Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 191945 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 245 PM EST FRI DEC 19 2014 .SYNOPSIS... WEAK HIGH PRESSURE MOVES ACROSS THE REGION THROUGH SATURDAY. AS THE HIGHS BUILDS OVER NORTHERN MAINE SUNDAY...ALLOWING THE FLOW TO TURN ONSHORE. A WEAK WEATHER DISTURBANCE MAY TRIGGER SOME FLURRIES OR LIGHT SNOW OVER SOUTHERN REGIONS LATER SUNDAY INTO SUNDAY NIGHT. HIGH PRESSURE WILL CONTINUE TO EXIT THROUGH THE CANADIAN MARITIMES ON MONDAY. A WEAK AREA OF LOW PRESSURE WILL MOVE UP THE COAST TUESDAY...WITH A MORE SIGNIFICANT SYSTEM GRADUALLY ORGANIZING WEDNESDAY...BEFORE MOVING OVER THE GREAT LAKES. THIS COULD BRING WINDY CONDITIONS AND THE POTENTIAL FOR HEAVY RAIN AROUND CHRISTMAS EVE INTO EARLY CHRISTMAS MORNING. && .NEAR TERM /THROUGH TONIGHT/... SFC HIGH PRES CONTINUES TO SLIDE EWD THRU THIS EVENING. AS IT DOES SO THE COLUMN WILL GRADUALLY DRY OUT...AND SKIES WILL EVENTUALLY CLEAR. SFC WINDS WILL ALSO TREND TOWARDS MORE NLY THEN NELY WITH TIME OVERNIGHT. THIS COULD BRING SOME OCEAN EFFECT AND MID LEVEL CLOUDS BACK OVER ERN AND COASTAL AREAS. THIS CHANGE IN LOW LEVEL FLOW WILL ALSO BRING AN END TO ANY LINGERING SHSN IN THE FAR NRN ZONES. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... BY SAT FLOW WILL BE NELY...AND TURNING ONSHORE ACROSS SRN NH. THIS WILL BRING MORE OCEAN EFFECT CLOUDS AND PERHAPS A SHSN TO SRN NH AND EXTREME SWRN ME. THE FOCUS OF THIS WILL MAINLY STAY OVER SRN NEW ENGLAND HOWEVER. THE FORECAST IS A LITTLE INTERESTING BY SAT NIGHT INTO SUN. THIS LOW LEVEL...MOIST...ONSHORE FLOW WILL EXIST MAINLY BENEATH RIDGING ALOFT. A WEAK S/WV TROF IS FORECAST TO DRIFT EWD ACROSS THE REGION LATE SAT AND EARLY SUN. THIS IS ENOUGH FORCING FOR ASCENT TO SATURATE AROUND H7. IN THIS CASE WE SET UP A NICE SEEDER-FEEDER PROCESS TO INCREASE THE SHSN ACTIVITY IN THE SRN ZONES. HAVE INCREASED POP TOWARDS 12Z SUN TO ACCOUNT FOR THIS. && .LONG TERM /SUNDAY THROUGH FRIDAY/... A WEAK WEATHER DISTURBANCE CROSSING NEW ENGLAND...IN COMBINATION WITH HIGH PRESSURE BRINGING A MOIST RETURN FLOW OFF THE GULF OF MAINE WILL ALLOW FOR SOME LIGHT SNOW OR FLURRIES OVER FAR SOUTHERN AREAS BY LATE SUNDAY. THIS WILL CONTINUE SUNDAY NIGHT INTO MONDAY...BUT AGAIN SHOULD BE VERY LIGHT. ON TUESDAY...MODEST CYCLOGENESIS WILL OCCUR ALONG THE MID ATLANTIC COAST REGION. THIS WILL SPREAD RAIN AND SNOW NORTHWARD. IF COLD AIR DAMMING IS STRONG ENOUGH...THERE MAY BE A PROLONGED PERIOD OF LIGHT SNOW JUST INLAND FROM THE COAST AND POSSIBLY A NARROW RIBBONOF MIXED PRECIP - FREEZING RAIN AND SLEET ALONG AND NEAR THE COASTAL FRONT. ON CHRISTMAS EVE...A STORM IS EXPECTED TO FORM A LOW PRESSURE RAPIDLY INTENSIFIES OVER THE NORTHERN OHIO VALLEY BEFORE MOVING OVER THE GREAT LAKES. THIS WILL SPREAD MILD TEMPERATURES INTO THE REGION IN ADDITION TO LOCALLY HEAVY RAINFALL. THE GFS IS VERY WET AT THIS TIME AND ALLOWS FOR 4+ INCH RAINFALL TOTALS IN THE HEADLANDS/FOOTHILLS. THIS...IN ADDITION TO SNOW MELT WOULD LEAD TO INLAND FLOODING OVER THE REGION. OTHER MODELS ARE NOT AS ROBUST WITH THE QPF...BUT STILL BRING OVER 3 INCHES PRECIP TO THIS REGION...WITH NORTH CONWAY SEAMING TO BE THE BULLSEYE. TIDES WILL BE AT THEIR MAX FOR THE MONTH ON CHRISTMAS EVE. COASTAL FLOODING AND SPLASH-OVER IS DEFINITELY POSSIBLE. STRONG GRADIENT WINDS WILL GRADUALLY BECOME ALIGNED ON CHRISTMAS EVE. THIS WILL TRIGGER STRONG WINDS ALONG THE COAST AND HIGHER SE FACING TERRAIN...POSSIBLY LEADING TO SOME DOWNED BRANCHES AND SOME POWER OUTAGES. VERY EARLY TO TELL AT THIS POINT...BUT THE SIGNAL IS THERE FOR A BRIEF PERIOD OF STRONG...GUSTY WINDS. SOUTHWESTERLY WINDS USHER IN DRIER AIR INTO THE REGION ON CHRISTMAS DAY. A COLDER...BREEZY PATTERN WILL FOLLOW THEREAFTER. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... SHORT TERM... LONG TERM...CONDITIONS DETERIORATING TO IFR ON TUESDAY IN LIGHT SNOW OR RAIN. IFR AND LIFR CONDITIONS WITH STRONG GUSTY WINDS AND LOCALLY HEAVY RAIN CHRISTMAS EVE INTO EARLY CHRISTMAS MORNING. THIS WILL LIKELY AFFECT HOLIDAY TRAVEL. CONDITIONS IMPROVEMENT SOMEWHAT CHRISTMAS DAY AS WINDS SHIFT TO THE SOUTHWEST ALLOWING DRIER AIR INTO THE REGION. && .MARINE... SHORT TERM...WINDS AND SEAS WILL REMAIN BELOW SCA CONDITIONS THRU SAT. LONG TERM...SCA WINDS/SEAS MAY DEVELOP AHEAD OF A WEAK AREA OF LOW PRESSURE ALONG THE NORTHEAST COAST BY TUESDAY. THEREAFTER...A STORM WILL LIKELY FORM WEDNESDAY MORNING OVER THE NORTHERN OHIO VALLEY...BEFORE MOVING OVER THE GREAT LAKES REGION. GALES ARE LIKELY CHRISTMAS EVENING WITH POSSIBLE STORM FORCE WIND GUSTS FROM THE SOUTHEASTERLY DIRECTION. LARGE BUILDING WAVES WILL LIKELY FORM IN RESPONSE TO THE GRADIENT WIND FIELD. GUSTY SOUTHWEST WINDS WILL FOLLOW ON CHRISTMAS DAY. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ LEGRO/JC

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