539
FXUS61 KCAR 191839
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
239 PM EDT SUN APR 19 2026
WHAT HAS CHANGED
SLOWED END OF CATEGORICAL POPS BASED ON TIMING OF HIGH
RESOLUTION GUIDANCE.
INCREASED POPS ON MONDAY BASED ON A BLEND OF THE HIGH RESOLUTION
MODELS.
KEY MESSAGES
1) RAIN, CHANGING TO SNOW ACROSS THE NORTH BEFORE ENDING INTO
TONIGHT, WITH BLACK ICE POSSIBLE OVERNIGHT/EARLY MONDAY
MORNING. ISOLATED TO SCATTERED SNOW SHOWERS MONDAY, THEN BLACK
ICE POSSIBLE AGAIN MONDAY NIGHT.
2) UNSEASONABLY COOL TEMPERATURES TO START THE WEEK, WITH NO
BIG STORM SYSTEMS EXPECTED THROUGH THE WEEK.
DISCUSSION
KEY MESSAGE 1...
RAIN, CHANGING TO SNOW ACROSS THE NORTH BEFORE ENDING INTO
TONIGHT, WITH BLACK ICE POSSIBLE OVERNIGHT/EARLY MONDAY
MORNING. ISOLATED TO SCATTERED SNOW SHOWERS MONDAY, THEN BLACK
ICE POSSIBLE AGAIN MONDAY NIGHT.
KEY MESSAGE 1 DESCRIPTION...
HAVE LEFT IN A SLIGHT CHANCE FOR THUNDER FOR THIS AFTERNOON ACROSS
PORTIONS OF DOWNEAST MAINE WITH THUNDER OBSERVED OVER COASTAL
SE MAINE ALREADY.
A FULL LATITUDE TROUGH SLOWLY APPROACHES FROM THE WEST THROUGH
MONDAY, WITH ITS AXIS CROSSING THE AREA MONDAY NIGHT. THE REGION
REMAINS UNDER DIFFLUENT FLOW ALOFT INTO THIS EVENING. ALLOWING
FOR CONTINUED LIGHT TO MODERATE RAINFALL. AS THE ASSOCIATED
SURFACE COLD FRONT PUSHES THROUGH THIS AFTERNOON/EARLY THIS
EVENING FROM NW TO SE, THE RAIN WILL MIX WITH, AND ACROSS THE
NORTH CHANGE TO SNOW FROM NW TO SE BEFORE ENDING BY AROUND
MIDNIGHT. ACROSS THE NORTH UP TO AROUND 1" OF SNOW IS POSSIBLE
FOR ELEVATIONS UP TO AROUND 1000 FT, WITH ACCUMULATIONS MAINLY
ON GRASSY SURFACES. AT ELEVATIONS ABOVE 1000 FT ACCUMULATIONS OF
1-3" ARE POSSIBLE ACROSS THE NORTH, WITH UP TO 4-5" POSSIBLE UP
ABOVE 3000 FT.
THERE SHOULD BE A LULL IN THE PRECIPITATION OVERNIGHT, WITH EVEN
POSSIBLY SOME CLEARING. THIS SHOULD ALLOW FOR THE POSSIBLE
FORMATION OF BLACK ICE, AS WINDS SHOULD BE GENERALLY LESS THAN
10KT. LOW LEVEL INSTABILITY INCREASES MONDAY DUE TO STRONG COLD
AIR ADVECTION ON NW FLOW ALOFT SHOULD BRING ISOLATED TO
SCATTERED SHOWERS. INITIALLY OVER THE NORTHWOODS AND CENTRAL
HIGHLANDS, THEN DURING THE AFTERNOON, POSSIBLY DOWN INTO
INTERIOR DOWNEAST MAINE. WHILE FOR THE MOST PART, LITTLE OR NO
ACCUMULATION IS EXPECTED, WITH AROUND 100 J/KG OF CAPE AND LOW
LEVEL LAPSE RATES OF AROUND 7.5-8.5 C/KM - CANNOT RULE SOME
ISOLATED STRONG SNOW SHOWERS. THESE COULD PRODUCE LOCALLY HEAVY
SNOWFALL, REDUCING VISIBILITIES TO UNDER 1 MILE, AND POTENTIALLY
BRINGING A QUICK ACCUMULATION (MOST LIKELY 1" OR LESS) OF SNOW,
EVEN ON ROADWAYS. ANY AREAS WHERE THERE WAS SNOWMELT AFTER
EXPERIENCING A SNOW SHOWER, COULD EXPERIENCE BLACK ICE MONDAY
NIGHT, WITH LOWS WELL INTO THE TEENS ACROSS THE NORTH AND 20S
ELSEWHERE.
KEY MESSAGE 2...UNSEASONABLY COOL TEMPERATURES TO START THE
WEEK, WITH NO BIG STORM SYSTEMS EXPECTED THROUGH THE WEEK.
KEY MESSAGE 2 DESCRIPTION...
AN UPPER LEVEL TROUGH OF UNSEASONABLY COOL AIR WILL DOMINATE
THROUGH MID WEEK. AFTERNOON HIGH TEMPERATURES WILL BE A FEW
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. NIGHTTIME
TEMPERATURES WILL GET BELOW FREEZING FOR MOST AREAS EXCEPT
DOWNEAST. ALTHOUGH A FEW SHOWERS ARE POSSIBLE AT TIMES MID
WEEK, NO BIG STORM SYSTEMS ARE EXPECTED TO AFFECT THE REGION.
MINIMUM AFTERNOON RELATIVE HUMIDITY VALUES ARE EXPECTED TO BE
THE LOWEST ON TUESDAY, GENERALLY RANGING FROM 25 TO 30 PERCENT.
FORTUNATELY, WINDS ARE EXPECTED TO BE ON THE LIGHT SIDE TO HELP
MITIGATE ANY FIRE WEATHER CONCERNS. MINIMUM RELATIVE HUMIDITY
VALUES RETURN TO ABOVE 40 PERCENT THE REST OF THE WEEK.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
MAINLY IFR OR LOWER TO GET STARTED, WITH A FEW POCKETS OF MVFR,
WITH ALL AREAS BECOMING IFR OR LOWER AGAIN THIS AFTERNOON. RAIN
CHANGES TO SNOW ACROSS NORTHERN TERMINALS THIS EVENING BEFORE
THE PRECIPITATION COMES TO AN END. ITS POSSIBLE FOR A COUPLE OF
HOURS OF MODERATE TO MAYBE EVEN HEAVY SNOW AT NORTHERN TERMINALS
THIS EVENING, HOWEVER ONLY CONFIDENT ENOUGH TO PLACE THIS IN A
PROB30 GROUP AT THIS TIME. SOUTHERN TERMINALS MIGHT MIX WITH
SNOW BEFORE ENDING, BUT CURRENTLY NOT CONFIDENT ENOUGH TO
REFLECT IN THE TAF. ALL TERMINALS BECOME VFR LATE TONIGHT/EARLY
MONDAY MORNING. MONDAY SHOULD MAINLY BE VFR, BUT CANNOT RULE OUT
AN ISOLATED SNOW SHOWER AT NORTHERN TERMINALS IN THE LATE
MORNING/EARLY AFTERNOON WITH A VERY LOW CHANCE OF MVFR
CONDITIONS.
WINDS HAVE GONE LIGHT AND VARIABLE KHUL/KBGR/KBHB AND SHOULD
PROBABLY REMAIN SO UNTIL THIS EVENING AT SOUTHERN TERMINALS AND
AROUND MID AFTERNOON AT KHUL. THEN WINDS BECOME NW THROUGHOUT
THIS EVENING AT AROUND 10KT WITH POSSIBLY SOME GUSTS TO 15-20KT
AT THE SOUTHERN TERMINALS AND KFVE. NW WINDS AT UNDER 10KT AT
ALL TERMINALS OVERNIGHT, WITH SOUTHERN TERMINALS PROBABLY
BECOMING LIGHT AND VARIABLE AGAIN. NW WINDS MONDAY G15-20KT
LIKELY FOR ALL BUT KBHB, WHERE CURRENTLY DO NOT HAVE THE
CONFIDENCE TO REFLECT IN THE TAFS.
LATE MONDAY AFTERNOON: MVFR OR LOWER POSSIBLE IN ANY SNOW
SHOWERS, OTHERWISE VFR. NW WINDS G15KT POSSIBLE.
MONDAY NIGHT: VFR. NW-N WINDS G15-20KT POSSIBLE IN THE EVENING.
TUESDAY-TUESDAY NIGHT: VFR. WINDS LIGHT AND VARIABLE.
WEDNESDAY-WEDNESDAY NIGHT: MVFR POSSIBLE IN SCT SHOWERS,
OTHERWISE VFR. S WINDS SHIFTING TO NW AROUND 5 KT.
THURSDAY: MVFR POSSIBLE IN SCT SHOWERS, OTHERWISE VFR. NW WINDS
5 TO 10 KT.
THURSDAY NIGHT-FRIDAY: VFR. N WINDS AROUND 5 KT.
MARINE
GUSTS TO 25 KT NOW EXPECTED ON THE INTRA-COASTAL WATERS
TONIGHT, SO HAVE EXPANDED THE SCA IN EFFECT FOR TONIGHT FOR THE
COASTAL OCEAN WATERS FOR TONIGHT TO INCLUDE THERE. THE COASTAL
AND INTRA-COASTAL WATERS SHOULD THEN EXPERIENCE SUB-SCA
CONDITIONS MONDAY. SCA CONDITIONS ARE THEN POSSIBLE AGAIN ON
THE COASTAL OCEAN WATERS MONDAY NIGHT. THE WATERS FROM 25-60NM
SHOULD EXPERIENCE SUB-GALE CONDITIONS TONIGHT-MONDAY NIGHT.
WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA TUESDAY
THROUGH FRIDAY.
CAR WATCHES/WARNINGS/ADVISORIES
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ050>052.
DISCUSSION...PM/SM/JMM
AVIATION...PM/SM/JMM
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