104
FXUS61 KGYX 080156
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
856 PM EST SAT NOV 7 2009
SYNOPSIS
A RIDGE OF HIGH PRESSURE MOVES EAST OF THE REGION TONIGHT. A WEAK
COLD FRONT MOVES ACROSS THE REGION SUNDAY. ANOTHER AREA OF HIGH
PRESSURE APPROACHES THE REGION SUNDAY NIGHT AND MOVES EAST OF THE
REGION ON MONDAY. A WEAK FRONTAL BOUNDARY THEN SETS UP ACROSS THE
REGION MONDAY NIGHT WITH A WEAK AREA OF LOW PRESSURE MOVING ALONG
THE FRONT AND ACROSS THE REGION TUESDAY. THE REMNANTS OF TROPICAL
STORM IDA THEN MOVE UP THE COAST WEDNESDAY...MOVING EAST OF CAPE
COD THURSDAY. A RIDGE OF HIGH PRESSURE APPROACHES THE REGION
THURSDAY NIGHT AND THEN CROSSES THE REGION FRIDAY.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
THE GRIDDED AND TEXT FORECASTS WERE UPDATED EARLIER THIS EVENING
TO ACCOUNT FOR TRENDS IN TEMPERATURES AND CLOUDS.
WATCHING A FAIRLY LARGE AREA OF WARM AIR ADVECTION CLOUDS APPROACHING
FROM THE WEST. THE MOISTURE TRAPPED UNDER THE INVERSION SHOULD
AFFECT MAINLY NORTHERN AND CENTRAL ZONES...AND THIS WAS ADDED TO
THE FORECAST. SOUTH OF THIS...THE ALTOCUMULUS MAY BE MORE
SCATTERED IN NATURE. WILL HAVE TO TRACK THE PROGRESS OF THE CLOUDS
AND ADD MORE TO SOUTHERN ZONES AS TRENDS WARRANT.
NOTED SOME WIDELY SCATTERED SHOWERS IN THE WARM AIR ADVECTION
ACROSS ONTARIO AND WESTERN QUEBEC. 0000 UTC SOUNDINGS SUGGEST THAT
THE COLUMN IS TOO DRY TO SUPPORT PRECIPITATION IN THE FORECAST
AREA...AT LEAST INITIALLY. THE WARM AIR ADVECTION WILL MOISTEN THE
COLUMN...BUT THE CROSS BARRIER FLOW MAY BE JUST ENOUGH FOR WIDELY
SCATTERED SHOWERS ACROSS THE MOUNTAINS. DUE TO A LACK OF FORCING...
LEFT THE MENTION OF PRECIPITATION OUT ELSEWHERE TONIGHT.
TEMPERATURES DROPPED QUICKLY IN THE CLEAR SKIES THIS EVENING IN
THE NORMALLY COLDER SPOTS. WILL PROBABLY SEE LOWS JUST BEFORE
MIDNIGHT ACROSS NORTHERN SECTIONS...AND LOWS WERE ADJUSTED DOWN IN
THESE AREAS. ELSEWHERE...A LIGHT SOUTHWEST FLOW MAY ALLOW
TEMPERATURES TO DROP A COUPLE OF DEGREES THIS EVENING BEFORE
BECOMING STEADY. THIS WAS ALSO ACCOUNTED FOR IN THE UPDATED
FORECAST.
SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/
CLOUDS SHOULD DISSIPATE FROM WEST TO EAST AROUND SUNRISE GIVE OR TAKE
A COUPLE OF HOURS AND THIS SHOULD LEAVE US WITH A MOSTLY SUNNY SUNDAY.
EXPECT LIGHT WINDS OUT OF THE WEST AFTER FRONTAL PASSAGE WITH SUNDAYS
TEMPERATURES SOME 10 TO 15 DEGREES ABOVE SEASONABLE NORMALS.
LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/
TO SAY THAT THE MODELS ARE IN DISAGREEMENT WITH THE EXTENDED
FORECAST WOULD BE A HUGE UNDERSTATEMENT. LONG TERM MODELS TRACK
FAIRLY CLOSE THROUGH TUESDAY NIGHT...WITH HIGH PRESSURE DOMINATING
THE WEATHER OVER THE REGION. THINGS FALL APART PRETTY QUICKLY
AFTER THAT THOUGH.
STARTING WITH THE 12Z GFS. AT 00Z WEDNESDAY THE GFS HAS THE
REMNANTS OF IDA OVER THE CAROLINAS...ALONG WITH A COLD FRONT
MOVING THROUGH THE GREAT LAKES. THE GFS MERGES THESE TWO SYSTEMS
JUST SOUTH OF CAPE COD BY 18Z WEDNESDAY...WITH OVERRUNNING PUSHING
WELL INTO NORTHERN NEW ENGLAND. THIS IS WHERE THINGS TAKE A TURN.
THE GFS BASICALLY HALTS THE SYSTEM AND DEEPENS IT. THIS DRAGS COLD
AIR INTO THE NORTH SIDE OF THE SYSTEM AND PRODUCES OVER AN INCH OF
QPF IN THE FORM OF SNOW...OR A RAIN/SNOW MIX. PRECIPITATION WOULD
CONTINUE THROUGH THE DAY ON THURSDAY BEFORE THE SYSTEM MIGRATES
EAST OF THE AREA.
THE 12Z ECMWF HAS A MUCH DIFFERENT SOLUTION. AGAIN...STARTING AT
00Z WEDNESDAY THE ECMWF HAS THE REMNANTS OF IDA OVER MISSISSIPPI
AND ALABAMA. IT ALSO HAS THE FRONTAL BOUNDARY OVER THE EASTERN
GREAT LAKES. THE MODEL THEN BUILDS HIGH PRESSURE INTO THE OHIO
RIVER VALLEY...WHICH PUSHES THE REMNANTS OF IDA OFF THE SOUTH
CAROLINA COAST BY 00Z. THE RESULT FOR NORTHERN NEW ENGLAND ON
THURSDAY IS HIGH PRESSURE AND PLENTY OF SUN.
BELIEVE THAT THE ECMWF HAS A BETTER HANDLE ON THE FORECAST AND IS
MORE PROGRESSIVE WITH THE LARGE SCALE FEATURES. WILL FOLLOW
CLOSELY TO THE HPC GUIDANCE WHICH RELIES HEAVILY ON THE ECMWF AND
DISCOUNTS THE GFS.
AVIATION /02Z SUNDAY THROUGH THURSDAY/
IN THE NEAR TERM /TONIGHT/...VFR CONDITIONS CONTINUE THIS EVENING.
WATCHING A FAIRLY LARGE ARE OF STRATOCUMULUS TRAPPED UNDER THE
WARM AIR ADVECTION INDUCED INVERSION. THE GENERAL MOTION HAVE BEEN
TO THE EAST SOUTHEAST...AND WILL LIKELY AFFECT KLEB AND KAUG.
THE INVERSION APPEARS TO BE HIGH ENOUGH TO KEEP CEILINGS AT VFR.
THERE IS A CHANCE THAT THE CLOUDS WILL BREAK QUICKLY ENOUGH LATE
TONIGHT TO ALL RADIATIONAL FOG TO FORM AT KLEB BETWEEN 0900 AND
1200 UTC. THIS MAY BE A LONG SHOT AS THE AIR IS DRY AND BREAKS IN
THE CLOUDS MAY HAVE HARD TO COME BY.
IN THE SHORT TERM /SUNDAY/...EXPECTING VFR CONDITIONS.
LONG TERM...FRONTAL BOUNDARY WILL MOVE THROUGH ON WEDNESDAY
PRODUCING RAIN SHOWERS AND SOME BRIEF MVFR/IFR CONDITIONS.
MARINE
IN THE NEAR TERM /TONIGHT/...WINDS ARE NEARING SMALL CRAFT LEVELS
IN THE COASTAL WATERS...ESPECIALLY ON THE OCEAN. WITH SURFACE HIGH
PRESSURE MOVING OFF THE MID ATLANTIC COAST...THE GRADIENT IN THE
RETURN SOUTHWEST FLOW WILL INCREASE TONIGHT. THE MIXED LAYER IN
THE WARM AIR ADVECTION PATTERN IS FAIRLY LOW...AND THIS SHOULD CAP
WINDS OVER THE OCEAN AT 25 TO 30 KNOTS IN GUSTS.
JUST ABOVE THE INVERSION...WINDS REACH 30 KNOTS AT ABOUT 6000
FEET. WOULD EXPECT TO REMAIN WELL ABOVE THE INVERSION AND THIS
WILL KEEP WINDS OUT OF THE GALE RANGE. THE FAVORABLE FETCH WILL
BRING SEAS ABOVE 5 FEET ACROSS THE OCEAN TONIGHT AND CLOSE TO 5
FEET AT THE MOUTH OF THE BAYS.
IN THE SHORT TERM /SUNDAY/...EXPECT TO GO BELOW SCA CRITERIA
SUNDAY MORNING BEFORE NOONTIME.
LONG TERM...DO NOT EXPECT ANY FLAGS IN THE LONG TERM.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 9 AM EST SUNDAY FOR
ANZ150>154.
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