Area Forecast Discussion
Issued by NWS Upton, NY

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634 FXUS61 KOKX 050810 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 410 AM EDT THU MAY 5 2016 .SYNOPSIS... A COASTAL LOW TRACKS FROM OFF THE MID ATLANTIC COAST TO NOVA SCOTIA THROUGH TONIGHT. ANOTHER COASTAL LOW MEANDERS NORTH UP THE MID ATLANTIC COAST FRIDAY AND FRIDAY NIGHT...THEN WEAKENS NEARBY ON SATURDAY. A COLD FRONT APPROACHES FROM THE WEST SATURDAY NIGHT...THEN CROSSES THE AREA SUNDAY. HIGH PRESSURE BUILDS INTO THE REGION EARLY NEXT WEEK...WITH A WARM FRONTAL BOUNDARY POSSIBLY STALLING THROUGH THE REGION MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ALL MODELS EXCEPT THE NAM TAKE A 700-500 HPA SHORTWAVE AND ASSOCIATED SURFACE LOW FAR ENOUGH TO THE EAST TODAY...THAT THE REGION SHOULD EXPERIENCE MINIMAL FORCING. AS A RESULT FORECASTING PATCHY DRIZZLE AND A SLIGHT CHANCE OF LIGHT RAIN FOR MOST OF THE DAY. DO INCREASE POPS TO CHANCE THIS AFTERNOON AS APPEARS THE REGION WILL BE UNDER A COUPLED UPPER JET STRUCTURE. FOR HIGHS TODAY A BLEND OF ECS/MET/MAV GUIDANCE...NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 950-925 HPA PER BUFKIT SOUNDINGS WAS USED. HIGHS SHOULD BE AROUND 10-15 DEGREES BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... LOW CHANCE POPS THIS EVENING AS COUPLED JET STRUCTURE EXITS TO THE NE. INCREASE POPS OVERNIGHT...BUT STILL IN CHANCE CATEGORY... AS 700-500 HPA DIFFERENTIAL POSITIVE VORTICITY ADVECTION INCREASES...AS WELL AS THE FLOW ALOFT BECOMES DIFFLUENT. THIS GENERAL SET UP CONTINUES ON FRIDAY...WITH 500 HPA COLD POOL BUILDING IN ALOFT...AND SHOWALTER INDICES FALLING TO -2 TO 2. AS A RESULT...MAINTAINED LIKELY POPS FOR RAIN AND ADDED A SLIGHT CHANCE OF THUNDER (ELEVATED IN NATURE) FRIDAY AFTERNOON. FOR LOWS TONIGHT A BLEND OF MAV/ECS/MET GUIDANCE AND NAM 2-METER TEMPERATURES WAS USED...WITH VALUES PROGGED TO BE NEAR TO SLIGHTLY BELOW NORMAL. HIGHS ON FRIDAY WERE BASED ON A BLEND OF MET/MAV/ECS GUIDANCE...NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 950 HPA PER BUFKIT SOUNDINGS. HIGHS SHOULD BE A FEW DEGREES WARMER THAN TODAY...BUT STILL AROUND 10-15 DEGREES BELOW NORMAL. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE GENERAL H5 FLOW ACROSS NORTH AMERICA THROUGH THE MIDDLE OF NEXT WEEK. AS USUAL...THERE ARE SOME TIMING AND AMPLITUDE DIFFERENCES THAT START TO DEVELOP OVER THE WEEKEND...ALTHOUGH THE GENERAL IDEA IS THAT THE PERSISTENT BLOCKED UPPER PATTERN ACROSS THE CONUS WILL FINALLY LOSE ITS GRIP NEXT WEEK. CUTOFF LOW PRES NEAR THE MID ATLANTIC COAST FRI NIGHT WILL GRADUALLY WEAKEN WHILE SLOWLY MOVING E THROUGH SAT NIGHT. MEANWHILE...A SHORTWAVE TROUGH DIVING OUT OF CENTRAL CANADA CUTS OFF OVER ONTARIO WITH THE TWO SYSTEMS CONSOLIDATING INTO A BROAD VORTEX OVER SE CANADA. THIS SYSTEM WILL GRADUALLY LIFT NE INTO THE MARITIMES EARLY NEXT WEEK AS RIDGING OVER THE UPPER MIDWEST FLATTENS WITH A SW UPPER FLOW DEVELOPING BY THE MIDDLE OF NEXT WEEK. AT THE SFC...WEAK SFC LOW PRES NEAR THE DELAWARE/NJ COAST GRADUALLY WEAKENS S OF THE AREA THROUGH THE DAY SAT. WIDESPREAD RAIN WILL GRADUALLY DRY OUT ACROSS THE AREA WITH DRY WEATHER RETURNING BY SAT NIGHT. THE STRENGTH AND EXACT TRACK OF THIS LOW STILL REMAIN IN QUESTION WHICH WILL IMPACT WIND STRENGTH/DIRECTION AND ULTIMATELY ANY CONTINUED COASTAL FLOOD IMPACTS ON SAT. SEE COASTAL FLOOD SECTION BELOW FOR MORE INFORMATION. A COLD FRONT APPROACHES FROM THE WEST SAT NIGHT AND TRACKS THROUGH ON SUN...BRINGING ANOTHER ROUND OF SHOWERS TO THE AREA. THERE ARE TIMING DISCREPANCIES WITH THIS...WITH THE EC BEING SLIGHTLY FASTER THAN THE GFS. THE BIGGER ISSUE THAT NEEDS TO BE RESOLVED IS THAT THE GFS IS INDICATING MAINLY POST-FRONTAL PRECIPITATION AND REALLY WRAPS THE SYSTEM UP ONCE IT PUSHES THROUGH RESULTING TO A MUCH STRONGER PRESSURE PATTERN ACROSS THE AREA. RIDGING THEN RETURNS THROUGH EARLY NEXT WEEK WITH TEMPERATURES GRADUALLY RETURNING TO NEAR TO ABOVE NORMAL LEVELS. A WARM FRONT APPROACHING FOR THE MIDDLE OF THE WEAK HAS THE POTENTIAL TO STALL OVER OR NEAR THE AREA WITH WAVES OF LOW PRES TRACKING ALONG IT. THERE IS HIGH BUST POTENTIAL IN THE TEMP FORECAST ON WED DUE TO THIS. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... LOW PRESSURE ALONG WITH A NEARLY STATIONARY FRONT WILL REMAIN SOUTH OF LONG ISLAND THROUGH TONIGHT. GENERALLY LOOKING AT IFR/MVFR CONDITIONS IN STRATUS THROUGH THE TAF PERIOD. SOME OF THE 00Z FORECAST GUIDANCE IS HINTING AT THE POSSIBILITY OF SOME VFR CONDITIONS DURING THE LATE AFTERNOON HOURS. CONFIDENCE NOT HIGH ENOUGH TO PUT IN THE TAF QUITE YET...BUT WILL CONTINUE TO MONITOR. VISIBILITIES ARE EXPECTED TO REMAIN VFR...HOWEVER SOME LOWER POCKETS OF MVFR OR EVEN IFR CAN NOT BE RULED OUT EARLY THIS MORNING. NORTHEAST FLOW IS EXPECTED THROUGH THE TAF PERIOD. SPEEDS WILL GENERALLY RANGE BETWEEN 10 AND 15 KT THROUGH THE TAF PERIOD..WITH GUSTS BETWEEN 20-25 KT. SOME LOCALLY HIGHER GUSTS WILL BE POSSIBLE. WIND GUSTS MAY BE OCCASIONAL THROUGH 12Z. MODERATE CONFIDENCE WITH WIND FORECAST. LOW CONFIDENCE WITH CATEGORY FORECAST MAINLY DUE TO UNCERTAINTY OF TIMING BETWEEN MVFR AND IFR CEILINGS...WHICH COULD BE SEVERAL HOURS OFF...ALONG WITH THE POSSIBILITY OF VFR CONDITIONS LATE THIS AFTERNOON. ...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: GUSTS MAY BE OCCASIONAL THIS MORNING. LOW CHANCE CONDITIONS IMPROVE TO VFR LATE THIS AFTERNOON OR EVENING FOR A FEW HOURS. KLGA FCSTER COMMENTS: GUSTS MAY BE OCCASIONAL THIS MORNING. LOW CHANCE CONDITIONS IMPROVE TO VFR LATE THIS AFTERNOON OR EVENING FOR A FEW HOURS. KEWR FCSTER COMMENTS: GUSTS MAY BE OCCASIONAL THIS MORNING. LOW CHANCE CONDITIONS IMPROVE TO VFR LATE THIS AFTERNOON OR EVENING FOR A FEW HOURS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: GUSTS MAY BE OCCASIONAL THIS MORNING. LOW CHANCE CONDITIONS IMPROVE TO VFR LATE THIS AFTERNOON OR EVENING FOR A FEW HOURS. KHPN FCSTER COMMENTS: GUSTS MAY BE OCCASIONAL THIS MORNING. LOW CHANCE CONDITIONS IMPROVE TO VFR LATE THIS AFTERNOON OR EVENING FOR A FEW HOURS. KISP FCSTER COMMENTS: GUSTS MAY BE OCCASIONAL THIS MORNING. LOW CHANCE CONDITIONS IMPROVE TO VFR LATE THIS AFTERNOON OR EVENING FOR A FEW HOURS. .OUTLOOK FOR 06Z FRI THROUGH MON... .THU NIGHT THROUGH SUNDAY MORNING...PERIODS OF RAIN/FOG/LOW CLOUDS WITH MVFR OR LOWER CONDITIONS. NE WINDS G15-20 KT FRI. .SUNDAY AFTERNOON/NIGHT...COLD FRONTAL PASSAGE SHOULD FINALLY BRING AN END TO DISMAL CONDITIONS...WITH CONDITIONS IMPROVING TO VFR AND NW WINDS G20KT. .MON...VFR. W WINDS G25KT POSSIBLE. && .MARINE... A TIGHTENING PRESSURE GRADIENT TODAY WILL PRODUCE 25-30KT GUSTS ON ALL WATERS BY MID-LATE MORNING THROUGH THE AFTERNOON. FOR THE OCEAN WATERS GUSTS OF 25-30 KT ARE EXPECTED THROUGH FRIDAY WITH SEAS OF 4-8 FT AS WELL. FOR THE NON-OCEAN WATERS...WIND GUSTS TO 25 KT MIGHT CONTINUE TONIGHT...BUT CONFIDENCE IN THIS IS ONLY MODERATE. GUSTS ON ON FRIDAY SHOULD BE AROUND 20 KT. AS A RESULT...HAVE MADE NO CHANGES TO THE SCA FOR THE COASTAL OCEAN WATERS THROUGH FRIDAY AND HAVE ISSUED AN SCA FOR THE NON- OCEAN WATERS FROM 12Z- 22Z TODAY. THE SCA HAS BEEN EXTENDED THROUGH FRI NIGHT ON THE OCEAN WATERS...MAINLY FOR SEAS. WHILE THE CURRENT FORECAST KEEPS MARGINAL SEAS ON THE OCEAN THROUGH SAT...THERE IS UNCERTAINTY THAT THIS WILL OCCUR. THE PRES GRADIENT WEAKENS...BUT WAVEWATCH IS INDICATING A SE-S SWELL CONTINUES THROUGH THIS TIME. A SLY FLOW INCREASES SAT NIGHT AHEAD OF AN APPROACHING COLD FRONT...WITH THE POTENTIAL FOR SCA CONDITIONS ON ALL WATERS BEHIND THE FRONT SUN...BEFORE SUBSIDING SUN EVE. 5 FT SEAS MAY LINGER ON THE EASTERN OCEAN WATERS INTO MON. && .HYDROLOGY... GENERALLY LESS THAN 1/10 OF AN INCH OF RAIN IS EXPECTED THROUGH TONIGHT. AROUND 1/2 TO 2/3 OF AN INCH OF RAIN IS EXPECTED FROM FRIDAY INTO SATURDAY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. PONDING OF WATER IS POSSIBLE IN AREAS RECEIVING LOCALLY HEAVY RAINFALL. UP TO 1/4 INCH IS POSSIBLE SATURDAY NIGHT INTO SUNDAY WITH A COLD FRONTAL PASSAGE. NO HYDROLOGIC ISSUES ARE EXPECTED. && .TIDES/COASTAL FLOODING... THE HIGHEST SPRING TIDE OF THE YEAR IS APPROACHING WITH THE NEW MOON ON FRIDAY. THE THREAT FOR MINOR TO LOCALLY MODERATE COASTAL FLOODING WILL INCREASE DURING THE EVENING HIGH TIDES THROUGH FRIDAY...AND LIKELY CONTINUE INTO THIS WEEKEND. WATER LEVELS MAY BRIEFLY TOUCH MINOR COASTAL FLOOD LEVELS IN A FEW SOUTH SHORE BAY LOCALES ON SOUTHWESTERN LONG ISLAND WITH THIS MORNINGS AND FRIDAY MORNINGS HIGH TIDES. FOR TONIGHTS HIGH TIDE...ASTRONOMICAL TIDES WILL BE AROUND 1/4-1/2 FT HIGHER THAN LAST NIGHT...WHILE TIDAL DEPARTURES SHOULD BE NEAR TO MAYBE A 1/4 FT HIGHER THAN LAST NIGHT. THIS WILL RESULT IN MORE WIDESPREAD MINOR COASTAL FLOODING ACROSS THE VULNERABLE LOCALES ALONG THE SOUTH SHORE BAYS OF WESTERN LONG ISLAND/NYC AND WESTERN LONG ISLAND SOUND AND NY HARBOR. AN ADVISORY HAS BEEN ISSUED FOR THESE AREAS. THERE IS POTENTIAL FOR THE MOST VULNERABLE SOUTH SHORE BAY LOCALES OF WESTERN GREAT SOUTH BAY TO HIT MODERATE FLOOD THRESHOLDS THIS EVENING...BUT THE PROBABILITY REMAINS TOO LOW FOR A WARNING AT THIS TIME. MINOR FLOOD LEVELS WILL BE APPROACHED AND POSSIBLY LOCALLY TOUCHED ACROSS THE REMAINING EASTERN COASTAL AREAS. FOR FRIDAY NIGHTS HIGH TIDES...WIDESPREAD MINOR COASTAL FLOODING IS EXPECTED ONCE AGAIN AS ASTRONOMICAL TIDES PEAK AND SURGE LIKELY REMAINS STEADY. THE POTENTIAL EXISTS FOR MODERATE COASTAL FLOODING IN VULNERABLE SOUTH SHORE BAYS LOCALES OF WESTERN LONG ISLAND AND QUEENS AT THAT TIME WITH ONLY 1 TO 1 1/4 FT SURGE NEEDED IN SPOTS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EDT TONIGHT FOR CTZ009-010. NY...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EDT TONIGHT FOR NYZ071-078-177. COASTAL FLOOD ADVISORY FROM 7 PM TO 10 PM EDT THIS EVENING FOR NYZ074-075-178-179. NJ...COASTAL FLOOD ADVISORY FROM 7 PM TO 10 PM EDT THIS EVENING FOR NJZ006-106-108. MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 6 PM EDT THIS EVENING FOR ANZ330-335-338-340-345. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...MALOIT/24 NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...24 AVIATION...BC MARINE...MALOIT/24 HYDROLOGY...MALOIT/24 TIDES/COASTAL FLOODING...

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