676
FXUS61 KCAR 261658
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
1258 PM EDT WED MAR 26 2025
SYNOPSIS
A WEAK AREA OF LOW PRESSURE CROSSES MAINE TODAY, THEN MOVES INTO
THE SOUTHERN MARITIMES TONIGHT. WEAK HIGH PRESSURE BUILDS IN
THURSDAY. A COMPLEX FRONTAL SYSTEM APPROACHES THURSDAY EVENING,
THEN SLOWLY CROSSES THE REGION LATE THURSDAY NIGHT AND FRIDAY
MORNING. HIGH PRESSURE THEN NOSES DOWN FROM CANADA INTO SATURDAY
NIGHT, AS A SERIES OF LOW PRESSURE SYSTEMS TRACK TO THE SOUTH. A
WARM FRONT SLOWLY APPROACHES FROM THE SOUTH ON SUNDAY.
NEAR TERM /THROUGH TONIGHT/
1255 PM UPDATE... AN UPPER LEVEL TROUGH REMAINS IN THE EASTERN
GREAT LAKES REGION AND IS SLOWLY PROPAGATING TOWARDS THE AREA.
EXPECT THE TROUGH TO GENERATE SUFFICIENT INSTABILITY FOR
AFTERNOON SNOW SHOWERS...MOSTLY IN NORTHERN ZONES. HOWEVER, THE
MORE SIGNIFICANT FEATURE IS ENERGY ROUNDING THE BASE OF THE
TROUGH THAT WILL RESULT IN CYCLOGENESIS SOUTH OF THE GULF OF
MAINE THIS AFTERNOON. THIS LOW WILL DEEPEN TONIGHT AND MOVE
SOUTH OF NOVA SCOTIA. AN INVERTED TROUGH EXTENDING WESTWARD FROM
THE LOW TOWARDS MAINE AND THE UPPER TROUGH IS EXPECTED TO
GENERATE LIGHT AMOUNTS OF SNOW TONIGHT...MOST LIKELY FOR
WASHINGTON COUNTY AND SOUTHERN AROOSTOOK COUNTY WHERE 1 TO 2
INCHES ARE POSSIBLE AFTER RAIN CHANGES TO SNOW THIS EVENING. DUE
TO THE WARM BOUNDARY LAYER, MUCH OF THE PRECIP IN WASHINGTON
COUNTY WILL BE IN THE FORM OF RAIN. LATEST ANALYSIS AND
GUIDANCE SHOWS SOMEWHAT GREATER SNOW AMOUNTS EAST OF THE
FORECAST AREA FOR TONIGHT.
PREVIOUS DISCUSSION...
A WEAK UPPER LEVEL SHORTWAVE RIDGE OVER THE AREA WILL BRING
CLOUDS AND SOME BREAKS OF SUNSHINE THIS MORNING. A NEW UPPER
LEVEL TROUGH WILL APPROACH FROM THE WEST THIS AFTERNOON. THIS
UPPER TROUGH WILL PLAY TWO ROLES IN ENHANCING SOME LOCALIZED
AREAS OF PRECIPITATION ACROSS THE AREA THIS AFTERNOON INTO
TONIGHT. THE FIRST WILL BE TO PRODUCE STEEP LAPSE RATES ACROSS
THE AREA, MOSTLY OVER THE WEST AND NORTH, WITH MARGINAL
INSTABILITY UP TO 12K FT WHICH WILL RESULT IN SCATTERED RAIN AND
SNOW SHOWERS. THIS MAY INCLUDE SOME LOCALIZED HEAVIER SNOW AND
GRAUPEL SHOWERS THIS AFTERNOON MAINLY OVER THE HIGHLANDS AND
NORTH. MEANWHILE, THE UPPER TROUGH WILL SUPPORT SURFACE LOW
PRESSURE WELL SOUTHEAST OF THE GULF OF MAINE. AN INVERTED TROUGH
EXTENDING NORTHWEST FROM THIS OFFSHORE LOW WILL REACH INTO THE
DOWNEAST REGION ENHANCING AN AREA OF WET SNOW MAINLY LATE THIS
AFTERNOON INTO THIS EVENING. THE SNOW MAY MIX WITH RAIN THROUGH
MID TO LATE AFTERNOON BEFORE BECOMING ALL SNOW TONIGHT. SNOW
SHOWERS INLAND SHOULD TAPER OFF THIS EVENING. THE SNOW DOWNEAST
SHOULD DIMINISH LATE TONIGHT AS THE OFFSHORE SURFACE LOW LIFTS
NORTH INTO THE MARITIMES.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
A NORTHERN STREAM SHORTWAVE TROUGH EXITS TO THE EAST THURSDAY
MORNING, FOLLOWED BY NORTHERN STREAM RIDGING BUILDING IN
THURSDAY AFTERNOON/EVENING, THEN EXITING TO THE EAST LATE
THURSDAY NIGHT AS A NORTHERN STREAM TROUGH MOVES INTO MAINE BY
FRIDAY MORNING, THEN LIFTS NORTHEAST INTO NEW BRUNSWICK AND FAR
SOUTHEASTERN QUEBEC FRIDAY AFTERNOON.
THESE TWO SYSTEM WILL BRING TWO ROUNDS OF PRECIPITATION, THE
FIRST MAINLY ISOLATED TO SCATTERED SNOW SHOWERS (POSSIBLY MIXED
WITH RAIN SHOWERS ACROSS EASTERN MAINE IN THE AFTERNOON). THE
NEXT BATCH OF PRECIPITATION BEGINS AS ISOLATED TO SCATTERED SNOW
SHOWERS ACROSS MAINLY THE NORTH THURSDAY NIGHT, THEN CONTINUES
INTO FRIDAY ACROSS THE ENTIRE REGION, MIXING WITH OR CHANGING TO
RAIN SHOWERS FROM SOUTHERN AROOSTOOK DOWN INTO THE PENOBSCOT
VALLEY AND DOWNEAST MAINE. PRECIPITATION SHOULD BE LIGHT WITH
LESS THAN 1/10 OF AN INCH OF LIQUID EQUIVALENT AND SNOW
ACCUMULATION OF LESS THAN 1/2 OF AN INCH, MAINLY ON GRASSY OR
UNTREATED SURFACES.
TEMPERATURES THURSDAY THROUGH FRIDAY SHOULD BE WITHIN A FEW
DEGREES OF NORMAL.
WEAK NORTHERN STREAM SHORTWAVE RIDGING QUICKLY CROSSES THE AREA
FOLLOWED BY A WEAK NORTHERN STREAM SHORTWAVE MOVING IN FRIDAY
NIGHT. IT SHOULD BE DRY FRIDAY EVENING, THEN THERE IS THE SLIGHT
CHANCE TO CHANCE OF SOME LIGHT SNOW OVER THE SW 2/3 OF THE CWA
LATE FRIDAY NIGHT, WITH THE BEST CHANCE OVER SOUTHWESTERN
PORTIONS OF THE NORTH WOODS, THE ENTIRE CENTRAL HIGHLANDS AND
BANGOR REGION, AND WESTERN DOWNEAST MAINE. THERE IS A THE
POTENTIAL FOR UP TO AN INCH OF SNOWFALL BY SATURDAY MORNING.
LOWS FRIDAY NIGHT SHOULD BE A FEW DEGREES BELOW NORMAL.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
A WEAK NORTHERN STREAM SHORTWAVE CROSSES THE AREA SATURDAY,
COUPLED WITH SOME WEAK LOW LEVEL WARM ADVECTION SHOULD BRING A
LIGHT SNOW TO MOST OF THE REGION, WITH THE BEST CHANCE FROM
MOUNT KATAHDIN ON SOUTH. THE SNOW COULD POSSIBLY MIX WITH RAIN
ACROSS COASTAL DOWNEAST. SNOWFALL AMOUNTS SHOULD REMAIN BELOW
ADVISORY LEVELS.
NORTHERN STREAM DEEP LAYERED RIDGING THEN BUILDS IN SATURDAY
NIGHT AND EXITS TO THE EAST ON SUNDAY. THIS SHOULD BE SUFFICIENT
TO PUSH MOST IF NOT ALL THE SNOW TO THE SOUTH SATURDAY NIGHT.
THERE THEN IS SOME QUESTION AS TO HOW FAST THE RIDGING EXITS TO
THE EAST SUNDAY, AND HENCE HOW QUICKLY PRECIPITATION RETURNS
FROM S TO N ON SUNDAY AS LOW LEVEL WARM ADVECTION STRENGTHENS
OVER THE REGION. FOR NOW IT APPEARS PRECIPITATION ON SUNDAY
SHOULD BE MAINLY SNOW ACROSS THE NORTH WITH A RAIN/SNOW MIX OVER
DOWNEAST MAINE. IN BETWEEN THERE COULD BE A WINTRY MIX WITH
POSSIBLY SOME FREEZING RAIN, ESPECIALLY OVER THE CENTRAL
HIGHLANDS, WHERE THE STRONGEST COLD AIR DAMMING SIGNAL TYPICALLY
OCCURS.
THE REGION IS UNDER SW FLOW ALOFT SUNDAY NIGHT AND MONDAY WITH
MULTIPLE SHORTWAVES EMBEDDED IN THIS FLOW CROSSING THE REGION.
THESE SHORTWAVES COUPLED WITH CONTINUED STRONG LOW LEVEL WARM
ADVECTION, WILL CONTINUE TO EXPAND THE REGION WITH A WINTRY MIX
SUNDAY NIGHT, WITH SNOW AND FREEZING RAIN (AND POSSIBLY SOME
SLEET - BUT THAT SHOULD BE MORE BRIEF/TRANSITORY SO HAVE LEFT
OUT OF THE FORECAST FOR NOW) ACROSS MOST OF THE FORECAST AREA -
WITH THE POSSIBLE EXCEPTION OF SNOW HOLDING ON OVER PORTIONS OF
THE CROWN OF MAINE AND RAIN NEAR THE IMMEDIATE COAST. THE
PRECIPITATION THEN MIXES WITH AND/OR CHANGES TO ALL RAIN FROM S
TO N DURING THE DAY ON MONDAY - WITH THE BEST CHANCE TO CHANGE
TO ALL RAIN ACROSS DOWNEAST MAINE AND THE BANGOR/PENOBSCOT
REGION.
A NORTHERN SHORTWAVE TROUGH MOVES IN MONDAY NIGHT ALLOWING FOR
ENOUGH COLD AIR TO BUILD BACK IN TO CHANGE THE PERCEPTION BACK
TO SNOW SHOWERS ACROSS THE ENTIRE REGION BEFORE TAPERING OFF
LATE MONDAY NIGHT.
THIS SYSTEM HAS THE POTENTIAL TO BRING A PROLONGED PERIOD OF
WINTRY PRECIPITATION FROM LATE SUNDAY INTO MONDAY, BEFORE THE
MIXING WITH/CHANGING TO RAIN. THERE IS STILL QUITE A BIT OF
UNCERTAINTY OF HOW QUICKLY ANY MIXING WILL OCCUR, AND HOW FAST
PRECIPITATION CHANGES TO ALL RAIN, AND HOW MUCH LIQUID
EQUIVALENT PRECIPITATION WILL FALL. THIS IS IN PART DUE TO
DIFFERENCES IN THE MODELS ON THE EXACT TIMING AND STRENGTH OF
THIS SYSTEM. AS A RESULT IT IS TO SOON TO SPECIFY IMPACTS, AS
THE LONGER THERE IS WINTRY PRECIPITATION, THE MORE DELAYED AND
POSSIBLY LIMITED ANY HYDROLOGIC IMPACTS WOULD BE, INCLUDING THE
MOVEMENT OF CURRENT ICE JAMS, WHERE AS A FASTER MIXING
WITH/CHANGING TO RAIN COULD LEAD TO MORE WIDESPREAD AND POSSIBLY
IMPACTFUL HYDROLOGIC IMPACTS.
FOR NOW IT APPEARS THAT THE STRONGEST WINDS WITH THIS SYSTEM
SHOULD STAY OFFSHORE UNTIL POSSIBLY LATE MONDAY NIGHT - WITH
QUITE A BIT OF UNCERTAINTY IN THE LATTER, AND MORE CERTAINTY IN
THE FORMER.
BOTTOM LINE, THERE WILL BE A PERIOD OF ACTIVE WEATHER FROM LATE
SUNDAY THROUGH MONDAY NIGHT, SO PLEASE CONTINUE TO MONITOR THE
FORECAST FOR CHANGES AND REFINEMENTS WITH FUTURE UPDATES.
THE MAIN NORTHERN STREAM TROUGH AXIS PASSES ON TUESDAY, WITH
GUSTY NW WINDS POSSIBLE ALONG WITH NOTICEABLY COOLER
TEMPERATURES. TUESDAY SHOULD BE DRY THOUGH, OTHER THAN POSSIBLY
SOME LINGERING MORNING SNOW SHOWERS ACROSS DOWNEAST MAINE.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
NEAR TERM: VFR TO MVFR CONDITIONS OVER THE NORTH MAY BRIEFLY
DROP TO IFR AT TIMES THIS MORNING, THEN IMPROVE TO MVFR AND VFR
THIS AFTERNOON INTO TONIGHT EXCEPT LOWER IN ANY SNOW SHOWERS. VFR
CONDITIONS ARE EXPECTED OVER THE SOUTH, POSSIBLY LOWERING TO
MVFR LATE TODAY INTO THIS EVENING IN SOME RAIN AND SNOW. WINDS
LIGHT S TODAY THEN LIGHT NW TONIGHT.
SHORT TERM:
THURSDAY MORNING...MVFR OR LOWER POSSIBLE AT NORTHERN TERMINALS
WITH SNOW SHOWERS AND VFR FOR BGR AND BHB. NW WINDS G15-25KT
POSSIBLE.
THURSDAY AFTERNOON/EVENING...BECOMING VFR THROUGHOUT BY LATE
AFTERNOON. NW WINDS G15KT POSSIBLE.
LATE THURSDAY NIGHT-FRIDAY MORNING...MVFR OR LOWER POSSIBLE.
FRIDAY AFTERNOON/EVENING...BECOMING VFR THROUGHOUT BY LATE
AFTERNOON. W-NW WINDS G15-20KT POSSIBLE.
LATE FRIDAY NIGHT-SATURDAY...IFR OR LOWER PROBABLE, MAINLY S OF
KHUL/MT KATAHDIN.
SATURDAY NIGHT...VFR.
SUNDAY...IFR OR LOWER PROBABLE, DEVELOPING FROM SW TO NW DURING
THE DAY. SE WINDS G15-20KT AND LLWS POSSIBLE - WITH BEST CHANCE
AT COASTAL TERMINALS.
MARINE
NEAR TERM: SEAS ARE SUSTAINED AT 5 TO 6 FT AND EXPECTED TO ONLY
VERY SLOWLY SUBSIDE LATER TODAY SO EXTENDED THE SCA FOR THE
OFFSHORE WATERS INTO LATE AFTERNOON. WINDS WILL BE LIGHT SW
TODAY AND LIGHT W TONIGHT.
SHORT TERM: SCA CONDITIONS POSSIBLE ON THE COASTAL OCEAN WATERS
FROM THURSDAY THROUGH FRIDAY NIGHT, WITH CONDITIONS LIKELY
REMAINING (JUST) BELOW SCA LEVELS ON THE INTRA-COASTAL WATERS
DURING THIS TIME FRAME. ALL WATERS SHOULD BE WELL BELOW SCA
LEVELS FROM SATURDAY-SATURDAY NIGHT. SCA CONDITIONS ARE PROBABLE
ON THE COASTAL OCEAN WATERS AND POSSIBLE ON THE INTRA-COASTAL
WATERS BY LATE SUNDAY.
HYDROLOGY
SEVERAL ICE JAMS REMAIN LOCKED IN PLACE ACROSS NORTHERN
MAINE.
ICE OUT IS ONGOING FOR MANY RIVERS ACROSS THE CROWN OF MAINE.
RIVER ICE IS LEADING TO A LOCALIZED RISK FOR ICE JAM FLOODING
EARLY THIS WEEK.
FLOODING IS ONGOING ON NORTH CARIBOU ROAD AT STRICKLAND ROAD
ALONG THE CARIBOU/FORT FAIRFIELD LINE DUE TO AN ICE JAM. A FLOOD
ADVISORY REMAINS IN EFFECT FOR THIS AREA.
AN ICE JAM REMAINS GROUNDED UPRIVER FROM WASHBURN AT THE
AROOSTOOK RIVER BEND NEAR CASTLE HILL AND WADE. A FLOOD
ADVISORY REMAINS IN EFFECT FOR THIS AREA.
CAR WATCHES/WARNINGS/ADVISORIES
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR ANZ050-
051.
NEAR TERM...BLOOMER
SHORT TERM...MALOIT
LONG TERM...MALOIT
AVIATION...BLOOMER/MALOIT
MARINE...BLOOMER/MALOIT
HYDROLOGY...
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