Area Forecast Discussion Issued by NWS Caribou, ME
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000
FXUS61 KCAR 060105
AFDCAR
Area Forecast Discussion
National Weather Service Caribou ME
905 PM EDT Mon Jun 5 2023
.SYNOPSIS...
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Low pressure south of Nova Scotia will slowly move northward
overnight and will gradually move north into the Maritimes
Tuesday. The low will remain stalled over the Maritimes through
Friday and move east of the region Saturday.-- End Changed Discussion --
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.NEAR TERM /THROUGH TUESDAY/...
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9:05 PM Update: The forecast remains on track with only minor
adjustments to account for the current and expected conditions
for the remainder of the night. The water vapor satellite
channel shows a mid level circulation to the south of Nova
Scotia that will lift north overnight. Area radars and
observations indicate manly dry conditions as of 9 PM with a bit
of light rain in spots across the North Woods and an isolated
shower in spots Downeast. The main area of rain is moving out of
Nova Scotia and into eastern New Brunswick. The rain will
continue to back toward eastern Maine overnight.
Previous discussion:
The vertically stacked low pressure south of Nova Scotia will
deepen tonight into early Tuesday as it drifts northward into
Nova Scotia. Blocking will prevent much movement of this system
and the entire closed low circulation will become much broader
tonight into Tuesday as a powerful upper jet moves southward on
the backside of the upper trough.
A shortwave rotating around the low was responsible for the
band of rain that lifted north across the area today and is
currently weakening/stalling in Aroostook County. This band
should dissipate in place this evening as upper level support
disappears.
A strong shortwave is currently rounding the base of the
offshore low with deep Atlantic moisture and strong lift moving
into western Nova Scotia. While some models such as the HRRR
suggest the southeastern corner of Washington County could be
clipped by this heavier precip, will go with a maximum of one
half inch tonight near Lubec and Eastport...and much less
further inland. As the cut-off low lifts north into Nova
Scotia, this moisture will eventually wrap cyclonically around
the closed circulation and approach the rest of eastern Maine
from the east after midnight. This wrap-around occlusion will
cause rain across the area all of Tuesday.
Although there is decent moisture transport westward into the
area on Tuesday, helped by an emerging H850 jet, lift will be
weak and PWs will be less than an inch. Therefore, QPF tonight
into Tuesday will be limited to between a quarter inch to one
half inch...in spite of somewhat continuous rainfall on
Tuesday.
The tight pressure gradient will lead to fairly gusty northerly
winds, but a low mixing depth and extensive cloud cover will
keep gusts maxed out around 25 mph.
The clouds, rain and cool air aloft will produce another day
with high temps limited to the low to mid 50s...only several
degrees above record low high temps and some 15 to 20 degrees
below normal readings.-- End Changed Discussion --
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.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Vertically stacked low pressure trough remains centered over
eastern Maine into the Canadian Maritimes through the mid-week
time period. This will persist the cool, cloudy, rainy pattern
that we have seen across the forecast area over the next several
days. With the blocking pattern in place, there is good model
consistency in this pattern remaining in place through the short
term.
Wednesday will be cool with highs in the lower 50s across the
north. Northwest to north winds will descend from the higher
terrain across the north into the lower terrain Downeast, and
this downsloping will help Downeast areas remain a bit milder
with highs in the upper 50s. Flow will shift more northerly
across the forecast area on Thursday, though more breaks in the
clouds are likely as the low begins to weaken overhead, so
temperatures will be warmer on Thursday with highs in the mid to
upper 50s across the north and around 60 Downeast. Low
temperatures each night will fall into the 40s and overcast
skies and lingering rain will limit how far temperatures fall,
limiting the threat for frost.
Downsloping will lead to a lesser chance of precip Downeast
through midweek as the air mass dries over higher terrain, with
a greater chance of consistent light to moderate rainfall over
the northern half of the forecast area. That said, enough mid
level moisture will fill this low pressure system such that rain
is expected to continue Downeast, just in lesser amounts than
across the north.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The trough of low pressure will begin to slowly break down and
exit the region through the end of the weak, allowing for a
narrow ridge of high pressure to build in across northern and
eastern Maine by Saturday, lasting through the weekend. Under
the high pressure, though there remains a chance for rain
showers each day (mostly diurnally driven), partly cloudy skies
will return and temperatures will lift back into the 70s for
daily highs across the forecast area.
Unfortunately, the warmer and quieter weather pattern under the
ridge of high pressure will not last long, as another low
pressure system approaches from the west. Better model
agreement now exists on the front for Sunday night into Monday
among the global models. This front will bring another round of
rain through the entire forecast area.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
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NEAR TERM: Generally MVFR ceilings this evening, although VFR at
times north of KHUL. The trend will be towards IFR cigs for all
sites later tonight through Tuesday. Ceilings may lift a bit to
low end MVFR later in the day Tuesday.
LLWS is possible during Tuesday, but it is borderline at this
time and was left out of the 00z Tafs.
N wind 5 to 10 knots the remainder of tonight, becoming N 10 to
15 knots on Tuesday.
SHORT TERM:
Tues night - Thurs night: MVFR cigs, with potential for cigs to
lift to VFR each afternoon. Winds NW 10 to 15 kts Tues night,
shifting N at 5 to 10 kts Wed through Thurs night.
Fri - Sat: Mainly VFR, though MVFR possible in scattered
showers. Winds N at 5 to 10 kts, becoming light and variable on
Saturday.-- End Changed Discussion --
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.MARINE...
NEAR TERM: Will continue the ongoing SCA into Tuesday morning.
The offshore low is deepening with a tightening pressure
gradient, but the cold waters will enhance stability and limit
mixing.
Cannot rule out some fog tonight into Tuesday morning as dew
points creep above water temperatures, but confidence was not
high enough to include in the forecast.
North winds will slowly shift to northwest by Tuesday afternoon.
There will be some decrease in wind speeds on Tuesday and saw no
need to extend the SCA.
SHORT TERM: Winds and seas will remain below SCA levels Tuesday
night through the end of the week. NW winds will briefly gust
near 20 kts on the coastal waters Tuesday night, but will
decrease and remain well below advisory criteria through the end
of the week. Seas will sit around 2 to 4 ft.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 8 AM EDT Tuesday for ANZ050-051.
&&
$$
Near Term...CB/MCW
Short Term...AStrauser
Long Term...AStrauser
Aviation...CB/MCW/AStrauser
Marine...CB/MCW/AStrauser