810
FXUS61 KGYX 181509 AAA
AFDGYX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GRAY ME
1009 AM EST WED DEC 18 2024
SYNOPSIS
HIGH PRESSURE EXITS NEW ENGLAND THIS MORNING. A DEVELOPING LOW
PRESSURE CENTER BRINGS A ROUND OF RAIN AND SNOW TO THE AREA
WEDNESDAY NIGHT, WITH COOLER AIR MOVING IN BEHIND THIS SYSTEM BY
THURSDAY NIGHT. A WEAK CLIPPER PASSES THROUGH FRIDAY NIGHT,
WITH ARCTIC AIR MOVING INTO NEW ENGLAND BEHIND THIS SYSTEM FOR
THE WEEKEND THROUGH EARLY NEXT WEEK.
NEAR TERM /UNTIL 6 PM THIS EVENING/
UPDATE...MINOR CHANGES TO REFLECT LATEST OBSERVATIONAL TRENDS.
PREVIOUSLY...SFC RIDGE PASSING TO OUR S THIS MORNING, SHOULD
ALLOW FOR A GENERALLY SUNNY MORNING, BUT SHOULD SEE CIRRUS
THICKEN DURING THE AFTERNOON, ALTHOUGH THE DAY;LIGHT HOURS LOOKS
MOSTLY DRY TODAY. HIGHS RANGE FROM THE MID TO UPPER 30S IN THE
MTNS TO THE LOW TO MID 40S S OF THE MTNS. A FEW SHSN COULD WORK
THEIR WAY INTO THE MTNS LATE THIS AFTERNOON.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/
OVERALL SYNOPTIC FORECAST FOR THIS SYSTEM CONTINUES TO SHOW A
FAST MOVING SYSTEM THAT WILL HAPPEN AFTER SUNSET AND WILL DONE
BEFORE SUNRISE, AS WEAK SFC LOW DEVELOPS NEAR NYC THIS EVENING
AND TRACKS TO NEAR HALIFAX BY THU MORNING. FOR THE MTNS, THE
PRECIP IS EXPECTED TO BE ALL SNOW, ALTHOUGH WARM BOUNDARY LAYER
WILL LIKELY MEAN THE HIGHER TERRAIN WILL SEE THE HIGHS AMOUNT,
WITH THE MORE POPULATED VALLEY AREAS SEEING LOW SNOW RATIOS AND
AMTS MORE ON THE ORDER OF 2-4”. FURTHER S IN THE FOOTHILLS,
EXPECTING SOME SNOW BUT IT’LL PROBABLY CLOSER TO 2” OR LESS IN
THIS AREAS. IT’S THE AREA BETWEEN THE FOOTHILLS AND THE COASTAL
ZONES WHERE THEY REMAINS SOME UNCERTAINTY. THE NBM KEEPS THIS
AREA MOSTLY SNOW-FREE, BUT BOTH THE 00Z EURO AND THE LATEST
HRRR, SUGGEST MORE SNOW, AS WE MAY SEE HIGH ENOUGH SNOWFALL
RATES FOR A COUPLE HOURS TO PRODUCE A FEW INCHES HERE. I HAVE,
SORT OF, SPLIT THE DIFFERENCE AND ENDED UP WITH AN INCH OR LESS
IN THIS AREA, BUT FELT THE NEED TO PUT SOME SNOW GIVEN THE
MODELS, ALTHOUGH TEMPS ARE LIKELY TO BE IN THE MID TO UPPER 30S
BEFORE ANY WET-BULB EFFECT BEGINS, SO THE FORECAST REMAINS
FRAUGHT WITH UNCERTAINTY. THE SNOW WILL START TO WIND FROM W TO
E AFTER MIDNIGHT, AND WILL LIKELY BE DONE BEFORE THE MORNING
COMMUTE, WITH LOWS GENERALLY IN THE UPPER 20S N TO THE LOW TO
MID 30S IN THE S.
THURSDAY WILL SEE THE WINDS PICK UP BEHIND THIS SYSTEM, WITH
COOLING TEMPS AND LOWERING TDS, BUT WILL WILL LIKELY SEE AT
LEAST PARTLY SUNNY SKIES OUTSIDE THE MTNS AND HIGHS IN THE 30S
TO LOW 40S.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
04Z WEDNESDAY LONG TERM FORECAST UPDATE... LITTLE CHANGE IN
LATEST ENSEMBLE AND DETERMINISTIC BASED FORECAST GUIDANCE. A
DISTURBANCE PASSING OFFSHORE ON FRIDAY NIGHT INTO SATURDAY
COMBINED WITH AN APPROACHING ARCTIC FRONT COULD RESULT IN SOME
SNOW SHOWER ACTIVITY WITH PERHAPS SOME LIGHT ACCUMULATIONS IN
SPOTS. AFTER THIS THE MAIN STORY WILL BE AN INTRUSION OF VERY
COLD AIR ALONG WITH GUSTY WINDS.
PREVIOUSLY...
OVERVIEW...
LOW PRESSURE MOVES AWAY BY THURSDAY MORNING. A CLIPPER CROSSES
THE NORTHEAST ON FRIDAY, DEVELOPING INTO A COASTAL STORM AS IT
MOVES AWAY TOWARD ATLANTIC CANADA. ARCTIC AIR POURS IN BEHIND
THIS DEPARTING STORM AS A TROUGH DIGS IN ACROSS NEW ENGLAND.
HIGH PRESSURE AT THE SURFACE SETTLES ACROSS NEW ENGLAND THIS
WEEKEND THROUGH EARLY NEXT WEEK.
DETAILS...
WEDNESDAY NIGHT'S SYSTEM WILL MOVE AWAY ON THURSDAY. TEMPS
REACH INTO THE LOW TO MID 40S SOUTH OF THE MOUNTAINS, BUT BEGIN
TO FALL BY THE EARLY AFTERNOON HOURS. STRENGTHENING
NORTHWESTERLY FLOW BRINGS UPSLOPE SNOW SHOWERS ACROSS THE HIGHER
TERRAIN AND ALONG THE CANADIAN BORDER. A COLDER AIR MASS
CONTINUES TO MOVE IN THROUGH FRIDAY, WITH HIGHS TOPPING OUT IN
THE 20S TO LOW 30S ON FRIDAY.
A CLIPPER SYSTEM WILL MOVE THROUGH THE GREAT LAKES ON FRIDAY,
MOVING INTO NEW ENGLAND FRIDAY NIGHT. WE HAVE BEEN WATCHING THIS
SYSTEM FOR THE POTENTIAL DEVELOPMENT OF A MORE SIGNIFICANT
COASTAL STORM AS IT PHASES WITH A MOISTURE RICH LOW OFF THE EAST
COAST. AT THIS POINT THERE HAS NOT BEEN A TREND TOWARD A
SOLUTION THAT BRINGS A SIGNIFICANT SNOWFALL TO THE REGION
AMONGST THE MODELS. WHILE THIS SCENARIO STILL CAN'T BE RULED
OUT, THERE IS NO INDICATION THAT THE FORECAST IS HEADING IN THIS
DIRECTION. SO AT THIS POINT, IT APPEARS SNOW LOVERS WILL HAVE
TO SETTLE FOR SOME SCATTERED SNOW SHOWER ACTIVITY FRIDAY NIGHT
INTO EARLY SATURDAY AS THE CLIPPER PASSES THROUGH. WITH THE TWO
LOW PRESSURE CENTERS, WE WILL NEED TO WATCH TO SEE IF ANY
INVERTED TROUGH SETUP DEVELOPS AND SERVES TO ENHANCE SOME LIGHT
SNOWFALL AMOUNTS, BUT WE'LL NEED TO WAIT UNTIL WE GET CLOSER TO
THE EVENT TO HAVE A BETTER HANDLE ON THIS SCENARIO.
THE DEVELOPING COASTAL STORM PASSES OUT TO SEA AS IT RAPIDLY
DEEPENS AND BRINGS A SIGNIFICANT STORM TO THE CANADIAN
MARITIMES. ARCTIC AIR POURS SOUTHWARD TO THE WEST OF THIS STORM
INTO NEW ENGLAND, BRINGING COLD CONDITIONS FOR THE WEEKEND AND
EARLY NEXT WEEK. HIGHS IN THE TEENS AND 20S LOOK LIKELY FOR
SATURDAY THROUGH MONDAY, WITH LOWS IN THE SINGLE DIGITS TO BELOW
ZERO. THE BEST CHANCES FOR THE COLDEST READINGS LOOK TO BE ON
SUNDAY NIGHT AND MONDAY NIGHT AS THE HIGH PRESSURE CENTER
SETTLES OVERHEAD.
AVIATION /15Z WEDNESDAY THROUGH SUNDAY/
SHORT TERM...VFR THROUGH THE DAYLIGHT HOURS TODAY, BUT EXPECT
CONDS TO DETERIORATE QUICKLY TO IFR OR LOWER IN SNRA AFTER
SUNSET. THESE CONDITIONS WILL PERSIST THROUGH MUCH OF THE NIGHT,
BUT SHOULD SEE A RETURN TO VFR BY EARLY THU MORNING, ALTHOUGH
KHIE LIKELY TO STAY AT MVFR THROUGH MUCH OF THE DAY WITH SHSN.
LONG TERM...MAINLY VFR CONDITIONS LOOK LIKELY FOR THURSDAY
THROUGH FRIDAY, EXCEPT AT HIE WHERE UPSLOPE MVFR CEILINGS ARE
LIKELY. SOME RESTRICTIONS ARE POSSIBLE FRIDAY AND EARLY SATURDAY
WITH SOME LIGHT SCATTERED SNOW SHOWER ACTIVITY. VFR CONDITIONS
RETURN ON SATURDAY AND PERSIST INTO EARLY NEXT WEEK. NORTHERLY
WIND GUSTS OF AROUND 25KTS ARE LIKELY DURING THE DAYTIME ON
SATURDAY AND SUNDAY.
MARINE
SHORT TERM...HAVE ENDED THE CURRENT SCA S BOTH WINDS/SEAS HAVE
SUBSIDED, BUT ISSUED ANOTHER ONE STARTING EARLY THU MORNING
THROUGH THE DAY ON THU IN NW FLOW BEHIND A COLD FRONT.
LONG TERM...WEST-NORTHWESTERLY WINDS POSSIBLY BRING SOME
MARGINAL SCA CONDITIONS ON THURSDAY BEHIND A PASSING COLD FRONT.
A WEAK LOW CROSSES THE WATERS LATE FRIDAY, DEVELOPING INTO A
STRONG STORM AS IT MOVES INTO ATLANTIC CANADA. BEHIND THIS
SYSTEM, FRESHENING NORTHERLY WINDS LIKELY BRING SCA TO LOW END
GALES FOR SATURDAY AND SUNDAY, ALONG WITH THE CHANCE FOR
FREEZING SPRAY.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 7 PM EST THURSDAY FOR
ANZ150>154.
NEAR TERM...LEGRO
SHORT TERM...CEMPA
LONG TERM...CLAIR/TUBBS
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