Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 191731 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1231 PM EST FRI DEC 19 2014 .SYNOPSIS... HIGH PRESSURE BUILDS IN FROM THE WEST AND MOVES OVER THE NORTHEAST INTO EARLY NEXT WEEK. A SERIES OF LOW PRESSURE SYSTEMS WILL THEN AFFECT THE REGION THROUGH THE MID-WEEK PERIOD. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CHASING STRATUS/STRATI-CU. GRAVITY WAVE FEATURE CONTINUES TO PROPAGATE SOUTHWEST AT A 70 DEGREE ANGLE INTO THE NORTHWEST FLOW. MOST SUNNY SKIES WILL SPREAD INTO WESTERN LONG ISLAND AND NEW YORK CITY. SENT A "NOW" FOR THIS. THINKING THAT CLOUDS RETURN IN WAKE OF THE SUBSIDENCE OF THE GRAVITY WAVE CONTINUES TO PROPAGATE SSW. WITH A 25 DEGREE SUN ANGLE (WINTER SOLSTICE IS SUNDAY 603 PM) AND THE EXPECTED CLOUD COVER - HAVE LOWERED TEMPS TO THOSE OF THE LATEST LAMP. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... FOR TONIGHT...UNCERTAINTY REMAINS WITH THE STRATUS...THUS LOW TEMPS MAY ONCE AGAIN BE OFF BY 5 DEGREES OR MORE. BASED ON 12Z NAM...IT APPEARS SUFFICIENT CLOUDS WILL REMAIN...THUS HAVE TRENDED TEMPS UP. OTHERWISE...WITH HIGH PRESSURE CONTINUING TO BUILD INTO THE REGION...WINDS WILL FURTHER LOWER. FOR SATURDAY...SAME SCENARIO HERE WITH HIGH PRESSURE CONTINUING TO BUILD IN. THIS DAY WILL FEATURE LOWER MAX TEMPS THOUGH BECAUSE OF LIMITED VERTICAL MIXING AND CLOUDS. THE WINDS IN THE LOW LEVELS WILL BE TRANSITIONING TO LIGHT N-NE FLOW...HELPING TO ADVECT IN SOME COOLER AIR. MAX TEMPS AGAIN WERE A BLEND OF GMOS/MET/MAV GUIDANCE AND UP TO 3-4 DEGREES COOLER ALONG THE COAST THAN THE PREVIOUS DAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... AS HIGH PRESSURE IN THE VICINITY OF MAINE SAT NIGHT SLOWLY SHIFTS EAST THROUGH MONDAY...MOISTURE STREAMS INTO THE TRI STATE AREA FROM OFF THE WATERS. DURING SATURDAY NIGHT...THIS MOISTURE WILL BE SHALLOW...SUPPORTING ONLY LIGHT/VERY LIGHT PCPN. SLIGHT CHC POPS FOR ROUGHLY THE SE HALF OF THE CWA. MID LEVELS WILL PROBABLY BE DRY WITH A LACK OF ICE NUCLEI. THERE IS HOWEVER A CHANCE THAT THE COLDEST TEMPERATURE IN THE SATURATED LAYER CLOSER TO THE SURFACE WILL BE COLD ENOUGH TO SUPPORT ICE CRYSTALS FOR LIGHT SNOW. WOULD BE MORE CONFIDENT FOR SNOW AS A PCPN TYPE IF THE LOW LEVEL FLOW WAS MORE VEERED TO THE EAST (SEA SALT AS NUCLEI)...BUT IN ANY CASE...OVERALL CHANCES OF PCPN ARE LOW. HAVE GONE WITH A MIX OF LIGHT SNOW/RAIN/FREEZING RAIN DEPENDING ON SURFACE TEMPS. MID LEVELS MOISTEN SUNDAY MORNING WITH A SHORTWAVE PASSING THROUGH...SO FREEZING RAIN IS PROBABLY OUT OF THE EQUATION BY THIS TIME. SLIGHT CHC OF LIGHT SNOW OR RAIN THEREFORE FOR SUNDAY. POPS INCREASE MONDAY...MAINLY IN THE AFTERNOON...AS A WAVE OF LOW PRESSURE FORMS ALONG A STALLED BOUNDARY NEAR CAPE HATTERAS AND PUSHES NORTH. A SLIGHT CHANCE OF LIGHT RAIN AND SNOW IN THE MORNING...THEN A CHANCE OF RAIN IN THE AFTERNOON AS THERMAL PROFILES BECOME TOO WARM FOR ANYTHING ELSE. WILL ALSO NEED TO MONITOR FOR THE POSSIBILITY OF MINOR COASTAL FLOODING STARTING WITH THE MONDAY MORNING HIGH TIDE CYCLE. WINDS WILL NOT BE PARTICULARLY STRONG LEADING UP IT...BUT THEY WILL BE ENE FOR SOME TIME AND TIDES WILL BE ON THE HIGHER SIDE ASTRONOMICALLY AS THERE IS A NEW MOON ON SUNDAY. FOR TUES AND WEDS...A MUCH STRONGER LOW PRESSURE SYSTEM AFFECTS THE AREA. LOOKS LIKE A PRIMARY LOW CENTER MOVES ACROSS THE GREAT LAKES WHILE A SECONDARY LOW CENTER FORMS BEFORE PASSING NEARBY WEDS EVENING. THIS STILL LOOKS LIKE AN ALL-RAIN EVENT. HAVE CAPPED POPS AT 50% FOR TUES DUE TO UNCERTAINTY WITH NORTHWARD ADVANCEMENT OF THE WEAKENING INITIAL LOW THAT HAD BEEN APPROACHING FROM THE CAROLINA COAST. MORE CONFIDENCE IN RAINFALL DURING WEDS AS THE SECONDARY LOW CENTER OF THE STRONGER STORM SYSTEM PASSES NEARBY. MINOR STREET FLOODING IS POSSIBLE DURING WEDS/WEDS EVENING. STILL A LOW CHANCE OF CONVECTION ENHANCING THE RAINFALL AS SOME ELEVATED INSTABILITY IS FORECAST BY BOTH GFS AND ECMWF. WINDS WILL PROBABLY BE THE BIGGER CONCERN WITH A TIGHTENING PRESSURE GRADIENT AND A DECENT LOW LEVEL JET PASSING THROUGH SOME TIME ON WEDS AFTERNOON/EVENING. A WIND ADVISORY COULD EVENTUALLY BE NEEDED FOR SOME AREAS. RIGHT NOW IT APPEARS THAT PCPN WILL BE OVER BY CHRISTMAS MORNING. HOWEVER...WITH A FAIRLY STRONG WESTERLY FLOW...LAKE EFFECT RAIN/SNOW SHOWERS COULD REACH THE NW ZONES. NEAR-WIND ADVISORY CRITERIA COULD STILL BE MET. TEMPERATURES ON CHRISTMAS MOSTLY 40-45. && .AVIATION /17Z FRIDAY THROUGH WEDNESDAY/... LOW PRESSURE WILL MOVE FURTHER EAST ACROSS THE CANADIAN MARITIMES AS HIGH PRESSURE MOVES EAST ACROSS NEW ENGLAND BY 12Z SAT. LOW END VFR EXPECTED THROUGH THIS EVENING WITH CIGS MAINLY 030-040FT UNTIL 22Z. LOW CHC OF BRIEF MVFR CIGS AT KISP. NAM FCST SOUNDINGS SUGGEST LOW LEVEL MOSITURE BECOMES MORE WIDESPREAD LATE TONIGHT AND SATURDAY WHICH MAY PRODUCED MVFR CONDITIONS AT TIMES ESPECIALLY AT THE COAST. WINDS 320-350 DEGREES MAGNETIC AT SPEEDS OF 10-15KT WITH GUSTS TO ARND 20KT UNTIL 22Z THEN BECOMING LIGHT AND DECREASING TO LESS THAN 10 KT OVERNIGHT. SATURDAY...EXPECT LIGHT N-NE WINDS LESS THAN 10 KT. 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: NO UNSCHEDULED AMENDMENTS EXPECTED EXCEPT FOR TIMING OF MVFR LATE TONIGHT KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED EXCEPT FOR TIMING OF MVFR LATE TONIGHT. KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED EXCEPT FOR TIMING OF MVFR LATE TONIGHT. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED EXCEPT FOR TIMING OF MVFR LATE TONIGHT. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED EXCEPT FOR TIMING OF MVFR LATE TONIGHT. KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED EXCEPT FOR TIMING OF MVFR LATE TONIGHT. .OUTLOOK FOR 18Z SAT THROUGH WED... .SAT NIGHT...MVFR CIGS POSSSIBLE. LIGHT EAST TO NORTHEAST WINDS. .SUNDAY...MVFR CIGS. LIGHT NORTHEAST WINDS. .MON...MVFR OR LOWER POSSIBLE IN E-SE FLOW. CHC OF RAIN. .MON NIGHT-TUE...IFR LIKELY AT TIMES IN RAIN...CIGS AND VSBYS. E-SE WINDS 10-20 KT. .TUE NIGHT AND WED...HIGH IMPACT EVENT POSSIBLE...IFR LIKELY WITH HEAVY RAIN AND GUSTY SE WINDS 25KT+ SHIFTING TO SW LATE WED. && .MARINE... HIGH PRESSURE GRADUALLY BUILDING IN FROM THE WEST THROUGH SATURDAY. AS LOW PRESSURE OVER THE MARITIMES RACES TO THE NORTHERN LATITUDES...A STEADY DECREASE IN THE PRESSURE GRADIENT OCCUR AND SURFACE WINDS DECREASE IN RESPONSE. OVERALL...SUB SCA CONDITIONS SHOULD PREVAIL THROUGH SATURDAY. TRANQUIL CONDITIONS CONTINUE THROUGH THE REST OF THE WEEKEND. WINDS AND SEAS BUILD ON MONDAY WITH A TIGHTENING PRESSURE GRADIENT. SCA CONDS THEN LIKELY FOLLOW MON NIGHT AND TUES. && .HYDROLOGY... DRY WEATHER IS FORECAST THROUGH SATURDAY WITH ONLY SLIGHT CHANCES OF PCPN SATURDAY NIGHT AND SUNDAY. NO HYDRO IMPACTS EXPECTED INTO EARLY NEXT WEEK. 1/4 TO 1/2 INCH OF RAIN IS POSSIBLE MONDAY AFTERNOON THROUGH TUESDAY AS LOW PRES PASSES SOUTH OF LONG ISLAND. NO HYDROLOGICAL IMPACTS EXPECTED. RAIN ON WEDNESDAY/WEDS NIGHT MAY AVERAGE 1-2 INCHES ACROSS THE REGION. MINOR STREET FLOODING IS POSSIBLE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JC/JM NEAR TERM...TONGUE SHORT TERM...JM/TONGUE LONG TERM...JC AVIATION...IRD MARINE...JM/TONGUE HYDROLOGY...JC/JM

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