE NORMAL. && .SHORT TERM /SUNDAY NIGHT/... THE AFOREMENTIONED SHORTWAVE RIDGING EXITS TO THE EAST BY EARLY AFTERNOON...FOLLOWED BY A NORTHERN STREAM TROUGH WHICH THEN CROSSES THE AREA SUNDAY AFTERNOON AND NIGHT. IT SHOULD BE NOTED THAT THE ECMWF IS A SLOW OUTLIER WITH THE TIMING OF THE TROUGH...SO USED A NON-ECMWF SOLUTION FOR SUNDAY AND SUNDAY NIGHT. NOTING THE GFS/CMC-REG/NAM/SREF ALL INDICATE SOME SHOWERS ACROSS MAINLY N INTERIOR ZONES MAINLY SUNDAY AFTERNOON INTO SUNDAY EVENING...HAVE INTRODUCED SLIGHT CHANCE POPS FROM ROUGHLY ORANGE COUNTY/WESTERN NE NJ ON NE INTO N MIDDLESEX COUNTY. APPEARS THAT SHOULD HAVE SUFFICIENT LOW LEVEL CAPE AND LOW LEVEL INSTABILITY...WITH SHOWALTER INDICES DOWN TO BELOW 3...TO WARRANT A SLIGHT CHANCE OF THUNDER AS WELL. TEMPERATURES ON SUNDAY WILL BE A FUNCTION OF HOW MUCH CLOUD COVER THERE IS AHEAD OF THE TROUGH. WITH MODELS HAVING 1000-500 RH OVER 70% OVER MOST OF THE AREA...HAVE INCREASED CLOUD COVER. HOWEVER...LOW LEVELS COULD BE SUFFICIENTLY DRY TO SUPPORT MIXING TO UP TO 850-825 HPA PER BUFKIT SOUNDINGS...EVEN WITH CLOUD COVER. SO FOR NOW FORECASTING HIGHS 5-10 DEGREES ABOVE NORMAL...WITH SOME READINGS AROUND 90 IN URBAN NE NJ AND POSSIBLY NYC. THIS CONSISTENT WITH BLENDING A MIX DOWN FROM 950-825 HPA PER BUFKIT SOUNDINGS WITH NAM 2-METER TEMPERATURES AND A BLEND OF MET/ECS/MAV GUIDANCE. WITH THE RELATIVELY DRY LOW LEVELS...HEAT INDICES ON SUNDAY AFTERNOON SHOULD PEAK OUT IN THE UPPER 80S IN URBAN AREAS...WHICH IS A FEW DEGREES BELOW THE FORECAST AIR TEMPERATURE. FOR LOWS SUNDAY NIGHT...USED A BLEND OF MAV/ECS/MET GUIDANCE AND NAM 2-METER TEMPERATURES WITH VALUES FORECAST TO BE AROUND 5-10 DEGREES ABOVE NORMAL. THERE IS A MODERATE RISK FOR THE DEVELOPMENT OF RIP CURRENTS ON SUNDAY. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE MAIN THEME OF THE LONG TERM PERIOD WILL BE THE CONTINUATION OF HEAT AND HUMIDITY ACROSS THE REGION. MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN ACROSS NORTH AMERICA INTO THE MIDDLE OF THE WEEK. AN UPPER LEVEL TROUGH WILL SLIDE THROUGH THE AREA ON MON BRINGING A WEAK BACK DOOR COLD FRONT INTO THE AREA. THERE WON`T BE MUCH RELIEF FROM THE HEAT AND HUMIDITY AS THE BOUNDARY WILL LIFT BACK TO THE N AS A WARM FRONT BY WED. AN UPPER LEVEL RIDGE MOVING THROUGH EASTERN CANADA WILL THEN MERGE WITH THE BERMUDA HIGH OVER THE ATLANTIC PROVIDING DRY AND UNSEASONABLY WARM WEATHER THROUGH THU POSSIBLY FRI. THIS WILL DEPEND ON THE TIMING OF THE NEXT COLD FRONT MOVING ACROSS WHICH IS CURRENTLY UNCERTAIN DUE TO DIFFERENCES THAT DEVELOP IN THE H5 FLOW DURING THE LATTER PORTION OF THE WEEK. COULD SEE A FEW SHOWERS OR TSTMS WITH THE FRONTAL PASSAGE WHICH IS CURRENTLY SLATED FOR FRIDAY...FOLLOWED BY DRY CONDITIONS AND COOLER BUT STILL ABOVE NORMAL TEMPS FOR THE WEEKEND. HIGHS WILL GENERALLY RANGE IN THE UPPER 80S TO LOWER 90S ACROSS THE AREA THROUGH MUCH OF THE WEEK...THE EXCEPTION BEING TUE AND FRI/SAT WITH THE FRONTAL BOUNDARIES IN/THROUGH THE AREA. HEAT INDICES ARE EXPECTED TO BE CLOSE TO THE AMBIENT AIR TEMP AND ARE NOT CURRENTLY EXPECTED TO REACH 95 DEGREES IN NYC THROUGH WED. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... HIGH PRESSURE SLIDES OFFSHORE. A TROUGH OF LOW PRESSURE CROSSES THE AREA LATE SUNDAY. VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD. INCREASING MID CLOUDS ARE ANTICIPATED SUNDAY...WITH MAINLY HIGH CLOUDS OVERNIGHT. AN ISOLATED SHOWER OR THUNDERSTORM CANNOT BE RULED OUT...MAINLY NW OF NYC TERMINALS DURING THE AFTERNOON SUNDAY. S-SW WINDS DIMINISH TO UNDER 10 KT OVERNIGHT. A W/SW FLOW 5 TO 10 KT IS FORECAST SUNDAY MORNING. THEN SEA BREEZES ARE LIKELY DURING THE AFTERNOON. SPEEDS INCREASE AND A FEW GUSTS IN THE 15 TO 20 KT RANGE ARE POSSIBLE. COASTAL TERMINALS WILL LIKELY OBSERVE STRONGER WINDS IN THE 15 TO 20 KT RANGE. .OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY... .SUNDAY NIGHT-THURSDAY...VFR. AFTERNOON SEABREEZES AT COASTAL TERMINALS EACH DAY. SW GUSTS AROUND 15 KT NEAR CITY TERMINALS MONDAY AFTERNOON. && .MARINE... A RELATIVELY RELAXED PRESSURE GRADIENT OVER THE REGION WILL KEEP SUSTAINED WINDS TO 15 KT OR LESS AND GUSTS TO 20 KT OR LESS THROUGH SUNDAY NIGHT. AS A RESULT...ABSENT ANY SIGNIFICANT SWELL...SEAS ON THE COASTAL OCEAN WATERS WILL BE 4 FT OR LESS AND SEAS/WAVES ON THE SOUND/HARBOR/BAYS 2 FT OR LESS THROUGH SUNDAY NIGHT AS WELL. MARGINAL SCA LEVEL SEAS MAY CLIP THE OUTERMOST PORTION OF ANZ350 ON MON...OTHERWISE SUB-SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED ON ALL WATERS MONDAY THROUGH THURSDAY. && .HYDROLOGY... NO SIGNIFICANT RAINFALL IS EXPECTED FOR THE REMAINDER OF THIS WEEKEND AND FOR THE UPCOMING WORK WEEK. && .TIDES/COASTAL FLOODING... WITH A RECENT FULL MOON...BRIEF MINOR INUNDATION IS POSSIBLE DURING THE TIMES OF HIGH TIDE ACROSS THE TYPICALLY VULNERABLE COASTAL LOCALES INTO THE START OF THE WORK WEEK. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$

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