Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 242209 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 509 PM EST WED DEC 24 2014 .SYNOPSIS... A COLD FRONT APPROACHES FROM THE WEST THIS EVENING...AND CROSSES THE TRI-STATE OVERNIGHT...WITH ITS ASSOCIATED LOW TRACKING INTO QUEBEC THURSDAY. HIGH PRESSURE BUILDS TO THE SOUTH OF THE REGION THROUGH SATURDAY. A COLD FRONT THEN CROSSES THE REGION ON SUNDAY AND STALLS WELL TO OUR SOUTH ON MONDAY. A WEAK WAVE OF LOW PRESSURE MOVES ALONG THE FRONT ON TUESDAY AND MAY BRUSH NEW YORK CITY AND LONG ISLAND. AT THIS TIME NEW YEARS EVE AND DAY LOOK DRY WITH SEASONABLE TEMPERATURES. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... WARM FRONT IS NOW ALONG A LINE FROM THE EASTERN LONG ISLAND SOUND TO PORT JEFFERSON TO OYSTER BAY TO CENTRAL QUEENS. TEMPS ARE NEAR 60 IN THE WARM SECTOR AND THE WINDS HAVE INCREASED OUT OF THE SOUTH WITH THE LOSS OF THE BOUNDARY LAYER STABILITY. WITH WATER TEMPS IN THE MID TO UPPER 40S AND AIR DEW POINT TEMPS IN THE UPPER 50S...ADVECTION FOG IS NOW A SIGNIFICANT HAZARD. EXPECT THE WARM FRONT TO PUSH NORTH OF I-95 IN CT THIS EVENING AND EXPECTING DENSE FOG THERE AS WELL. STRONG LOW LEVEL JET IS PULLING THE RECORD WARMTH AT KISP. EXPECTING THE LINE OF CONVECTION WITH THE FROPA TOWARDS MORNING. SOME STRONGER GUSTS COULD MIX DOWN FROM ALOFT. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... SHOWERS SHOULD TAPER OFF CHRISTMAS MORNING FROM WEST TO EAST...AS THE COLD FRONT MOVES OFFSHORE. BEHIND THE FRONTAL PASSAGE EXPECT DRY CONDITIONS WITH BELOW ADVISORY LEVEL WIND GUST OF 30 TO 40 MPH. WINDS WILL DIMINISH CHRISTMAS NIGHT AS THE FRONT PUSHES FURTHER EAST. THE MAX TEMPERATURES FOR CHRISTMAS DAY SHOULD BE IN THE LOW TO MID 50S...WITH TEMPERATURES DROPPING OFF INTO THE 40S BY LATE AFTERNOON AND EVENING. LOW TEMPERATURES CHRISTMAS NIGHT SHOULD BE IN THE UPPER 20 TO AROUND 30 INLAND...AND MID TO UPPER 30S ALONG THE COAST. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... NWP GUIDANCE HAS MADE A SIGNIFICANT SHIFT TODAY WITH THE SOUTHERN BRANCH OF THE JET RESULTING A MORE PROGRESSIVE PATTERN. BASED ON AGREEMENT OF GEFS WITH THE DETERMINISTIC GFS AND ECMWF TREND...HAVE REPOPULATED FCST. 12Z GEM REMAINS MORE ACTIVE...BUT WAS NOT INCORPORATED INTO THE FCST BASED ON GEFS/EC SIMILARITY. THUS...FCSTING THE COLD FRONTAL PASSAGE ON SUNDAY...THEN SEASONABLE AND DRY. DUE TO THE SHIFT IN THE NWP...CONFIDENCE IS LOWER THAN NORMAL AND WE COULD HAVE A WINDSHIELD WIPER EFFECTS IN THE DETERMINISTIC GUIDANCE. ONLY POPS OUT SIDE OF THOSE WITH THE COLD FRONT ON SUNDAY ARE LATE TUESDAY WITH A WEAK WAVE SEEN IN THE ECMWF. GEFS HAS SOME MEMBERS THAT SUPPORT THIS FEATURE (NOT SEEN IN THE DETERMINISTIC GFS). PARALLEL GFS ALSO SUPPORTS THE IDEA OF A WEAK LOW PASSING TO THE SOUTH LATE TUESDAY. AS FOR TEMPS...MOS HAS TRENDED HIGHER FRIDAY AND SATURDAY AND SEEMS LOGICAL WITH TEMPS A GOOD 10 DEGREES ABOVE NORMAL ON SATURDAY. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... ***HIGH IMPACT EVENT INTO TONIGHT*** A WARM FRONTAL BOUNDARY WILL CONTINUE TO MOVE NORTH THROUGH LONG ISLAND AND INTO COASTAL CONNECTICUT THROUGH THIS EVENING. WARM FRONT WILL LIKELY BE SLOWER WORKING INTO NE NJ AND LOWER HUDSON VALLEY TERMINALS. MEANWHILE A COLD FRONT WILL BE APPROACHING TONIGHT...CROSSING THROUGH THE AREA FROM AROUND 10Z TO 15Z THURSDAY. LIFR/VLIFR CONDS EXPECTED TO CONTINUE/DEVELOP FOR KHPN/KLGA/KJFK AND EASTERN TERMINALS IN THE WAKE OF THE WARM FRONT WITH ADVECTION FOG...CONTINUING INTO TONIGHT. FOR KEWR/KTEB/KSWF...CONDITIONS MORE LIKELY REMAIN LIFR/IFR TONIGHT...WITH A LOW PROBABILITY OF VLIFR. WINDS WILL INCREASE TO S 15 TO 20 MPH WITH GUSTS UP TO 30 MPH IN WAKE OF WARM FRONT AND UNTIL COLD FRONTAL PASSAGE. LOW PROBABILITY OF 40 MPH GUSTS. A LOW LEVEL S/SW JET STREAM OF 50 TO 60 KT WILL RESULT IN LEVEL WIND SHEAR UNTIL THE COLD FRONTAL PASSAGE. PERIODS OF LIGHT TO MODERATE RAIN TONIGHT...AND THEN A BAND OF MODERATE TO HEAVY RAIN WITH EMBEDDED TSTM LIKELY TO CROSS THE REGION BETWEEN 06Z AND 12Z. POTENTIAL FOR AN ORGANIZED LINE OF CONVECTION...WITH LOW PROB OF ISOLATED 40+ KT GUSTS. CONDITIONS IMPROVE QUICKLY TO VFR WITH THE RAIN ENDING AS THE FRONT MOVES THROUGH. VFR...WITH 15 TO 20 KT WESTERLY WINDS WITH GUSTS 30 TO 35 KT. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .THU AFT...VFR. WESTERLY WIND 15-20G30-35KT. CHANCE OCCASIONAL GUSTS 35-40KT. .THU NIGHT...VFR. WIND AND GUSTS DIMINISHING. .FRI-SAT...VFR. .SUN...MARGINAL VFR. CHANCE OF RAIN AND SNOW. .MON...VFR. && .MARINE... DENSE ADVECTION FOG ON THE WATERS UNTIL JUST BEFORE MORNING WITH THE COLD FRONTAL PASSAGE. WINDS INCREASE ON ALL WATERS TO SCA LEVELS TONIGHT. SCA LEVEL SEAS ON THE COASTAL OCEAN WATERS IN EFFECT WITH GUSTS TO GALE FORCE LIKELY DEVELOPING CHRISTMAS MORNING AND CONTINUING INTO EARLY EVENING. SCA GUSTS THEN EXPECTED FOR THE REMAINDER OF THE EVENING...TAPERING OFF TO BELOW SCA LEVELS AFTER MIDNIGHT. SUB-SCA CONDITIONS ARE ANTICIPATED ON FRIDAY INTO NEXT WEEK THOUGH THERE IS UNCERTAINTY IN HOW FAR SOUTH THE STALLED FRONTAL BOUNDARY WILL REMAIN NEXT WEEK. && .HYDROLOGY... UP TO THREE QUARTERS OF AN INCH OF RAINFALL HAVE FALLEN ACROSS THE HYDROLOGIC SERVICE AREA...AND AN ADDITION ONE TO ONE AND A HALF INCHES IS EXPECTED THROUGH CHRISTMAS MORNING. THE MAIN THREAT FROM THIS IS MINOR URBAN AND POOR DRAINAGE FLOODING LIKELY. DRY FRI-SATURDAY NIGHT. LIGHT PCPN IS POSSIBLE ON SUNDAY WITH THE PASSAGE OF A COLD FRONT. AT THIS TIME...THE FRONT IS EXPECTED TO STALL WELL TO OUR SOUTH LEAVING NEXT WEEK BASICALLY DRY...THOUGH THERE IS UNCERTAINTY ON HOW FAR SOUTH THE FRONT WILL STALL. && .CLIMATE... RECORD MAXIMUM MINIMUMS FOR CHRISTMAS DAY... LOCATION.......RECORD/YEAR NEWARK.............47/1979 BDRIDGEPORT........45/1964 CENTRAL PARK.......50/1979 LAGUARDIA..........48/1964 JFK AIRPORT........46/1987 ISLIP AIRPORT......45/1987 THESE RECORDS LIKELY WILL NOT FALL AS TEMPERATURES ARE CURRENTLY FORECAST TO FALL TO AROUND 40 DEGREES AT OR BEFORE 11:59 PM ON THE 25TH. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 6 AM EST THURSDAY FOR CTZ009>012. NY...DENSE FOG ADVISORY UNTIL 6 AM EST THURSDAY FOR NYZ075-078>081- 176>179. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ330-335-338- 340-345-350-353-355. SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ330-335- 338-340-345-350-353-355. GALE WARNING FROM 6 AM TO 7 PM EST THURSDAY FOR ANZ330-335-338- 340-345-350-353-355. && $$ SYNOPSIS...FIG/TONGUE NEAR TERM...FIG/TONGUE SHORT TERM...FIG LONG TERM...TONGUE AVIATION...MET MARINE...FIG/TONGUE HYDROLOGY...FIG/TONGUE TIDES/COASTAL FLOODING... CLIMATE...

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