Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 171506 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1006 AM EST WED DEC 17 2014 .SYNOPSIS... LOW PRESSURE MOVES NORTHEAST TODAY...TOWARD THE CANADIAN MARITIMES TONIGHT AND THURSDAY. HIGH PRESSURE WILL BUILD INTO NEW ENGLAND AT THE END OF THE WEEK AND SLOWLY DEPART OVER THE WEEKEND AS LOW PRESSURE TRACKS ACROSS THE SOUTHERN U.S. THIS LOW WILL TRACK FROM THE SOUTHEAST COAST TO THE MID ATLANTIC COAST EARLY NEXT WEEK BEFORE CONTINUING ON A NORTHEAST TRACK. MEANWHILE A STRONGER LOW PRESSURE SYSTEM WILL APPROACH FOR THE MIDDLE OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPPER LEVEL SHORTWAVE PIVOTS NORTHEASTWARD THIS MORNING AROUND CLOSED LOW OVER THE GREAT LAKES REGION THIS MORNING. THE LOW SLOWLY MOVES EAST TOWARD THE AREA TODAY. THIS CLOSED LOW MOVES TO NY STATE BY LATE IN THE DAY. AT THE SURFACE...LOW PRESSURE OVER CAPE COD THIS MORNING WILL TRACK TOWARD THE GULF OF MAINE BY AFTERNOON. PARENT LOW NEAR LAKE ONTARIO WEAKENS AS SECONDARY COASTAL LOW DEEPENS BY LATE IN THE DAY. CANNOT RULE OUT A FEW SHOWERS NORTH OF AND WEST THE CITY THIS AFTERNOON DUE TO INSTABILITY AND APPROACHING PVA. WESTERLY WINDS INCREASE TODAY AND WILL BE GUSTY BY AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS BEHIND THE LOW. AS FOR HIGH TEMPS TODAY...ANY COLD AIR ADVECTION WILL ARRIVE TOO LATE TO PREVENT TEMPS FROM REACHING THE UPPER 40S TO AROUND 50. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... ALOFT...CLOSED UPPER LOW MOVES ACROSS SOUTHERN NEW ENGLAND TONIGHT...WITH ASSOCIATED PVA MOVING THROUGH BEFORE MIDNIGHT. THIS LOW PIVOTS TOWARD THE CANADIAN MARITIMES...WITH CYCLONIC FLOW THROUGH THURSDAY FOR OUR REGION. SURFACE LOW PRESSURE CONTINUES TO DEEPEN THROUGH THE PERIOD AS IT SLOWLY MOVES TOWARD THE CANADIAN MARITIMES. HIGH PRESSURE BUILDS WELL TO THE WEST. FOR TONIGHT...ANY LINGERING RAIN SHOWERS WILL TRANSITION TO SNOW SHOWERS OR FLURRIES AS COLDER AIR ARRIVES. FEEL MOISTURE IS DEEP ENOUGH EARLY TONIGHT FOR ANY PRECIP TO BE IN THE FORM OF SNOW...FROM WEST TO EAST. AS THE STACKED LOW LIFTS NORTHEAST LATE TONIGHT AND THROUGH THURSDAY...DEEPENING NW FLOW SHOULD PRECLUDE ADDITIONAL SNOW SHOWER ACTIVITY. MOISTURE LOOKS TO BE RATHER SHALLOW PER TIME HEIGHTS OF ECMWF/GFS AND NAM. WITH COLDER AIR MOVING IN...GUSTY NW WINDS IN A TIGHT PRESSURE GRADIENT CAN BE EXPECTED LATER TONIGHT AND THROUGH THE DAY THURSDAY. MIXED LAYER DEEP ENOUGH FOR STRONGER GUSTS OF 20 TO 30 MPH DURING THE DAY THURSDAY. AS FOR TEMPERATURES...CLOSER TO NORMAL READINGS ARE FORECAST. EXPECT LOWS TONIGHT TO RANGE FROM THE UPPER 20S INLAND TO THE LOWER TO MID 30S NEAR THE COAST. ON THURSDAY...HIGH TEMPS SHOULD RISE TO THE LOWER TO MID 40S. MOS NUMBERS ARE FAIRLY CLOSE...BUT LEANED TOWARD THE COOLER GUIDANCE WHERE APPROPRIATE. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MODELS ARE IN DECENT AGREEMENT WITH THE H5 FLOW ACROSS NOAM INTO THE WEEKEND...BUT START TO DIVERGE ON SUNDAY WITH TIMING AND AMPLITUDE DIFFERENCES APPARENT BY EARLY NEXT WEEK. ANOMALOUS UPPER RIDGE NEAR JAMES BAY IN SOUTHERN CANADA WILL TRACK EWD ACROSS NRN NEW ENGLAND WHILE WEAKENING. THIS WILL RESULT IN DRY AND SEASONABLE WEATHER FROM THU NIGHT THROUGH SAT. A SHORTWAVE TROUGH WILL MOVE ACROSS THE AREA LATE SAT NIGHT INTO SUN WITH SOME LIGHT PCPN EXPECTED. MAINLY SNOW INLAND AND RAIN AT THE COAST. GFS IS UP TO ITS OLD TRICKS OF DEPARTING THE RIDGE TOO QUICKLY...SO LEANED HEAVILY TOWARDS THE EC SOLN WITH THIS FEATURE AND THEN BACKED OFF A BIT WITH LOW PRES TRACKING UP THE COAST FROM THE SE FOR EARLY NEXT WEEK. THE GFS UPPER FLOW IS PROBABLY TOO FLAT AND TAKING IT TOO FAR OUT TO SEA...BUT ALSO THINK THE 00Z EC IS TOO FAR W. SO HAVE COMPROMISED THIS PART OF THE FORECAST WITH A 60-40 12Z ECMWF/00Z GFS BLEND. THIS RESULTS IN LOW POP MON NIGHT INTO TUE. THEN...THERE IS GOOD AGREEMENT AMONGST THE GUIDANCE THAT A STRONGER AREA OF LOW PRES WILL IMPACT THE AREA FOR THE MIDDLE OF THE WEEK...ALTHOUGH TIMING REMAINS UNCERTAIN AND THEREFORE IMPACTS AS WELL. HOWEVER IT DOES LOOK LIKE MOSTLY A LIQUID EVENT AT THIS TIME. TEMPS THROUGH THE REMAINDER OF THE PERIOD LOOK TO BE NEAR NORMAL LEVELS. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE DEEPENS INTO GULF OF MAINE AND CANADIAN MARITIMES THROUGH THURSDAY AS HIGH PRESSURE TO THE WEST...EVENTUALLY SLOWLY BUILDS INTO THE AREA. KGON/KISP ON THE VERGE OF BECOMING VFR WITH CLEARING SKIES. STAYING OPTIMISTIC FOR THIS AFTERNOON WITH LOW-END VFR AS BKN STRATOCU FIELD DEVELOPS...BUT THERE COULD BE A PD OF MVFR CONDS BEFORE 20Z. MVFR CONDS ARE ALSO POSSIBLE TONIGHT WITH A SLIGHT CHANCE OF RAIN AND/OR SNOW SHOWERS. WNW WINDS LEFT OF 310 MAGNETIC WILL INCREASE TO 10-15 KT WITH GUSTS 20-25 KT. WINDS SHOULD STAY UP TONIGHT...BUT GUSTS COULD DROP OFF INTERMITTENTLY AT KSWF/KHPN. ...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: BRIEF MVFR CIGS POSSIBLE 18Z-19Z. KLGA FCSTER COMMENTS: BRIEF MVFR CIGS POSSIBLE 18Z-20Z. KEWR FCSTER COMMENTS: BRIEF MVFR CIGS POSSIBLE 18Z-19Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: BRIEF MVFR CIGS POSSIBLE 18Z-20Z. KHPN FCSTER COMMENTS: MVFR CIGS MAY BE POSSIBLE THIS AFTERNOON. KISP FCSTER COMMENTS: MVFR CIGS MAY BE POSSIBLE THIS AFTERNOON. .OUTLOOK FOR 12Z THU THROUGH SAT... .THU...VFR. NW WINDS 10-15G20-25KT. .FRI-SAT...VFR. .SUNDAY...MVFR OR LOWER CONDS IN RAIN AND/OR SNOW. && .MARINE... WESTERLY WINDS THIS MORNING WILL INCREASE AS LOW PRESSURE PULLS AWAY FROM THE WATERS. THE LOW DEEPENS AS IT TRACKS TOWARD THE CANADIAN MARITIMES TONIGHT AND THURSDAY. WINDS WILL INCREASE TO SMALL CRAFT ADVISORY LEVELS...OR GUSTS TO 25 KT LATER THIS MORNING FOR THE OCEAN WATERS...AND LATE THIS AFTERNOON FOR THE WATERS SURROUNDING LONG ISLAND. THESE INCREASINGLY STRONG AND GUSTY WINDS CONTINUE TONIGHT AND THURSDAY AS THE WINDS SHIFT TOWARD THE NORTHWEST. AN OCCASIONAL GUST TO 35 KT IS NOT OUT OF THE QUESTION...MAINLY ACROSS THE OCEAN ZONES. CONFIDENCE IN THIS HAPPENING...OR FREQUENT GUSTS TO 35 KT...IS QUITE LOW...SO WILL NOT CONSIDER GALE WARNINGS AT THIS TIME. SEAS BUILD TODAY AND TONIGHT AS THE WESTERLY WINDS INCREASE. WAVE WATCH III OUTPUT LOOKED REASONABLE...AND WAS BLENDED WITH PREVIOUS FORECAST. SCA CONDS MAY LINGER ON THE OCEAN WATERS INTO THU NIGHT. SUB-ADVY CONDS ARE THEN EXPECTED THROUGH THE REMAINDER OF THE FORECAST PERIOD AS HIGH PRES BUILDS ACROSS THE AREA WITH A WEAK PRES GRADIENT. && .HYDROLOGY... MAINLY DRY THROUGH SATURDAY. LIGHT QPF AMOUNTS EXPECTED SAT NIGHT INTO SUN. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM EST THURSDAY FOR ANZ330-335-338-340-345. SMALL CRAFT ADVISORY UNTIL 6 PM EST THURSDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...24/PW NEAR TERM...JC/PW SHORT TERM...PW LONG TERM...24 AVIATION...GOODMAN/JM MARINE...24/PW HYDROLOGY...24/PW

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