Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 211444 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1044 AM EDT THU AUG 21 2014 .SYNOPSIS... HIGH PRESSURE REMAINS CENTERED TO THE NORTH AND EAST OF THE AREA THROUGH TONIGHT. MEANWHILE...WAVES OF LOW PRESSURE ALOFT MOVE ACROSS THE REGION TODAY AND TONIGHT. AN UPPER LEVEL DISTURBANCE WILL TRACK THROUGH THE AREA ON FRIDAY AS HIGH PRESSURE BUILDS DOWN FROM EASTERN CANADA. THE HIGH WILL CONTINUE TO BUILD SOUTHWARD INTO THE REGION ON SATURDAY...AND REMAIN ANCHORED OVER THE AREA THROUGH THE BEGINNING OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ISO-SCT SHOWERS MAINLY NORTH/WEST OF NYC METRO WITH A STRAY TSTM PSBL THROUGH THIS AFTN AS AN UPPER LVL TROUGH PIVOTS THROUGH THE REGION. SLIGHTLY ADJUST POPS THROUGH EARLY AFTN WITH 14Z RADAR REFLECTIVITY SHOWING MOST OF THE PCPN NORTH OF THE AREA. MESO MODELS STILL SHOWING DEVELOPMENT MAINLY OVER WESTERN AREAS THIS AFTN AFTR 18Z WHERE THE BEST INSTABILITY CAN BE EXPECTED...GENERALLY AROUND 1000 J/KG. ONSHORE FLOW OVER EASTERN AREAS/ALONG THE COAST WILL MAINTAIN A MORE STABLE ATMO...RESULTING IN MOSTLY DRY CONDITIONS TILL THIS EVENING. FLOW ALOFT LESS THAN 10 KTS...SO WHILE FLASH FLOODING IS NOT A BIG CONCERN...THERE IS THE POTENTIAL FOR A BRIEF PERIOD OF HEAVY RAINFALL WITH THE SLOW MOVING CELLS. WITH A LACK OF A SIGNIFICANT LIFTING MECHANISM...NOT LOOKING FOR ANYTHING STRONG OR SEVERE. CLOUD COVER WILL HELP TO KEEP TEMPERATURES SLIGHTLY BELOW NORMAL FOR THE MOST PART. GENERALLY HIGHS WILL BE IN THE UPPER 70S TO LOWER 80S. TEMPS ARE THUS FAR ON TRACK FOR THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... THE CHANCE FOR SHOWERS CONTINUES TONIGHT AS THE CLOSED UPPER LOW ASSOCIATED WITH THE TROUGH MOVES INTO NEW ENGLAND AND A SHORTWAVE MOVES AROUND ITS BASE. WITH THE LOSS OF DAYTIME HEATING...THE CHANCE FOR THUNDERSTORMS DECREASES...AND THUS JUST PLAIN SHOWERS ARE IN THE FORECAST. SOUTHWESTERLY FLOW OFF THE OCEAN EARLY TONIGHT WILL ALLOW FOR A MOIST AIRMASS. DEWPOINTS WILL RISE INTO THE MIDDLE 60S. WINDS SHIFT MORE TO THE NORTHEAST LATE TONIGHT...AND DEWPOINTS WILL COME BACK DOWN TO THE LOWER 60S BY DAYBREAK FRIDAY. THIS NORTHEASTERLY FLOW WILL THEN MEAN AN EVEN COOLER DAY ON FRIDAY AS COMPARED TO THURSDAY...WITH HIGHS GENERALLY IN THE LOWER TO MIDDLE 70S. SOME UPPER 70S FOR THE NYC METRO REGION. HIGH PRESSURE FROM THE NORTHEAST WILL NOSE INTO THE AREA FRIDAY...ALLOWING THE CHANCES FOR SHOWERS TO END FROM EAST TO WEST ON FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... SOLID MODEL CONSENSUS THRU TUE. HIPRES BUILDS INTO THE AREA THEN STRENGTHENS AS THE UPR RIDGE TRANSLATES EWD. ON WED...THE ECMWF BRINGS A CDFNT CLOSE...BUT THE GFS KEEPS THE FEATURE OFF THE LOCAL MAP. HAVE SIDED WITH THE SLOWER GFS SOLN AS THIS FITS A FAST MODEL BIAS AT THIS TIME RANGE. A MARITIME POLAR AIRMASS IS LOCKED IN FRI NGT INTO THE FIRST PART OF SAT. VIRTUALLY NO LIFT IN THE MOIST LAYER...SO HAVE ONLY FCST SPRINKLES. THE CLOUDS BEGIN TO CLR IN THE AFTN FROM NE TO SW AS STRONG SUBSIDENCE KICKS IN. DRY WITH LGT WINDS SUN-WED COURTESY OF THE HIGH. SOME CIRRUS AT TIMES. TEMPS BLW NORMAL SAT...THEN A GRADUAL WARMING TREND TAKES PLACE SUN-TUE AS HEIGHTS INCREASE. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... WEAK HIGH PRESSURE REMAINS OVER THE AREA. GENERALLY EXPECT VFR CONDITIONS THROUGH THE AFTERNOON HOURS. THERE WILL BE ISOLATED TO SCATTERED SHOWERS...AND ANY SHOWER COULD REDUCE CEILINGS OR VSBYS TO MVFR BRIEFLY. BEST CHANCE FOR SHOWERS ACROSS NYC METRO AND NORTH AND WEST...LATER IN THE DAY. POSSIBLE HIGHER COVERAGE OF SHOWERS TONIGHT AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH. BEST CHANCE NYC METRO AND NORTH AND WEST. VFR CEILINGS AND VSBYS MAY LOWER TO MVFR OR EVEN IFR LATE AT NIGHT. LIGHT WINDS WILL EVENTUALLY BECOME SOUTHEAST OR SOUTH 5 TO 10 KTS THIS AFTERNOON. WINDS TONIGHT SHOULD LIGHTEN AS THEY TURN TO THE EAST. 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: LIGHT AND VARIABLE WINDS WILL BECOME SOUTHEAST THIS AFTERNOON. KLGA FCSTER COMMENTS: LIGHT AND VARIABLE WINDS ARE EXPECTED TO BECOME SOUTHEAST THIS AFTERNOON. TIMING COULD BE OFF AN HOUR OR TWO. KEWR FCSTER COMMENTS: LIGHT WINDS BECOME SOUTHEAST...JUST TO THE RIGHT OF 130 MAGNETIC. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. .OUTLOOK FOR 12Z FRI THROUGH MON... .FRI MORNING...SUB VFR POSSIBLE IN LOW CLOUDS AND FOG. .FRI AFTERNOON-MON...VFR. && .MARINE... WINDS AND SEAS FORECAST ON TRACK FOR TODAY. THERE WILL BE A CHANCE FOR SHOWERS TODAY AS AN UPPER LEVEL DISTURBANCE MOVES TOWARD THE AREA. AN ISOLATED THUNDERSTORM IS POSSIBLE ACROSS THE WESTERN SOUND AND HARBOR. WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA...BUT MAY APPROACH SCA CRITERIA BRIEFLY IN ANY THUNDERSTORM. THE CHANCES FOR SHOWERS CONTINUE INTO TONIGHT AND FRIDAY...WITH CHANCES DIMINISHING THROUGHOUT THE DAY FRIDAY. WINDS AND WAVES CONTINUE TO REMAIN BELOW SCA FOR TONIGHT AND FRIDAY. WINDS WILL APPROACH SCA LVLS FRI NGT...THEN DIMINISH DURING THE DAY ON SAT. SEAS ON THE OCEAN WILL BUILD TO AROUND 4 FT LATE FRI NGT...THEN LINGER THRU MOST OF SAT BEFORE SUBSIDING. A SCA MAY BE NEEDED ESPECIALLY ON THE OCEAN FRI NGT AND SAT. OTHERWISE...WINDS AND SEAS WILL BE BLW SCA LVLS SUN-AT LEAST TUE. && .HYDROLOGY... A FEW SLOW MOVING THUNDERSTORMS ARE POSSIBLE TODAY ACROSS THE LOWER HUDSON VALLEY AND INTERIOR NE NJ AND INTO NYC. THESE STORMS WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAIN...BUT BASIN AVERAGED TOTALS ARE FORECAST TO REMAIN LIGHT WITH THE ISOLATED NATURE OF THE STORMS. TRACE AMOUNTS OF PCPN ARE POSSIBLE FRI NGT INTO SAT. IT WILL THEN REMAIN DRY THRU THE BEGINNING OF NEXT WEEK. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JMC/JP NEAR TERM...JMC/JP/SEARS SHORT TERM...JP LONG TERM...JMC AVIATION...IRD MARINE...JMC/JP/SEARS HYDROLOGY...JMC/JP

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