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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