Area Forecast Discussion
Issued by NWS Portland, ME

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000
FXUS61 KGYX 272351
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
651 PM EST FRI FEB 27 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE WEST TONIGHT THROUGH
SATURDAY AND WILL SHIFT OFFSHORE SOUTH OF NEW ENGLAND ON SUNDAY. A
WEAK AREA OF LOW PRESSURE WILL MOVE IN FROM THE WEST SUNDAY NIGHT
AND WILL QUICKLY SHIFT EAST OF THE REGION ON MONDAY. HIGH PRESSURE
WILL BUILD IN FROM THE WEST MONDAY NIGHT AND WILL CREST OVER THE
REGION ON TUESDAY BEFORE MOVING OFFSHORE. LOW PRESSURE WILL MOVE
NORTHEAST OUT OF THE SOUTHERN GREAT LAKES TUESDAY NIGHT AND WILL
PASS NORTHWEST OF THE REGION ON WEDNESDAY AND WEDNESDAY NIGHT.

&&

.NEAR TERM /TONIGHT/...
7PM UPDATE...
HAVE MADE A FEW MINOR ADJUSTMENTS TO OVERNIGHT LOW TEMPERATURES.
COMPARED TO THIS MORNING TEMPERATURES JUST ABOUT EVERYWHERE SHOULD
BE A FEW DEGREES COLDER. IN GOOD RADIATIONAL COOLING CONDITIONS
THERE IS ALWAYS HIGH BUST POTENTIAL IN THE FORECAST AS LOCAL COOL
SPOTS CAN DROP VERY QUICKLY. ONLY ADJUSTMENTS WITH THIS UPDATE
WERE TO BRING TYPICAL COOL SPOT WISCASSET DOWN A FEW DEGREES. ALSO
DROPPED SOUTHWEST NEW HAMPSHIRE BY A FEW DEGREES TO BRING THEM
COLDER THAN THEY WERE THIS MORNING AND MORE IN LINE WITH FORECASTS
FROM NEIGHBORING OFFICES. SHOULD SEE TEMPERATURES FALL BELOW ZERO
THERE AS WELL AS MOST OF THE FORECAST AREA TONIGHT.

ORIGINAL DISCUSSION...
SPRAWLING HIGH PRESSURE IS CENTERED OVER THE MID MISSISSIPPI
VALLEY THIS AFTERNOON...BRANCHING TOWARDS NEW ENGLAND TO THE EAST.
WEAK COLD FRONT IS EXITING THE COAST AT THIS HOUR AS WELL. THIS
BOUNDARY IS MORE PERCEPTIBLE ALOFT...WITH SLIGHTLY COOLER AIR
MOVING IN. AT THE SURFACE IT IS MOSTLY A NW WIND...WHICH COMBINED
WITH SUNNY SKIES IS ALLOWING SOME DOWNSLOPE WARMING WELL INTO THE
20S NEAR THE COAST.

SURFACE RIDGE AXIS SETTLES OVERHEAD TONIGHT HOWEVER...AND SKIES
REMAIN CLEAR. CONDITIONS LOOK FAVORABLE FOR DECOUPLING OF THE
BOUNDARY LAYER. SUCH A SMALL SCALE PROCESS IS ALWAYS QUITE
DIFFICULT TO FORECAST...BUT GENERALLY LEANED TOWARDS THE COLDER
MET GUIDANCE AND LOWERED THE USUAL COLD SPOTS A COUPLE MORE
DEGREES.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
HIGH PRESSURE REMAINS IN CONTROL SATURDAY...WITH SKIES REMAINING
MOSTLY SUNNY. GUIDANCE HAS STRUGGLED THE LAST FEW DAYS WITH
SUNSHINE...KEEPING MAX TEMPERATURES ON THE COLD SIDE. BLENDED
MAV/MET WITH CMC-REGIONAL AND NAM12 2 M TEMPERATURES FOR MAX
TEMPERATURES...THEN RAISED A COUPLE DEGREES TO OVERCOME THAT COOL
BIAS.

TEMPERATURES WARM ALOFT SATURDAY NIGHT...SO NOT EXPECTING MIN
TEMPERATURES QUITE AS COLD AS TONIGHT. INITIALLY SURFACE RIDGE
AXIS REMAINS ALIGNED QUITE FAVORABLY FOR THE AREA...SO A QUICK
DROP IN TEMPERATURES IN LIKELY. AS RIDGE AXIS SLOWLY SINKS
SOUTH...THE COMBINATION OF SLIGHT MIXING AND WARMING ALOFT SHOULD
LEVEL TEMPERATURES OFF.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
A BROAD AREA OF WARM AIR ADVECTION WILL ENTER THE REGION SUNDAY
NIGHT AS AN UPPER LEVEL TROUGH APPROACHES FROM THE NORTHWEST. THIS
WILL ALLOW LIGHT SNOW TO DEVELOP ACROSS THE REGION SUNDAY EVENING.
THIS SYSTEM IS PROGRESSIVE...WHICH WILL ALLOW ACCUMULATIONS TO BE
IN THE 2 TO 3 INCH RANGE.

DRIER AIR WILL BE USHERED INTO THE REGION ON STRONG NORTHWEST
WINDS ON MONDAY...HOWEVER THERE MAY BE A STRAY FLURRY LEFTOVER.
HIGH PRESSURE WILL BUILD EAST...CRESTING OVER NEW ENGLAND ON
TUESDAY.

THE STORM TRACK HAS CHANGED...ALLOWING THE NEXT SYSTEM TO
POTENTIALLY PASS TO OUR WEST TUESDAY NIGHT INTO WEDNESDAY.
SUFFICIENTLY ENOUGH COLD AIR IN PLACE TUESDAY NIGHT TO ALLOW FOR
MOSTLY SNOW ACROSS MAINE AND NEW HAMPSHIRE. HOWEVER...WARM AIR
EVENTUALLY MAKES IT IN ALOFT TO CHANGE MUCH OF THE PRECIPITATION
OVER TO A PERIOD OF RAIN OR RAIN AND SNOW MIX BEFORE IT ENDS.

A FEW LEFTOVER RAIN SHOWERS ARE POSSIBLE WEDNESDAY BEHIND A COLD
FRONT THAT WILL EVENTUALLY CHANGE OVER TO SNOW SHOWERS BY
THURSDAY.

ANOTHER BRIEF SHOT OF VERY COLD AIR IS LIKELY TOWARDS THE END OF
THE WEEK.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR CONDITIONS WILL PREVAIL THRU SUNDAY MORNING.

LONG TERM...AREAS OF IFR CONDITIONS IN SNOW SUNDAY NIGHT. SNOW TO
MIX WILL LEAD TO IFR CONDITIONS TUESDAY NIGHT INTO EARLY
WEDNESDAY.

&&

.MARINE...
SHORT TERM...WINDS AND SEAS WILL REMAIN BELOW SCA THRESHOLDS THRU
SUNDAY MORNING. BITTERLY COLD TEMPERATURES TONIGHT WILL LEAD TO
MODERATE FREEZING SPRAY NORTH OF CAPE ELIZABETH...AND ADVISORY IS
IN EFFECT THRU 12Z SATURDAY.

LONG TERM...WINDS SHOULD INCREASE TO SCAS MONDAY NIGHT BEHIND
DEPARTING AND STRENGTHENING SURFACE LOW PRESSURE SYSTEM OVER THE
MARITIMES. GUSTY WINDS NEXT THURSDAY NIGHT AND FRIDAY AS WELL OUT
OF THE WEST.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...FREEZING SPRAY ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM EST
     SATURDAY FOR ANZ150>152.

&&

$$

NEAR TERM UPDATE...KIMBLE
SHORT TERM...LEGRO
LONG TERM...CANNON
AVIATION...CANNON/LEGRO
MARINE...CANNON/LEGRO


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