Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 180544 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1244 AM EST THU DEC 18 2014 .SYNOPSIS... HIGH PRESSURE WILL PASS TO THE NORTH AND EAST OF THE AREA THROUGH THE WEEKEND...WHILE WEAK LOW PRESSURE OVER THE NORTHERN GULF COAST EMERGES ALONG THE SOUTHEAST COAST ON SUNDAY. THIS LOW WILL TRACK SLOWLY NORTH AND EAST MONDAY INTO TUESDAY...PASSING SOUTH OF THE AREA TUESDAY MORNING. MEANWHILE...THERE IS THE POTENTIAL FOR A STRONG STORM SYSTEM TO IMPACT THE AREA LATE TUESDAY NIGHT INTO WEDNESDAY AS DEEPENING LOW PRESSURE TRACKS UP INTO THE OHIO VALLEY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LATEST WATER VAPOR IMAGERY HAS 500 HPA TROUGH AXIS STRETCHING BACK FROM LAKE ONTARIO DOWN INTO NW OHIO. THIS PIVOTS THROUGH THE TRI- STATE OVERNIGHT. AHEAD OF THIS...EVEN THOUGH MOISTURE IS LIMITED...SHOULD HAVE JUST ENOUGH FORCING FOR A MENTION OF ISOLATED SPRINKLES. COULD ALSO POSSIBLY MIX WITH FLURRIES ACROSS SOME OF THE NORTHERN ZONES AS MOISTURE COULD EXTEND JUST DEEP ENOUGH FOR ICE CRYSTALS TO FORM. UPDATED LOW TEMPERATURES WITH BLEND OF LAV/MET/MAV GUIDANCE AND THEY SHOULD BE AROUND 5-10 DEGREES ABOVE NORMAL. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/... HIGH PRESSURE CONTINUES TO BUILD IN THROUGH THE PERIOD. A TIGHT PRESSURE GRADIENT WILL RESULT IN A BREEZY DAY FOR THURSDAY. WENT WITH THE WARMER MAV MOS FOR HIGH TEMPS BASED ON MIXING TO 900MB AND A MODERATE DOWNSLOPE FLOW COMPONENT. OVERNIGHT LOWS THURS NIGHT IS AN EVEN BLEND OF NAM AND MAV MOS. DRY WEATHER CONTINUES FOR FRIDAY WITH LIGHTER WINDS. THE WARMER MAV MOS ONCE AGAIN WAS USED FOR HIGH TEMPS BASED ON TEMPS ALOFT. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... GLOBAL MODELS...IN PARTICULAR THE 12Z GFS AND ECMWF...ARE IN AMAZINGLY GOOD AGREEMENT WITH A STRONG MID WEEK STORM SYSTEM THAT TAKES A TRACK WEST OF THE AREA. PRIOR TO THAT TIME...THERE ARE MULTIPLE WAVES OF LOW PRESSURE MOVING OFF THE SE COAST...WITH SOME UNCERTAINTY IN THE NORTHERN EXTENT OF ONE OF THESE WAVES MON NIGHT INTO TUE. THE LATTER OF WHICH THE ECMWF IS MORE AGGRESSIVE WITH IN TAKING THE LOW THE FARTHEST NORTH...WHILE THE GGEM AND GFS ARE SUPPRESSED TO THE SOUTH. PREFERENCE THOUGH IS TOWARD A MORE AMPLIFIED PATTERN IN THE LAST 24H...SO LEANING TOWARD THE ECMWF. THIS ALL SPELLS OUT A PROLONGED PERIOD OF WET WEATHER FROM LATE SAT NIGHT INTO THE MID WEEK PERIOD. THERMAL PROFILES ARE GENERALLY WARM WITH PERHAPS A LIGHT RAIN/SNOW MIX SAT NIGHT INTO SUN...PRIMARILY NORTH AND WEST OF NYC. AT THE SURFACE...HIGH PRESSURE PASSES TO THE NORTH AND EAST OF THE REGION THIS WEEKEND. A LOW-LEVEL EASTERLY FLOW INTERACTS WITH A MID LEVEL SHORT WAVE SAT NIGHT INTO SUN MORNING WITH POSSIBLY LIGHT PRECIPITATION. LOW PRESSURE THEN EMERGES OFF THE SE COAST ON SUN AND TAKES A TRACK SLOWLY NORTH THROUGH TUE. A MUCH MORE ROBUST AREA OF LOW PRESSURE THEN RAPIDLY DEEPENS ACROSS THE TN/OH VALLEYS TUE NIGHT INTO WED...EVENTUALLY WRAPPING UP OVER THE GREAT LAKES WED NIGHT INTO THU WITH PRESSURES APPROACHING 960 MB. THIS TRACK WOULD KEEP THE FORECAST AREA IN THE WARM SECTOR OF THE STORM WITH THE POTENTIAL FOR CONVECTION AND EVEN STRONG WINDS. THE CAVEAT HERE IS THAT THE STORM IS ABOUT A WEEK AWAY WITH A LOT OF TIME FOR CHANGE IN TRACK AND TIMING. IN ADDITION...THE FAST PAC FLOW WOULD LEAD ONE TO BELIEVE THAT THERE ARE GOING TO BE TIMING ISSUES WITH THE SOUTHERN BRANCH SHORT WAVE ENERGY. TEMPS OVER THE WEEKEND START OFF AT NEARLY NORMAL LEVELS AND THEM MODERATE BY MID WEEK. HIGHS NEAR 50 ON WED COULD BE UNDERDONE IF THE PATTERN AND STORM TRACK PANS OUT. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... DEEPENING LOW PRESSURE WILL DRIFT THROUGH THE CANADIAN MARITIMES THROUGH THU. SCT-BKN 035-050 CIGS SHOULD PREVAIL THROUGH MUCH OF THE OVERNIGHT. ISOLD RAIN/SNOW SHOWERS LATE TONIGHT FOR NORTHERN AND EASTERN TERMINALS. POTENTIAL FOR BRIEF MVFR CONDITIONS WITH ANY SNOW SHOWERS. WINDS GENERALLY 290-330 MAGNETIC THROUGH THURSDAY. WINDS INCREASE TO NEAR 15-20G25-30KT...HIGHEST AT THE NYC METROS...AFTER 07-08Z AS A STRONG DISTURBANCE MOVES ACROSS. THESE WINDS AND GUSTS SHOULD BRIEFLY DECREASE BETWEEN 10-12Z OUTSIDE OF NYC METRO TERMINALS...THEN PICK UP AFTER 14Z-15Z. WINDS AND GUSTS DECREASE LATE THURSDAY INTO EVENING. GENERALLY VFR THU INTO THU EVE WITH SCT-BKN CIGS OF 3500-4000FT. LOW PROB OF MVFR CIGS IN THE AFTERNOON. .OUTLOOK FOR 06Z FRI THROUGH SAT... .LATE THU NIGHT...VFR. .FRI-SAT...VFR. .SAT NIGHT...VFR TO START...THEN MVFR OR LOWER CONDITIONS WITH LIGHT PRECIP POSSIBLE. CONDITIONAL PTYPE...BRIEF ONSET AS SNOW POSSIBLE AT COASTAL TERMINALS BEFORE CHANGING TO RAIN. SLOWER TRANSITION TO RAIN ACROSS INTERIOR TERMINALS. MAINLY SNOW AT KSWF. .SUNDAY...MVFR OR LOWER CONDITIONS...WITH LIGHT PRECIP CHANGING TO RAIN THROUGHOUT. .MON...CHANCE OF RAIN WITH MVFR OR LOWER CONDITIONS. && .MARINE... MINOR CHANGES MADE THIS UPDATE TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. WINDS INCREASE TONIGHT IN RESPONSE TO COLD AIR ADVECTION AND A TIGHTENING PRESSURE GRADIENT. SCA REMAINS POSTED FOR ALL WATERS THROUGH THURSDAY...WITH THE OCEAN WATERS EXTENDED THROUGH THURSDAY NIGHT AS GUSTS TO 25 KT CONTINUE. THERE MAY BE A GUST OR TWO UP TO 35 KT OVER THE EASTERN OCEAN WATERS LATE TONIGHT INTO EARLY THURSDAY MORNING...BUT NOT ENOUGH TO WARRANT A GALE WARNING. WINDS THEN SUBSIDE THROUGH FRIDAY WITH SUB-SCA CONDITIONS. SUB-ADVISORY CONDITIONS ARE FORECAST SAT-MON AS HIGH PRES PASSES TO THE NORTH OF THE WATERS. WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM THE SOUTH ON MON WITH A GRADUALLY STRENGTHENING NE FLOW. && .HYDROLOGY... MAINLY DRY THROUGH SATURDAY. LIGHT QPF AMOUNTS EXPECTED SAT NIGHT INTO TUE. THERE IS THE POTENTIAL FOR A MORE SIGNIFICANT RAINFALL EVENT LATE TUE INTO WED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330- 335-338-340-345. SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ350-353-355. && $$ SYNOPSIS...JC/DW NEAR TERM...MALOIT SHORT TERM...JC LONG TERM...DW AVIATION...JM/NV MARINE...JC/MALOIT/DW HYDROLOGY...JC/DW

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