NWS Caribou, Maine Area Forecast Discussion

FXUS61 KCAR 182225

Area Forecast Discussion
National Weather Service Caribou ME
525 PM EST Sat Nov 18 2017

Strong low pressure will approach from the west tonight then
cross Maine Sunday drawing a cold front across the region. High
pressure will build toward the region later Monday.

Intensifying low pressure will approach from the west tonight
drawing a warm front toward the region. The low will track
across northern Maine Sunday drawing the warm front across the
region during the morning, with a cold front then crossing
during the afternoon. Precipitation will develop across the
region early tonight then expand northward overnight. Across
central and Downeast areas expect precipitation mostly in the
form of rain, though a chance of mixed precipitation could exist
from southern Piscataquis to northern Washington counties
during the onset of precipitation. Have issued a Winter Weather
Advisory across northern areas overnight where low level cold
air will be more persistent with evaporational cooling help
maintain the low level cold air. A mixture of snow, sleet and
freezing rain is expected across northern areas overnight. Snow
accumulations of up to around an inch are possible with ice
accumulations generally a tenth of an inch or less.
Precipitation will trend toward rain later tonight with warmer
air moving north. Could still have a chance of freezing rain
across the Saint John Valley early Sunday. Otherwise, rain is
expected across the region Sunday. The rain will diminish in the
wake of the cold front Sunday afternoon, with a chance of
afternoon snow showers across the north and mountains. Gusty
winds will also develop in the wake of the cold front Sunday,
with gusts up to around 40 mph possible. Low temperatures will
occur early tonight then warm overnight. High temperatures
Sunday will range through the 40s north, to the lower to mid 50s

Deep low pressure lifting north into Quebec will pull strong gusty
westerly winds across our area following a cold frontal passage
Sunday night. Some rain showers across the north may change over to
snow showers before ending Sunday evening. Downeast should be mostly
clear. Gusty westerly winds will likely continue through the night
and through the day on Monday with the sky mostly cloudy over the
north Monday and mostly clear Downeast. Monday night and Tuesday
will continue to be dry. A southerly wind will increase behind
departing high pressure on Tuesday which will bring milder air
across the region during the afternoon. Tuesday will be partly
cloudy to mostly clear and dry.

Looking ahead to mid-week, our focus will be on a southern branch
shortwave lurking across the deep south and a trough of low pressure
sliding through the Great Lakes region. The question is when or if a
shortwave diving through the lakes trough will pick up the southern
branch wave to bring it north as an east coast storm. The latest GFS
keeps Wednesday into Thursday dry and tranquil then lifts a system
offshore Thursday night to brush southeastern areas with some snow
and coastal rain. The ECMWF is now only bringing a front through on
Wednesday with the rest of the southern branch low sliding well to
the south. This is a big difference from last nights ECMWF which was
bringing the southern low well north and warming up the
atmosphere enough for rain. Given the complexity of how a
northern branch shortwave may mesh with the southern branch
wave, it may take a couple days to iron out the details of this
system. For now will keep forecast close to ECMWF and model
blend with showers possible on Wednesday, but otherwise dry
through the rest of the week.

NEAR TERM: VFR conditions early tonight will lower to IFR/LIFR
levels overnight. IFR/LIFR conditions are expected early
Sunday, with MVFR/IFR conditions during the afternoon. A wintry
mix of snow, sleet and freezing rain will occur across
northern areas overnight with rain across the remainder of the
region. Generally rain is expected across the region Sunday,
though a wintry mix could still be possible across the Saint
John Valley early. West to southwest winds could gust up to
around 40 mph Sunday afternoon.

SHORT TERM: Strong gusty winds may result in some turbulance
Sunday evening. Conditions will likely be MVFR to VFR across the
north and VFR Downeast. VFR conditions are likely Monday
through Tuesday. Conditions may drop to MVFR for a period
Tuesday night as a cold front moves through. VFR conditions are
then likely Wednesday into Thursday.

NEAR TERM: Winds will increase overnight along with building
seas. A Gale Warning is in effect starting late tonight which
will remain in effect through Sunday. Visibilities will be
reduced in rain and fog later tonight into Sunday.

SHORT TERM: A gale will likely be needed for strong gusty
westerly winds Sunday evening. A SCA may be needed after that
through Tuesday night for continued gusty winds. The wind should
finally diminish a bit later Wednesday into Thursday.

ME...Winter Weather Advisory from midnight tonight to 6 AM EST
     Sunday for MEZ001-002.
     Winter Weather Advisory from 9 PM this evening to 6 AM EST
     Sunday for MEZ003>006-010.
MARINE...Gale Warning from 6 AM Sunday to 1 AM EST Monday for



Near Term...Norcross
Short Term...Bloomer
Long Term...Bloomer

NWS CAR Office Area Forecast Discussion