Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 031826
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
226 PM EDT TUE MAY 3 2016

.SYNOPSIS...
WEAK HIGH PRESSURE SPREADS OVER NORTHERN NEW ENGLAND TONIGHT.
AN EASTERLY ONSHORE FLOW DEVELOPS ON WEDNESDAY BETWEEN LOW
PRESSURE TO THE SOUTH AND HIGH PRESSURE TO THE NORTH. THIS WILL
KEEP TEMPERATURES COOL WITH PLENTY OF CLOUD COVER. ANOTHER AREA OF
LOW PRESSURE WILL DEVELOP AND TRACK NORTHWARD TO THE EAST OF CAPE
COD WEDNESDAY AFTERNOON AND NIGHT AND WILL BRING MORE RAIN TO THE
AREA. PERSISTENT LOW PRESSURE LINGERS THROUGH THE WEEKEND KEEPING
COOL TEMPERATURES AND SHOWERY WEATHER IN THE FORECAST.

&&

.NEAR TERM /THROUGH TONIGHT/...
WEAK HIGH PRESSURE RIDGING WILL BUILD DOWN THROUGH THE GULF OF
MAINE TONIGHT. THE EASTERLY FLOW THAT DEVELOPS IN RESPONSE TO THIS
WILL ENSURE MOSTLY CLOUDY SKIES OVERNIGHT. MOST AREAS WILL REMAIN
DRY...BUT A FEW SHOWERS WILL BE POSSIBLE NEAR THE MASS BORDER THIS
EVENING. SOME PATCHY DRIZZLE AND FOG MAY DEVELOP LATER TONIGHT AS
THE LOW LEVEL EASTERLY FLOW STRENGTHENS.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
COOL AND CLOUDY EASTERLY FLOW WILL CONTINUE ON WEDNESDAY. A MAINLY
DRY MORNING IS EXPECTED. HOWEVER...FORCING FOR ASCENT WILL ARRIVE
FROM THE WEST AND SOUTH DURING THE AFTERNOON ALLOWING FOR SHOWERS
OR A CHILLY LIGHT RAIN TO DEVELOP DURING THE AFTERNOON
HOURS...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE CWA. A RAINY
EVENING IS IN STORE WEDNESDAY EVENING AS FORCING FOR ASCENT
ASSOCIATED WITH LOW PRESSURE TO OUR SOUTHEAST MAXIMIZES. THE
STEADIER/HEAVIER RAIN SHOULD MOVE OUT LATE WEDNESDAY NIGHT OR
AROUND DAWN THURSDAY. HOWEVER...DRIZZLE WILL PROBABLY REPLACE THE
LARGER RAINDROPS AS THE MID LEVELS DRY OUT BUT LOW LEVELS REMAIN
MOIST.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
LOW PRESSURE SLOWLY INTENSIFIES...PASSING EAST OF NANTUCKET ISLAND
ON THURSDAY. CONDITIONS REMAIN QUITE UNSETTLED FRIDAY AS A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM REMAINS NEARLY STATIONARY OVER THE
MID ATLANTIC REGION. THIS WILL ALLOW A BROAD AREA OF LOW PRESSURE
TO REMAIN OVER THE COASTAL WATERS INTO THIS WEEKEND...PRODUCING
COOL AND SHOWERY WEATHER CONDITIONS.

CYCLOGENESIS OCCURS OVER THE COASTAL WATERS OR THE CANADIAN
MARITIMES LATE ON SUNDAY. THIS WILL ALLOW FOR DRIER AIR TO ENTER
THE REGION ON INCREASING WESTERLY WINDS. THERE IS STILL A FAIR
AMOUNT OF UNCERTAINTY AS TO THE LOCATION OF THIS INTENSIFICATION.
THE EURO AND GEFS ARE MORE PROGRESSIVE WITH THIS SYSTEM...WHILE
THE GGEM STRENGTHENS THE SURFACE LOW IN THE GULF OF MAINE.

A DRIER WESTERLY FLOW WILL FOLLOW THEREAFTER...HOWEVER A COOL
CYCLONIC FLOW ALOFT WILL ALLOW FOR A FEW DIURNALLY DRIVEN
SCATTERED SHOWERS...MAINLY IN THE MOUNTAINS AND FOOTHILLS.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHORT TERM...MVFR TO LOW-END VFR CONDITIONS ARE EXPECTED THIS
EVENING BEFORE GOING BACK DOWN TO MVFR LATER TONIGHT. A FEW AREAS
OF IFR CIGS POSSIBLY ESPECIALLY ON THE COAST. IMPROVEMENT TO
HIGH-END MVFR OR LOW-END VFR IS EXPECTED AGAIN BY LATE WED MORNING
BUT WILL TREND DOWN ONCE AGAIN BY LATE AFTERNOON AS RAIN DEVELOPS.
IFR OR LOWER IN RAIN WED EVENING AND NIGHT.

LONG TERM...AREAS OF LIFR CONDITIONS WITH A RAW NORTHEAST FLOW OFF
THE GULF OF MAINE ON THURSDAY. OTHERWISE...A PROLONGED PERIOD OF
MVFR AND IFR CONDITIONS THROUGH EARLY SUNDAY. THEREAFTER...DRIER
WESTERLY WINDS WILL ENTER THE REGION.

&&

.MARINE...
SHORT TERM...SEAS WILL REMAIN BELOW SMALL CRAFT LEVELS THROUGH
TONIGHT. INCREASING EASTERLY FLOW MAY ALLOW FOR SCA WINDS/SEAS TO
BUILD LATER WEDNESDAY NIGHT.

LONG TERM...SEAS WILL CONTINUE TO SLOWLY BUILD ON THURSDAY AS LOW
PRESSURE REMAINS OFF THE NEW ENGLAND COASTLINE AND A GUSTY
NORTHEAST GRADIENT DEVELOPS. EXPECT WAVES IN THE 4-6 FOOT RANGE
TO CONTINUE...ABOVE SCA CRITERIA INTO THIS WEEKEND.

WINDS INCREASE FROM THE WEST LATE IN THE WEEKEND AS LOW PRESSURE
DEVELOPS OVER THE CANADIAN MARITIMES.

&&

.FIRE WEATHER...
WILL CONTINUE TO SEE A PROLONGED PERIOD OF MOIST ONSHORE FLOW
HELPING TO KEEP RELATIVE HUMIDITY VALUES HIGH AND RAIN IN THE
FORECAST.

&&

.TIDES/COASTAL FLOODING...
BEGINNING THURSDAY THROUGH THE WEEKEND...WE ARE SET FOR A PERIOD
OF HIGH ASTRONOMICAL TIDES. THE HIGHEST TIDES WILL BE FRIDAY AND
SATURDAY NIGHTS WHEN PORTLAND IS FORECAST TO REACH 11.9 FEET AT
1135 PM AND 1226 AM RESPECTIVELY. COASTAL FLOODING MAY BE POSSIBLE
DURING THIS TIME PERIOD...AS WINDS WILL GENERALLY BE EASTERLY TO
NORTHEASTERLY. IF LOW PRESSURE DEVELOPS A LITTLE SOONER OR
STRONGER...MINOR COASTAL FLOODING ISSUES COULD BEGIN AS EARLY AS
THE THURSDAY EVENING TIDE. ANY FLOODING WOULD LIKELY BE LIMITED
TO AREAS NEAR AND SOUTH OF PORTLAND.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...EKSTER
SHORT TERM...EKSTER
LONG TERM...CANNON



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