894
FXUS61 KCAR 180236
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
936 PM EST TUE DEC 17 2024
SYNOPSIS
HIGH PRESSURE WILL BUILD SOUTH OF THE AREA TONIGHT. LOW
PRESSURE WILL APPROACH WEDNESDAY AND CROSS THE AREA WEDNESDAY
NIGHT. HIGH PRESSURE WILL APPROACH ON THURSDAY AND CONTINUE TO
BUILD INTO THE AREA THROUGH FRIDAY. LOW PRESSURE WILL PASS SOUTH
OF THE REGION ON SATURDAY, WITH HIGH PRESSURE RETURNING ON
SUNDAY.
NEAR TERM /THROUGH WEDNESDAY/
9:36 PM UPDATE: ADJUSTED WIND GUSTS DOWN TO MATCH CURRENT
OBSERVATIONS. TEMPERATURES ARE DROPPING A LITTLE SLOWER THAN
ORIGINALLY FORECAST, WITH WITH SOME COLD AIR ADVECTING IN BEHIND
THE OCCLUDED FRONT, TEMPERATURES SHOULD STILL REACH LOW-TO-MID
30S TONIGHT. OTHERWISE, FORECAST IS ON TRACK.
PREVIOUS DISCUSSION:
THE EXITING LOW PRESSURE SYSTEM WILL BRING WRAP AROUND MOISTURE
INTO THE REGION FROM THE WEST THIS EVENING AND TONIGHT. WITH
THE AFTERNOON BREAK IN CLOUDS, DAYTIME HEATING WILL FUEL ANY
LINGERING SHOWERS INTO THE REGION. DUE TO THE EARLIER SUNSET,
THESE SHOWERS SHOULD LOSE INSTABILITY AND DISSIPATE BY TONIGHT.
UPPER AIR MODEL SOUNDINGS SHOW THE INVERSION SETTING UP EARLY,
THUS A GRADUAL DECREASE IN W WINDS. WITH CLOUDS CLEARING IN THE
SOUTH, ESPECIALLY ALONG THE COAST, DECIDED TO DECREASE TEMPS
FASTER THAN THE MODELS WERE INDICATING. LOW 30S ACROSS THE
REGION WITH LOWEST TEMPS TOWARDS WEDNESDAY MORNING.
BY WEDNESDAY, THE LOW PRESSURE SYSTEM WILL BEGIN TO APPROACH
FROM THE WEST. THE WINDS WILL DECREASE TO CALM AND SHIFT TO THE
S. WITH THE ONSHORE FLOW AND WARM AIRMASS, TEMPS WILL INCREASE
INTO THE UPPER 30S ACROSS THE REGION, WHILE COASTAL DOWNEAST
WILL SEE LOW 40S. CLOUDS WILL THICKEN THROUGHOUT THE DAY AS THE
INITIAL PRECIP ENTERS FROM THE WEST DURING THE EVENING.
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
A TROUGH OF LOW PRESSURE WILL CROSS THROUGH THE AREA WEDNESDAY
NIGHT INTO EARLY THURSDAY MORNING. THE TROUGH WILL BE FAIRLY
QUICK MOVING, WITH NOT MUCH PRECIPITATION EXPECTED. THE LITTLE
THAT DOES FALL AS SNOW, HOWEVER, COULD APPROACH ADVISORY LEVELS
THROUGH THURSDAY MORNING ALONG A LINE FROM GREENVILLE UP THROUGH
PRESQUE ISLE. TEMPERATURES WILL BE A BATTLE BETWEEN LIGHT
SOUTHERLY WARM AIR ADVECTION AHEAD OF THE TROUGH AXIS AND
EVAPORATIONAL COOLING EARLY ON IN THE EVENT. ENSEMBLE PLOTS
INDICATE THAT TEMPERATURES WILL LIKELY CAVE TO ANY STEADIER
PRECIPITATION RATES, FALLING TO OR JUST BELOW FREEZING INTO
EARLY THURSDAY MORNING. BUT AREAS ALONG THE IMMEDIATE COAST
WHICH SEE LIGHTER PRECIPITATION RATES COULD HAVE A STRONGER
INFLUENCE FROM THE LIGHT WARM AIR ADVECTION AND THIS COULD AID
IN KEEPING THESE AREAS ALL RAIN THROUGH THE EVENT.
THE TROUGH AXIS WILL SLIDE EASTWARD INTO THE DAY ON THURSDAY,
WITH WINDS SHIFTING WESTWARD AS COLD AIR ADVECTION STRENGTHENS
THROUGH THE DAY. THE BREEZY, WESTERLY COLD WINDS OVER THE ST.
LAWRENCE RIVER COULD GENERATE "LAURENTIAN PLUMES:" STREAMS OF
TRAINING SNOW SHOWERS THAT COULD TRACK FROM WEST TO EAST ACROSS
THE NORTHERN HALF OF THE FORECAST AREA THURSDAY AFTERNOON. HIGH
PRESSURE WILL BUILD INTO THE REGION THURSDAY NIGHT THROUGH
FRIDAY, LEADING TO DRIER WEATHER AND LIGHTER WINDS.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
POSSIBLE LIGHT SNOW FRIDAY NIGHT/SATURDAY...
ANOTHER UPPER TROUGH APPROACHES THE REGION FROM THE WEST LATE
FRIDAY. THIS TROUGH HAS MORE AMPLITUDE THAN THE LAST, AND HAS A
GREATER TEMPERATURE GRADIENT TO WORK OVER THE REGION. IT LOOKS
LIKELY THAT SURFACE LOW PRESSURE WILL DEVELOP OFF THE SOUTHEAST
COAST FRIDAY AHEAD OF THE DEEPENING UPPER TROUGH, AND TRACK
NORTHEAST TOWARD NOVA SCOTIA, STRENGTHENING INTO A MODERATELY
STRONG SYSTEM AS IT MOVES TOWARD NOVA SCOTIA. UNCERTAINTY STILL
REMAINS AS TO THE TRACK OF THIS SYSTEM AND THE ENSEMBLES HAVE
YET TO CONVERGE TOWARDS A SOLUTION. THE EPS AND GEPS ENSEMBLES
SHOW A TRACK CLOSER TO THE COAST WHICH COULD RESULT IN SOME
LIGHT SNOW, PARTICULARLY ALONG THE COAST. MEANWHILE, THE GEFS
ENSEMBLE SOLUTIONS REMAIN FARTHER OFF THE COAST WHICH WOULD
LIKELY RESULT IN LITTLE TO NO SNOW FROM THE SYSTEM. KEPT A
CHANCE OF POPS IN THE FORECAST FOR NOW UNTIL MODELS BETTER
CONVERGE ON A SOLUTION.
SUNDAY TO TUESDAY...
LIKELY DRY SUNDAY/MONDAY WITH ARCTIC AIR MOVING IN. HIGHS GENERALLY IN
THE TEENS TO LOW 20S AND LOWS AROUND 0. A FEW PLACES COULD DIP
BELOW 0, ESPECIALLY IF WE GET ANY SNOW FROM THE POTENTIAL
FRIDAY NIGHT/SATURDAY SYSTEM. HEADING TOWARD TUESDAY AND THEN
INTO CHRISTMAS AND BEYOND, THE PATTERN SHIFTS TO ONE WITH
TEMPERATURES LIKELY WARMER THAN AVERAGE, PERHAPS SIGNIFICANTLY
WARMER THAN AVERAGE.
AVIATION /03Z WEDNESDAY THROUGH SUNDAY/
NEAR TERM: MVFR CEILINGS AT TIMES AT THE AROOSTOOK TERMINALS,
MAINLY NORTH OF KHUL THROUGH 06-08Z, OTHERWISE VFR OVERNIGHT
AND WEDNESDAY MORNING. THE NORTHERN TERMINALS LOWER TO MVFR
CIGS BY LATE AFTERNOON WITH THE APPROACHING PRECIP.
WEST/SOUTHWEST WIND 5 TO 10 KNOTS.
SHORT TERM:
WEDNESDAY NIGHT AND THURSDAY...IFR WEDNESDAY NIGHT IN LIGHT SNOW
NORTH AND AND RAIN/SNOW MIX DOWNEAST, THEN IMPROVING TO VFR
DOWNEAST THURSDAY MORNING, AND MVFR OR VFR NORTH. WINDS VARIABLE
AND LIGHT WEDNESDAY NIGHT, BECOMING WNW AT 10 TO 15 KTS GUSTING
TO 20 TO 25 KTS THURSDAY AFTERNOON.
THURSDAY NIGHT AND FRIDAY...MAINLY VFR WITH FAIRLY LIGHT WINDS.
FRIDAY NIGHT - SUNDAY...LIKELY VFR ACROSS ALL TERMINALS, THOUGH
DOWNEAST TERMINALS COULD FALL TO MVFR/IFR SHOULD SNOW SHOWERS
AND LOWER CIGS MOVE ONSHORE FROM A SYSTEM TO THE EAST. N TO NW
WINDS 5 TO 10 KTS POSSIBLY GUSTING TO 20 KTS IN THE AFTERNOONS.
MARINE
NEAR TERM: A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR TONIGHT
FOR ALL WATERS DUE TO HIGH WINDS AND SEAS. BY WEDNESDAY, BOTH
WINDS AND SEAS WILL DECREASE TO BELOW SCA LEVELS.
SHORT TERM: WINDS WILL BEGIN TO INCREASE WEDNESDAY NIGHT INTO
THURSDAY AS A LOW PRESSURE SYSTEM CROSSES THE WATERS, INCREASING
TO 25 TO 30 KTS BY THURSDAY AFTERNOON. SEAS WILL GRADUALLY
RESPOND, REACHING 4 TO 6 FT BY THURSDAY NIGHT. WINDS AND SEAS
WILL QUICKLY DECREASE LATE THURSDAY NIGHT AND INTO FRIDAY,
BEFORE A POTENTIAL FOR GALES THIS WEEKEND WITH THE NEXT STORM.
CAR WATCHES/WARNINGS/ADVISORIES
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR ANZ050-051.
NEAR TERM...BRENNAN/CB/LAFLASH
SHORT TERM...ASTRAUSER
LONG TERM...MELANSON
AVIATION...CB/LAFLASH/ASTRAUSER
MARINE...CB/LAFLASH/ASTRAUSER
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