Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 280001 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 801 PM EDT WED MAY 27 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT...THEN MOVE ACROSS THURSDAY INTO THURSDAY NIGHT. HIGH PRESSURE WILL RETURN ON FRIDAY...QUICKLY MOVING INTO THE WESTERN ATLANTIC LATE FRIDAY AFTERNOON INTO THE WEEKEND. A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST WILL EVENTUALLY MOVE IN SATURDAY NIGHT AND STALL NEARBY FOR SUNDAY INTO EARLY NEXT WEEK. HIGH PRESSURE WILL BUILD IN FROM THE NORTH LATE TUESDAY INTO THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... LINE OF SHRA/TSRA NOT MOVING INTO SOUTHERN CT. STORMS HAVE DISSIPATED AROUND NYC...AND ANOTHER AREA OF SHRA/TSRA MOVING INTO NE NJ. WITH STABLE...MARINE AIRMASS OVER LONG ISLAND/NYC/COASTAL CT...NOT EXPECTING MANY STORMS TO SURVIVE OR DEVELOP IN THAT ATMOSPHERE. WILL CARRY LIKELY POPS FOR WESTERN CT...THROUGH NYC...AND INTO SOUTHERN PORTIONS OF NE NJ FOR A FEW HOURS THIS EVENING...AND STORMS SHOULD DIMINISH SHORTLY AFTER SUNSET WITH LOSS OF DIURNAL HEATING. NOT EXPECTING TOO MANY SEVERE STORMS...SO WILL ALLOW SVR TSTM WATCH TO EXPIRE AT 7 PM. SHOULD BE A HUMID NIGHT WITH LOWS IN THE 60S. THERE IS SOME POTENTIAL FOR PATCHY FOG LATE TONIGHT NORTH/WEST OF NYC WHERE HEAVIER RAIN FALLS. NOTING THAT FOG HAS NOT MATERIALIZED THE PAST FEW NIGHTS...STILL DO NOT HAVE THE CONFIDENCE TO MENTION. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... MODELS DIFFER ON COVERAGE/EXTENT OF CONVECTION WITH A COLD FRONT ON THURSDAY. ALSO DIFFER ON TIMING WITH THE GFS/ECMWF FASTER THAN THE NAM/CMC-REG. NOTING 700-500 HPA FLOW HAS A FAIRLY DECENT PERPENDICULAR COMPONENT TO THE FRONT...LEANED TOWARDS THE FASTER TIMING OF THE GFS/ECMWF FOR POPS. WITH A WEAKENING FRONT THOUGH...DID NOT FEEL COMFORTABLE GOING WITH HIGHER THAN CHANCE POPS AT THIS TIME. PROBABILITIES ARE GENERALLY HIGHER FROM NYC AND AREAS JUST NORTH/WEST. WITH LESS MLCAPE...500-1000 J/KG OVER THE INTERIOR THAN TODAY...AND THE BEST DYNAMIC FORCING FORECAST TO THE N OF THE REGION...DO NOT THINK THERE IS AS MUCH OF A THREAT FOR SEVERE WEATHER. THOUGH AN ISOLATED STRONG TO SEVERE STORM OR TWO CANNOT BE COMPLETELY RULED OUT. HIGHS ON THU SHOULD BE IN THE 80S INLAND...AND IN THE 70S NEAR THE COAST...MAINLY PER WARMER NAM MOS GUIDANCE. WOULD NOT BE SURPRISING IF A FEW LOCATIONS IN NE NJ APPROACHED 90. DEWPOINTS ON THURSDAY SHOULD BE A TAD LOWER THAN TODAY...MAINLY IN THE LOWER 60S. A WEAK COLD FRONT WILL MOVE ACROSS THURSDAY NIGHT. LITTLE TO NO PRECIPITATION IS EXPECTED WITH THE FRONT. LOWS SHOULD BE IN THE 60S IN MOST PLACES...EXCEPT MID/UPPER 50S IN THE VALLEYS WELL NORTH/WEST OF NYC. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... RIDGING TREND RESUMES ALOFT WITH JET STREAM WELL NORTH OF THE REGION FOR FRIDAY. THIS RIDGE SHIFTS SLOWLY OFFSHORE AND BECOMES LESS AMPLIFIED AS A LONGWAVE TROUGH PUSHES EASTWARD ACROSS SOUTHERN CANADA. THE SAME PATTERN REMAINS THROUGH THE FIRST HALF OF THE WEEKEND AND THEN THE JET PUSHES FARTHER SOUTH INTO THE REGION FOR THE REST OF THE WEEKEND INTO EARLY NEXT WEEK. THE MID LEVEL RIDGE WILL BECOME MORE BROAD SUNDAY WITH A SHORTWAVE MOVING IN EARLY NEXT WEEK. THE RIDGING RESUMES BY MID NEXT WEEK WITH JET STREAM ONCE AGAIN MOVING WELL NORTH OF THE REGION. AT THE SURFACE...HIGH PRESSURE FROM THE CANADIAN MARITIMES QUICKLY SETTLES INTO THE WESTERN ATLANTIC LATE AFTERNOON FRIDAY AND INTO THE WEEKEND. THE INFLUENCE OF THE HIGH WILL LESSEN WITH TIME AS A SLOW MOVING COLD FRONT APPROACHES FROM THE WEST. THE PARENT LOW ATTACHED TO THIS FRONT WILL NOT BE THAT STRONG...SLOWLY DEEPENING WITH EASTWARD PROGRESS THROUGH SATURDAY AND THEN DEEPENS MORE WITHIN THE CANADIAN MARITIMES SUNDAY THROUGH SUNDAY NIGHT. THE COLD FRONT WILL BE MOVING WITHIN CLOSER PROXIMITY OF 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. HIGH PRESSURE RETURNS LATE TUESDAY FROM THE CANADIAN MARITIMES...BUT ONCE AGAIN BECOMES RE-ESTABLISHED QUICKLY OFFSHORE INTO THE WESTERN ATLANTIC. IN TERMS OF WEATHER...CONDITIONS REMAIN DRY FRIDAY AND FRIDAY NIGHT. HOWEVER...WITH THE MOIST SOUTHERLY FLOW FRIDAY NIGHT INTO SATURDAY MORNING...EXPECTING SOME PATCHY FOG ACROSS THE REGION...ESPECIALLY COASTAL REGIONS. SOME MODELS ARE SHOWING THIS MOISTURE AS VERY LIGHT QPF. THERE WILL BE A GRADUAL INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS FIRST NORTH AND WEST OF NYC SATURDAY AHEAD OF THE COLD FRONT. THE CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE SATURDAY NIGHT ACROSS THE WHOLE FORECAST REGION WITH SHOWERS BECOMING LIKELY SUNDAY AND SUNDAY NIGHT. THUNDERSTORMS WILL BE MORE LIMITED SUNDAY AND SUNDAY NIGHT WITH DECREASING INSTABILITY WITH A MORE NORTHERLY AND EASTERLY FLOW DEVELOPING DURING THE DAY. WITH THE FRONT STALLING NEAR THE REGION...CHANCES FOR 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 INTO NEXT WEDNESDAY. THE AIR MASS WILL STAY MOSTLY AS MARITIME TROPICAL THROUGH THE LONG TERM BUT A LITTLE COOLER FOR MONDAY AND TUESDAY NEXT WEEK. THE HIGHS ARE FORECAST TO BE AROUND OR SLIGHTLY MORE THAN 5 DEGREES ABOVE NORMAL ON AVERAGE FRIDAY AND SATURDAY...NEAR NORMAL FOR SUNDAY...AROUND 5 DEGREES BELOW NORMAL MONDAY AS WELL AS A FEW DEGREES BELOW NORMAL TUESDAY. TEMPERATURE RETURN TO NEAR NORMAL BY MID NEXT WEEK. LOWS AT NIGHT OVERALL ARE FORECAST TO BE NEAR TO ABOVE NORMAL. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE REMAINS ACROSS THE NORTH ATLANTIC. MEANWHILE A LOW WILL BE MOVING THROUGH EASTERN CANADA TONIGHT THROUGH THURSDAY BRINGING A WEAKENING COLD FRONT TOWARD THE AREA THURSDAY AFTERNOON. THE FRONT IS EXPECTED TO CROSS THE LOWER HUDSON VALLEY LATE IN THE AFTERNOON...AND POSSIBLY MOVE THROUGH THE NYC AREA TERMINALS RIGHT AROUND 00Z FRIDAY. THERE IS A LOW CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS WITH THE FRONT. AT 00Z THURSDAY A WEAKENING LINE OF SHOWERS AND ISOLATED THUNDERSTORMS WAS MOVING THROUGH THE NYC AREA TERMINALS AND WILL WEAKEN AS THE LINE MOVES EAST. VFR CONDITIONS EXPECTED WITH LOCAL AND BRIEF MARGINAL CEILINGS WITH THE SHOWERS. OTHERWISE VFR UNTIL LATE TONIGHT WHEN MARGINAL CEILINGS IN STRATUS ARE EXPECTED WITH CEILINGS 1000 TO 2000 FT. LOCAL MARGINAL VFR FOG IS POSSIBLE. HIGH CONFIDENCE IN THE STRATUS MOVING IN...LOW CONFIDENCE IN FOG DEVELOPMENT. ANY MARGINAL VFR CEILINGS BECOME VFR AFTER 15Z THURSDAY. 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: SHOWERS EXIT THE TERMINAL AROUND 01Z. SOUTHERLY WIND GUSTS UP TO 30 KT END QUICKLY AROUND 03Z. MARGINAL CEILINGS AROUND 1200 FT DEVELOP LATE TONIGHT AND COULD BE A HOUR OR SO EARLIER THAN FORECAST...THEN REMAIN THROUGH THE MORNING. HIGH CONFIDENCE IN THE FORECAST. KLGA FCSTER COMMENTS: SHOWERS EXIT THE TERMINAL AROUND 01Z. MARGINAL CEILINGS AROUND 1300 FT DEVELOP LATE TONIGHT AND COULD BE A COUPLE OF HOURS EARLIER THAN FORECAST...THEN REMAIN THROUGH THE MORNING. LOW CHANCE OF FOG TONIGHT. HIGH CONFIDENCE IN THE FORECAST. KEWR FCSTER COMMENTS: SHOWERS EXIT THE TERMINAL BY 01Z. MARGINAL CEILINGS AROUND 1300 FT DEVELOP TOWARD SUNRISE...AND COULD BE A COUPLE OF HOURS EARLIER THAN FORECAST...THEN REMAIN THROUGH THE MORNING. LOW CHANCE OF FOG TONIGHT. HIGH CONFIDENCE IN THE FORECAST. KTEB FCSTER COMMENTS: SHOWERS EXIT THE TERMINAL BY 01Z. MARGINAL CEILINGS AROUND 1500 FT DEVELOP LATE TONIGHT...AND POSSIBLE COULD BE NEARER TO 06Z. MARGINAL VFR CEILINGS THEN REMAIN THROUGH THE MORNING. AS WINDS BECOME LIGHT LATE TONIGHT MARGINAL VFR FOG IS LIKELY. HIGH CONFIDENCE IN THE FORECAST. KHPN FCSTER COMMENTS: SHOWERS EXIT THE TERMINAL BY 01Z. MARGINAL CEILINGS AROUND 1000 FT DEVELOP LATE TONIGHT...AND POSSIBLE COULD BE NEARER TO 06Z. MARGINAL VFR CEILINGS THEN REMAIN THROUGH THE MORNING. AS WINDS BECOME LIGHT LATE TONIGHT MARGINAL VFR FOG IS LIKELY. THERE IS A LOW CHANCE OF IFR CONDITIONS AROUND SUNRISE. HIGH CONFIDENCE IN THE FORECAST. KISP FCSTER COMMENTS: SOME STRATUS AROUND 1200 FT REMAINS THIS EVENING. THERE IS A LOW CHANCE OF A SHOWER 0030Z TO 0130Z WITH MARGINAL VFR CEILINGS. IFR CEILINGS ARE POSSIBLE LATE TONIGHT. HIGH CONFIDENCE THAT THE CEILINGS WILL BE MARGINAL VFR WITH A IFR CEILINGS FOR A WHILE TOWARD SUNRISE. MARGINAL CEILINGS LINGER INTO THE AFTERNOON. MODERATE CONFIDENCE IN THE FORECAST OF CEILINGS AND TIMING. .OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY... .THU NIGHT...COLD FRONT MOVES THROUGH EARLY IN THE EVENING WITH THE WIND SHIFTING TO NW TO N. VFR. .FRI...VFR. LGT NE WINDS VEERING THRU THE DAY. .SAT...MRNG MVFR OR LOWER POSSIBLE. CHC SHWRS AND TSTMS IN THE AFTN AND OVERNIGHT WITH MVFR OR LOWER. STRONG SLY FLOW. .SUN...MVFR OR LOWER IN SHOWERS/TSTMS POSSIBLE. SHIFTING WINDS TO THE E/NE. .MON...POSSIBLE IMPROVEMENT TO VFR IF SHOWERS/TSTMS MOVE TO THE SOUTH. E/NE FLOW. && .MARINE... SEAS SHOULD BUILD TO 5 FT OVER THE OCEAN WATERS BY TONIGHT...WITH GUSTS UP TO 25 KT EAST OF SANDY HOOK WITH USUAL LATE DAY/EVENING SOUTHERLY SEA BREEZE ENHANCEMENT. NY HARBOR AND WRN LONG ISLAND SOUND COULD EXPERIENCE EITHER DIRECT TSTM IMPACTS OR A GUST FRONT FROM WEAKENING INLAND STORMS TOWARD EVENING. PERSISTENT SOUTHERLY FETCH COULD BUILD SEAS ON THE OCEAN TO 5 FT SATURDAY...AND REMAIN THERE FOR THE REST OF THE FCST PERIOD...EVEN AS WINDS SWITCH TO MORE EASTERLY SUNDAY INTO EARLY NEXT WEEK. && .HYDROLOGY... THERE IS THE POTENTIAL FOR BASIN AVERAGE OF 1/4 TO 1/2 INCH OF RAIN ACROSS THE LOWER HUDSON VALLEY/NE NJ/SW CT THIS AFTERNOON/EVENING. NOTING PRECIP EFFICIENCY OF JUST OVER 1.5 INCH AND CORFIDI VECTORS 10 KT OR LESS...THERE IS THE POTENTIAL FOR TRAINING OF CELLS THAT COULD LEAD TO RAINFALL OF 1-2 INCHES...WITH MINOR FLOODING OF URBAN/POOR DRAINAGE AREAS. ON THURSDAY THERE IS THE POTENTIAL FOR LESS THAN 1/4 OF AN INCH OF BASIN AVERAGE RAINFALL. HOWEVER...WITH STORM MOTION OF AROUND 10 KT AND PRECIP EFFICIENCY NEAR 1.25 INCHES...THERE IS STILL POTENTIAL FOR SLOW MOVING STORMS PRODUCING LOCALLY MODERATE TO HEAVY RAINFALL...ESPECIALLY OVER SOUTHERN CT. THIS COULD RESULT IN THE MINOR FLOODING OF URBAN/POOR DRAINAGE AREAS...ESPECIALLY IF IT OCCURS OVER AREAS RECEIVING LOCALLY HEAVY RAINFALL TODAY. THERE IS POTENTIAL FOR HEAVY RAIN SUNDAY AND SUNDAY NIGHT WITH PW FORECAST TO REACH UP TO NEAR 1.75 INCHES. THERE WILL BE POTENTIAL AS WELL FOR AN EXTENDED WIDESPREAD RAINFALL LATE THIS WEEKEND INTO EARLY NEXT WEEK WITH A COLD FRONT STALLING NEARBY. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...GOODMAN NEAR TERM...MPS SHORT TERM...GOODMAN LONG TERM...JM AVIATION...MET MARINE...MPS HYDROLOGY...GOODMAN/JM

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