Area Forecast Discussion
Issued by NWS Portland, ME

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000
FXUS61 KGYX 270351
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
1151 PM EDT THU MAR 26 2015

.SYNOPSIS...
LOW PRESSURE WILL CROSS THE GULF OF MAINE OVERNIGHT. HIGH
PRESSURE WILL THEN GRADUALLY BUILD INTO THE REGION FRIDAY THROUGH
SUNDAY. LOW PRESSURE WILL MOVE EASTWARD ACROSS QUEBEC ON MONDAY
AND WILL DRAG A COLD FRONT ACROSS OUR REGION MONDAY NIGHT. QUICK
MOVING LOW PRESSURE CROSSES THE AREA TUESDAY NIGHT INTO WEDNESDAY
AND AGAIN ON THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...

1150 PM...AT 03Z A 1003 MILLIBAR LOW WAS VICNITY OF 44005 BUOY
ALONG WAVY FRONTAL BOUNDARY. A SURFACE COLD FRONT WAS DRAPED ALONG
THE SAINT LAWRENCE VALLEY. THE STEADIER PRECIPITATION WITH THE
OFFSHORE LOW AND ASSOCIATED BOUNDARY WILL GRADUALLY SLIDE OFFSHORE
OVERNIGHT. I MADE MINOR ADJUSTMENTS TO 1ST PERIOD GRIDS TO REFLECT
THE CURRENT MESONET.

PREV DISC... UPDATE... NORTHERLY WINDS WILL CONTINUE TO ADVECT
SLIGHTLY COOLER AND DRIER AIR INTO THE REGION DURING THE OVERNIGHT
HOURS. THIS WIND SHIFT CONTINUES TO ALLOW FOR THE AREAS OF DENSE
FOG TO LIFT. CURRENTLY...ONLY SPOTTY REPORTS OF VSBYS A 1/4 MILE
OR LESS...SO WILL BE DROPPING THE DENSE FOG ADVISORIES THIS
FORECAST PACKAGE.

ONLY TWEAKS AND MINOR ADJUSTMENTS TO THE REMAINDER OF THE GRIDDED
DATABASE.

PREV UPDATE...
DENSE FOG HAS BECOME WIDESPREAD ACROSS MUCH OF SOUTHERN MAINE AND
SOUTHERN NEW HAMPSHIRE. HAVE ISSUED A DENSE FOG ADVISORY UNTIL 11
PM. NORTHERLY WINDS SHOULD ADVECT SLIGHTLY DRIER AIR INTO THE
REGION AND MIX OUT SOME OF THE FOG AT THAT TIME.

AREAS OF RAIN AND RAIN SHOWERS CONTINUE TO MOVE RAPIDLY TO THE
NORTHEAST IN A STRONG GRADIENT FLOW ALOFT. THE CHANGEOVER TO SNOW
WILL CONTINUE THIS EVENING ACROSS THE HIGHER TERRAIN OF THE
NORTHERN MOUNTAINS. SNOW WILL MIX IN OVER CENTRAL AREAS AS WELL BY
AROUND 08Z...BUT THIS IS MAINLY AN ELEVATION BASED SNOW EVENT.

PREV DISC...A POSITIVE TILTED AND PROGRESSIVE LONG WAVE TROUGH
WILL MOVE ACROSS NEW ENGLAND TONIGHT. AHEAD OF IT WARM AIR AT ALL
LEVELS SPREAD ACROSS THE REGION DURING THE AFTERNOON. A WEAK WAVE
WILL DEVELOP ALONG THE BASE OF THIS TROUGH AND MOVE ACROSS
SOUTHERN NEW ENGLAND TONIGHT. TO THE NORTH OF THIS WAVE
OVERRUNNINGRAIN IS EXPECTED ACROSS THE REGION WITH SNOW OVER THE
HIGHER ELEVATIONS. QPF AMOUNTS WILL RANGE FROM .50-.75 INCHES
WHICH SHOULD NOT POSE ANY FLOODING PROBLEMS. OVERNIGHT COLD AIR
ADVECTION GRADUALLY SPREADS SOUTH ALLOWING THE RAIN TO CHANGE TO
SNOW IN THE LOWER ELEVATIONS IN THE MOUNTAINS AND FOOTHILLS WITH
SOME LIGHT ACCUMULATIONS EXPECTED BY MORNING. OVER SOUTHERN AREAS
THE PRECIPITATION WILL PROBABLY END BEFORE ENOUGH COLD AIR SPREADS
SOUTH TO CAUSE ANY CHANGEOVER. USED A BLEND OF THE MODELS FOR QPF
AND OVERNIGHT LOWS.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRIDAY AND FRIDAY NIGHT THE BASE OF THE UPPER TROUGH SLOWLY
PROGRESSES EAST BUT WILL HAVE PLENTY OF CLOUD COVER LINGERING
ACROSS THE AREA. SOME PARTIAL CLEARING MAY OCCUR OVER NORTHERN
AREAS WHILE SOUTHERN AREAS REMAIN MOSTLY CLOUDY. TEMPERATURES WILL
BE NEAR SEASONAL ON FRIDAY AND FRIDAY NIGHT AS A BLEND OF THE
MODEL GUIDANCE SUGGESTS.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE BULK OF THE PRECIPITATION ASSOCIATED WITH A DEEPENING LOW
PRESSURE WAVE ALONG THE OFFSHORE FRONT WILL REMAIN IN THE GULF
OF MAINE ON SATURDAY... HOWEVER COASTAL SECTIONS OF NH AND MAINE
WILL HAVE A SLIGHT CHANCE OF SHOWERS THROUGH THE DAY. SKIES WILL
BE CLOUDY CONTRIBUTING TO A SMALL DIURNAL RISE INTO THE MID 30S
OVER THE COASTAL PLAIN. FARTHER NORTH MID TO UPPER 20S FOR HIGHS
IS MORE LIKELY.

SKIES BEGIN TO CLEAR OUT NORTH TO SOUTH OVERNIGHT AND COLDER AIR
FILTERS IN MAKING FOR A CHILLY NIGHT. SPRAWLING HIGH PRESSURE
COVERING MOST OF THE NATION MOVES INTO THE SOUTHEASTERN STATES
BRINGING A NORTHERLY AND THEN EVENTUALLY WESTERLY WIND GRADIENT
TO NEW ENGLAND. SURFACE TEMPERATURES FOR MUCH OF THE AREA RESPOND
TO THIS DOWNSLOPING COMPONENT AS WELL AS SYNOPTIC SCALE WARMING
RESULT IN A WARMING TREND SUNDAY.

THE NEXT CHANCE OF PRECIPITATION ARRIVES MONDAY AS WARM AIR
ADVECTION RAMPS UP AHEAD OF A DEEPENING SURFACE CYCLONE WELL TO
OUR NORTH. THE LITTLE BIT OF COLD AIR ASSOCIATED WITH THIS SYSTEM
SHOULD MOSTLY DAM NORTH OF THE MOUNTAINS AND MODERATE WITHIN 12-18
HOURS. OVER THE COASTAL PLAIN WE WILL CONTINUE TO SEE READINGS
REACH THE 40S IN THE AFTERNOON WITH THE OCCASIONAL 50 DEGREE
READING TUESDAY AND WEDNESDAY. A WEAK WAVE TRANSPORTS QUICK MOVING
LOW PRESSURE ACROSS THE AREA TUESDAY NIGHT INTO WEDNESDAY BEFORE
MOVING IT OUT TO SEA. THIS WILL BRING CHANCE PRECIPITATION TO THE
REGION... AT THIS TIME IT LOOKS LIKE IT WOULD BRING MIXED PTYPE.
LASTLY MODELS FOLLOW THIS WITH A STRONGER SYSTEM FOR EASTER
WEEKEND WHICH MAY CAUSE HAVE TRAVEL IMPLICATIONS.

&&

.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...IFR CONDITIONS ARE EXPECTED LATER THIS AFTERNOON AND
TONIGHT IN RAIN...WITH SNOW AT HIGHER ELEVATIONS ACROSS NORTHERN
NH AND THE WESTERN ME MOUNTAINS. VFR CONDITIONS WILL GRADUALLY
RETURN ON FRIDAY AND CONTINUE FRIDAY NIGHT.

LONG TERM...SCATTERED MVFR CONDITIONS POSSIBLE IN MOUNTAIN AND
COASTAL SNOW SHOWERS SATURDAY. SCATTERED MVFR CONDITIONS POSSIBLE
MONDAY IN RAIN AND SNOW SHOWERS AS A COLD FRONT CROSSES FROM NORTH
TO SOUTH.

&&

.MARINE...
SHORT TERM...
A SCA WILL BE REQUIRED OVER THE OUTER WATERS DUE TO EXPECTED
BUILDING SEAS LATER THIS EVENING AND CONTINUING THROUGH FRIDAY.
WINDS WILL REMAIN WELL BELOW SCA CRITERIA THROUGH FRIDAY NIGHT.

LONG TERM...WAVES REMAIN HIGH ON SATURDAY BEFORE DROPPING BY
SUNDAY MORNING. SEAS AND WINDS INCREASE BRIEFLY MONDAY MORNING TO
SCA CRITERIA AHEAD OF A COLD FRONTAL PASSAGE.

&&

.HYDROLOGY...
WARMER WEATHER AND ONE HALF TO THREE QUARTERS OF AN INCH OF RAIN
WILL INDUCE SOME RUNOFF THIS EVENING. WE WILL LIKELY SEE SOME
RISES ON SOUTHERN RIVERS. AT THE CURRENT TIME WE DO NOT EXPECT ANY
BIG ISSUES. PERHAPS SOME MINOR POOR DRAINAGE FLOODING THIS
EVENING. HOWEVER...WILL HAVE TO MONITOR FOR ICE MOVEMENT ON
RIVERS AND STREAMS.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT FRIDAY
     FOR ANZ150-152-154.

&&

$$
ES


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