114
FXUS61 KCAR 221653
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
1253 PM EDT THU APR 22 2021
SYNOPSIS
LOW PRESSURE WILL SLOWLY MOVE NORTHEAST INTO THE NORTHERN
MARITIMES THROUGH TONIGHT. AN UPPER LEVEL DISTURBANCE WILL
REMAIN NEAR THE REGION FRIDAY. HIGH PRESSURE BUILDS INTO THE
REGION SATURDAY, QUICKLY FOLLOWED BY LOW PRESSURE PASSING SOUTH
OF THE AREA LATE SUNDAY INTO MONDAY.
NEAR TERM /THROUGH TONIGHT/
945 AM UPDATE: OUTSIDE OF UPDATING FCST HRLY TEMPS/DWPTS TO AFTN
HI TEMPS FROM TRENDS SEEN IN LATEST SFC OBS, NO SIG CHGS TO THE
FCST THIS UPDATE FROM THE LAST. LATEST RADAR REF IS SHOWING
SOME ENHANCED BANDING XTNDG FROM N CNTRL TO E CNTRL AREAS, BUT
WITH STRONG LATE APR MIDDAY/ERLY AFTN BACKGROUND RADIATION,
MOST ACCUMULATION IS LIKELY OCCURRING IN SHADED NEAR/WITHIN TREE
COVERED GROUND AREAS RATHER THAN ROADWAYS, WHICH MAY ACCUMULATE
A BRIEF SLUSHY ACCUMULATION DURG HEAVIER SN RATES.
CURRENT ENHANCED SN BANDING OVER N AND E CNTRL AREAS WILL
BECOME SCT SN SHWRS AND WILL LIKELY REFORM OVR THE FAR N TNGT.
PREV DISC: THE LOW IS MAKING ITS WAY TO THE NE WITH A STRONG
COLD FRONT BEHIND IT. FOR TODAY, THIS FRONT WILL MOVE OUT OF
MAINE BY THIS MORNING. RECENT 1000-850MB THICKNESS MODELS SHOW
COOLING TEMPS IN AREAS NORTH OF THE CENTRAL HIGHLANDS TO THE LOW
30S WHILE AREAS SOUTH WILL BE IN THE UPPER 30S. THIS WILL KEEP
THE SNOW LINE IN THE NORTH AS THE MOISTURE LINGERS WITH THIS FOR
MOST OF TODAY. THE MAIN CONCERN WILL BE THE SNOW AMOUNTS
PRODUCED. QPF MODEL RUNS AND WPC GUIDANCE HAVE THE MAJORITY OF
THE SNOWFALL IN THE NORTHERN AND WESTERN PARTS OF THE REGION IN
THE FORM OF HEAVY WET SNOW. AS THE DAY PROGRESSES, HIGH-RES
MODELS INDICATE THAT THERE IS A POSSIBILITY OF SOME STRONGER
SNOW BANDS WRAPPING BEHIND THIS SYSTEM, WHICH COULD INCREASE
SNOWFALL AMOUNTS IN THESE AREAS. IN ADDITION, TIGHT PRESSURE
GRADIENTS BEHIND THE SYSTEM WILL BRING GUSTY WNW WINDS ACROSS
THE ENTIRE REGION FOR TODAY INTO TONIGHT.
BY TONIGHT, THE MAJORITY OF THE PRECIP WILL MOVE N WITH THE LOW,
MAKING FOR DRYER CONDITIONS IN THE AREAS S OF THE CENTRAL
HIGHLANDS. NAM, GFS, AND HIGH-RES MODELS ARE IN AGREEMENT THAT
THE REST OF THE REGION SHOULD SEE THE ENDING OF PRECIP AROUND
MIDNIGHT. THOUGH CAN'T RULE OUT A LINGERING SNOW SHOWER IN THE
FAR NORTH AS THE LOW CONTINUES ITS SLOW TREK NE. THE PRESSURE
GRADIENTS WILL CONTINUE TO TIGHTEN, CREATING SOME VERY GUSTY
WINDS AROUND 35 TO 40 MPH. COLD AIR BEHIND THE LOW WILL KEEP
NIGHTTIME TEMPS IN THE UPPER 20S.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
CONDITIONS WILL IMPROVE FRIDAY AS THE SURFACE AND UPPER LEVEL
LOWS CONTINUE TO MOVE NORTHEAST. LINGERING SNOW SHOWERS WILL
BECOME MORE SPORADIC, LIFT NORTH, AND MIX WITH RAIN THROUGHOUT
THE DAY. A BRISK NORTHWEST WIND IS EXPECTED WITH FREQUENT GUSTS
OF 35 TO 40MPH AND PEAK GUSTS AROUND 45 TO 50MPH, FALLING JUST
SHY OF ADVISORY CRITERIA BASED ON CURRENT DATA. DUE TO THE
INCREASED LOAD OF HEAVY, WET SNOW, THESE WINDS COULD LEAD TO
TREE DAMAGE ACROSS NORTHERN MAINE. LESSER IMPACTS ARE EXPECTED
ELSEWHERE. SKIES WILL CLEAR ACROSS THE SOUTHWESTERN HALF OF THE
FORECAST AREA BY THE AFTERNOON, WITH LINGERING CLOUD COVER
ACROSS THE NORTHEAST KEEPING HIGH TEMPERATURES IN THE 40S. SKIES
CLEAR ACROSS ALL BUT THE FAR NORTHEAST FRIDAY NIGHT AND WINDS
DECREASE, BUT A MODEST PRESSURE GRADIENT WILL MAINTAIN ENOUGH OF
A BREEZE TO PREVENT DECOUPLING AND KEEP LOWS FROM FALLING BELOW
THE 30S EXCEPT IN THE COLDEST SHELTERED LOCATIONS OF NORTHERN
MAINE.
RIDGING BUILDS ACROSS THE AREA FOR SATURDAY WITH PARTLY TO
MOSTLY SUNNY SKIES AND HIGH TEMPERATURES RANGING FROM THE MID TO
UPPER 60S DOWNEAST TO MID 50S ACROSS THE NORTH. WINDS WILL BE
GUSTY BUT NOT AS STRONG AS THE PREVIOUS DAYS. RELATIVE HUMIDITY
WILL DROP BELOW 30 PERCENT DOWNEAST, WHICH COULD LEAD TO FIRE
WEATHER CONCERNS FOR FINER FUELS THAT DRY OUT QUICKLY AFTER THE
RECENT RAINS. INCREASING CLOUDS ARE EXPECTED OVERNIGHT WITH
LIGHTER WINDS. DEPENDING ON TIMING AND THICKNESS OF CLOUD COVER,
TEMPERATURES SHOULD BE ABLE TO COOL RELATIVELY EFFICIENTLY WITH
LOWS RANGING FROM THE 20S ACROSS THE NORTH TO LOW 40S DOWNEAST.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
CONDITIONS TURN INCREASINGLY UNSETTLED ON SUNDAY AS A COUPLE
SHORTWAVE TROUGHS APPROACH THE AREA, ONE ALONG THE NORTHERN
BRANCH OF THE JET STREAM AND ONE ALONG THE SOUTHERN STREAM. LOW
PRESSURE WILL DEVELOP OFF THE COAST WITH MOST GUIDANCE TAKING IT
CLOSE ENOUGH FOR A SIGNIFICANT RAINFALL ACROSS THE AREA.
HOWEVER, THERE ARE STILL SEVERAL ENSEMBLE MEMBERS AND
DETERMINISTIC MODELS SUCH AS THE ICON AND CANADIAN THAT TAKE THE
SYSTEM FAR ENOUGH OFFSHORE TO KEEP THE AREA DRY. WHILE THEY ARE
OUTLIERS, THEY DECREASE CONFIDENCE ENOUGH TO LIMIT POPS TO
LIKELY INSTEAD OF CATEGORICAL. A MILD AIR MASS WILL BE IN
PLACE, SO A MAINLY RAIN EVENT IS EXPECTED. HOWEVER, SOME MIXING
REMAINS POSSIBLE OVER FAR NORTHWESTERN AREAS DEPENDING ON THE
LOW TRACK AND TIMING OF PHASING BETWEEN THE AFOREMENTIONED
SHORTWAVES. UPSTREAM BLOCKING WILL STRENGTHEN AS A NEGATIVE NAO
FORMS, SO THE SYSTEM IS EXPECTED TO MOVE SLOWLY WITH SHOWERS AND
SEASONABLY COOL TEMPERATURES LINGERING INTO MONDAY. DRIER
CONDITIONS AND A WARMING TREND CAN THEN BE EXPECTED TOWARDS MID-
WEEK AS RIDGING BUILDS BACK INTO THE REGION.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
NEAR TERM: IFR VSBY/CIGS WITH THE CONTINUING SNOWFALL. ALL
TERMINALS ARE EXPECTED TO IMPROVE TO MVFR BY THIS AFTERNOON AND
VFR TONIGHT AS THE SNOW MOVES NORTH. WNW WINDS WILL BE BREEZY
WITH GUSTS AROUND 25 TO 30 KT. LLWS AT NORTHERN TERMINALS
TONIGHT.
SHORT TERM: FRIDAY...MVFR/TEMPO IFR VSBY/CIGS ACROSS THE NORTH.
VFR DOWNEAST. WINDS W 10-20KTS WITH GUSTS UP TO 40KTS.
FRI NIGHT-SAT NIGHT...VFR ACROSS ALL TERMINALS. WINDS W 10KTS
SHIFTING S AND BECOMING LIGHT SATURDAY NIGHT.
SUN-MON...BECOMING MVFR/IFR IN RAIN. WINDS S 5-15KTS SHIFTING N
AND INCREASING TO 15-25 KTS WITH GUSTS TO 40 KTS MONDAY.
MARINE
NEAR TERM: INCREASING WNW WINDS AND HIGH SEAS 7 TO 12 FEET ARE
EXPECTED THIS MORNING THROUGH TONIGHT. A GALE WARNING IS STILL
IN EFFECT FOR THIS TIME.
SHORT TERM: A STRONG GALE WILL BE ONGOING FRIDAY MORNING. WINDS
AND SEAS WILL GRADUALLY SUBSIDE TOWARDS SCA LEVELS BY FRIDAY
EVENING. SCA CONDITIONS WILL PERSIST THROUGH SATURDAY BEFORE
FALLING BELOW SCA SATURDAY NIGHT INTO SUNDAY. WINDS AND SEAS
INCREASE AGAIN SUNDAY NIGHT INTO MONDAY. GALES ARE POSSIBLE
DURING THIS PERIOD DEPENDING UPON THE TRACK OF AN AREA OF LOW
PRESSURE.
CAR WATCHES/WARNINGS/ADVISORIES
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR
MEZ003-004-010.
WINTER WEATHER ADVISORY UNTIL 4 AM EDT FRIDAY FOR MEZ001.
MARINE...GALE WARNING UNTIL 4 PM EDT FRIDAY FOR ANZ050>052.
NEAR TERM...VJN
SHORT TERM...MSTRAUSER
LONG TERM...MSTRAUSER
AVIATION...VJN/MSTRAUSER
MARINE...VJN/MSTRAUSER
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