677
FXUS61 KGYX 152021
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
321 PM EST SUN DEC 15 2024
SYNOPSIS
HIGH PRESSURE MOVES EAST OF NEW ENGLAND OVERNIGHT, WITH A WEAK
WARM FRONT CROSSING OVERNIGHT. A COLD FRONT APPROACHES ON
MONDAY, AND CROSSES NEW ENGLAND MONDAY NIGHT. DURING THE LATTER
HALF OF THE WORK WEEK A STRONGER STORM SYSTEM IS POSSIBLE WITH
THE CHANCE FOR SOME SNOWFALL. A COLDER AIR MASS RETURNS BY NEXT
WEEKEND.
NEAR TERM /THROUGH TONIGHT/
HIGH CLOUDS GRADUALLY FILTER IN THROUGH THE EVENING AS HIGH
PRESSURE SLIPS OFF TO THE EAST. A WEAKENING WARM FRONT
APPROACHING FROM THE SOUTHWEST BRINGS A PUSH OF WAA ALOFT
OVERNIGHT, BRINGING THE CHANCE FOR SOME PERIODS OF LIGHT SNOW OR
FLURRIES TO SOUTHWESTERN AREAS. ANY SNOW WOULD BE VERY LIGHT AS
THE MOISTURE HAS TO OVERCOME THE DRY AIR IN PLACE.
ADDITIONALLY, THE WEAKENING PUSH OF THE WAA MAKES LITTLE
PROGRESS PAST SOUTHERN AREAS, KEEPING THE CHANCE OF FLAKES TO
MAINLY SOUTHWEST AND SOUTHERN NH. A DUSTING CAN'T BE RULED OUT,
BUT EVEN THIS WOULD BE AN ACHIEVEMENT IN THE FACE OF ALL THE
DRY AIR PRESENT.
ELSEWHERE, CLOUDS INCREASE OVERNIGHT AND MOSTLY HOLD
TEMPERATURES STEADY AFTER COOLING OFF THROUGH THE EVENING. LOWS
DROP INTO THE TEENS AND 20S ACROSS THE AREA, WITH THE COOLEST
READINGS FOUND IN THE NORTHERN VALLEYS. TEMPS LIKELY START TO
CREEP UP AFTER MIDNIGHT ALONG THE COAST AS A WEAK SOUTHERLY FLOW
DEVELOPS.
SHORT TERM /MONDAY THROUGH MONDAY NIGHT/
LOW PRESSURE TRACKING NORTH OF THE GREAT LAKES BRINGS AN
INCREASING SOUTHERLY FLOW INTO THE NORTHEAST TOMORROW. HOWEVER,
DEPARTING HIGH PRESSURE LEAVES A COOL AND DRY AIRMASS IN PLACE
ACROSS NEW ENGLAND, LEAVING BEHIND A CAD TEMPERATURE SIGNATURE
ACROSS THE AREA. ALTHOUGH THE COOL AIR WILL GRADUALLY RETREAT
LATE TOMORROW AND TOMORROW NIGHT, THESE SET UPS CONSISTENTLY
RESULT IN MORE DELAYED WARMING THAN THE GUIDANCE SHOWS, WITH
THIS LIKELY TO BE ANOTHER SUCH OCCURRENCE. WITH THIS IN MIND,
TEMPERATURES FOR TOMORROW AND TOMORROW NIGHT WERE BROUGHT DOWN
WITH COOLER HIGH RES GUIDANCE, AND COOLED A BIT MORE AS NEEDED.
THIS RESULTS IN HIGHS MOSTLY IN THE 30S FOR THE DAY TOMORROW
WITH MORE CLOUDS TO THE SOUTH, AND MORE SUN TO THE NORTH.
BY TOMORROW NIGHT, MOISTURE BEGINS TO INCREASE AS THE LOW
TRACKS WELL NORTH OF NEW ENGLAND, AND THE ASSOCIATED COLD FRONT
APPROACHES FROM THE WEST. THE LINGERING CAD LIKELY HAS ENOUGH
TIME TO ERODE ALONG THE COASTAL PLAIN BEFORE THE PRECIPITATION
ARRIVES, WITH TEMPS LIKELY WARMING THROUGH THE NIGHT IN THESE
AREAS. ACROSS THE INTERIOR AND THE NORTHERN VALLEYS,
TEMPERATURES LIKELY START AT OR BELOW FREEZING WITH THE PRECIP'S
ARRIVAL. WITH WARM TEMPERATURES ALOFT, ANY SNOW FLAKES QUICKLY
TRANSITION TO A PERIOD OF FREEZING RAIN BEFORE TEMPS WARM TO
FREEZING OVERNIGHT. ICING LOOKS TO REMAIN LIMITED, WITH LESS THE
A TENTH OF AN INCH EXPECTED IN THE AREAS THAT DO SEE FREEZING
RAIN. THE MOUNTAINS AND HILLTOPS COULD SEE A LITTLE BIT MORE ICE
ACCRETION, BUT THIS WOULD REMAIN VERY LOCALIZED IN COVERAGE.
TEMPS WARM TO AT LEAST FREEZING ACROSS THE INTERIOR OVERNIGHT,
WITH RAIN TO END THE EVENT ACROSS THE FORECAST AREA. QPF AMOUNTS
OF GENERALLY 0.25-0.50 INCH ARE EXPECTED, WITH SLIGHTLY HIGHER
AMOUNTS THROUGH THE WHITE MOUNTAINS. THE BULK OF THE RAIN WILL
EXIT EASTERN AREAS BY DAYBREAK ON TUESDAY.
ADDITIONALLY, A PERIOD OF BREEZY CONDITIONS ALONG THE COAST IS
LIKELY WITH SOUTHERLY WIND GUSTS UP TO 30-40 MPH. THESE DIE OFF
WITH THE PASSAGE OF THE COLD FRONT TUESDAY MORNING.
LONG TERM /TUESDAY THROUGH SATURDAY/
KEY MESSAGES: WINTRY PRECIP POSSIBLE WED NIGHT INTO EARLY THU.
IT WILL DEPEND ON TRACK/TIMING...BUT SOME SNOW/MIX IS LOOKING
MORE LIKELY IN THE MTNS. THE COAST AND SOUTHERN NH IS MORE OF A
TOSS UP BETWEEN ALL RAIN AND SNOW/MIX.
OVERVIEW: GRADUAL BUILDING OF A WESTERN CONUS RIDGE WILL SUPPORT
A DEEPENING EAST COAST TROF THRU THE END OF THE PERIOD. THE TROF
WILL BE CARVED OUT BY SEVERAL S/WV TROFS THAT WILL BRING AT
LEAST A COUPLE CHANCES OF WINTRY PRECIP TO PARTS OF THE FORECAST
AREA THRU THE WEEKEND.
DETAILS: COLD FRONT/OCCLUSION WILL SWEEP THRU EARLY TUE AND
BRING AN END TO STEADY RAIN. TEMPS ARE A BIT TRICKY...AS THERE
WILL LIKELY BE SOME IN SITU COLD AIR DAMMING. HOWEVER THE FRONT
ITSELF MAY BRIEFLY MIX THINGS OUT AND TEMPS COULD SPIKE FOR AN
HOUR OR TWO BEFORE COLD ADVECTION KICKS IN. OVERALL I LEANED
COLDER ON HOURLY TEMPS...WITH A HIGH TEMP GRID SEVERAL DEGREES
WARMER TO COVER THE POTENTIAL SPIKE. DESPITE THE COLD AIR
DAMMING THOUGH THE PTYPE SHOULD BE MAINLY RAIN EXCEPT FOR THE
HIGHEST PEAKS.
THERE WILL BE A BREAK WED. HIGH PRESSURE WILL NOT QUITE BUILD
IN...BUT SURFACE RIDGING DOES BRIEFLY NOSE NORTHWARD INTO NEW
ENGLAND. THE NEXT WAVE WILL BE CLOSE ON ITS HEELS. THIS NORTHERN
STREAM S/WV TROF WILL APPROACH THE SURFACE BAROCLINIC ZONE AND
PRECIP SHOULD BEGIN TO BLOSSOM ALONG THAT BOUNDARY. ON THE
POLEWARD SIDE OF OF THE FRONT CONDITIONS LOOK FAVORABLE FOR AT
LEAST SOME LIGHT SNOW. ENSEMBLE GUIDANCE OVERWHELMINGLY FAVORS
SNOW ACCUMULATIONS IN THE MTNS. CLOSER TO THE COAST AND ACROSS
SOUTHERN NH THE ENSEMBLE MEMBERS ARE SPLIT CLOSER TO 50/50...AND
SOME OF THOSE SNOW MEMBERS TRANSITION TO RAIN AS WELL. HOWEVER
THIS TYPE OF EVENT WILL BE THREADING A NEEDLE...AND SMALL MOVES
IN SYNOPTIC FEATURES CAN LEAD TO LARGE CHANGES IN SENSIBLE
WEATHER AT THE SURFACE. SO ANY FORECAST IS FAIRLY LOW CONFIDENCE
AT THIS POINT.
THIS IS ESPECIALLY TRUE AS MODEL GUIDANCE HAS BEEN TRENDING AWAY
FROM A LARGER PHASED STORM SYSTEM AND TOWARDS TWO SEPARATE
EVENTS INCLUDING THIS EARLY THU EVENT AND ANOTHER SAT.
AVIATION /20Z SUNDAY THROUGH FRIDAY/
SHORT TERM...VFR CONDITIONS PREVAIL THROUGH MOST OF TONIGHT,
WITH MVFR CEILINGS ARRIVING TOMORROW MORNING. VFR CEILINGS
LIKELY RETURN FOR A PERIOD TO NORTHERN TERMINALS TOMORROW
AFTERNOON, WITH MVFR AND IFR CEILINGS ARRIVING THROUGH MONDAY
EVENING. IFR TO LIFR CEILINGS AND RAIN ARE EXPECTED TOMORROW
NIGHT, WITH VFR RETURNING TUESDAY MORNING TOWARD DAYBREAK.
SOUTHERLY WIND GUSTS OF AROUND 25-30KT ARE LIKELY ALONG COASTAL
TERMINALS TOMORROW NIGHT.
LONG TERM...WIDESPREAD IFR OR LOWER CONDITIONS CONTINUE AHEAD OF
THE COLD FRONT EARLY TUE. BY THIS TIME ALL PRECIP SHOULD BE RA.
LLWS IS POSSIBLE FOR COASTAL TERMINALS. ONCE THE FRONT CROSSES
CONDITIONS WILL QUICKLY IMPROVE TO VFR AND LLWS WILL COME TO AN
END. UPSLOPE MVFR CIGS MAY LINGER AROUND HIE INTO THE AFTERNOON.
THERE WILL BE ADDITIONAL CHANCES FOR PRECIP TO END THE
WEEK...AS EARLY AS THU. AREAS OF IFR CONDITIONS ARE
POSSIBLE...BUT PRECIP TYPE IS LOW CONFIDENCE AT THIS RANGE.
MARINE
SHORT TERM...HIGH PRESSURE CONTINUES TO MOVE EAST OF THE
WATERS, WITH A WEAK WARM FRONT PASSING THROUGH OVERNIGHT. A COLD
FRONT THEN APPROACHES FROM THE WEST TOMORROW, AND CROSSES THE
WATERS LATE TOMORROW NIGHT. A PERIOD OF SCA CONDITIONS ARE
LIKELY TOMORROW NIGHT WITH SOUTHERLY WINDS, AND SOME LOW END
GALES ARE POSSIBLE, ESPECIALLY ACROSS THE EASTERN WATERS. WINDS
THEN SHIFT TO WEST-SOUTHWESTERLY BY DAYBREAK ON TUESDAY WITH THE
PASSAGE OF THE FRONT.
LONG TERM...EARLY TUE A LLJ WILL BE LIFTING ACROSS THE WATERS
AHEAD OF AN APPROACHING COLD FRONT. FORECAST SOUNDINGS INDICATE
THAT THERE IS SOME POTENTIAL FOR 35 KT GUSTS TO MIX DOWN OUTSIDE
OF THE BAYS. IT WILL BE A BRIEF WINDOW...AROUND 3 HR...BUT GALE
CONDITIONS ARE POSSIBLE. WINDS AND SEAS DIMINISH BUT SCA
CONDITIONS LINGER INTO EARLY WED. WINDS AND SEAS WILL REMAIN
NEAR MARGINAL SCA CONDITIONS THRU THE END OF THE WEEK AS A
SERIES OF SYSTEM APPROACH AND PASS NEAR THE GULF OF ME.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...NONE.
NEAR TERM...CLAIR
SHORT TERM...CLAIR
LONG TERM...LEGRO
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