Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 280238 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 938 PM EST SAT DEC 27 2014 .SYNOPSIS... A COLD FRONT WILL MOVE INTO NORTHERN NEW HAMPSHIRE AND NORTHWEST MAINE LATE TONIGHT AND WILL MOVE OFF SHORE ON SUNDAY. A LITTLE LIGHT RAIN CAN BE EXPECTED...AND PERHAPS A LITTLE LIGHT FREEZING RAIN TONIGHT ACROSS THE NORTHERN FORECAST AREA. COLD HIGH PRESSURE RETURNS AGAIN SUNDAY NIGHT AND WILL BE OVER THE AREA THROUGH AT LEAST MIDWEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 940 PM UPDATE: NO CHANGES NEEDED ATTM. 645 PM UPDATE: MINOR TWEAKS TO TEMPS OTRW NO CHANGES NEEDED ATTM. PREV DISC: LOW PRESSURE WILL PASS OUR AREA FROM THE NORTH TONIGHT AND DRAG A COLD FRONT ACROSS THE REGION LATE TONIGHT AND TOMORROW. LOOKS LIKE ONLY LIGHT MEASURABLE PRECIP WITH THIS FRONT ACROSS THE NORTH AND MOUNTAINS...WHILE THE CHANCE FOR ANY MEASURABLE PRECIP WILL DECREASE FARTHER SOUTH. FIGURING PRECIP TYPE ACROSS THE NORTH LATE TONIGHT IS CHALLENGING AS A FEW SPOTS MAY HOLD ON TO THE COLD AIR AS MESOSCALE MODELS ARE INDICATING. THIS COULD BRING A VERY LIGHT COATING OF ICE WITH FREEZING FOR A FEW HOURS BEFORE THE TEMPERATURE CLIMBS ABOVE FREEZING EVERYWHERE BY EARLY SUNDAY MORNING. STILL NOT CONFIDENT THAT THIS WILL ACTUALLY OCCUR AND IF IT DOES IT MAY BE IN ONLY A FEW ISOLATED LOCATIONS WHERE COLD AIR IS TRAPPED...SO HAVE DECIDED NOT TO ISSUE FREEZING RAIN ADVISORIES FOR THESE NORTHERN ZONES DUE TO THE UNCERTAINTY. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... FRONT WILL MOVE OFFSHORE BY ABOUT NOON TOMORROW AND CLEARING SHOULD TAKE PLACE FROM NW TO SE. FLOW WILL SHIFT BACK TO THE NW AND THIS WILL KEEP CLOUDS LINGERING IN THE MOUNTAINS WITH UPSLOPE FLOW...HOWEVER DECREASING CLOUDS AND HIGH TEMPERATURES WELL ABOVE NORMAL LEVELS CAN BE EXPECTED ONCE AGAIN SOUTH AND EAST OF THE MOUNTAINS. && .LONG TERM /MONDAY THROUGH SATURDAY/... A MUCH COOLER EXTENDED IS ON TAP...VERSUS THE WX WE HAVE BEEN HAVING FOR MUCH OF DEC. COLD...CANADIAN HIGH PRES WILL BUILD SWD INTO THE CONUS...AND THOUGH THE CENTER WILL REMAIN WELL TO OUR W...A BRANCHING AXIS WILL DROP THRU NEW ENGLAND LATE MON INTO TUE. CURRENT FORECAST IS FOR THE COLDEST MORNING TEMPS SINCE THE FIRST WEEK OF DEC. MUCH OF THE REST OF THE WEEK IS RELATIVELY QUIET. NO LARGE SCALE CHANGES ARE NOTED IN THE LATEST SUITE OF ENSEMBLE GUIDANCE. 27/12Z GEFS...CMC ENSEMBLES...AND ECMWF EPS ALL CONTINUE TO FEATURE HIGHER THAN NORMAL HEIGHTS INTO AK THRU THE EXTENDED. THIS SHOULD KEEP CANADA PLENTY COLD...AND KEEP IT NEARBY NRN NEW ENGLAND. TEMP FORECAST REMAINS NEAR TO BELOW NORMAL THRU THE EXTENDED. LOW HEIGHTS ACROSS ERN CANADA AND THE SWRN CONUS...PLUS THE SERN CONUS RIDGING WILL KEEP FAST FLOW ALOFT...AND FAST MOVING S/WV TROFS CROSSING THE AREA. EXPECT THAT THE MTNS WILL SEE SOME SHSN ACTIVITY FROM THESE FEATURES...WITH A POSSIBLY STRONGER SIGNAL FOR SHSN THU WITH REINFORCING COLD FNT. MAIN S/WV TROF LOOKS TO EJECT FROM THE SWRN CONUS LATE IN THE WEEK...ARRIVING ACROSS THE NORTHEAST SOMETIME THIS WEEKEND. ECMWF HAS DELAYED THIS EJECTION SOME 18 TO 24 HOURS THAN THE GFS. KNOWING THE ECMWF BIAS FOR HOLDING ENERGY TOO LONG IN THE SOUTHWEST...A BLEND TOWARDS THE QUICKER GFS AND CMC SEEMS APPROPRIATE. HOWEVER WITH LOTS OF ENERGY IN THE SOUTHWEST...FAST FLOW...AND LITTLE BLOCKING AHEAD OF THE SYSTEM MODEL GUIDANCE WILL LIKELY CONTINUE TO WAFFLE ON STRENGTH...TRACK...AND TIMING FOR THE NEXT SEVERAL DAYS. THE SIGNAL IS STRONG FOR PCPN AROUND THIS TIME THOUGH...SO HIGH CHANCE TO LOW LIKELY POP IS MAINTAINED IN THE FORECAST. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... SHORT TERM...A COLD FRONT WILL PUSH THROUGH THE REGION TONIGHT. THIS MAY ALLOW FOR A LITTLE LIGHT RAIN AS WELL AS MVFR CONDITIONS. VFR IS EXPECTED LATE SUNDAY MORNING ONWARD. LONG TERM...VFR CONDITIONS EXPECTED TO PREVAIL THRU THE EXTENDED. LONE EXCEPTION WILL BE IN THE NRN MTNS...WHERE SCT MVFR OR LOWER IS POSSIBLE IN LINGERING UPSLOPE SHSN. && .MARINE... SHORT TERM...SCA FOR MOST ZONES AFTER MIDNIGHT TONIGHT THROUGH SUNDAY AS WINDS AND SEAS BUILD IN ADVANCE OF A COLD FRONT. LONG TERM...GENERAL OFFSHORE FLOW PATTERN WILL PERSIST THRU MIDWEEK. WINDS AND SEAS LOOK TO REACH SCA THRESHOLDS THU WITH PASSAGE OF A COLD FNT ACROSS THE WATERS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FROM 3 AM TO 5 PM EST SUNDAY FOR ANZ150>152-154. && $$

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