Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 160950 CCA AFDOKX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE NEW YORK NY 443 AM EST TUE DEC 16 2014 .SYNOPSIS... HIGH PRESSURE MOVES EAST. LOW PRESSURE APPROACHES TONIGHT AND MOVES TO THE EAST WEDNESDAY. LOW PRESSURE SLOWLY EXITS INTO THE CANADIAN MARITIMES WEDNESDAY NIGHT THROUGH FRIDAY. HIGH PRESSURE THEN BUILDS IN FROM THE NORTH FOR FRIDAY NIGHT AND SATURDAY BEFORE LOW PRESSURE STARTS TO APPROACH FROM THE SOUTH. THE LOW RIDES SOUTH OF THE REGION TO CLOSE OUT THE WEEKEND...EXITING WELL EAST OF THE REGION EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPPER RIDGE AXIS MOVES EAST...QUICKLY GIVING WAY TO SHORTWAVE THAT TRACKS NORTHWEST OF THE AREA LATE. AT THE SURFACE...HIGH PRESSURE GIVES WAY TO LOW PRESSURE THAT IS FORECAST TO TRACK ACROSS THE GREAT LAKES REGION THIS AFTERNOON. A WARM FRONT APPROACHES FROM THE SOUTHWEST LATE IN THE DAY. PLENTY OF CLOUDS ARE EXPECTED TODAY AS STRATUS LIKELY LINGERS THROUGH THE DAY. WARM AIR ADVECTION WILL BE UNDERWAY AND STRONG MID LEVEL LIFT IS EXPECTED AHEAD OF THE SHORTWAVE THIS AFTERNOON. EXPECT RAIN TO MOVE INTO WESTERN ZONES LATER THIS AFTERNOON. PRIOR TO THAT...PATCHY DRIZZLE IS POSSIBLE...ALTHOUGH NARRE/HRRR ARE NOT SHOWING MUCH OF THIS. IF ANY DRIZZLE OR DENSE FOG IS REALIZED...LIGHT ICING COULD BE THE RESULT EARLY THIS MORNING AS TEMPS REMAIN BELOW FREEZING. THIS WILL NEED TO BE MONITORED. TEMPS DO RISE QUICKLY AS WARM AIR ADVECTION GETS UNDERWAY AS MENTIONED. EXPECT MAX TEMP READINGS AROUND 40 ACROSS THE INTERIOR...WITH 40S TO NEAR 50 ELSEWHERE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... MODELS IN GENERAL AGREEMENT ON OVERALL FEATURES THIS TIME FRAME. UPPER SHORTWAVE MOVES NORTHEAST TONIGHT...WITH CLOSED LOW SLOWLY APPROACHING AS IT TRACKS EAST WEDNESDAY. THE LOW WILL BE LOCATED OVER NY STATE BY LATE WEDNESDAY. AT THE SURFACE...WARM FRONT APPROACHES TONIGHT AS SECONDARY LOW PRESSURE MOVES OVERHEAD AFTER MIDNIGHT. OCCLUDED FRONT EXTENDS NORTHWESTWARD TO PARENT LOW OVER THE GREAT LAKES REGION. THE COASTAL LOW TRACKS TOWARD THE NEW ENGLAND COAST WEDNESDAY AFTERNOON...WITH INLAND LOW MOVING NORTH OF LAKE ONTARIO. RAIN ASSOCIATED WITH UPPER SHORTWAVE...MID LEVEL LIFT ALONG WITH LOW LEVEL ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL IMPACT THE AREA TONIGHT. THE AREA OF RAIN MOVES NORTHEASTWARD TONIGHT INTO WEDNESDAY. MOST OF THE RAIN ALONG THE FRONT REMAINS TO THE NORTH WEDNESDAY...BUT CLOUDS REMAIN DUE TO PRESENCE OF UPPER LOW. WINDS SHIFT AROUND TO THE WEST BEHIND THE FRONT AND LOW PRESSURE WEDNESDAY...AND BECOME GUSTY. COLD AIR ADVECTION ENSUES. HOWEVER...TEMPS WILL ALREADY BE QUITE MILD TONIGHT...AND WEDNESDAY MORNING. AS SUCH...MILD READINGS DO CONTINUE INTO WEDNESDAY BEFORE COLD AIR ADVECTION IMPACTS BOUNDARY LAYER. WILL FOLLOW MOS CLOSELY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
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QUASI-ZONAL UPPER LEVEL FLOW THROUGH THE LONG TERM WITH MAIN JET STAYING SOUTH OF THE REGION MOST OF THE TIME. THIS JET STARTS TO PUSH NORTHWARD ACROSS THE REGION EARLY NEXT WEEK. WEATHER WILL BE INFLUENCED MAINLY BY A LARGE LOW PRESSURE TROUGH WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. MAIN SHORTWAVE PIVOTS ACROSS THE REGION WEDNESDAY NIGHT...WITH SOME POSSIBLE RAIN OR SNOW SHOWERS WITH ITS POSITIVE VORTICITY ADVECTION. WITH TIMING...MUCH OF THE PRECIP IF ANY WERE TO OCCUR...WOULD BE IN THE FORM OF SNOW SHOWERS. JUST LIGHT AMOUNTS LIKE A COATING AT MOST. MODELS SHOW NO QPF ACROSS THE FORECAST AREA...MAINLY JUST FOR NORTHWEST AND SOUTHEAST OF THE AREA BUT THE VERY STRONG VORTICITY ADVECTION DOES WARRANT A MENTION OF THE POSSIBILITY OF PRECIPITATION. THE OTHER REMARKABLE FEATURE WILL BE GUSTY WINDS...EXEMPLIFIED BY THE STEEP PRESSURE GRADIENT BETWEEN THE LOW IN THE CANADIAN MARITIMES AND THE HIGH PRESSURE TO THE NORTH AND WEST. THIS WILL REINFORCE COLD AIR ADVECTION AS WELL. FOR FRIDAY NIGHT AND SATURDAY...THE UPPER LEVEL LOW AND ASSOCIATED TROUGH EXIT EAST OF THE REGION. RIDGING WILL TAKE OVER ALOFT AND AT THE SURFACE. THE RESULT WILL BE A WEAKENING PRESSURE GRADIENT AND HENCE WINDS AS WELL. FLOW WILL TRANSITION TO BECOME MORE EASTERLY AS WELL. MONITORING NEXT MAIN MID LEVEL SHORTWAVE AND UPPER LEVEL JET STREAK POISED TO MOVE IN FROM THE SOUTH CENTRAL U.S. LATE SATURDAY INTO SUNDAY. THERE WILL BE AN ASSOCIATED LOW IN THE GULF THAT WILL EVENTUALLY MOVE OFF THE CAROLINAS. A LOT OF UNCERTAINTY WITH THIS WITH THE LAST TWO RUNS OF THE ECMWF CONVEYING THIS. THE DIFFERENCES BETWEEN THE LAST TWO ECMWF RUNS SHOW A VIVID FLUCTUATION OF 15-25 MB WITH THE CENTER OF THE LOW SATURDAY NIGHT INTO SUNDAY NIGHT. THE TREND HAS BEEN GOING TO A WEAKER ONE. THIS IS SIMILAR TO THE 00Z RUN OF THE GFS WITH ITS DEPICTION OF THE LOW. THE FORECAST WAS NOT CHANGED THAT MUCH FROM BEFORE DUE TO THE AFOREMENTIONED UNCERTAINTY. SO A MIX OF RAIN AND SNOW SATURDAY NIGHT THROUGH SUNDAY NIGHT. WHILE MODEL FORECAST AMOUNTS HAVE LOWERED...STILL CANNOT RULE OUT THERE BEING MORE WIDESPREAD SIGNIFICANT PRECIPITATION IF MODELS TREND BACK TO A STRONGER LOW WITH A LARGER ASSOCIATED AREA OF PRECIP EXTENDING OUTWARD. IN ANY CASE...A DRIER TREND FOLLOWS FOR MONDAY WITH HIGH PRESSURE RETURNING FROM THE WEST. THE TEMPERATURES OVERALL WILL BE NEAR NORMAL FOR LOWS BUT FRIDAY NIGHT PROBABLY SEVERAL DEGREES BELOW NORMAL WITH THE BETTER ANTICIPATED RADIATIONAL COOLING CONDITIONS FORECAST. THESE ARE ESSENTIALLY LIGHTER WINDS AND LESS CLOUDS. FOR HIGHS...NEAR NORMAL THURSDAY BUT A FEW DEGREES BELOW NORMAL FOR THE REST OF THE DAYS THEREAFTER IN THE FORECAST PERIOD.
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&& .AVIATION /09Z TUESDAY THROUGH SATURDAY/... HIGH PRESSURE FROM THE CANADIAN MARITIME AND EXTENDING INTO THE NORTHEAST WILL SLOWLY RETREAT AS A WARM FRONT APPROACHES FROM THE SOUTH. LIGHT AND VARIABLE WINDS REMAIN THROUGH THE REMAINDER OF THE OVERNIGHT. MVFR CIGS ADVANCING ONTO LONG ISLAND AND SE CT FROM THE OCEAN SINCE MIDNIGHT...BUT HIGH CLOUDS MOVING OHD FROM THE WEST ARE STARTING TO OBSCURE THEIR VIEW. INCREASING MOISTURE BECOMING TRAPPED BENEATH A LOW LEVEL INVERSION IS EXPECTED TO CONTINUE WITH THE DEVELOPMENT OF CIGS BETWEEN 1500 AND 2500 FT EARLY THIS MORNING. THE WARM FRONT WILL MOST LIKELY REMAIN TO THE SOUTH TODAY AS A WAVE OF LOW PRESSURE DEVELOPS AND TRACK ACROSS THE AREA LATE THIS AFTERNOON THROUGH THE EVENING. A LIGHT SOUTHEAST FLOW...AROUND 5 KT...IS POSSIBLE AFTER SUNRISE. HOWEVER...SOME OF THE TERMINALS MAY REMAIN LIGHT AND VARIABLE. MARGINAL CONDITIONS WILL LOWER TO IFR AS LIGHT DRIZZLE DEVELOPS IN THE AFTERNOON...AND THEN A MORE STEADY LIGHT RAIN. ...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: TIMING OF MVFR AND IFR CIGS MAY BE +/- 1-2 HOURS. THE ONSET OF DRIZZLE OR RAIN COULD BE OFF SEVERAL HOURS AS WELL. KLGA FCSTER COMMENTS: TIMING OF MVFR AND IFR CIGS MAY BE +/- 1-2 HOURS. THE ONSET OF DRIZZLE OR RAIN COULD BE OFF SEVERAL HOURS AS WELL. KEWR FCSTER COMMENTS: TIMING OF MVFR AND IFR CIGS MAY BE +/- 1-2 HOURS. THE ONSET OF DRIZZLE OR RAIN COULD BE OFF SEVERAL HOURS AS WELL. KTEB FCSTER COMMENTS: TIMING OF MVFR AND IFR CIGS MAY BE +/- 1-2 HOURS. THE ONSET OF DRIZZLE OR RAIN COULD BE OFF SEVERAL HOURS AS WELL. KHPN FCSTER COMMENTS: TIMING OF MVFR AND IFR CIGS MAY BE +/- 1-2 HOURS. THE ONSET OF DRIZZLE OR RAIN COULD BE OFF SEVERAL HOURS AS WELL. KISP FCSTER COMMENTS: TIMING OF MVFR AND IFR CIGS MAY BE +/- 1-2 HOURS. THE ONSET OF DRIZZLE OR RAIN COULD BE OFF SEVERAL HOURS AS WELL. .OUTLOOK FOR 06Z WED THROUGH SAT... .TONIGHT...MVFR/IFR IN RAIN AND FOG. IMPROVING AFTER 08Z. .WED...VFR. W 10-15KT. GUSTS 20-25KT. .THU...VFR. NW 10-15KT. GUSTS 20-25KT. .FRI-SAT...VFR. && .MARINE...
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SOUTH FLOW IS EXPECTED TODAY AS HIGH PRESSURE DEPARTS TO THE EAST. WINDS SHOULD BACK TO THE EAST/SOUTHEAST AHEAD OF A WARM FRONT LATE TODAY INTO TONIGHT. WINDS MAY BE QUITE VARIABLE FOR A TIME TONIGHT AS LOW PRESSURE DEVELOPS ALONG THE FRONT AND MOVES OVER THE WATERS. THEN WINDS SHIFT TO THE WEST AND INCREASE LATE TONIGHT AND THROUGH THE DAY WEDNESDAY. IN FACT...SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED OVER THE OCEAN WATERS WEDNESDAY. HIGHER CONFIDENCE FOR THE OCEAN...WITH LESS CONFIDENCE FOR THE SHELTERED WATERS AROUND LONG ISLAND. OCEAN SEAS LIKELY BUILD TO 5 FT AS WELL...SO WILL ISSUE SCA FOR THE OCEAN ONLY AT THIS TIME. A TIGHT PRESSURE GRADIENT WILL ALLOW FOR SCA CONDITIONS TO PROBABLY CONTINUE MUCH OF THE PERIOD FROM WEDNESDAY NIGHT THROUGH EARLY FRIDAY. THE LOW WILL BE SLOW TO EXIT FAR AWAY FROM THE REGION...GOING FROM THE GULF OF MAINE WEDNESDAY NIGHT TO THE AROUND NOVA SCOTIA BY EARLY FRIDAY. HIGH PRESSURE EXERTS MORE INFLUENCE THEREAFTER THROUGH SATURDAY WITH LESS OF A PRESSURE GRADIENT AND THEREFORE WEAKENING WINDS. CONDITIONS ARE FORECAST TO BE BELOW SCA. SCA COULD POTENTIALLY RETURN BY THE 2ND HALF OF THE WEEKEND AS LOW PRESSURE APPROACHES FROM THE SOUTH...BUT THERE IS UNCERTAINTY WITH THIS ESPECIALLY WITH ITS MAGNITUDE.
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&& .HYDROLOGY... 1/4 TO AS MUCH AS 1/2 INCH QPF IS EXPECTED LATE TODAY THROUGH WEDNESDAY MORNING. NO HYDROLOGIC ISSUES ARE ANTICIPATED. NO SIGNIFICANT WIDESPREAD PRECIP WEDNESDAY THROUGH SATURDAY. THERE IS A LOW PROBABILITY OF SIGNIFICANT PRECIP FROM A COASTAL LOW SAT NIGHT INTO SUN NIGHT. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST WEDNESDAY FOR ANZ350-353-355. && $$ SYNOPSIS...JM/PW NEAR TERM...PW SHORT TERM...PW LONG TERM...JM AVIATION... MARINE...JM/PW HYDROLOGY...JM/PW

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