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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KGYX 212335
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
735 PM EDT TUE MAY 21 2013

.SYNOPSIS...
A WARM FRONT WILL REMAIN STALLED ACROSS SOUTHERN NEW HAMPSHIRE AND
SOUTHWEST MAINE TONIGHT AND WEDNESDAY...FINALLY LIFTING NORTH OF THE
REGION WEDNESDAY NIGHT. A COLD FRONT WILL SLOWLY APPROACH FROM THE
NORTHWEST THURSDAY AND WILL GRADUALLY PUSH OFFSHORE LATE THURSDAY
NIGHT AND FRIDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT OVER THE
GULF OF MAINE FRIDAY NIGHT AND WILL MOVE NORTHEAST INTO THE
MARITIMES ON SATURDAY. LOW PRESSURE WILL CONTINUE TO SHIFT OFF TO
THE NORTHEAST SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BUILDS IN
FROM THE WEST THROUGH MONDAY.

&&

.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
-- Changed Discussion --
730 UPDATE...
JUST UPDATED GRIDS TO TREAK TEMPS/DEWPTS TO MOST RECENT OBS. COLD
FRONT HAS PUSHED WESTWARD THROUGH NEW HAMPSHIRE. CONVECTION THAT
DEVELOPED ALONG THE CONNECTICUT RIVER VALLEY HAS BEEN FALLING
APART AS IT MOVES OVER COLDER AIR. SHOWERS OVER VT HAVE ALSO BEEN
WEAKENING AS THEY MOVE EAST...SO THREAT OF SHOWERS AND TSTMS OVER
NORTHERN AND CENTRAL NH THIS EVENING HAS BEEN DIMINISHING. MUCH
LARGER AREA OF CONVECTION OVER WESTERN NY WILL MOVE ACROSS THE AREA
OVERNIGHT. ALTHOUGH SFC TEMPS WILL BE COOL...SHOWERS AND A FEW
TSTMS ARE EXPECTED AS THIS SYSTEM MOVES THROUGH DUE TO ELEVATED
INSTABILITY.

PREVIOUS DISCUSSION...
WARM FRONT CURRENTLY STALLED ACROSS SOUTHWEST AND WESTERNMOST NEW
HAMPSHIRE AS OF 245 PM. TEMPERATURES SOUTH OF THE FRONT HAVE RISEN
INTO THE 70S AND 80S. MEANWHILE EVERYONE ELSE ACROSS THE CWA
REMAIN NORTH OF THE FRONT AND SUBSEQUENTLY IN A MUCH COOLER
AIRMASS WITH CLOUDS AND DRIZZLE/SHOWERS.

THE INCREASED SUNSHINE AND WARM TEMPS AS WELL AS RELATIVELY HIGH
DEWPOINTS IN SWRN NH HAVE ALLOWED FOR MODERATE INSTABILITY TO
DEVELOP THERE. THIS COMBINED WITH AMPLE WIND SHEAR MAY ALLOW FOR A
FEW STRONG STORMS IF DEEP MOIST CONVECTION WERE TO INITIATE. AS OF
RIGHT NOW...IT LOOKS LIKE THE BEST CHANCE OF INITIATION WILL BE
OVER MASSACHUSETTS...BUT IT/S NOT OUT OF THE QUESTION ONE OR TWO
STORMS DEVELOP ACROSS SOUTHWESTERN NH THROUGH ABOUT 5 OR 6 PM.
THEREAFTER...A MUCH MORE STABLE AIRMASS WILL ARRIVE FROM THE
NORTHEAST AND SUBSEQUENTLY SQUASH ANY SURFACE-BASED INSTABILITY.

TO THE NORTH...OCCASIONAL DRIZZLE...FOG...AND SHOWERS WILL PERSIST
INTO THE EVENING HOURS.

LATER TONIGHT...A SHORT WAVE TROUGH WILL MOVE ACROSS THE REGION
AND INCREASE CHANCES FOR SHOWERS ACROSS THE ENTIRE AREA...MAINLY
ACROSS THE NORTH WHERE THE BEST FORCING FOR ASCENT IS EXPECTED TO
OCCUR. SUFFICIENT ELEVATED INSTABILITY FOR A FEW THUNDERSTORMS
SHOULD BE PRESENT AS WELL...SO MADE SURE THEY WERE INCLUDED IN THE
FORECAST FOR ALL ZONES DESPITE THE COOL STABLE LOW LEVEL
CONDITIONS. LOCALLY HEAVY DOWNPOURS MAY OCCUR...BUT SEVERE WEATHER
IS NOT EXPECTED AT THIS TIME.
-- End Changed Discussion --

&&

.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
THE WARM FRONT WILL TRY TO MAKE A PUSH NORTHWARD ONCE AGAIN ON
WEDNESDAY AND LIKELY SUCCEED IN DOING SO AS FAR NORTH AS NORTHERN
NH TO JUST SOUTH OF PORTLAND. TEMPS WILL WARM APPRECIABLY TO THE
SOUTH OF THE FRONT...AT LEAST WELL INTO THE 70S. HOWEVER...AT THE
IMMEDIATE COAST NORTHWARD TO CENTRAL MAINE THE WARM FRONT PROBABLY
WON/T MAKE IT. IT WILL THEREFORE BE COOLER IN THOSE AREAS. AS FAR
AS PRECIPITATION CHANCES GO ON WEDNESDAY...THE SHOWERS/STORMS WITH
THE SHORT WAVE TROUGH MOVING THROUGH TONIGHT SHOULD END EARLY ON.
THE BULK OF THE MORNING MAY BE MAINLY DRY. THEREAFTER...THE
HEATING OF THE DAY WILL LIKELY PROMOTE ADDITIONAL SCT SHOWER AND
THUNDERSTORM DEVELOPMENT...ALTHOUGH FORCING FOR ASCENT IS NOT
EXPECTED TO BE ALL THAT ROBUST.

SCT SHOWERS AND THUNDERSTORMS MAY CONTINUE WED NIGHT AS WARM FRONT
TRIES TO LIFT THROUGH.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
SURFACE COLD FRONT WILL GRADUALLY APPROACH FROM THE WEST ON THURSDAY
AS DEEP UPPER TROUGH SWINGS IN FROM THE WEST. DAY MAY START DRY FOR
MOST AREAS BUT WILL SEE INCREASING POPS IN NORTHWEST ZONES DURING
THE MORNING AND EARLY AFTERNOON AS THE FRONT NEARS AND DAYTIME
HEATING DESTABILIZES THE AIR AHEAD OF IT. EXPECT ENOUGH INSTABILITY
TO DEVELOP IN THE AFTERNOON THROUGHOUT THE FORECAST AREA FOR SHOWERS
AND THUNDERSTORMS EXCEPT FOR MID COAST MAINE WHERE AN ONSHORE FLOW
WILL LIMIT CAPES. BEST CHANCES OF PRECIP WILL BE IN THE MOUNTAINS AND
CONNECTICUT VALLEY. HIGH TEMPS WILL BE LIMITED BY CLOUD COVER BUT
MOST AREAS AWAY FROM THE COAST WILL RANGE THROUGH THE 70S TO NEAR
80.

THE FRONT WILL SLOWLY SAG SOUTHEAST THURSDAY NIGHT AND FRIDAY
KEEPING SHOWERS AND A CHANCE OF THUNDERSTORMS IN THE FORECAST
THROUGH THE PERIOD. SEVERAL SURGES OF ENERGY DIVING INTO APPROACHING
UPPER TROUGH WILL COMPLICATE THE FORECAST FRIDAY AND BEYOND. AS
USUAL MODELS HAVING DIFFICULTY WITH TIMING AND STRENGTH OF THESE
FEATURES BUT BOTTOM LINE APPEARS TO HAND THE NORTHEAST ANOTHER
LINGERING CLOSED LOW PUTTING A DAMPER ON WEATHER OVER THE NORTHEAST
EXTENDING INTO THE WEEKEND.

IF THE 12Z GFS VERIFIES...COULD BE A BLUSTERY...COLD AND DAMP WEEKEND.
FOR NOW...LEANING MORE TOWARD THE OPTIMISTIC 00Z ECMWF WHICH LIFTS
THE UPPER LOW OUT A LITTLE QUICKER. THIS WOULD BRING LINGERING
SHOWERS TO AN END BY SATURDAY EVENING WITH IMPROVING BUT CHILLY
CONDITIONS ON SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST.

LOOKING FOR FAIR WEATHER TO CONTINUE ON MONDAY ALONG WITH SLIGHTLY
MODERATING TEMPS AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
WEST.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...IFR OR LOWER TONIGHT IN FOG/DRIZZLE/SHOWERS/LOW
CLOUDS. SOME IMPROVEMENT FOR WEDNESDAY AS WARM FRONT TRIES TO LIFT
NORTHWARD. LOW CONDITIONS LIKELY TO RETURN WEDNESDAY NIGHT.

LONG TERM...VFR THURSDAY WITH MVFR/IFR CEILINGS DEVELOPING
THURSDAY NIGHT AND PERSISTING THROUGH SATURDAY. BECOMING VFR
SATURDAY NIGHT. VFR SUNDAY.

&&

.MARINE...
SHORT TERM...NO FLAGS EXPECTED TONIGHT AND WEDNESDAY...BUT FOG
DRIZZLE AND SHOWERS EXPECTED TO SIGNIFICANTLY REDUCE VSBYS.

LONG TERM...SCA`S LIKELY THURSDAY THROUGH THURSDAY NIGHT.

&&

.FIRE WEATHER...
NO PROBLEMS ANTICIPATED THROUGH THURSDAY.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...JENSENIUS