930 FXUS61 KBGM 290551 AFDBGM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1251 AM EST SUN DEC 29 2013 .SYNOPSIS... A STORM SYSTEM MOVING UP THE EAST COAST WILL BRING CLOUDS TO THE AREA OVERNIGHT...FOLLOWED BY RAIN AND SNOW ON SUNDAY. THE PRECIPITATION WILL START AS RAIN EARLY SUNDAY AND CONTINUE THROUGH THE DAY. AS COLDER AIR BEGINS TO RETURN TO THE AREA SUNDAY AFTERNOON AND EVENING...THE RAIN WILL CHANGE TO SNOW A A LIGHT ACCUMULATION IS POSSIBLE...ESPECIALLY OVER THE HIGHER ELEVATIONS. && .NEAR TERM /THROUGH TODAY/... CLOUDS OVER THE NORTHERN PORTION OF THE FORECAST AREA SWEPT OUT TO THE NORTHEAST. A LITTLE FOG DEVELOPED IN THE ROME AREA BUT SHOULD ONLY LAST A FEW HOURS AT BEST. HIGH CIRRUS AHEAD OF THE NEXT WEATHER SYSTEM HAVE RAPIDLY MOVED IN FROM THE SOUTHWEST ACROSS NE PA AND CENTRAL NY. HAVE MADE MINOR ADJUSTMENT TO THE FORECAST FOR OVERNIGHT. TEMPERATURES ARE RUNNING WARMER ON THE HILLS WITH COLDER IN THE VALLEYS. VALLEYS SAW A QUICK DROP IN TEMPS UNDER CLEAR SKIES ONCE THE SUN WAS LOW TO THE HORIZON. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... INTRSTG WX EVENT APRCHG IN THE SHRT TERM AS A DVLPG LOW MVES UP THE EAST CST. PLENTY OF COLD AIR AVBL BUT SYSTEM IS BLOCKED FROM GRABBING THE COLD AIR...AT LEAST AT THE BEGINNING...MAINLY DUE TO A LACK OF PHASING WITH A NRN STREAM SYSTEM RIDING ALONG THE ARCTIC FNT OVER SRN CANADA. EVENTUALLY...SOME EVAPORATIONAL COOLING AND A BIT OF COLDER AIR ALLOWS THE PCPN TO FALL AS SNOW VERY LATE IN THE DAY SUN...AND AS THE STORM PULLS OUT SUN NGT. AS THE PCPN MVES IN...A LL WARM LYR KEEPS THE PCPN AS RAIN UNTIL A TRICKY AND DEEP ISOTHERMAL LYR NEAR FRZG DVLPS LATE IN THE DAY. THIS WILL EVENTUALLY ALLOW A CHG OVER TO SNOW...PRBLY OVER THE HIER ELEVATIONS IN NY FIRST...ESP THE WRN CATS AND PARTS OF THE FINGER LAKES. HWVR...AS THE SFC REMAINS RGT NEAR FRZG...ACCUMULATION OF SNOW WILL BE SLOW AT FIRST. THEN...OVRNGT...A QUICK CPL INCHES PSBL. HWVR...A QUICKER CHG OVER COULD BOOST ACCUMS TO NEARER 4 INCHES. CAA CONTS ON MON WITH H8 TEMPS DROPPING TO -14C BY LATE IN THE DAY. HWVR...SIGNIFICANT SHEAR SHD LIMT LE TO SCT SNOW SHWRS...MAINLY OVER THE FINGER LAKES AND WRN SUSQ REGION. SFC HIPRES BLDS IN FOR TUE KEEPING CONDS GNRLY DRY OTR THAN SOME LGT LE. MODEL GUID CONTD TO BE IN DECENT AGREEMENT THRU THE PD RESULTING IN HIER CONFIDENCE IN TEMPS AND POP FCSTS. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... PNA PTRN PREVAILS...AND FOLLOWED WPC GUIDANCE. HOWEVER...CHGS WERE MADE TO THE TUE NGT/WED TIME FRAME WITH MORE CLDS AND HIGHER POPS AS MDLS SHOW DVLPMNT OF LGT OVERRUNNING PCPN ASSCD WITH A S/WV SCOOTING FROM THE OH VLY INTO THE NRN MID ATLC. AFTER THIS TIME...DIFFS ARISE WITH LATE WEEK SYSTEM...WITH GFS SUGGESTING MORE OF IMPACT ON THE FCST AREA. 00Z EURO KEEPS THE BULK OF THIS ACTION WELL SOUTH OF THE RGN. COLD TEMPS WITH HIGHS IN THE TEENS AND LOWS DROPPING INTO THE SINGLE DIGITS (COLDER IN NRN SXNS) BEFORE MODERATING LATE IN THE PD. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... LOW PRES WILL TRACK THROUGH THE MID ATLANTIC REGION THIS MORNING THEN ALONG THE EAST COAST LATE THIS AFTERNOON THROUGH THE EVENING HOURS. EXCEPT FOR MVFR/IFR FOG AT KRME THROUGH DAYBREAK, VFR CONDITIONS WILL CONTINUE AS MID/HIGH CLOUDS THICKEN. LIGHT RAIN WITH MVFR CONDITIONS WILL SPREAD FROM SOUTH TO NORTH ACROSS THE TERMINALS DURING THE LATE MORNING AND EARLY AFTERNOON PERIOD. AT KITH/KBGM/KELM, MIXED RAIN/SNOW WILL OCCUR BEGINNING AROUND 21Z. CONFIDENCE HERE IS LOW FOR P-TYPE DUE TO MODEL DIFFERENCES AND BOUNDARY LAYER TEMPS VERY CLOSE TO FREEZING. AT KRME/KSYR, BY 03Z CAA WILL ALLOW ANY REMAINING PRECIP TO CHANGE TO MVFR SNOW SHOWERS. AT KITH/KBGM/KELM, AFTER 03Z PRECIP WILL END BUT MVFR CIGS WILL PERSIST. AT KAVP, IFR CONDITIONS IN LIGHT TO MODERATE RAIN WILL PREVAIL THROUGH THE MID/LATE AFTERNOON THEN END AROUND 00Z BUT MVFR CIGS WILL CONTINUE. LIGHT WINDS EARLY THIS MORNING BECOMING S/SE AROUND 5 KNOTS GRADUALLY SHIFTING TO THE SOUTHWEST THEN WEST LATE IN THE TAF PERIOD. OUTLOOK... MON...SCT MVFR IN -SHSN ACRS CNTRL NY. MON NGT...MAINLY VFR. TUE...SCT MVFR IN -SHSN ACRS CNTRL NY. TUE NGT/WED...IFR/MVFR IN -SHSN. THU...IFR SNOW DEVELOPING. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DGM NEAR TERM...BMW SHORT TERM...DGM LONG TERM... AVIATION...RRM