Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 211646
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1146 AM EST Mon Jan 21 2019

.SYNOPSIS...
Low pressure will exit across the Maritimes this afternoon
through tonight. High pressure will cross the region Tuesday.
Low pressure will cross the region Wednesday into Thursday.
&&

.NEAR TERM /THROUGH TONIGHT/...
Update...
Low pressure is exiting across the Gulf of Saint Lawrence. Snow
showers, most numerous across northern areas, in the wake of
the low will persist this afternoon. Any additional snow
accumulations will be an inch or less, with the better chances
of any accumulation across the north and mountains. North to
northwest winds gusting up to around 30 mph will persist across
the region through the afternoon. Widespread blowing snow is
expected across northern and central areas this afternoon. With
the expiration of the Winter Storm Warning have issued a Winter
Weather Advisory for Blowing Snow across Northern Washington
and Central Penobscot counties through 7 AM Tuesday with this
update. A Winter Storm Warning remains in effect until 1 PM
across the remainder of northern Maine which will also
transition to Winter Weather Advisories for Blowing Snow upon
expiration. Otherwise, mostly cloudy skies are expected this
afternoon. High temperatures will generally range through the
single digits above zero north, to 10 to 15 interior Downeast
with mid to upper teens along the Downeast coast. Have also
updated the forecast to adjust for current conditions along with
afternoon temperatures, clouds and snow shower chances.

Previous Discussion...
The big storm which brought heavy snow on Sunday will be
tracking northeast and away through the Maritimes today.
However, the upper low supporting the storm will remain back to
our southwest. Moisture wrapping back around the main low, and
into the upper low will continue to bring clouds and snow
showers across the area today, especially across the north. The
strong gradient west of the low will also continue to bring
extensive blowing and drifting, especially in open areas of the
north today through tonight. A northwest wind will continue
tonight. Clouds and some snow showers will be around through the
first part of the night with clearing toward morning as the
band of moisture shifts east and high pressure builds in.
&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
NW winds will stay up during the day on Tuesday w/a continuation
of blowing snow across the northern areas into the Central Maine
Highlands. The gradient will relax later in the day as high pres
over the Carolinas will ridge across the region Tuesday night.
Clear skies, light winds w/an inversion setting up will allow
for temps to drop quickly in the evening. WAA aloft during the
night w/cold air trapped under the inversion will allow for a
very cold night across the region. Areas across the northern
1/2 of the region will see temps below 0F w/lying areas
possibly seeing temps go below -10F before leveling off due to
increasing clouds later at night.

A warm front is forecast to lift across the region on Wednesday
w/light snow breaking out across the region. Temps look like
they will stay cold enough for snow all the way to the coast
during the day. There could be a period of moderate snow along
the region of strongest convergence which looks to be from the
Central Maine Highlands northward into Aroostook County. There
does appear to be 40kt jet from 850-700mb to provide the necessary
forcing. The NAM/GEM and GFS support this setup. Therefore,
decided to go w/2-3 inches snow. Temps will warm up into the 20s
across the north and west while central and downeast areas will
see low to mid 30s.
&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
There appears to be a break in the action Wednesday evening as
the warm front lifts ne. Temps will remain steady in the evening
adn then gradually warm overnight. Low pres is forecast to
develop near Long Island and lift ne overnight into Thursday.
This low will bring another round of precipitation to the
region. The 00Z ECMWF and Canadian Global show perception
arriving into southern areas later Wednesday night and then
overspreading the entire region on Thursday. These two model
guidances show precip in the form of snow/mixed precip
initially, but then show a change to rain as warmer air gets
pushed northward w/temps going well above 32F over the Downeast
and coast by daybreak Thursday, and remaining above freezing
through the day. As a matter of fact, they both bring rain/snow
line all the way into the St. John Valley w/snow going to rain.
As the low lifts into the Maritimes, colder air gets pulled back
in on the backside of the low turning rain back to snow w/some
accumulation. The ECMWF is by far the wettest w/QPF of 0.5-1.0"
while the Canadian Global is not as wet and keeps the bulk of
the QPF to the central and downeast areas w/less than 0.75". The
00Z GFS is the coldest of the long range guidance as it brings
the low across the Gulf of Maine. This track would keep the
colder air in from Caribou to the northern Maine border allowing
for precip in the form of snow. Another thing to note is that
there is not a strong wind field through 850 mbs and it looks to
be a crossing SW wind over a light south wind at the sfc. This
could impeded the warmer air aloft to mix down to the surface.
Attm, decided to take a consensus and brought the rain/snow line
to Caribou w/the St. John Valley staying below 32F. For
precipitation type, decided to go snow/rain and did not
introduce any freezing precip attm. There is still some time to
nail the precip type w/the next set of model runs. Colder air is
shown by all the long range guidance to sweep back in Thursday
evening w/any rain going back to a period of snow w/some
accumulation on the backside of the low.

A break on Friday as high pres slides quickly across the region.
Daytime temps are expected to be above normal for late January.
Another weather system could affect the region by Saturday
w/some light snow. Turning much colder later Saturday into
Sunday.
&&

.AVIATION /16Z MONDAY THROUGH FRIDAY/...
NEAR TERM: Generally expect MVFR/IFR conditions across the
north and mountains today, with VFR/MVFR conditions Downeast.
Blowing snow will produce variable conditions across northern
areas this afternoon through tonight. North to northwest winds
will gust up to around 30 mph this afternoon through tonight.
VFR/MVFR conditions are expected across the north and mountains
tonight, with VFR conditions developing Downeast.

SHORT TERM: VFR Tuesday into Tuesday night for all the
terminals. MVFR/IFR on Wednesday for all terminals w/some snow.
IFR to possibly LIFR later Wednesday night into Thursday
w/another round of snow and possibly freezing precip & rain.
&&

.MARINE...
NEAR TERM: A Gale Warning remains in effect into Tuesday
afternoon. A Heavy Freezing Spray Warning remains in effect
from later this evening into Tuesday morning. Moderate freezing
spray is expected this afternoon. Visibilities could be reduced
in any scattered snow showers this afternoon.

SHORT TERM: Gales look like they could persist into Tuesday
afternoon w/gusts to 35 kts on NW winds. The gradient is
forecast to relax by Tuesday night w/winds dropping back below
to 20 kts. The winds are forecast to pick back up on Wednesday
out of the SW w/speeds of 20-25 kt. Decided to follow a blend of
the GFS and CONSRAW for winds and leaned w/gusts close to 30
by Wednesday afternoon, especially for the outer waters. The
local wave model and the WNA wave model show seas building to
7-9 ft by Wednesday night w/a southerly fetch. Decided to lean
close to the scenario and brought 8-9 foot seas Wednesday night
into Thursday morning. As low pres lifts up into teh Canadian
Maritimes, winds will shift to the NNW w/seas dropping back to
5-6 ft.
&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Warning until 1 PM EST this afternoon for
     MEZ001>006-010-031.
     Winter Weather Advisory until 7 AM EST Tuesday for MEZ011-032.
MARINE...Heavy Freezing Spray Warning from 11 PM this evening to 9 AM
     EST Tuesday for ANZ050>052.
     Gale Warning until 1 PM EST Tuesday for ANZ050>052.

&&

$$

Near Term...Norcross/Bloomer
Short Term...Hewitt
Long Term...Hewitt
Aviation...Norcross/Hewitt
Marine...Norcross/Hewitt



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