Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 271817 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 217 PM EDT FRI MAR 27 2015 .SYNOPSIS... A COLD FRONT WILL PUSH FARTHER TO THE EAST THIS AFTERNOON. LOW PRESSURE WILL DEVELOP OFFSHORE TONIGHT...AND TRACK TOWARD THE CANADIAN MARITIMES ON SATURDAY. AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS ON SATURDAY AND PASS TO THE EAST SATURDAY NIGHT...FOLLOWED BY HIGH PRESSURE. FOR THE NEW WORK WEEK...A SERIES OF CLIPPER LOWS WILL BE MOVING ACROSS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MOST OF THE SHOWERS HAVE TAPERED OFF OVER THE AREA...BUT SEVERAL SHORTWAVES CONTINUE TO PASS THROUGH THE REGION THROUGH THIS AFTERNOON. THERE ARE SOME RADAR RETURNS MOVING TOWARDS THE NORTHEAST...BUT THERE ARE NOT MANY SFC OBS CONFIRMING PRECIP REACHING THE GROUND. WILL LOWER POPS TO SLIGHT CHANCE FOR THE AFTERNOON...AS SHOWERS WILL BE SPOTTY. NORTHERLY WINDS WILL SLOWLY ADVECT COLDER AIR INTO THE REGION...NOT ALLOWING TEMPS TO RISE MUCH FROM MORNING LOWS. CLOUD COVER WILL KEEP TEMPS A FEW DEGREES BELOW SEASONABLE IN THE MID TO UPPER 40S. AROUND 50 NYC/NJ METRO. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... DEEP UPPER TROUGH GRADUALLY PIVOTS TO THE EAST COAST TONIGHT INTO SATURDAY NIGHT...WITH POTENTIAL CLOSED LOW TRACKING OVER THE TRI- STATE TO MID-ATLANTIC VICINITY SATURDAY NIGHT. AT THE SURFACE...LOW PRESSURE TRACKS NE ALONG THE COLD FRONT WELL SE OF THE REGION TONIGHT INTO SAT NIGHT. OPERATIONAL MODELS AND RESPECTIVE ENSEMBLE ARE IN FAIRLY GOOD AGREEMENT WITH THE LOW STAYING FAR ENOUGH OFFSHORE TO KEEP THE HEAVIEST PRECIP FROM THIS LOW OFFSHORE. BUT THE MAJORITY OF SOLUTIONS...EXCEPT FOR OPERATIONAL ECMWF...DO SPREAD WESTERN EDGE OF LIGHT PRECIP SHIELD INTO EASTERN LI/SE CT TONIGHT INTO SAT NIGHT. SUNYSB SENSITIVITY ANALYSIS DEPICTS A SLIGHT SPREAD IN ENSEMBLE MEMBERS ON WEST SIDE OF LOW TRACK...DEPICTING A LOW PROB OF SLIGHTLY FARTHER WEST SOLUTION IF THE TROUGH DIGS A BIT DEEPER. THIS WOULD INCREASE PRECIP POTENTIAL FOR LI/CT. AT THE SAME TIME...SEVERAL MODELS HAVE BEEN SIGNALING A WEAK INVERTED TROUGH HANGING BACK OVER THE REGION TONIGHT INTO SAT AS CLOSED MID-LEVEL LOW APPROACHES. THE TRACK/INTENSITY OF THE MID- LEVEL CLOSED LOW AND ASSOCIATED SURFACE TROUGH LOCATION WILL BE KEY TO POTENTIAL DEVELOPMENT OF ANY STEADIER AND MORE WIDESPREAD PRECIP FRIDAY NIGHT INTO SAT NIGHT. THE STRENGTH/POSITION OF THIS FEATURE HAS WAVERED FROM MODEL RUN TO MODEL RUN FROM SOUTHERN NEW ENGLAND TO NORTHERN MID ATLANTIC OVER THE LAST SEVERAL DAYS...INSPIRING LITTLE CONFIDENCE ON WHERE THIS FEATURE SETS UP. FOR LOCATIONS THAT DO NOT FALL UNDER THE INVERTED TROUGH OR WESTERN EDGE OF PRECIP SHIELD...THERE WILL BE AN ISO/SCT THREAT FOR MAINLY DIURNAL SHOWER ACTIVITY ACROSS THE AREA ON SATURDAY UNDER COMBO OF MID-LEVEL VORT ENERGY AND COLD POOL INSTABILITY. WITH THE ABOVE MENTIONED UNCERTAINTY AND PRECIP POTENTIAL HAVE MAINTAINED AN W TO E GRADIENT OF CHANCE POPS TONIGHT INTO SAT NIGHT. THEREAFTER...MODELS IN GENERAL AGREEMENT WITH THE UPPER TROUGH SLIDING EAST AND SURFACE HIGH BUILDING TOWARDS THE REGION LATE SATURDAY NIGHT WITH GRADUAL TAPERING OF PRECIP ACROSS EASTERN TRI- STATE. IN TERMS OF P-TYPE...CAA TONIGHT INTO SAT SHOULD ALLOW PRECIP TO MIX WITH/CHANGE TO WET SNOW LATE TONIGHT. IF PRECIP IS STEADY/HEAVY ENOUGH A MAINLY WET SNOW WOULD BE EXPECTED ON SATURDAY BASED ON THERMAL PROFILE ALOFT...BUT IF IT IS VERY LIGHT AND SCATTERED IN NATURE A RAIN/SNOW MIX WOULD BE LIKELY DUE TO INABILITY TO COOL BOUNDARY LAYER SUFFICIENTLY. MOST LIKELY SCENARIO AT THIS POINT IS 1-2 INCHES OR LESS OF WET SNOW FRI NIGHT INTO SAT NIGHT ACROSS EASTERN LI/SE CT...WITH A COATING TO NOTHING FURTHER WEST. IF INVERTED TROUGH DEVELOPS OVER THE REGION...OR OFFSHORE LOW TRACKS A BIT FARTHER WEST...AN ADVISORY LEVEL WET SNOW WOULD BE POSSIBLE ACROSS MAINLY LI/CT...WITH A LIGHT COATING TO INCH FARTHER WEST. THIS LATTER SCENARIO IS A LOW PROBABILITY AT THIS TIME. TEMPS ON SAT/SAT NIGHT WILL LIKELY RUN ABOUT 10 TO 15 DEGREES BELOW SEASONABLE UNDER THE UPPER TROUGH AND COLD POOL. && .LONG TERM /SUNDAY THROUGH THURSDAY/... HIGH PRESSURE BUILDS INTO THE AREA AT THE SURFACE ON SUNDAY...WITH THE CENTER OF THE HIGH PASSING WELL TO THE SOUTH...WHILE AT THE SAME TIME THERE WILL BE RIDGING ALOFT. THICKNESSES QUICKLY BUILD ON SUNDAY AS THE HIGH PUSHES OFF THE SOUTHEAST COAST LATE IN THE DAY...WHICH MEANS WARMER TEMPERATURES AS COMPARED TO SATURDAY...MAINLY FOR NYC...NORTHEAST NJ...AND LOWER HUDSON VALLEY. LONG ISLAND AND SOUTHERN CT MAY SEE ONLY SLIGHTLY WARMER TEMPERATURES AS WINDS SHIFT TO MORE OF A SOUTHERLY DIRECTION DURING THE DAY. THIS ONSHORE FLOW OFF THE COLD OCEAN WATERS WILL KEEP TEMPERATURES COOLER THAN INLAND AREAS. A COLD FRONT THEN APPROACHES THE AREA SUNDAY NIGHT...AND MOVES THROUGH LATE MONDAY INTO MONDAY NIGHT. SOME LIGHT PRECIPITATION IS POSSIBLE OUT AHEAD OF THE FRONT SUNDAY NIGHT. THERE IS LIMITED MOISTURE TO WORK WITH HOWEVER...SO ONLY SLIGHT CHANCE POPS. WARM AIR ADVECTION AHEAD OF THE FRONT WILL MEAN PRECIPITATION IN THE FORM OF RAIN SHOWERS FOR MUCH OF THE AREA. HOWEVER...THERE MAY BE SOME SNOW SHOWERS WELL INLAND. ANY SNOW WILL CHANGE TO RAIN DURING THE MORNING ON MONDAY. PATTERN BECOMES RATHER PROGRESSIVE AS THE UPPER LEVEL FLOW IS PRETTY ZONAL. AT THE SURFACE...WEAK HIGH PRESSURE BUILDS IN FOR TUESDAY. A QUICK MOVING CLIPPER SYSTEM MOVES THROUGH ON TUESDAY NIGHT...DEPARTING THE AREA ON WEDNESDAY. AGAIN...MUCH OF THE AREA SHOULD BE WARM ENOUGH FOR RAIN...WITH THE POSSIBILITY OF SOME FLAKES MIXING IN TUESDAY NIGHT ACROSS SOUTHERN CT AS COLDER AIR MOVES IN BEHIND THE LOW. A WARM FRONT APPROACHES THE AREA ON WEDNESDAY NIGHT...MOVING THROUGH ON THURSDAY...FOLLOWED QUICKLY BY THE ASSOCIATED COLD FRONT. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... WEAK HIGH PRESSURE WILL GRADUALLY BUILD IN THROUGH THIS EVENING WHILE AN UPPER LEVEL DISTURBANCE SLIDES ACROSS. SURFACE LOW PRESSURE WILL THEN DEVELOP OFF THE COAST LATE TONIGHT AND PASS WELL TO THE SOUTHEAST ON SATURDAY. ANOTHER UPPER LEVEL DISTURBANCE AND WEAK SURFACE LOW PRESSURE TROUGH WILL MOVE ACROSS ON SATURDAY. DIFFICULT FORECAST FOR NYC METRO LATE THIS AFTERNOON AND EVENING. WEAK HIGH PRESSURE WILL BE BUILDING IN...BUT THE PASSING UPPER LEVEL DISTURBANCE IS LIKELY TO BRING ABOUT MOSTLY MVFR CIGS DURING THIS TIME. CIGS SHOULD LIFT BY LATE EVENING...THEN EXPECT ANOTHER ROUND OF MVFR CIGS AND ISOLD-SCT SNOW SHOWERS SAT MORNING. EXCEPTION TO THE ABOVE WILL BE AT KGON...WHICH SHOULD MAINTAIN MVFR CIGS INTO TONIGHT...THEN IS LIKELY TO SEE SOME LIGHT SNOW LATE TONIGHT INTO SAT MORNING...WITH RUNWAY ACCUMULATION OF 1-3 INCHES POSSIBLE. NNW WINDS GENERALLY LESS THAN 10 KT INTO MOST OF TONIGHT WILL INCREASE TO 10-15 KT WITH GUSTS EITHER SIDE OF 20 KT LATE TONIGHT INTO SAT MORNING AS THE OFFSHORE LOW DEVELOPS. ...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: OCNL VFR CIGS POSSIBLE LATE THIS AFTERNOON AND EVENING. KLGA FCSTER COMMENTS: OCNL VFR CIGS POSSIBLE LATE THIS AFTERNOON AND EVENING. KEWR FCSTER COMMENTS: OCNL VFR CIGS POSSIBLE LATE THIS AFTERNOON AND EVENING. KTEB FCSTER COMMENTS: OCNL VFR CIGS POSSIBLE LATE THIS AFTERNOON AND EVENING. KHPN FCSTER COMMENTS: OCNL VFR CIGS POSSIBLE LATE THIS AFTERNOON AND EVENING. KISP FCSTER COMMENTS: UNSCHEDULED AMD NOT EXPECTED. .OUTLOOK FOR 18Z SAT THROUGH TUE... .SAT AFTERNOON...CHANCE OF MVFR CONDS WITH ANY RAIN OR SNOW SHOWERS. NW WINDS G20KT. .SAT NIGHT...CHANCE OF MVFR CONDS WITH ANY SNOW OR RAIN SHOWERS... MAINLY IN THE EVENING. NW WINDS G20-25KT. .SUNDAY...VFR. .MON...VFR. W WINDS G20KT. .TUE...VFR. .TUE NIGHT...CHANCE OF MVFR CONDS WITH ANY RAIN SHOWERS. .WED...VFR. && .MARINE... MARGINAL SCA WINDS THIS MORNING WITH SCA OCEAN SEAS TODAY AS HIGH SOUTHERLY SWELLS ONLY SLOWLY SUBSIDE. MARGINAL SCA CONDS EXPECTED ON OCEAN TONIGHT INTO SAT MORNING WITH GUSTY NW FLOW...CAA...AND RESIDUAL SOUTHERLY SWELLS. BETTER CHANCE OF SCA CONDS ON OCEAN AND POSSIBLY ALL WATERS WILL BE SAT NIGHT IN WAKE OF DEPARTING OFFSHORE LOW AND AS HIGH PRESSURE BUILDS IN FROM THE WEST. WAVES DIMINISH TO SUB SCA ON SUNDAY...BUT BUILD TO ABOVE SCA CRITERIA ON A SOUTHERLY FLOW LATE SUNDAY NIGHT INTO MONDAY AHEAD OF AN APPROACHING WARM FRONT. WINDS MAINLY OVER THE OCEAN WATERS WILL GUST TO 25 KT LATE SUNDAY NIGHT INTO MONDAY NIGHT. WINDS AND WAVES WILL DIMINISH ON TUESDAY AS THE PRESSURE GRADIENT RELAXES WITH WEAK HIGH PRESSURE BUILDING IN. WAVES QUICKLY BUILD AGAIN TO ABOVE SCA CRITERIA TUESDAY NIGHT IN RESPONSE TO SOUTHERLY FLOW AHEAD OF AN APPROACHING CLIPPER SYSTEM...THEN DIMINISH ON WEDNESDAY AS THE SYSTEM DEPARTS THE REGION. && .HYDROLOGY... AN ADDITIONAL TENTH OF AN INCH OR SO OF QPF THROUGH THIS AFTERNOON. NO SIGNIFICANT WIDESPREAD PRECIPITATION EXPECTED THROUGH THIS WEEKEND INTO NEXT WEEK. RIVERS AND STREAMS ARE EXPECTED TO REMAIN BELOW BANK FULL...BUT INCREASED RIVER/STREAM FLOW ACROSS THE LOWER HUDSON VALLEY AND SOUTHERN CONNECTICUT WILL CONTINUE ICE BREAKUP AND MOVEMENT INTO THIS WEEKEND. ISOLATED ICE JAMS ARE POSSIBLE...WHICH IF THEY OCCUR...COULD RESULT IN LOCALIZED FLOODING. SINCE ICE JAM FLOODING IS UNPREDICTABLE AND SUDDEN...INTERESTS ALONG ICE COVERED RIVERS SHOULD MONITOR NWS FORECASTS FOR THE LATEST INFORMATION. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...JP/NV NEAR TERM...MPS SHORT TERM...NV LONG TERM...JP AVIATION...GOODMAN MARINE...JP/NV HYDROLOGY...JP/NV

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.