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000
FXUS61 KCAR 192203
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
603 PM EDT Fri Apr 19 2024

.SYNOPSIS...
An occluded front approaches tonight, crosses the region
Saturday, then exits across the Maritimes Sunday. A strong
cold front crosses the region Sunday night into Monday. High
pressure then builds across the region later Monday into
Tuesday. Low pressure approaches Wednesday.

&&

.NEAR TERM /THROUGH SATURDAY/...
6:03 PM Update: Weak frontal systems will approach the FA
tonight with a warm front late this evening to be followed by a
cold front Saturday morning. Precipitation in the form of
scattered rain showers will develop from the west late this
evening and overnight. A disturbance tracking along the weak
cold front and rounding the base of an upper trough is expected
to develop into an area of steadier rain toward daybreak
Saturday across the southern half of the FA. A mild south flow
combined with increasing clouds tonight will keep lows much
miler than the past couple of nights with most spots tonight
expected to drop into the lower 40s. The ongoing forecast
handles this well with only minor tweaks to account for the
current and expected conditions tonight.

Previous discussion:
Surface/upper level ridging exit across the Maritimes tonight,
with an occluded front approaching the region late. Scattered
showers will occur across the forecast area tonight. The
occlusion will cross the region Saturday. Aloft, an upper trof
approaches with a disturbance rotating through the base of the
trof. Models have been trending toward more pronounced troffing
with a stronger disturbance moving through the trof. This has
led to a more pronounced area of rain, mostly south and east of
a line from Houlton to Dover-Foxcroft, with the greater totals
across Downeast areas. Rain totals diminish rapidly northwest
of that line. The rain will begin to taper to showers later
Saturday. Low temperatures tonight will range from around 40 to
the lower 40s across the forecast area. High temperatures
Saturday will generally range from the upper 40s to lower 50s
with the cooler temperatures occurring with the most persistent
rain.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Saturday Night...
Some showers could persist early in the evening along and south/east
of I-95. However, they will quickly move off to the east leaving
us dry with skies becoming mostly clear. Some slightly cooler
and drier air will be moving in from the west, with a bit of a
westerly breeze persisting through the night.

Sunday...
A strong upper trough with a strong associated surface cold
front will begin approaching us from the northwest on Sunday.
Cold front won`t yet be here by the end of the day, but the
approaching trough should provide enough support for a chance of
showers, mainly over the north. Should be mostly rain, but can`t
rule out some graupel. Highs Sunday generally in the low to mid
50s with a westerly breeze 10-15 mph with higher gusts.

Sunday Night and Monday...
All models/ensembles have latched onto the strong Arctic cold
front for later Sunday night, with an associated strong upper
trough, diving southeast into our area. This is quite a change
in thinking from a couple days ago, when models had it quiet and
mild, but the models shifted hard and now appear locked in. The
strong cold front appears to reach extreme northwest Maine
around midnight, progressing southeast to around Houlton around
dawn. The cold front and cold air push behind the front will be
a lot stronger in the north than Downeast. There is some concern
for snow showers or perhaps snow squalls with and just behind
the cold front. Thankfully, the front will be moving through
around a time of less impact in the north in the pre-dawn hours
mostly. Also, without diurnal heating, the line of snow showers
with the front will probably be weakening as it approaches and
moves through our area. Still, bears close watching. Think that
any snow accumulations should be less than an inch and limited
to areas north of Houlton and Greenville, as there just isn`t
much moisture to work with. Also, any snow we do get could blow
around Monday morning with gusty northwest winds behind the
front gusting 25-35 mph in the north. Temperatures will drop
handily behind the front especially in the north, with readings
in the mid to upper 30s before the front and low to mid 20s
behind the front. Don`t expect much of a warmup Monday
afternoon, with highs only around freezing in the far north. Not
quite as cold Downeast, with highs Monday in the low to mid
40s. Expect post-frontal snow showers Monday morning to be
short-lived, with dry conditions by midday, and clearing skies.
The airmass moving in Monday will be bone-dry, with dewpoints
late Monday around zero in the north and 10 above near the
coast.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Surface high pressure briefly builds in Monday night. If we
decouple, could get quite chilly. Going for lows generally in
the 20s with some teens cooler valleys. Airmass then warms
significantly Tuesday and Tuesday night ahead of the next
approaching system, with the cold airmass retreating to our
north. The next weather system for later Tuesday night through
Thursday is going to be a tough one. We have not only a
deepening trough approaching from the west, but also an upper
low further north that may merge into the approaching upper
trough. If they merge, we could see a strong, cold upper low
park itself over the area. If not, things could be more
progressive and we could get a quick shot of precip with things
then drying out. The predictability is not high with this sort
of setup, and many things could happen. We will very likely get
some precipitation some time late Tuesday night to Thursday,
with progressively colder air and perhaps a changeover to
accumulating snow toward Wednesday night or Thursday. Whether
we change to accumulating snow depends on the position of the
upper low and how long it hangs out over our area.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR conditions expected this evening. MVFR
conditions with scattered showers are then expected after
midnight. MVFR/IFR, occasional LIFR, with rain Saturday. The
lowest ceilings are expected at KBGR and KBHB. South winds 10
to 15 knots with gusts up to around 20 knots tonight.
South/southwest winds 10 to 15 knots with gusts up to around 20
knots Saturday. Southwest low level wind shear later this
evening through early morning.

SHORT TERM:
Saturday Night... MVFR/IFR early Downeast in showers, becoming
VFR areawide by about 3z. W wind 5 kts.

Sunday...Mainly VFR, though brief MVFR in scattered showers
from MLT and GNR north. W wind 10-15 kts with gusts around 20
kts.

Sunday Night...VFR until after 6z in the north, when a cold
front moves in from the NW. This could bring brief MVFR/IFR to
areas from PQI north. Winds will be SW 5-10 kts, shifting to the
NW 10-20 kts with gusts to 30 kts late and in the north behind
the cold front.

Monday...Generally VFR, except local MVFR early mainly N of HUL.
W/NW winds 10-20 kts with gusts 20-30 kts.

Monday Night...VFR with light winds.

Tuesday...VFR with S wind 10-15 kts.

Tuesday Night and Wednesday...Low confidence, but potential for
MVFR/IFR late Tuesday night into Wednesday with rain. Generally
S wind 10-20 kts.

&&

.MARINE...
NEAR TERM: Winds/seas below small craft advisory levels tonight
through Saturday. Increasing shower chances late tonight. Rain
Saturday.

SHORT TERM: Next chance of small craft comes Sunday night and
Monday. Then a likelihood of small craft late Tuesday into
Wednesday.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.

&&

$$


Near Term...Norcross
Short Term...CB/Foisy
Long Term...Foisy
Aviation...Norcross/CB/Foisy
Marine...Norcross/CB/Foisy