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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCAR 172113
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
413 PM EST Thu Jan 17 2019

.SYNOPSIS...
Weak low pressure moves across the region Friday, followed by
an Arctic cold front Friday night and Arctic high pressure on
Saturday. A Noreaster is expected to approach from the southwest
Sunday and move through the Gulf of Maine Sunday evening.
&&

.NEAR TERM /THROUGH FRIDAY/...
High pressure ovr the CWA as of 20z this afternoon with next
lopres system in the OH Vly. This system wl spread east
overnight with light snow mvg into the far swrn areas around
daybreak. All guidance showing light snow on the order of 1-2
inches, though hires models are hinting at a band dvlpng ovr
the ern border in the aftn with potential for advisory levels.
However, feel this banding could be covered with a short-fused
SPS so as not to distract from the more significant storm on
Sunday.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
The last of the snow will move out Friday evening with up to an
inch in Washington County and along the eastern border. The
Arctic front follows and there could be snow squall with the
front. The snow squall parameter is flashing some decent signals
in northern Aroostook County during Friday evening. Behind the
Arctic front, temperatures and wind chills will plummet and a
Wind Chill Advisory has been issued starting 1 am EST Friday
night into Saturday afternoon for the northern half of the
forecast area. H925 temps on Saturday will drop as low as -30C
towards the Saint John Valley. These temps will translate into
the season`s first subzero high temperatures on Saturday...at
least in most of Aroostook County. Temperatures will be a bit
higher further south with low to mid teens along the coast.
Winds will die off in the afternoon into the evening with a very
brief window of radiational cooling before high clouds thicken
and lower ahead of the storm. A massive area of low pressure
will track out of the Ohio River valley towards the New England
coast by Sunday morning. This developing Nor`easter will bring
an impressive swath of southern stream moisture
northward...overrunning the bitterly cold Arctic air mass. Used
a multi-model ensemble mean for temps Saturday night into Sunday
night. The very cold low level wedge of air will remain in
place all the way to the coast with unusually cold temperatures
to go with moderate to heavy snow. Current forecast wind chills
on Sunday meet advisory criteria in northern zones...something
that is difficult to recall in the past decade. Our current
storm track takes the deepening low across the Gulf of Maine
towards the southern side of the Bay of Fundy. It will follow an
intense coastal front that will set up early Sunday. This
coastal front will feature an H925 thermal gradient of over 30C
within 100 miles. This coastal front and higher PW values will
ensure the heaviest storm QPF is near the coast and manage to
produce enough warm air aloft to create mixed precip for coastal
Hancock and Washington counties. This will be in the form of
sleet for the most part and could accumulate some 1 to 3 inches
on top of a foot of snow. Intense banding with greater than 2
inch an hour snowfall rates are likely late Sunday night through
the day Sunday. Overall totals could reach around 20 inches
towards Bangor...tapering towards a foot in far northwestern
Aroostook County. Snow ratios start on the high side, with a
deep profile in the DGZ, but will be reduced by both increasing
winds, and in the southern half of the area, the warm nose
aloft. In terms of P-type, blended upper level thermal profiles
from the 12Z NAM and GFS for the coastal sleet. While a Winter
Storm Watch has now been issued, we will have to give serious
consideration to a blizzard with winds and snowfall rates in the
ballpark. Regardless, blowing and drifting snow with potential
whiteout conditions will be a tremendous problem impacting
travel Sunday into Monday. Travel late Saturday night through
Sunday night should be avoided and that message cannot be
stressed enough. Overall snowfall totals in this forecast area
will probably be heavier than areas to the south and east as the
sfc low really strengthens later Sunday as the southern and
northern branches phase and a trowal extends significant
snowfall into Sunday night.
&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
On Sunday night, the northern and southern streams fully phase
and an upper level cut-off low forms while the surface low
continues to deepen in the Canadian Maritimes. This means the
snow continues in the forecast area with pops slowly decreasing
by Monday morning. Most of the snow will fall before midnight,
but north winds will continue increasing as the storm deepens.
Any consideration of a blizzard headline will have to be
extended into Sunday evening as snowfall rates could still be
formidable in eastern Aroostook County with the trowal. Wind
gusts to 40 mph through the night will continue to make travel
extremely hazardous due to blowing and drifting snow.
Furthermore, wind chills will remain well below zero through the
night and into Monday. Snow continues to wrap around the closed
system into the area through Monday until the upper low exits
east by Monday evening. High pressure and lighter winds arrive
Tuesday. Tuesday night into Thursday, a warm advection event is
expected to generate snow that will generate mixed precip by
Wednesday night. Cooler and drier weather returns Thursday into
Friday. There is still a lot of uncertainty involving the mid-
week system into terms of timing as well as phasing between the
northern and southern streams.
&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
NEAR TERM: VFR conditions expected until closer to 12z Fri as
low MVFR cigs move in ahead of next light snow event. Expect
that IFR snow will likely occur after this time for all but FVE
terminals thru end of TAF valid time.

SHORT TERM: On Friday night, expect tempo IFR to LIFR in showers
during the evening...followed by VFR for all sites. VFR
continues through Saturday evening. Later Saturday night, all
sites decrease to LIFR to VLIFR in heavy snow through the day on
Sunday and into Sunday night. Conditions improve to IFR on
Monday and VFR returns Monday night into Tuesday...outside of
occasional MVFR cigs north of GNR and HUL.
&&

.MARINE...
NEAR TERM: Winds will come up ahead of the system tomorrow
morning with marginal SCA levels expected in the morning.

SHORT TERM: A Small Craft Advisory has been issued for Friday
night into Saturday morning. An advisory for freezing spray may
be needed Saturday morning. A gale...and quite possibly...a
storm will be needed Sunday into Monday night with a Nor`easter.
&&

.TIDES/COASTAL FLOODING...
An intense coastal storm is expected to move through the Gulf of
Maine on Sunday generating a storm surge of 2-3 feet along the
Eastern Maine Coast. In addition to this the astronomical tide
is expected to be close to the highest levels of the month
during the Sunday Morning high tide cycle between 9:15 and 9:45
AM. Even though the highest storm surge is not expected until
later in the afternoon, tide levels are expected to be high
enough near the time of high tide to result in possible minor
coastal flooding. Even though the largest waves are not expected
until late afternoon, building wave heights along the coast in
the morning may also produce overtopping, splash over, and beach
erosion.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Watch from late Saturday night through Monday
     morning for MEZ001>006-010-011-015>017-029>032.
     Wind Chill Advisory from 1 AM to 2 PM EST Saturday for
     MEZ001>006-010.
MARINE...Small Craft Advisory from 9 PM Friday to 11 AM EST Saturday
 for ANZ050>052.
&&
$$

Near Term...Farrar
Short Term...MCW
Long Term...MCW
Aviation...Farrar/MCW
Marine...Farrar/MCW
Tides/Coastal Flooding...Mignone