Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 040832 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 332 AM EST THU FEB 4 2016 .SYNOPSIS...
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A COLD FRONT WILL EXIT THE COAST THIS MORNING BEFORE STALLING TO OUR EAST. COLDER AIR WILL GRADUALLY FILTER INTO THE REGION BEHIND THIS FRONTAL SYSTEM LATER TODAY AND TONIGHT. LOW PRESSURE WILL TRACK NORTHEAST ALONG THIS STALLED FRONTAL BOUNDARY EARLY FRIDAY. THE WESTERN EDGE OF THE SNOW SHIELD WITH THIS SYSTEM COULD BRUSH COASTAL SECTIONS WITH SOME LIGHT SNOW ACCUMULATION. A RIDGE OF HIGH PRESSURE FOLLOWS FOR FRIDAY NIGHT INTO SATURDAY. A COLD FRONT WILL CROSS THE REGION SUNDAY. THERE IS A CHANCE THAT A COASTAL STORM AFFECTS THE REGION EARLY NEXT WEEK.
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&& .NEAR TERM /THROUGH TODAY/...
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AT 07Z...A 997 MILLIBAR LOW WAS OVER QUEBEC WITH A TRAILING COLD FRONT THROUGH WESTERN NEW ENGLAND AND A SECONDARY COLD FRONT THROUGH THE UPPER GREAT LAKES. FOR TODAY...THE FRONT WILL RACE EAST AND EXIT THE COAST ALONG WITH ANY LINGERING SHOWER ACTIVITY BY MID MORNING. WE`LL SEE QUICK CHANGES IN SURFACE TEMPERATURES AHEAD OF THIS BOUNDARY AS WE MIX OUT NEAR THE SURFACE. WE`LL SEE SOME SUNNY BREAKS BEHIND THE COLD FRONT TODAY AND WITH THE COLD AIR TAKING ITS TIME FILTERING IN THE RECORD HIGH AT PORTLAND / 50F SET IN 1991/ AND CONCORD 61F SET IN 1991/ COULD BE TIED OR BROKEN. IN EITHER EVENT...IT`LL BE ANOTHER DAY WITH HIGH TEMPERATURES A GOOD 20 TO 25 DEGREES ABOVE AVERAGE. THE FRONT WILL HANG UP JUST OFFSHORE LATER TODAY AS IT BECOMES NEARLY PARALLEL TO THE UPPER FLOW.
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&& .SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
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AN IMPULSE WILL RACE NORTHEAST FROM THE GULF STATES AND EXIT THE MID ATLANTIC TO OUR SOUTH ON FRIDAY. THIS SHORTWAVE WILL DEVELOP A SURFACE LOW ON THE STALLED OFFSHORE FRONT WHICH WILL TRACK NORTHEAST TONIGHT AND FRIDAY. THE WESTERN PERIPHERY OF THE PRECIPITATION SHIELD MAY BRUSH COASTAL SECTIONS WITH SOME LIGHT SNOW LATE TONIGHT INTO FRIDAY MORNING AS IT RACES EAST-NORTHEAST. CLOUDS...AND COLDER AIR BEING DRAWN INTO THE AREA BY THE OFFSHORE LOW...WILL RESULT IN TEMPERATURES ONLY A FEW DEGREES ABOVE AVERAGE FOR FRIDAY.
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&& .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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THE MAIN FORECAST CONCERNS REVOLVE AROUND THE POTENTIAL FOR A COASTAL STORM TO AFFECT THE REGION EARLY NEXT WEEK...MAINLY LATER MONDAY THROUGH TUESDAY. BEFORE THEN...RATHER BENIGN WEATHER IS EXPECTED. THE ONLY WEATHER MAKER THROUGH THE WEEKEND MAY BE A COLD FRONT WITH THE POTENTIAL TO BRING SNOW SQUALLS LATER SATURDAY NIGHT INTO SUNDAY MORNING. THE BTV SNOW SQUALL PARAMETER SHOWS POTENTIAL FOR THIS ON SEVERAL DETERMINISTIC MODELS. TURNING OUR ATTENTION TO EARLY NEXT WEEK...UNCERTAINTY IN EVOLUTION IN SHORT WAVE TROFS CONTINUES TO ALLOW FOR LOW CONFIDENCE IN TIMING OF A POTENTIAL SNOWFALL AS WELL AS ANY SORT OF AMOUNTS. THE DETERMINISTIC RUNS OF THE GFS AND ECMWF CONTINUE TO SHOW DIFFERENT SCENARIOS WITH THE MAIN PLAYERS ON THE TABLE...IE...A SOUTHERN STREAM SHORT WAVE TROUGH MOVING OFF THE SOUTHEAST COAST AND A LARGER MORE POTENT TROUGH OR CLOSED LOW MOVING SOUTHEASTWARD INTO THE GREAT LAKES AND OHIO VALLEY REGIONS. THE 00Z DETERMINISTIC ECMWF RUN CONTINUES TO SHOW THE SOUTHERN STREAM ENERGY BEING MORE OF A PLAYER HERE AS IT ALLOWS THIS TROUGH AND RESULTANT SFC LOW TO TRACK CLOSER TO THE COAST AND INTERACT WITH THE APPROACHING NORTHERN STREAM LOW. ONE OF THE CAUSES FOR THIS IS THE AMPLIFICATION OF UPSTREAM RIDGING OVER THE MARITIMES AS A NORTHERN STREAM SHORT WAVE TROUGH EXISTS THAT AREA RATHER QUICKLY. THE RESULT IS A MAINLY LIGHT TO POTENTIALLY MODERATE SNOWFALL FOR THE REGION STARTING BY EARLY MONDAY AFTERNOON AND LASTING THROUGH A GOOD PORTION OF TUESDAY. THE 00Z GFS ON THE OTHER HAND KEEPS THE SOUTHERN STREAM SHORT WAVE TROUGH AND SFC LOW WELL OFFSHORE AND NOT MUCH OF A PLAYER HERE. AS THAT SYSTEM SPEEDS OUT TO SEA...THE LARGE CLOSED LOW AMPLIFYING AS IT MOVES ACROSS THE GREAT LAKES AND OHIO VALLEY TRANSFERS SOME ENERGY TO THE COAST AND ALLOWS A SECONDARY TO FORM NEARBY. THIS SOLUTION WOULD ALSO BRING US A BOUT OF SNOW...PERHAPS HEAVY...AND PERHAPS ALSO WITH SOME MIXED PRECIP INVOLVED. THIS WOULD START MONDAY NIGHT AND CONCLUDE LATE TUESDAY. SO IN A NUTSHELL...WHILE THE ECMWF AND GFS SOLUTIONS ARE DIFFERENT IN HANDLING OF THE SYSTEMS...THE NET RESULT WOULD BE SOMEWHAT SIMILAR IN THAT ACCUMULATING SNOW WOULD PROBABLY OCCUR CENTERED ON MONDAY NIGHT AND AT LEAST THE FIRST PART OF TUESDAY. HOWEVER...DUE TO THE HIGH UNCERTAINTY IN SYSTEM EVOLUTION...LOW CONFIDENCE EXISTS IN ANY DETAILS SINCE A MYRIAD OF OUTCOMES ARE STILL POSSIBLE. IT IS WORTH NOTING THAT MOST OF THE GFS ENSEMBLE MEMBERS SUPPORT THE DETERMINISTIC GFS RUN AND KEEP THE SOUTHERN STREAM LOW AWAY FROM THE AREA. MUCH OF THE ECMWF ENSEMBLE MEMBERS SEEM TO AGREE WITH THAT SOLUTION ALSO BUT THE MEAN IS FURTHER NORTH. HOPEFULLY THERE WILL BE BETTER AGREEMENT ON THE HANDLING OF THE TWO STREAMS SOON.
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&& .AVIATION /07Z THURSDAY THROUGH MONDAY/...
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SHORT TERM...GRADUAL IMPROVEMENT TO VFR BY MID MORNING. AREAS OF MVFR PSBL BTW 09Z AND 15Z FRI VCNTY OF THE COAST IN SNOW WITH LCL IFR CONDS PSBL NR KPSM. LONG TERM...LOCAL IFR IN SNOW SHOWERS POSSIBLE LATE SATURDAY NIGHT INTO SUNDAY MORNING. THEREAFTER...IFR CONDITIONS POSSIBLY TO DEVELOP LATE MONDAY IN SNOW.
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&& .MARINE...
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SHORT TERM...WINDS HAVE DIMINISHED AND GALE HAS BEEN REPLACED WITH A SMALL CRAFT MAINLY FOR SEAS THROUGH EARLY EVENING. WE`LL SEE A BRIEF LULL TONIGHT BEFORE SMALL CRAFT CONDITIONS RETURN ON FRIDAY AS LOW PRESSURE PASSES BY OFFSHORE. SLY JET VEERING TO SSWLY WILL CONTINUE TO INCREASE INTO THE EVENING. GALE FORCE GUSTS WILL BECOME MORE FREQUENT...WITH A FEW GUSTS TO NEAR 45 KTS ON THE OUTER WATERS. WINDS AND SEAS WILL GRADUALLY DIMINISH THURSDAY...THOUGH SCA CONDITIONS WILL CONTINUE THROUGH THE DAY. LONG TERM...SCA CONDITIONS ARE LIKELY SATURDAY NIGHT AND SUNDAY IN ASSOCIATION WITH A COLD FRONT. A COASTAL STORM COULD AFFECT THE WATERS EARLY NEXT WEEK WITH SCA OR GALE CONDITIONS BUT UNCERTAINTY REMAINS HIGH AT THIS TIME.
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&& .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ150>154.
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&& $$ NEAR/SHORT TERM...SCHWIBS LONG TERM...EKSTER

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