-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCAR 180427
AFDCAR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
1227 AM EDT SAT MAY 18 2013

.SYNOPSIS...
LOW PRESSURE ACROSS THE MARITIMES WILL CONTINUE TO SLOWLY PULL
AWAY FROM THE AREA. THE REGION WILL REMAIN IN A COOL NORTHWEST
FLOW ALOFT THROUGH SATURDAY AS HIGH PRESSURE BUILDS INTO THE AREA.
HIGH PRESSURE WILL CREST THE AREA SATURDAY NIGHT THEN MOVE EAST ON
SUNDAY...ALLOWING FOR SOME MODERATION IN TEMPERATURES.

&&

.NEAR TERM /THROUGH TODAY/...
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1227 AM UPDATE: PATCHES OF CLOUDS AROUND 9K FT AGL ARE MOVING
FROM NW TO SE ACROSS THE AREA...BUT GENERALLY THINNING OUT WITH
TIME. MANY AREAS THAT ARE CURRENTLY CLOUDY WILL BECOME M/CLEAR
OVER THE NEXT FEW HOURS AS THE CLOUDS CONTINUE TO DISSIPATE. TEMPS
HAVE FALLEN INTO THE M/U 30S AS OF MIDNIGHT IN MANY AREAS WHERE
THE SKY HAS BECOME CLEAR. WILL UPDATE THE HOURLY GRIDS WITH THE
LATEST OBSERVATIONS...OTHERWISE THE ONGOING FORECAST IS IN GOOD
SHAPE.

PREVIOUS DISCUSSION...
WINDS HAVE CONTINUE TO SUBSIDE ACROSS THE AREA. LOW CLOUDS ACROSS
NRN ME HAVE CLEARED OUT. UPDATE TO BRING THE GRIDS CURRENT.

LOW PRES REMAINS ACROSS XTRM ERN NS ATTM W/ A RATHER MOIST CYC
NRLY FLOW CONTG ACROSS THE AREA. THIS RESULTING IN WIDESPREAD SC
ACROSS THE REGION ALONG W/ A FEW POPCORN TYPE SHOWERS ACROSS ERN
MAINE/WRN NB. A VERY WEAK INVERTED SFC TROF XTNDG SE-NW ACROSS THE
AREA ALSO HELPING TO KEEP THINGS UNSETTLED... LOW PRES IS FCST TO
SLOWLY CONT TO MV AWAY TO THE E TNGT AS LARGE AREA OF HIGH PRES
CURRENTLY XTNDG N-S ACROSS ERN ONT INTO THE GRT LAKES BEGINS TO
BUILD EWRD INTO THE REGION TNGT THRU SAT. WILL TAKE SOME TIME TO
DRY OUT THE LOWER-LEVEL MOISTURE SO EXPECT ONLY SOME DECREASE IN
CLDS OVRNT TNGT THO LOSS OF HEATING SHOULD BE ENUF TO BRING ANY
SHOWERS TO AN END BY EVE. CLD COVER TNGT WILL HAVE SIGNIFICANT
IMPACTS ON LOWS AND WILL OBVIOUSLY BE TUF TO DROP OFF TOO MUCH IF
THICKER CLDS PREVAIL. HOWEVER...AIRMASS IS QUITE CHILLY AND WILL
NOT BE DIFF TO REALIZE FCST LOWS IF MUCH CLEARING OCCURS.  THEREFORE...FOR
NOW HAVE STAYED THE COURSE AND WILL CONT TO CARRY PATCHY FROST
ACROSS THE N W/ THE FROST ADV UP FROM 06-12Z. STILL EXPECT SOME SC
CLDS ON SAT BUT SHOULD BE DECREASED OVR TODAY AND AS A RESULT
SHOULD SEE MAXES A FEW DEGREES HYR THAN TODAY...
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&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
HIGH PRESSURE IS EXPECTED TO DRIFT JUST TO THE EAST OF THE STATE
SUNDAY MORNING. STILL COLD AIR MASS OVER THE REGION AND HIGH
PRESSURE IS CLOSE ENOUGH FOR LIGHT WINDS. SO ANOTHER COLD MORNING
POSSIBLE ALTHOUGH EXPECT SOME CLOUDS ACROSS THE SOUTH. HAVE
BLENDED THE NAM12...GFS40...SREF AND ECMWF FOR POPS AND QPF. FOR
WINDS WILL USE A BLEND OF THE GMOS AND NAM12 FOR SUSTAINED WIND
WITH 150 PERCENT OF SUSTAINED WIND FOR GUST SPEED. TEMPERATURE
GRIDS INITIALIZED WITH THE GMOS. EXPECT RADIATIONAL COOLING
SATURDAY AND SUNDAY SO WILL LOWER MINIMUM TEMPERATURE FEW DEGREES
BUT WILL INCREASE MOS TEMPERATURE FOR MAXIMUM TEMPERATURE SUNDAY
AFTERNOON.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COMPLEX WEATHER PATTERN WILL TAKE HOLD FOR THE LONG RANGE DUE IN
PART TO A SPLIT FLOW IN THE JET STREAM. AS A RESULT THERE
CONTINUES TO BE SIGNIFICANT INTER AND INTRA MODEL VARIABILITY IN
THE MODEL FORECAST SOLUTIONS FOR NEXT WEEK. GIVEN THE UNCERTAINTY,
UTILIZED A BLEND OF THE GMOS, GFS AND ECMWF FOR THIS FORECAST AND
ALSO DID SOME BLENDING WITH THE PREVIOUS FORECAST. THE MOST LIKELY
SOLUTION FOR EARLY IN THE PERIOD WILL BE FOR A FRONTAL BOUNDARY
LOCATED OVER THE NORTHERN TIER TO SLOWLY SHIFT SOUTH MONDAY NIGHT
INTO TUESDAY. DURING THIS TIME A SERIES OF DISTURBANCES RIDING
ALONG THIS BOUNDARY WILL BRING PERIODS OF RAIN AND SHOWERS WITH
THE HIGHEST POPS SLOWLY SHIFTING SOUTH WITH TIME. THE UNCERTAINTY
GROWS HEADING INTO WEDNESDAY WITH THE 00Z ECMWF AND THE 12Z GEM
NOW PUSHING THIS FRONT FAR ENOUGH SOUTH TO KEEP THE AREA DRY WHILE
THE GFS KEEPS THE FRONT AND ASSOCIATED SHOWERS HUNG UP OVER THE
AREA. ONLY MADE MINOR CHANGES TO THE PREVIOUS FORECAST WITH THIS
UPDATE KEEPING CHANCE POPS IN ACROSS THE SOUTH AND SLIGHT CHANCE
POPS IN FOR THE NORTH.

POPS INCREASE HEADING INTO THURSDAY AS SEPARATE DISTURBANCES
ASSOCIATED WITH EACH BRANCH OF THE FLOW TRIES TO MERGE AS THEY
APPROACH THE AREA. HOWEVER THERE ARE DISCREPANCIES BETWEEN THE GFS
AND THE ECMWF ON HOW THIS PHASING OCCURS AND THE SUBSEQUENT AREA
OF LOW PRESSURE DEVELOPS. THE GFS FAVORS A MORE PROGRESSIVE
SOLUTION AND CLEARS THE AREA OUT FOR FRIDAY WHILE THE ECMWF
DEEPENS THE UPPER TROUGH OVER THE GREAT LAKES FRIDAY AS A SURFACE
LOW PASSES OFF THE COAST OF SOUTHERN NEW ENGLAND. CONTINUED TO
PLAY THE MIDDLE GROUND KEEPING CHANCE POPS IN FOR ALL AREAS
THURSDAY THEN LIMITING THE CHANCE OF PRECIPITATION TO SOUTHERN
AREAS FOR FRIDAY. TEMPERATURES GENERALLY LOOK TO BE IN THE
SEASONAL RANGE THROUGH THE PERIOD.

&&

.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
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NEAR TERM: VFR EXPECTED OVERNIGHT THROUGH SATURDAY.

SHORT TERM: EXPECT VFR CONDITIONS SUNDAY. MVFR/IFR CONDITIONS EXPECTED
MONDAY.

EXPECT THE POTENTIAL FOR MVFR/IFR TO CONTINUE AT LEAST THROUGH TUESDAY
DUE TO A FRONTAL BOUNDARY OVER THE AREA WITH ASSOCIATED CLOUDS AND
SHOWERS. IMPROVEMENT IS POSSIBLE BY WEDNESDAY, ESPECIALLY NORTH, AS
THE FRONT SHIFTS SOUTH.
-- End Changed Discussion --

&&

.MARINE...
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NEAR TERM: WNDS/SEAS EXPECTED TO REMAIN BLO SCA LEVELS THRU SAT.

SHORT TERM: HAVE BLENDED THE NAM12 AND GFS40 TO INITIALIZE GRIDS
FOR SUSTAINED WIND SPEED. WILL TAKE 10 PERCENT OFF WIND GUIDANCE
DUE TO COLD SEA SURFACE IN GULF OF MAINE. USED 125 PERCENT OF THE
SUSTAINED WIND FOR GUST SPEED. WAVES: WITH LIGHT WIND AT BEGINNING
OF PERIOD LONG PERIOD SOUTHERLY WAVES PREDOMINATE. A NEW SOUTHERLY
FETCH DEVELOPS FROM THE GULF OF MAINE SOUTHWARD AS HIGH MOVES OFF-
SHORE SUNDAY. WILL USE NAM/SWAN OUT TO 0000Z MONDAY THEN
TRANSITION TO THE WNA/4.

FOR THE LONGER TERM, MARGINAL SCA CONDITIONS DUE TO WINDS AND
SEAS WILL BE POSSIBLE MONDAY NIGHT AND TUESDAY WITH THESE
CONDITIONS DIMINISHING WEDNESDAY.
-- End Changed Discussion --

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
ME...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MEZ001>006.
MARINE...NONE.
-- End Changed Discussion --

&&

$$
NEAR TERM...CB/NORTON/KHW
SHORT TERM...MIGNONE
LONG TERM...FITZSIMMONS
AVIATION...CB/NORTON/KHW/MIGNONE
MARINE...CB/NORTON/KHW/MIGNONE