Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 040957 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 557 AM EDT MON MAY 4 2015 .SYNOPSIS... THE REGION WILL REMAIN IN BETWEEN HIGH PRESSURE CENTERED WELL OFF THE MID ATLANTIC COAST AND A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST THROUGH TUESDAY MORNING. THIS COLD FRONT WILL THEN CROSS THE TRI-STATE TUESDAY AFTERNOON AND EVENING. HIGH PRESSURE THEN BUILDS IN FROM LATE TUESDAY NIGHT THROUGH SATURDAY NIGHT. A COLD FRONT APPROACHES FROM THE NORTH ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK. CURRENTLY MONITORING PATCHY FOG AT KFOK...FOG CHANNEL AND OTHER NEAR BY OBS SUGGESTS CONTAINED TO THAT LOCATION...SO WILL NOT REFLECT IN FORECAST AT THIS TIME. WILL UPDATE IF AREA OF FOG EXPANDS. THE AXIS OF A DEEP LAYERED RIDGE WILL SLIDE OVER THE AREA THIS MORNING...THEN TO THE EAST THIS AFTERNOON. SUBSIDENCE WITH THIS RIDGE WILL KEEP CLOUD COVER AT A MINIMUM. IT WILL ALSO SERVE TO LIMIT MIXING UNTIL THIS AFTERNOON...WITH THE BEST MIXING OCCURRING OVER WESTERN PORTIONS OF THE TRI-STATE. DO EXPECT A SEABREEZE TO DEVELOP THIS AFTERNOON...WITH SOME GUSTINESS OVER THE TYPICAL AMBROSE JET REGION. FOR HIGHS TODAY USED A BLEND OF MAV...MET AND ECS GUIDANCE WITH NAM 2-METER TEMPERATURES WITH A MIX DOWN FROM 1000 HPA NEAR THE COAST TO 725 HPA WELL INLAND PER BUFKIT SOUNDINGS. HIGHS TODAY SHOULD RUN 15 TO 20 DEGREES ABOVE NORMAL. A COMBINATION OF LOW RELATIVE HUMIDITIES AND SOME GUSTY WINDS IN THE AFTERNOON BRINGS FIRE WEATHER CONCERNS WITH IT. REFER TO THE FIRE WEATHER SECTION OF THE AFD FOR DETAILS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... ZONAL FLOW WILL PREVAIL AT 500-700 HPA TONIGHT AND TUESDAY...FOLLOWED BY A WEAK NORTHERN STREAM TROUGH PASSING AT THESE LEVELS TUESDAY NIGHT. WITH THE COLD FRONT MAINLY ALIGNED WITH THE ZONAL FLOW...IT WILL MAKE SLOW PROGRESS INTO THE REGION...SO HAVE SLOWED TIMING OF PRECIPITATION ACCORDINGLY. SLIGHT CHANCE POPS ARE CONFINED TO FAR NW ZONES LATE TONIGHT AS A RESULT. MODELS STILL SUGGEST THAT WITH BEST FORCING GOING TO THE N...THAT ANY PRECIPITATION COULD BREAK UP AS IT MOVES INTO THE AREA ON TUESDAY...FOR THIS REASON HAVE KEPT POPS IN THE CHANCE CATEGORY...BUT DID CHANGE TO AREAL COVERAGE WORDING IN THE AFTERNOON. SHOWALTER INDICES IN THE AFTERNOON/EARLY EVENING ARE FORECAST TO BE AROUND ZERO ACROSS THE CWA...SO ALSO HAVE A SLIGHT CHANCE OF THUNDER IN THE AFTERNOON AND EARLY EVENING AS WELL. SINCE ANY THUNDERSTORMS WILL MOST LIKELY BE ELEVATED IN NATURE...DO NOT EXPECT ANY ISSUES WITH WIND OR HAIL. HOWEVER...IF THE NAM IS CORRECT AND DO ACHIEVE SEVERAL HUNDRED J/KG OF CAPE IN THE LATE AFTERNOON ACROSS N/W INTERIOR ZONES THEN COULD SEE A FEW STRONG STORMS...AND AN ISOLATED SEVERE STORM COULD NOT BE 100 PERCENT RULED OUT IF THE NAM IS CORRECT. THE NAM BEING CORRECT IS PREDICATED ON THERE BEING SOME EXTENSIVE BREAKS IN THE CLOUDS TUESDAY AFTERNOON. GIVEN SLOWER TIMING OF THE FRONT...DID RAISE HIGHS...BUT NOT AS WARM AS THE NAM WOULD SUGGEST. APPEARS LOW LEVELS SHOULD BE TOO MOIST TO SUPPORT EXTENSIVE BREAKS IN THE CLOUDS AT THIS TIME. BASED ON SLOWER FRONTAL TIMING...HAVE CONTINUED CHANCE POPS INTO THE EVENING...THEN TAPER OFF FROM NW TO SE THROUGH THE NIGHT. FOR LOWS TONIGHT...USED A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM 2-METER TEMPERATURES. LOWS SHOULD BE AROUND 10 DEGREES ABOVE NORMAL. FOR HIGHS ON TUESDAY USED A BLEND OF ECS/MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 825-800 HPA PER BUFKIT SOUNDINGS. NOTING THE 10 DEGREE TEMPERATURE SPREAD BETWEEN THE NAM BASED TEMPERATURES AND NON-NAM TEMPERATURES THIS BLEND ACCOUNTS FOR THE SLOWER FRONTAL MOTION BUT DOES NOT ALLOW FOR EXTENSIVE BREAKS IN THE CLOUDS...CONSISTENT WITH EARLIER REASONING. HIGHS SHOULD BE AROUND 10-15 DEGREES ABOVE NORMAL. A BLEND OF NAM 2-METER TEMPERATURES AND ECS/MET/MAV GUIDANCE WAS USED FOR LOWS TUESDAY NIGHT...WITH VALUES FORECAST TO BE 5-10 DEGREES ABOVE NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE COLD FRONT CONTINUES TO MOVE SOUTH AND EAST OF THE AREA WEDNESDAY MORNING. MUCH OF THE REGION WILL BE DRY AFTER 12Z WEDNESDAY...WITH ONLY A SLIGHT CHANCE FOR A SHOWER ACROSS SOUTHERNMOST ZONES. CLEARING SKY CONDITIONS FROM NORTH TO SOUTH ARE FORECAST FROM LATE MORNING THROUGH THE REMAINDER OF THE DAY AS HIGH PRESSURE BUILDS INTO THE AREA. THURSDAY THROUGH SUNDAY...DEEP UPPER LEVEL RIDGING TAKES HOLD OF THE LARGE SCALE PATTERN SETTING THE STAGE FOR A PERIOD OF MAINLY DRY WEATHER AND ABOVE NORMAL TEMPERATURES. MODELS INDICATE POTENTIAL FOR A COLD FRONT TO SINK SOUTH TOWARDS THE AREA LATE SATURDAY THROUGH SUNDAY. HAVE KEPT SATURDAY DRY...BUT WITH THE FRONT IN CLOSER PROXIMITY ON SUNDAY...HAVE DECIDED TO CARRY SLIGHT CHANCE POPS FOR THE ENTIRE AREA. FOR TEMPERATURES...HIGHS IN THE LOWER AND MIDDLE 70S FORECAST FOR WEDNESDAY THROUGH FRIDAY...COOLEST NEAR THE COAST. TEMPERATURES WARM SATURDAY INTO THE UPPER 70S AND LOWER 80S FROM THE CITY NORTH AND WEST...WITH LOWER TO MIDDLE 70S NEAR THE COAST. SLIGHTLY COOLER CONDITIONS ON SUNDAY THAN SATURDAY WITH A BIT MORE CLOUD COVER AND FRONT IN THE VICINITY. LOW TEMPERATURES WEDNESDAY NIGHT FALL INTO THE UPPER 40S AND LOWER 50S. LOWS THEN MODERATE THURSDAY NIGHT INTO THE LOWER 50S AND THEN EVEN MILDER FRIDAY NIGHT AND SATURDAY NIGHT INTO THE MIDDLE AND UPPER 50S. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... VFR THROUGH THIS EVENING AS HIGH PRESSURE REMAINS JUST OFF THE MID ATLANTIC COAST. A COLD FRONT APPROACHES FROM THE NW LATE TONIGHT. LGT AND VRB WINDS EARLY THIS MORNING...BECOMING SSW WINDS AND INCREASING WITH SPEEDS GENERALLY 10-15KT AFT 16Z AS PRES GRADIENT TIGHTENS. ELSEWHERE...FRQ GUSTS BETWEEN 18-22 KT SHOULD PREVAIL AFT 17Z...DIMINISHING IN THE EVE. KGON MAY NOT GUST AT ALL DUE TO LIMITED MIXING. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: ANTICIPATING AMBROSE JET AFT 20Z WITH SUSTAINED WINDS AROUND 20KT. GUSTS UP TO 25 KT ARE POSSIBLE BETWEEN 20Z AND 02Z...BUT LOW CONFIDENCE. KLGA FCSTER COMMENTS: PK GUSTS OF 25 KT POSSIBLE BETWEEN 20Z AND 02Z. KEWR FCSTER COMMENTS: PK GUSTS OF 25 KT POSSIBLE BETWEEN 20Z AND 00Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: GUSTS COULD BE A FEW KT HIGHER THAN FORECAST. KHPN FCSTER COMMENTS: GUSTS COULD BE A FEW KT HIGHER THAN FORECAST. KISP FCSTER COMMENTS: GUSTS COULD BE A FEW KT HIGHER THAN FORECAST. .OUTLOOK FOR 06Z TUE THROUGH FRI... .TONIGHT...VFR. .TUE-WED MORNING...SLOW COLD FROPA. MVFR OR LOWER CONDS POSSIBLE WITH ANY SHOWERS. LOW CHANCE FOR TSTMS TUE AFTERNOON/EVENING. .WED AFTERNOON-FRI...VFR. && .MARINE... MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK. FOR NOW EXPECT WIND GUSTS TO REMAIN JUST BELOW SCA LEVELS THIS AFTERNOON/EVENING AS COOL WATERS SHOULD PROMOTE SUFFICIENT OF AN INVERSION TO LIMIT GUSTS TO MAINLY AROUND 20 KT...WITH MAYBE AN OCCASIONAL GUST TO AROUND 25 KT NEAR SHORE. THESE WINDS COUPLED WITH A PERSISTENT SE SWELL COULD BRING SEAS TO AROUND 5 FT ON THE COASTAL OCEAN WATERS TONIGHT. WINDS THEN DIMINISH TO 10 KT OR LESS OVER ALL WATERS BY TUESDAY AFTERNOON AND REMAIN SO THROUGH AT LEAST FRIDAY MORNING. EVEN WITH A DEVELOPING RETURN FLOW LATER ON FRIDAY...STILL EXPECT SUB-SMALL CRAFT CONDITIONS THEN AS WELL. && .FIRE WEATHER... HAVE THE HIGHEST CONFIDENCE IN FREQUENT GUSTS TO GREATER THAN 25 MPH...COUPLED WITH RELATIVE HUMIDITIES FORECAST GENERALLY UNDER 30 PERCENT...IS OVER NE NJ/NYC/NASSAU COUNTY AND THE LOWER HUDSON VALLEY THIS AFTERNOON. NOTING THAT THE 950 HPA JET PEAKS AT AROUND 21Z OVER THIS AREA...AND HAVE THE BEST MIXING THEN...HAVE ISSUED A RED FLAG WARNING FOR THIS AREA FROM 17-23Z TODAY. ELSEWHERE...WHILE OCCASIONAL GUSTS GREATER THAN 25 MPH ARE POSSIBLE OVER S CT AND SUFFOLK COUNTY...AT THIS TIME DO NOT HAVE CONFIDENCE THAT THEY WILL BE FREQUENT. ALSO...ONSHORE FLOW COULD KEEP RELATIVE HUMIDITIES JUST OVER 30 PERCENT. SO WILL ADDRESS RISK OF FIRE SPREAD HERE WITH A SPECIAL WEATHER STATEMENT. && .HYDROLOGY... GENERALLY EXPECT FROM 1/10 TO 1/4 INCH OF BASIN AVERAGE RAINFALL TUESDAY AND TUESDAY NIGHT FROM ANY SHRA/ISOLD TSTMS WHICH DOES OCCUR. HOWEVER CANNOT COMPLETELY RULE OUT LOCALLY HEAVY RAINFALL IN ANY STRONGER CONVECTION. IF THIS DOES OCCUR OVER AN AREA...THEN LOCALIZED MINOR FLOODING OF URBAN AND POOR DRAINAGE AREAS WOULD BE POSSIBLE. MAINLY DRY CONDITIONS ARE EXPECTED WEDNESDAY THROUGH THE WEEKEND. && .EQUIPMENT... KOKX RADAR REMAINS OUT OF SERVICE. REPAIRS WILL BEGIN LATER TODAY ONCE PARTS ARRIVE. UPDATED ESTIMATE FOR COMPLETION OF REPAIR IS THIS EVENING. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS EVENING FOR NYZ067>075-176>179. NJ...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS EVENING FOR NJZ002-004-006-103>108. MARINE...NONE. && $$ SYNOPSIS...MALOIT/DS NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...DS AVIATION...24 MARINE...MALOIT/DS FIRE WEATHER... HYDROLOGY...MALOIT/DS EQUIPMENT...

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