500
FXUS61 KCAR 202022
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
322 PM EST SAT DEC 20 2025
SYNOPSIS
LOW PRESSURE WILL TRACK NORTH OF THE REGION SUNDAY DRAWING A
COLD FRONT ACROSS THE AREA. HIGH PRESSURE WILL CROSS THE REGION
MONDAY. LOW PRESSURE WILL CROSS THE REGION TUESDAY. HIGH
PRESSURE WILL APPROACH WEDNESDAY, THEN CROSS THE REGION
THURSDAY.
NEAR TERM /THROUGH SUNDAY NIGHT/
* KEY MESSAGES:
1) LIGHT SNOW FOR ALL BUT DOWNEAST TONIGHT. A COUPLE INCHES OF
ACCUMULATION EXPECTED IN THE NORTH.
2) SNOW SQUALLS POSSIBLE SUNDAY, MAINLY OVER NORTHERN AND
CENTRAL MAINE.
WHAT HAS CHANGED:
* DECREASED SNOW ACCUMULATIONS SLIGHTLY FOR TONIGHT OVER
NORTHERN AREAS.
* INCREASED CONFIDENCE IN SNOW SQUALL POTENTIAL
KEY MESSAGE 1:
AS LOW PRESSURE MOVES NORTHWEST OF MAINE TONIGHT, WARM AIR
ADVECTION WILL GENERATE SUFFICIENT LIFT FOR THE DEVELOPMENT OF
LIGHT SNOW OVER NORTHERN MAINE. THE LIGHT SNOW SHOULD BEGIN THIS
EVENING AND SPREAD EAST AND SOUTH, EVENTUALLY EXITING THE
DOWNEAST COAST SHORTLY AFTER DAYBREAK. AS PRECIPITATION REACHES
THE DOWNEAST AREA THE SNOW WILL LIKELY TURN TO RAIN AS THE
SOUTHERLY ONSHORE FLOW WILL RESULT IN ANTI DIURNAL WARMING
OVERNIGHT BRINGING TEMPERATURES INTO THE MID TO UPPER 30S.
CURRENTLY EXPECTING THE GREATEST ACCUMULATIONS OF ABOUT 1 TO 2
INCHES OVER NORTHERN MAINE. THIS IS SLIGHTLY REDUCED FROM
EARLIER IN PART DUE TO THE THINKING THAT GUSTY WINDS OVERNIGHT
WILL LOWER SLRS FROM CRYSTAL BREAKUP.
KEY MESSAGE 2:
AS THE LOW MOVES NORTH OF MAINE EARLY TOMORROW THE COLD FRONT IS
EXPECTED TO PASS THROUGH THE STATE WHICH IS LIKELY TO RESULT IN
THE DEVELOPMENT OF SNOW SHOWERS ALONG THE BOUNDARY. THE NAM AND
GFS MODELED SNOW SQUALL PARAMETER EMPHASIZE THE POTENTIAL FOR
SNOW SHOWERS REACHING SQUALL CRITERIA AND A DEEPER DIVE INTO THE
DYNAMICS SHOW SUFFICIENT MOISTURE, LIFT, AND WINDS IN THE MIXED
LAYER. ONE QUESTION WILL BE HOW MUCH INSTABILITY IS AVAILABLE
TO ANY SNOW SHOWERS. MODELS SHOW SOME RELATIVELY MODEST VALUES
AVAILABLE TO THE FRONT ONCE IT REACHES EASTERN AROOSTOOK AND
DAYTIME HEATING HAS PRIMED THE LOW LEVELS. THUS, THINKING THAT
THE GREATEST SNOW SQUALL RISK WILL BE TOWARDS THE EAST WHERE
SOME INSTABILITY WILL BE ABLE TO DEVELOP BEFORE THE FRONT MOVES
THROUGH AROUND MID DAY. THERE IS STILL POTENTIAL FOR SNOW
SQUALLS ANYWHERE IN NORTHERN AND CENTRAL MAINE AS STRONG WINDS
COULD STILL MAKE IT TO THE SURFACE WITH LITTLE TO NO INSTABILITY AS
LONG AS THE LOW LEVELS REMAIN WELL MIXED. FARTHER SOUTH IN THE
BANGOR AND DOWNEAST REGIONS SOME PRECIPITATION IS POSSIBLE BUT
TEMPERATURES WILL LIKELY BE TOO WARM FOR SNOW.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
SURFACE HIGH PRESSURE BUILDS TOWARD THE REGION MONDAY, WHILE AN
UPPER LEVEL DISTURBANCE CROSSES NORTHERN MAINE. EXPECT PARTLY
SUNNY SKIES NORTH, MOSTLY SUNNY DOWNEAST, MONDAY. HIGH PRESSURE
CROSSES THE REGION MONDAY NIGHT WITH PARTLY CLOUDY/MOSTLY CLEAR
SKIES. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE WEST
LATER TUESDAY, WITH A SECONDARY LOW STARTING TO DEVELOP LATE.
UNCERTAINTY STILL EXISTS REGARDING THE TRACK OF THE APPROACHING
LOW ALONG WITH WHERE AND HOW RAPIDLY THE SECONDARY LOW
DEVELOPS. HOWEVER, THERE HAS BEEN A GENERAL SOUTHWARD TREND
WITH THE DEVELOPING SECONDARY LOW. EXPECT INCREASING CLOUDS
TUESDAY ALONG WITH A CHANCE OF MOSTLY AFTERNOON SNOW. THE
SECONDARY LOW INTENSIFIES WHILE TRACKING SOUTH OF THE GULF OF
MAINE AND SOUTHEAST OF NOVA SCOTIA TUESDAY NIGHT. BASED ON THIS
TREND, SNOW CHANCES HAVE DIMINISHED ACROSS NORTHERN MAINE
TUESDAY NIGHT. SNOW CHANCES DOWNEAST WILL BE DEPENDENT ON WHERE
AND HOW RAPIDLY THE SECONDARY LOW DEVELOPS. TEMPERATURES WILL
BE AT SLIGHTLY BELOW NORMAL LEVELS MONDAY/TUESDAY.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
THE INTENSIFYING OCEAN LOW EXITS SOUTHEAST OF NOVA SCOTIA
WEDNESDAY, WHILE HIGH PRESSURE BUILDS TOWARD THE REGION. COULD
STILL HAVE A CHANCE OF SNOW SHOWERS EARLY WEDNESDAY, WITH
DECREASING AFTERNOON CLOUDS. HIGH PRESSURE CROSSES THE REGION
THURSDAY, WITH LOW PRESSURE POSSIBLY STARTING TO APPROACH LATE.
GENERALLY EXPECT PARTLY SUNNY/MOSTLY CLOUDY SKIES THURSDAY WITH
ONLY A SLIGHT CHANCE OF SNOW SHOWERS. UNCERTAINTY EXISTS WITH
THE TRACK OF THE LOW THURSDAY NIGHT INTO FRIDAY. PRECIPITATION
CHANCE/TYPES/AMOUNTS THURSDAY NIGHT INTO FRIDAY WILL BE
DEPENDENT ON WHERE THIS SYSTEM EVENTUALLY TRACKS. HIGH PRESSURE
SHOULD BUILD TOWARD THE REGION SATURDAY. GENERALLY EXPECT PARTLY
SUNNY/MOSTLY CLOUDY SKIES SATURDAY WITH ONLY A SLIGHT CHANCE/LOW
CHANCE OF SNOW SHOWERS. EXPECT SLIGHTLY BELOW NORMAL LEVEL
TEMPERATURES WEDNESDAY/THURSDAY/SATURDAY, WITH NEAR NORMAL
LEVEL TEMPERATURES FRIDAY.
AVIATION /20Z SATURDAY THROUGH THURSDAY/
NEAR TERM:
NORTHERN TERMINALS...VFR THROUGH EARLY TONIGHT BEFORE
DETERIORATING TO MVFR WITH LIGHT SNOW BY AROUND MIDNIGHT BUT
POSSIBLY EARLIER AT FVE. MVFR CONDITIONS EXPECTED TO PERSIST
THROUGH AROUND MID DAY SUNDAY WITH OCCASIONAL REDUCTIONS IN
VISIBILITY DUE TO SNOW SHOWERS. VFR SUNDAY NIGHT. LLWS TONIGHT
BETWEEN 03Z AND 12Z. W WINDS THIS AFTERNOON BECOME LIGHT AND
VARIABLE THIS EVENING. S WINDS TONIGHT AT 10 TO 15 KTS WITH
GUSTS UP TO 25 KT, BECOMING WESTERLY SUNDAY AFTERNOON AND
NORTHWESTERLY SUNDAY NIGHT.
SOUTHERN TERMINALS...VFR THROUGH SUNDAY NIGHT. A CHANCE OF LIGHT
SHSNRA AT BGR AND -SHRA AT BHB LATE TONIGHT THROUGH EARLY
SUNDAY. VCSH EARLY SUNDAY AFTERNOON. LLWS TONIGHT BETWEEN 03Z
AND 10Z. S WINDS TONIGHT AT 10 TO 15 KTS WITH
GUSTS UP TO 25 KT, BECOMING WESTERLY SUNDAY AFTERNOON AND
NORTHWESTERLY SUNDAY NIGHT.
SHORT TERM:
MONDAY THROUGH MONDAY NIGHT...VFR. NORTHWEST WINDS 10 TO 15
KNOTS WITH GUSTS UP TO 20 TO 25 KNOTS MONDAY. NORTHWEST WINDS 10
TO 15 KNOTS, BECOMING VARIABLE 5 TO 10 KNOTS MONDAY NIGHT.
TUESDAY...VFR EARLY, THEN VFR/MVFR WITH A CHANCE OF SNOW.
VARIABLE WINDS 5 TO 10 KNOTS.
TUESDAY NIGHT...VFR/MVFR NORTH WITH A CHANCE OF SNOW. MVFR/IFR,
OCCASIONAL LIFR, DOWNEAST WITH SNOW LIKELY. VARIABLE WINDS 5 TO
10 KNOTS.
WEDNESDAY...VFR/MVFR. A CHANCE OF SNOW SHOWERS, MOSTLY EARLY.
VARIABLE WINDS 5 TO 10 KNOTS.
WEDNESDAY NIGHT...VFR. VARIABLE WINDS 5 TO 10 KNOTS.
THURSDAY...VFR/MVFR. A SLIGHT CHANCE OF SNOW SHOWERS LATE.
VARIABLE WINDS 5 TO 10 KNOTS.
MARINE
NEAR TERM: WINDS DECREASE BRIEFLY BELOW SMALL CRAFT CRITERIA
LATE THIS AFTERNOON AND EVENING WITH SEAS REMAINING ABOVE
CRITERIA AT 7 TO 10 FT. WINDS INCREASE TO GALES TONIGHT AND
REMAIN ABOVE GALE CRITERIA THROUGH SUNDAY NIGHT. SEAS PEAK AT 10
TO 12 FT TONIGHT BEFORE DECREASING SUNDAY AND SUNDAY NIGHT BUT
REMAINING ABOVE SMALL CRAFT CRITERIA.
SHORT TERM: GALE FORCE WIND GUSTS POSSIBLE EARLY MONDAY. SMALL
CRAFT ADVISORY CONDITIONS LATER MONDAY INTO TUESDAY. GALE FORCE
WIND GUSTS POSSIBLE AGAIN TUESDAY NIGHT INTO WEDNESDAY. SNOW
LIKELY TUESDAY INTO TUESDAY NIGHT. LIGHT FREEZING SPRAY EARLY
MONDAY, THEN AGAIN MONDAY NIGHT.
CAR WATCHES/WARNINGS/ADVISORIES
ME...NONE.
MARINE...GALE WARNING FROM 10 PM THIS EVENING TO 7 AM EST MONDAY
FOR ANZ050>052.
NEAR TERM...SM
SHORT TERM...CN
LONG TERM...CN
AVIATION...SM/CN
MARINE...SM/CN
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