Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 250340 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1040 PM EST WED DEC 24 2014 .SYNOPSIS... A COLD FRONT CROSSES THE TRI-STATE AROUND SUNRISE. HIGH PRESSURE THEN 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 HAS MOVED THROUGH MUCH OF THE REGION EXCEPT FOR THE LOWER HUDSON VALLEY AND CENTRAL INTERIOR CONNECTICUT AS OF LATE THIS EVENING. RADAR REFLECTIVITY IS WEAK WITH ECHOES MOVING IN FROM THE WEST. A GENERAL MIST BEING REPORTED AT MOST SITES BUT DRIZZLE AND RAIN COULD EASILY DEVELOP WITH SUCH A SATURATED AIRMASS IN PLACE...ESPECIALLY ACROSS THE COAST. USED OCCASIONAL WORDING FOR DRIZZLE AND RAIN UNTIL SHARPER TROUGH ASSOCIATED WITH COLD FRONT APPROACHES FROM THE WEST. THIS WILL ALLOW FOR A RELATIVELY MORE CONVECTIVE MODE WITH SOME SREF AND NAM SOUNDING SHOWING SOME ELEVATED INSTABILITY AHEAD OF THE FRONT. SO...STILL THINK IN A GENERAL 3-6AM TIMEFRAME...WILL HAVE A NARROW CONVECTIVE LINE WITH PERHAPS SOME ISOLATED LIGHTNING STRIKES THAT WILL MOVE ACROSS WEST TO EAST. OTHERWISE...AREAS OF DENSE FOG ALONG MUCH OF THE COAST THAT WILL DECREASE WITH GREATER INTENSITY OF SHOWERS LATE TONIGHT INTO EARLY THURSDAY MORNING. TEMPERATURES ADJUSTED SLIGHTLY WITH AN INCREASE SLIGHTLY ACROSS EASTERN LONG ISLAND. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... BASED ON LATEST NWP...HAVE MOVED UP THE ENDING OF PCPN FROM WEST TO EAST TO EARLY MORNING 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 /03Z THURSDAY THROUGH MONDAY/... A WARM FRONTAL BOUNDARY HAS PUSHED NORTH OF CT TERMINALS...BUT WILL BE SLOWER WORKING INTO NJ TERMINALS...AND PERHAPS NOT INTO KSWF UNTIL JUST AHEAD OF COLD FRONTAL PASSAGE. MEANWHILE A COLD FRONT WILL BE APPROACHING OVERNIGHT...CROSSING THROUGH THE AREA FROM AROUND 09Z TO 13Z THURSDAY. LIFR/VLIFR CONDS EXPECTED TO CONTINUE FOR KHPN/KLGA/KJFK AND EASTERN TERMINALS IN THE WAKE OF THE WARM FRONT WITH ADVECTION FOG. FOR KEWR/KTEB/KSWF...CONDITIONS MORE LIKELY REMAIN LIFR/IFR TONIGHT...WITH A LOW PROBABILITY OF VLIFR. ALTHOUGH WINDS A GUSTS HAVE SUBSIDED A BIT...WINDS WILL INCREASE AHEAD OF THE COLD FRONT ONCE AGAIN AFTER 07Z TO S 15 TO 20 MPH WITH GUSTS UP TO 30 MPH UNTIL COLD FRONTAL PASSAGE. A LOW LEVEL S/SW JET STREAM OF 50 TO 60 KT WILL CONTINUE IN LOW LEVEL WIND SHEAR UNTIL THE COLD FRONTAL PASSAGE. PERIODS OF LIGHT RAIN AND DRIZZLE TONIGHT...AND THEN A BAND OF MODERATE TO HEAVY RAIN WITH EMBEDDED TSTM LIKELY TO CROSS THE REGION W TO E BETWEEN 06Z AND 13Z. POTENTIAL FOR AN ORGANIZED LINE OF CONVECTION WITHIN THIS...WITH LOW PROB OF ISOLATED 40+ KT GUSTS. CONDITIONS IMPROVE QUICKLY TO VFR WITH THE RAIN ENDING AS THE FRONT MOVES THROUGH EARLY THU MORNING. VFR ON THU...WITH 15 TO 20 KT WESTERLY WINDS WITH GUSTS 30 TO 35 KT. LOW PROB OF GUSTS 35-40 KT. .OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY... .THU NIGHT...VFR. WIND AND GUSTS DIMINISHING. .FRI-SAT...VFR. .SUN...MARGINAL VFR. CHANCE OF RAIN AND SNOW. .MON...VFR. && .MARINE... WAVES SLIGHT ADJUSTMENT DOWN FOR NEXT FEW HOURS ON THE OCEAN TO BETTER MATCH OBSERVED TRENDS WITH OTHERWISE MARINE FORECAST REMAINING ON TRACK. 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 NYZ071-075- 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...JM SHORT TERM...FIG LONG TERM...TONGUE AVIATION...NV MARINE...FIG/JM/TONGUE HYDROLOGY...FIG/TONGUE CLIMATE...

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