581
FXUS61 KGYX 180349
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
1049 PM EST TUE DEC 17 2024
SYNOPSIS
HIGH PRESSURE CROSSES NEW ENGLAND THROUGH EARLY WEDNESDAY. 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 AM WEDNESDAY MORNING/
1040 PM UPDATE... CLOUDS ARE CONTINUING TO PROGRESS EASTWARD
OVER THE REGION IN ASSOCIATION A SUBTLE H5 S/WV TROUGH AXIS THAT
IS CURRENTLY LOCATED OVER EASTERN VT. LATEST RADAR IMAGERY SHOWS
SOME WEAK RETURNS OVER THE WESTERN ME MTNS AND THE WHITE MTNS
WITH WEBCAMS SHOWING THAT SOME OF THIS IS MAKING IT TO THE
GROUND AS SPRINKLES AND FLURRIES. WHILE MOST OF THIS WILL REMAIN
ACROSS THE MTNS AND NORTH, SOME COULD SPILL INTO THE FOOTHILLS
OVERNIGHT. OTHER THAN MAKING SOME MINOR ADJUSTMENTS TO
TEMPERATURES AND SKY COVER, THE INHERITED FORECAST REMAINS
LARGELY UNCHANGED.
PREVIOUSLY...
600 PM UPDATE... MINOR CHANGES TO REFLECT LATEST OBSERVATIONAL
TRENDS. CLOUDS ALONG WITH FLURRIES/SPRINKLES CONTINUE ACROSS
THE MTNS AT THIS HOUR WITH MAINLY CLEAR SKIES AND COOLING
TEMPERATURES FURTHER TO THE SOUTH.
PREVIOUSLY...
WEST SOUTHWEST FLOW IS EXPECTED TO CONTINUE THRU THE NIGHT.
UPSLOPE SNOW SHOWERS ARE ALSO EXPECTED TO CONTINUE...BUT FLOW
DIRECTION IS NOT OVERLY FAVORABLE FOR SIGNIFICANT ACTIVITY
AND/OR ACCUMULATION. FROUDE NUMBER IS ALSO FORECAST TO HOVER
RIGHT AROUND 1...SO SNOW SHOWERS SHOULD STAY NEAR HIGH TERRAIN.
I DID INCLUDE SOME FLURRIES INTO THE EVENING FOR ANY SPILLOVER
PRECIP. GRADIENT WINDS WILL KEEP TEMPS MILD FOR DEC
OVERNIGHT...GENERALLY BOTTOMING OUT AROUND FREEZING.
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/
KEY MESSAGE: LIGHT SNOW LIKELY WED NIGHT, LOW CONFIDENCE IN
LOCATIONS WHERE LARGEST ACCUMULATIONS WILL OCCUR.
DETAILS: MUCH OF WED WILL BE QUIET. CAA WILL BRING HIGH TEMPS
DOWN A GOOD 10 TO 15 DEGREES FROM TODAY. UNDER SURFACE RIDGING
WINDS WILL BE LIGHT AND VARIABLE.
ATTENTION IS MOSTLY ON PRECIP MOVING IN WED NIGHT. AN UPPER TROF
WILL BE ROTATING INTO THE REGION...AND THE FORECAST AREA WILL BE
BENEATH THE RIGHT ENTRANCE PORTION OF A STRENGTHENING JET
STREAK. THERE IS A QUICK MOVING BUT DECENT WAA/CAA COUPLET
MOVING THRU THE AREA...AND MID LEVEL FLOW IS LARGELY CONVERGENT
AND FRONTOGENETICAL LOCALLY. ALL OF THIS SUPPORTS AN AREA OF
PRECIP MOVING THRU WED NIGHT...MIRRORING IN THE CONCEPTUAL MODEL
FOR A LATERAL QUASI-STATIONARY BAND ON THE NORTHWEST SIDE OF A
WEAK LOW PRESSURE PASSING INTO THE GULF OF ME. THIS TYPE OF
BANDED PRECIP CAN LEAD TO RATHER LARGE CUTOFF TO QPE ON THE
NORTHWEST SIDE...BUT WITHIN THE BAND CAN BE LOCALLY ENHANCED
RELATIVE TO MODEL FORECASTS. SO AT THIS TIME I HAVE FAIRLY LOW
CONFIDENCE IN PRECIP AMOUNTS...WITH LITTLE WOBBLES IN TRACK OVER
THE NEXT 30 TO 36 HOURS RESULTING IN THAT SHARP QPF GRADIENT
MOVING AROUND.
WHAT I AM GENERALLY MORE CONFIDENT ABOUT IS THAT TEMPS SHOULD
WETBULB DOWN INTO THE LOW TO MID 30S...AND ADDITIONAL PRECIP
LOADING AND MELTING WILL SUPPORT MIN WETBULB TEMPS RIGHT AROUND
32 OR 33 DEGREES. HI-RES GUIDANCE SHOWS THIS WELL AND I TENDED
TO BLEND MORE OF THAT GUIDANCE IN TO REFLECT 2 M TEMP TRENDS. SO
WHILE PRECIP MAY START AS RAIN OR RAIN/SNOW MIXED FOR MANY
LOCATIONS EARLY WED EVENING...SNOW SHOULD MAKE A STEADY MARCH
TOWARDS THE COAST THRU THE OVERNIGHT. BUFKIT FORECAST SOUNDINGS
SUPPORT A COUPLE INCHES EVEN AS FAR SOUTH AND EAST AS PSM AND
PWM. MUCH OF THE LO-RES GUIDANCE HAS TEMPS TOO SMOOTHED AND
WASHED OUT NEAR THE COAST...AND SO IT IS HARD TO GENERATE MUCH
SNOW WITH WETBULB TEMPS TOO WARM. AS A RESULT I HAD TO DO QUITE
A BIT OF MANUAL ADJUSTING TO GET SNOWFALL INTO THE I-95
CORRIDOR. I DO THINK THAT THERE IS A GOOD CHANCE...IF THE STORM
TRACK REMAINS LIKE TODAY...FOR THIS AREA TO SEE LIGHT
ACCUMULATIONS. THE GOOD NEWS IS THAT MUCH OF THE PRECIP SHOULD
BE DONE BY THE THU MORNING COMMUTE...WHICH SHOULD MITIGATE
IMPACTS SOMEWHAT. AS CONFIDENCE GROWS IN LOCATION OF TRACK AND
ATTENDANT FORCING...A SMALL WINTER WEATHER ADVISORY MAY BE
NEEDED FOR SNOWFALL AMOUNTS NEAR 4 INCHES.
LONG TERM /THURSDAY 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 /04Z WEDNESDAY THROUGH SUNDAY/
SHORT TERM...WIDESPREAD VFR CONDITIONS EXPECTED THRU WED.
UPSLOPE SNOW SHOWERS WILL CONTINUE FOR MUCH OF THE NIGHT
TONIGHT...BUT GENERALLY EXPECTED MVFR CIGS TO AVOID HIE. NEXT
STORM APPROACHES WED NIGHT AND WILL OVERSPREAD PRECIP QUICKLY
FROM SOUTHWEST TO NORTHEAST. CONDITIONS WILL QUICKLY DROP TO IFR
OR LOWER...ESPECIALLY AS SN BECOMES THE DOMINANT PRECIP TYPE
AROUND MIDNIGHT. VFR CONDITIONS WILL RETURN QUICKLY EARLY THU AS
WINDS BECOME NORTHWESTERLY AGAIN.
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...WINDS AND SEAS ARE GRADUALLY DIMINISHING BUT SCA
CONDITIONS WILL LINGER OUTSIDE THE BAYS THRU AT LEAST MIDNIGHT.
I HAVE EXTENDED THE SCA THRU THE NEXT FORECAST PACKAGE TO ALLOW
THE MIDNIGHT SHIFT TIME TO MAKE A DECISION ON WHEN TO DROP IT.
NEXT WEAK STORM APPROACHES WED NIGHT...BUT WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW SCA THRESHOLDS.
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 UNTIL 4 AM EST WEDNESDAY FOR ANZ150-152-
154.
NEAR TERM...TUBBS
SHORT TERM...LEGRO
LONG TERM...CLAIR/TUBBS
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