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000
FXUS61 KCAR 210753
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
353 AM EDT Fri Sep 21 2018

.SYNOPSIS...
Strong low pressure will track north of the region this afternoon
into tonight. A strong cold front will move through late
tonight.

&&

.NEAR TERM /THROUGH TONIGHT/...
Two significant concerns: dense fog Northern Maine this morning,
then strong winds late today into tonight.

Fog has become quite dense over much of Northern Maine. Expanded
the dense fog advisory south a bit to cover areas from Patten to
Houlton. Fog shouldn`t last too long thankfully, as winds pick
up fast this morning as the strong weather system approaches.

Winds with the weather system are by far the main concern late
today into tonight, as rain will be rather modest with generally
less than one quarter inch Downeast and up to one half inch in
the St John Valley. Winds aloft are exceptionally strong for
the warm season, which is concerning because leaves are on the
trees making them much more susceptible to damage. 850mb winds
reach 70 knots from the southwest this evening over Northern
Maine. SPC sounding climatology for Caribou doesn`t have any
soundings with 850mb winds over 60 knots for the month of
September, and only a handful of times does it reach 70 knots at
850mb at Caribou in the winter. Winds aren`t quite as impressive
aloft Downeast, but significant enough to be of concern. The
prefrontal airmass is fairly stable at least initially this
afternoon into early evening, so the brunt of the winds will
have trouble mixing down to the surface except over higher
terrain. However, convective showers move through around mid-evening
into the overnight hours as the cold front approaches, and any
of these showers (or possibly isolated storms) could bring the
strong winds to the surface. And certainly, with the cold front
passage after midnight, strong winds will mix down to the
surface. At least winds aloft won`t be quite as strong when the
cold front arrives, but still strong enough to cause tree damage
considering leaves are still on the trees. Generally expect
peak gusts 45 to 50 mph most places, with a better shot of the
highest gusts Northern Maine, as well as higher terrain. While
gusts 45 to 50 mph may not sound like much, again, we need to
reiterate that we don`t see winds like this often when leaves
are still on the trees, other than local warm season
thunderstorm winds or the rare tropical system. Leaves on the
trees leads to much greater impact than when there are no
leaves.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
The cold front will be off the coast first thing Saturday
morning. Any lingering early morning clouds and showers will
give way to a mainly sunny day with gusty northwest winds
continuing into midday. The winds will begin to diminish as high
pressure builds into the region. Highs on Saturday will range
from the mid 50s to near 60 degrees north and low to mid 60s
central and downeast, which is close to seasonal for this time
of year. The stage will be set for areas of frost to develop
Saturday night, especially across northern and central areas. An
approaching cold front from the northwest brings some
increasing clouds across the north by Sunday morning. The cold
front crosses the region Sunday but the front is expected to
cross the region dry. Even cooler air is expected to follow the
passage of this front. Sunday night will be a very chilly night
as a large Canadian high pressure system settles across the
region. Widespread frost with freezing temperatures are possible
by Monday morning across the far north with areas of frost
possible central and downeast.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Monday morning starts off very chilly with frost before
afternoon temperatures moderate into the 50s by afternoon along
with abundant sunshine. Monday night is another cold night with
more frost possible. After a dry day Tuesday, a bit of a
moderating temperature trend is expected by mid week but along
with the milder temperatures will come the chance for showers.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: Dense fog northern TAF sites early this morning
should end by mid-morning as south winds begin to increase ahead
of the weather system. Generally low VFR to MVFR conditions
during the day today, with greater chance of MVFR in the north.
Winds steadily increasing through the day and into the evening.
Tonight, ceilings lowering to IFR or low MVFR. Of larger concern
tonight is the gusty winds, plus low level wind shear (primarily
speed shear).

SHORT TERM: VFR conditions through middle of next week. The exception
will be patchy late night and early morning river valley fog
which could bring local IFR conditions in reduced visibilities.

&&

.MARINE...
NEAR TERM: Gale force winds tonight, with rough seas building to
6 to 10 feet as well. Delayed onset of gale a few hours to 6
PM.


SHORT TERM: The Gale Warning will likely need to be replaced
with a Small Craft Advisory Saturday morning with gusty
Northwest winds expected to continue into the afternoon. The
could be another opportunity for Small Craft conditions Sunday
afternoon and into Sunday night in the cold advection behind a
departing cold front.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Dense Fog Advisory until 8 AM EDT this morning for MEZ001-002-
     005-006.
     Wind Advisory from 2 PM this afternoon to 8 AM EDT Saturday
     for MEZ001>006-010-011-015>017-029>032.
MARINE...Gale Warning from 6 PM this evening to 8 AM EDT Saturday for
     ANZ050>052.

&&

$$

Near Term...Foisy
Short Term...Duda
Long Term...Duda
Aviation...Foisy/Duda
Marine...Foisy/Duda