408
FXUS61 KCAR 192337
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
637 PM EST THU DEC 19 2024
SYNOPSIS
HIGH PRESSURE WILL CREST NORTH OF THE AREA TONIGHT. LOW PRESSURE
WILL DEVELOP OFF THE MID-ATLANTIC COAST ON FRIDAY AND INTENSIFY
AS IT TRACKS SOUTH OF NOVA SCOTIA FRIDAY NIGHT AND INTO THE
EASTERN MARITIMES ON SATURDAY. HIGH PRESSURE WILL BUILD IN FROM
THE WEST SUNDAY INTO MONDAY. A CLIPPER SYSTEM WILL CROSS THE
AREA ON TUESDAY.
NEAR TERM /THROUGH FRIDAY/
637 PM UPDATE: A FEW SNOW FLURRIES REMAIN ACROSS THE NORTH AND
EAST DUE TO THE CONTINUED NW WINDS PULLING MOISTURE OFF THE ST
LAWRENCE. DUE TO THE LACK OF SUNLIGHT AND DECREASING WINDS, THIS
SNOW WILL CONTINUE TO TAPER OFF THROUGH THE EVENING. CURRENT IR
SATELLITE IMAGERY ALSO INDICATES THAT CLOUD COVER IS BEGINNING
TO DISSIPATE THROUGHOUT THE FORECAST AREA, POTENTIALLY SETTING
UP A STRONG RADIATIONAL COOLING NIGHT, ESPECIALLY COUPLED WITH
THE RECENT NEW SNOW COVER. THE PREVIOUS FORECAST REMAINS ON
TRACK WITH ONLY MINOR ADJUSTMENTS MADE TO ADD FLURRIES INTO THE
FORECAST AND ADJUST TEMPERATURES AND WINDS BASED ON CURRENT
OBSERVATIONS AND TRENDS.
PREVIOUS DISCUSSION:
SCATTERED SNOW SHOWERS HAVE DEVELOPED ALONG AND NORTHWEST TO
SOUTHEAST LINE FROM THE KATAHDIN REGION INTO EASTERN AROOSTOOK
AND NORTHERN WASHINGTON COUNTIES. WEBCAMS SHOW MINOR
ACCUMULATION WHERE THESE SNOW SHOWERS ARE CROSSING INTERSTATE 95
AROUND ISLAND FALLS. THESE SNOW SHOWERS WILL DIMINISH THIS
EVENING AS INSTABILITY DECREASES WITH THE LOSS OF DAYTIME
HEATING. WINDS WILL DIMINISH AS WELL AS HIGH PRESSURE BUILDS IN.
THIS WILL ALLOW FOR SOME RADIATIONAL COOLING. HOWEVER, CLOUDS
ARE FORECAST TO BUILD IN LATER TONIGHT AHEAD OF THE NEXT SYSTEM.
THUS, COOLING POTENTIAL WILL BE LIMITED, WITH THE BEST
POTENTIAL IN THE NORTH WOODS. LOWS TONIGHT WILL BE NEAR OR BELOW
ZERO IN THE NORTH WOODS, WITH MAINLY TEENS ABOVE ZERO
ELSEWHERE.
FRIDAY WILL FEATURE AN UPPER TROUGH MOVING EASTWARD FROM THE
OHIO VALLEY. THIS TROUGH WILL HELP SPAWN A LOW PRESSURE SYSTEM
OFF THE MID-ATLANTIC COAST. NOT EXPECTING PRECIPITATION BEFORE
SUNSET FRIDAY AS THE SYSTEM WILL BE TOO FAR AWAY. IT WILL BE A
COLDER DAY ON FRIDAY. HIGHS WILL LIKELY NOT GET OUT OF THE TEENS
IN THE FAR NORTH, WITH 20S ELSEWHERE.
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/
FRIDAY NIGHT INTO SATURDAY IS A LITTLE BIT OF A TRICKY FORECAST
WITH THE LATEST TRENDS IN OPERATIONAL MODELS FOR SOME OF THE
CWA.
FRIDAY NIGHT A 500MB SHORTWAVE WILL BE ROUNDING THE BASE OF
THE LONG WAVE TROF OVER THE EAST AND TILTING NEGATIVELY. AT THE
SAME TIME THE JET STREAM INCREASES OFF THE MID-ATLANTIC AND LOW
PRESSURE DEEPENS WITH THE UPPER LEVEL DIVERGENCE. EXPECTING THE
LOW TO STAY WELL EAST OF GEORGES BANK AND THE GULF OF MAINE.
HOWEVER, A SECONDARY UPPER LEVEL SHORTWAVE DIVES MORE S-SE INTO
THE MAIN TROF AND WILL PULL THE LOW SLIGHTLY CLOSER TO MAINE.
THIS WILL LIKELY RESULT IN A BAND OF LIGHT SNOW ON THE BACKSIDE
OF THE LOW TO PUSH BACK FROM NEW BRUNSWICK INTO EASTERN MAINE
ALONG THE BORDER. THIS COULD PRODUCE 1-2 INCHES OF FLUFFY SNOW
WITH PERHAPS FAR EASTERN WASHINGTON COUNTY SEEING 2-4 INCHES
MAINLY FROM MACHIAS TO EASTPORT TO CALAIS. OTHERWISE, JUST SNOW
SHOWERS ACROSS THE CWA WITH THE UPPER LEVEL TROF IN THE AREA.
COLD AIR IN PLACE WILL RESULT IN HIGH RATIOS OF 15-20:1 SNOWFALL
SO IT WILL BE VERY FLUFFY. NOW, HOW MUCH WE GET IS HIGHLY
UNCERTAIN GIVEN THE TRACK AND SLIGHT WIGGLES COULD RESULT IN
MORE OR LESS. ENSEMBLES FOR THE MOST PART KEEP ANY SNOWFALL
CONFINED WELL EAST OF I-95 AND CLOSER TO THE NEW BRUNSWICK
BORDER. AS THE LOW DEEPENS NORTH WINDS WILL INCREASE 10-20MPH
WITH GUSTS POTENTIALLY UP TO 30MPH AND MIGHT RESULT IN SOME
BLOWING SNOW SATURDAY. HIGHS ON SATURDAY WILL TOP OUT IN THE 20S
FOR MOST WITH TEENS IN THE NORTH WOODS. ANY STEADY SNOW TAPERS
TO SNOW SHOWERS IN THE AFTERNOON.
SUNDAY WILL FEATURE INCREASING SUNSHINE WITH COLDER AIR WORKING
BACK IN BEHIND THE LOW. NW WINDS WILL BE GUSTY WITH GUSTS
15-25MPH BUT GRADUALLY WEAKENING THROUGH THE DAY AS THE PRESSURE
GRADIENT WEAKENS. TEMPERATURES IN THE SINGLE DIGITS SUNDAY AM
WITH BREEZY WINDS MAY RESULT IN WIND CHILLS 5 TO 15 DEGREES
BELOW ZERO. SUNDAY'S HIGHS WILL BE IN THE TEENS FOR MOST WITH
AROUND 20F AT THE SHORE. WIND CHILLS IN THE SINGLE DIGITS BELOW
ZERO ACROSS THE NORTH AND SINGLE DIGITS ABOVE ZERO ACROSS THE
SOUTH.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
OVERALL LOOKING AT THE TELECONNECTIONS IN THE LONG TERM MAINLY
POSITIVE NAO TRENDING TOWARDS NEUTRAL IN THE LATEST GEFS
ENSEMBLE PLOTS. THE PNA REMAINS POSITIVE SHOWING THE AMPLIFIED
TROF/RIDGE PATTERN OVER THE UNITED STATES WITH MAINLY RIDGING
OUT WEST AND THE 500MB TROF EAST. THIS WILL KEEP THE FLOW MAINLY
COLD AND OUT OF THE NORTHWEST BUT THIS MEANS TYPICALLY A DRY
PATTERN.
SUN NIGHT INTO MON SURFACE HIGH PRESSURE WILL DRIFT OVERHEAD
WITH 925MB TEMPS FALLING TO -13C TO -16C ACROSS THE CWA. NW
WINDS WILL KEEP STIRRING BUT WITH SUCH COLD AIR IN PLACE AND THE
HIGH NEARLY OVERHEAD OPTED TO BLEND IN SOME 25TH PERCENTILE FOR
THE LOWS MON AM. EXPECTING TEMPS TO BOTTOM OUT IN THE SINGLE
DIGITS BELOW ZERO FROM A LINE STRETCHING FROM GREENVILLE TO
BAXTER TO DANFORTH NORTHWARD TO THE ST. JOHN VALLEY. ACROSS THE
REST OF THE CENTRAL HIGHLANDS INCLUDING BANGOR REGION EAST ALONG
ROUTE 9 WILL BE AROUND 0F TO +3F AND DOWN TO 5-10F ALONG THE
DOWNEAST COAST. ANY STIRRING WINDS MAY KEEP TEMPS SLIGHTLY
WARMER BUT RESULT IN WIND CHILLS 5-15 DEGREES BELOW ZERO. HIGH
TEMPERATURES WILL TOP OUT IN THE LOW TO MID TEENS NORTH WITH
UPPER TEENS TO LOW 20S SOUTH. THANKFULLY WESTERLY WINDS WILL BE
ON THE LIGHTER SIDE SO NOT EXPECTING WIND CHILL ISSUES BUT
PERHAPS SOME SINGLE DIGIT WIND CHILLS OVER THE FAR NORTH.
TUE WILL FEATURE AN ALBERTA CLIPPER DIVING SE THROUGH NEW
ENGLAND AND WILL LIKELY KICK OFF SOME SNOW SHOWERS. THERE IS
SOME UNCERTAINTY IN THE MODELING WITH SOME OF THE GLOBAL
ENSEMBLES SUGGESTING DEEPENING UPPER LEVEL TROF BUT REMAINING
POSITIVE AXIS MIGHT BE ABLE TO ENHANCE SNOWFALL WITH PERHAPS
SOME SQUALLS DEPENDING ON HOW MUCH INSTABILITY DEVELOPS. WILL
HAVE TO MONITOR THE TRENDS SINCE THAT IS A TYPICAL TRAVEL DAY
FOR THE CHRISTMAS HOLIDAY. TEMPS START THE MORNING AROUND ZERO
ACROSS THE NORTH, SINGLE DIGITS ABOVE ZERO OVER THE CENTRAL
HIGHLANDS AND UPPER SINGLE DIGITS TO LOW TEENS ALONG THE COAST.
AFTERNOON HIGHS TOP OUT AROUND 20F ACROSS THE NORTH AND MID TO
UPPER 20S FOR THE CENTRAL HIGHLANDS TO THE DOWNEAST COAST.
THINGS GET TRICKY FOR CHRISTMAS DAY INTO THURSDAY ON WHAT
HAPPENS...SOME OF THE GLOBAL MODELS ARE SHOWING STRONG
DETERMINISTIC SIGNALS OF SHARP NEGATIVE NAO WITH A BIG UPPER LOW
DEVELOPING OVER THE MARITIMES ORIGINATING FROM THE CLIPPER
SYSTEM. OTHERS SHOWING IT MORE PROGRESSIVE WHICH IS TYPICAL OF
NEUTRAL NAO BUT GIVEN THE SPREAD IN THE PNA THIS MAKES SENSE.
OVERALL, WHAT THAT MEANS IS THE BLEND IS YOUR FRIEND FOR NOW AND
STICKING WITH NBM GIVES US A CHANCE OF SNOW SHOWERS ON CHRISTMAS
DAY. STARTING OUT IN THE SINGLE DIGITS AND TEENS FROM N TO S
OVER THE CWA AND TOPPING OUT IN THE 20S GIVEN THE WARMER AIR
WORKING INTO THE AREA WITH SOME LOW 30S POSSIBLE FROM BANGOR TO
THE COAST. WILL IT BE A WHITE CHRISTMAS, 1 INCH OF SNOW ON THE
GROUND AT 7AM EST? PROBABLY IN MANY SPOTS BUT NOT EVERYWHERE,
HOWEVER VERY LITTLE SNOW WILL BE ON THE GROUND COMPARED TO OTHER
HISTORICAL YEARS.
A LOT OF SIGNALS POINT TOWARDS A SIGNIFICANT WARM UP HEADING
INTO THE LAST WEEK OF 2024, BUT WILL ADD THE CAVEAT OF IF
STRONG NAO BLOCKING SETS UP AND SHARP RIDGE IN THE WEST IT WILL
BE COLDER. FOR NOW STUCK WITH BLEND AND THAT DOES RESULT IN
TEMPERATURES GETTING TO OR ABOVE FREEZING DURING THE DAYS OUT AT
D7-8.
AVIATION /23Z THURSDAY THROUGH TUESDAY/
NEAR TERM: VFR TONIGHT THROUGH THE DAY ON FRIDAY. SOME SNOW
FLURRIES EARLY THIS EVENING AT EASTERN TERMINALS, BUT VIS IS
LIKELY TO REMAIN VFR. NW WINDS 5 TO 10 KTS WITH GUSTS 20 TO 25
KTS EARLY THIS EVENING WILL DIMINISH BY MIDNIGHT, WITH WINDS
LIGHT AND VARIABLE INTO THE DAY ON FRIDAY.
SHORT TERM: SAT...VFR/MVFR WITH -SHSN OR -SN POSSIBLE
ESPECIALLY AT AROOSTOOK TERMS. N-NNW WINDS 10-15KT WITH GUSTS UP
TO 25KT.
SUN...VFR. NW WINDS 10-15KT WITH GUSTS UP TO 25KT.
MON...VFR. W WIND 5-10KT.
TUE...VFR/MVFR. -SHSN POSSIBLE. WINDS LIGHT AND VARIABLE.
MARINE
NEAR TERM: A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR ALL
WATERS THROUGH MIDNIGHT TONIGHT. WINDS WILL GUST UP TO 30 KTS
ON THE OUTER WATERS AND UP TO 25 KTS ON THE INTRA-COASTAL
WATERS THROUGH EARLY THIS EVENING. SEAS WILL REACH UP TO 5 FEET
ON THE OUTER WATERS THROUGH EARLY THIS EVENING. WINDS AND SEAS
SUBSIDE BELOW SCA CRITERIA LATER TONIGHT AS HIGH PRESSURE
BUILDS IN. CONDITIONS BUILD BACK TOWARDS SCA LEVELS LATE FRIDAY
AS A LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTH.
SHORT TERM: LOW PRESSURE WILL DEEPEN INTO THE MARITIMES SAT AND
INCREASING N-NW WINDS 15-25KT WITH GUSTS UP TO 40KT POSSIBLE
OVER THE OUTER WATERS. LIGHT SNOW WILL BE POTENTIALLY DROPPING
VSBY AT TIMES. HAVE OPTED TO HOIST A GALE WATCH FOR THE OUTER
WATERS LATE FRI NIGHT INTO SAT WITH SCA CONDITIONS LIKELY ON THE
INTRA-COASTAL WATERWAYS. WINDS/SEAS WILL FALL BELOW SCA THROUGH
SUNDAY AND LIKELY REMAIN BELOW SCA THROUGH CHRISTMAS DAY.
CAR WATCHES/WARNINGS/ADVISORIES
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ050>052.
GALE WATCH FROM FRIDAY EVENING THROUGH SATURDAY AFTERNOON FOR
ANZ050-051.
NEAR TERM...ASTRAUSER/CLARK
SHORT TERM...SINKO
LONG TERM...SINKO
AVIATION...ASTRAUSER/CLARK/SINKO
MARINE...ASTRAUSER/CLARK/SINKO
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