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000
FXUS61 KCAR 152128
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
528 PM EDT Sun Apr 15 2018

.SYNOPSIS...
Cold Canadian high pressure will remain in place into tonight.
Low pressure will approach from the Midwest Monday and slowly
cross the area Tuesday into Wednesday.
&&

.NEAR TERM /THROUGH MONDAY/...
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An unusually cold 1047mb high centered over Quebec is the
dominant feature in area weather through Monday. The cold and
dry air will provide one last chilly night...most notably in
Aroostook County where teens are expected. Further south, clouds
will be too thick for radiational cooling. Overrunning high
clouds will thicken and overspread the entire area as the night
progresses and lows will be posted well before dawn. The warm
advection aloft will feature a warm nose at H700 that will
ensure precip begins as mostly sleet later in the night. An
initial band of sleet...and some freezing rain...will advect
into southwestern portions of the forecast area early in the
morning. While most of the precip should be sleet, some freezing
rain could mix. As a result, have issued a Winter Weather
Advisory for southern Piscataquis, southern Penobscot, and
Hancock counties. The concern is for slick roads for the early
morning commute before road surfaces warm. It`s possible that
the advisory could need to be extended towards Washington and
central Penobscot counties, but the general thinking is that the
initial precip band will dissipate as it moves northeastward
into the drier air...and any remaining precip will be just
sleet. The cold air damming and frontal inversion will last all
day with highs mostly in the low 30s except the immediate
coast. It`s conceivable that sleet and freezing rain could be
the dominant P-types much of the day with resultant extension of
advisories. However, due to the time of year and surface
temperatures near 32F, am hesitant to have any advisories
beyond Monday morning for now. Warming aloft will increase such
that H850 temps will become 10C by afternoon and any sleet will
gradually change to rain and freezing rain. This thermal ridge
could also serve as a base for some elevated instability on
Monday afternoon, but will hold off any mention of convection in
the forecast at this point. Pops will increase through the day
as the low level dry air is wiped out from west to east. Upslope
and coastal front precip will develop in the afternoon, but the
real significant precip will arrive late day as a potent
shortwave rotates around the closed Great Lakes upper low with a
triple point low moving into southern New England...aided by
strong upper jet support.

Besides the mixed precip, the other concern during Monday will
be high winds along the coast. A 60-kt easterly H925 LLJ is
expected to develop in the afternoon along the coast. Expect a
deep enough mixed layer to cause some strong gusts and have
issued the wind advisory for this event as well as the stronger
LLJ that arrives Monday night.
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&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
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An occluded front will cross the region Monday night through
Tuesday. A mix of sleet, freezing rain and rain will change to
mostly rain across northern and central areas Monday night,
with mostly rain Downeast. A strong low level jet will cross
the region Monday night, with the strongest winds along the
Downeast coast where gusts up to 50 mph are expected. A Wind
Advisory is in effect for the Downeast coast Monday night. Rain
will persist in advance of the occlusion Tuesday then diminish
during the afternoon. Vertically stacked surface/upper level low
pressure will slowly cross the region Tuesday night through
Wednesday. With cooling temperatures, expect precipitation will
transition back to snow showers or a rain/snow shower mix
across northern areas later Tuesday night, with rain showers
transitioning to a rain/snow shower mix Downeast. Expect a
chance of rain/snow showers across the north and mountains
Wednesday, with a chance of rain showers Downeast. Temperatures
will remain at below normal levels Tuesday/Wednesday.
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&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
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Snow showers north, with a slight chance of rain/snow showers
Downeast will persist Wednesday night. Uncertainty then exists
regarding the track of low pressure Thursday into Friday.
Precipitation amounts Thursday/Friday will be dependent on the
eventual track of the low. Precipitation types will be largely
tied to diurnal temperature trends, with snow or a snow/rain mix
overnight into the morning hours and mostly rain through the
afternoon into the evening. Precipitation should taper to snow
showers Friday night. High pressure should then build across the
region Saturday into Sunday with generally partly cloudy skies.
Temperatures will remain at below normal levels Thursday
through Saturday, with near normal level temperatures Sunday.
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&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
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NEAR TERM: VFR conditions continue until late tonight. MVFR
cigs/vis will start to affect BGR and BHB late tonight into
Monday morning. The cause of the vis reduction will be sleet and
freezing rain. This mixed precip will spread northward and
affect all zones by late afternoon. LLWS will be a threat Monday
afternoon for BHB and coastal airfields. BGR may also be
affected.

SHORT TERM: IFR/LIFR conditions are expected across the region
Monday night through Tuesday. Low level wind shear is a concern
Monday night with a strong low level jet crossing the region.
East to southeast winds are expected to gust up to 50 mph along
the Downeast coast Monday night. A mix of sleet, freezing rain
and rain will change to mostly rain across central and northern
areas Monday night, with generally rain Downeast. Rain is
expected across the region Tuesday. MVFR/IFR conditions are
expected across the region Tuesday night through early
Wednesday, with occasional MVFR conditions later Wednesday.
MVFR/IFR conditions are possible Thursday into Friday dependent
on the eventual track of low pressure.
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&&

.MARINE...
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NEAR TERM: Gale conditions will develop Monday morning. Winds
and seas will continue to increase through the day, but not
quite to storm conditions.

SHORT TERM: A Gale Warning is in effect for the waters Monday
night. Small craft advisory conditions are then expected
Tuesday into Wednesday, mostly for seas. Visibilities will be
reduced in rain Monday night into Tuesday.
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&&

.HYDROLOGY...
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With cooler temperatures, along with less rainfall and snowmelt
expected with this storm, the immediate flood threat has
diminished. However, river levels will still rise. Temperatures
through the remainder of the week should then allow for a
controlled snowmelt. Across the Saint John, Aroostook and
Allagash River basins along with their tributaries river levels
will rise along with weakening ice. This could allow the ice to
move with ice jams possible later this week.
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&&

.TIDES/COASTAL FLOODING...
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Minor coastal flooding is possible during Monday nights high tide
due to wave run-up action causing coastal overwash and minor beach
erosion. This isn`t a major storm by any means but almost perfect
timing of the high tide, 1 to 1.3 foot storm surge and strong
onshore flow creating 5 to 10 foot near shore waves.  Total Water
Level guidance is providing minor flood threat for most of the wave
run-up impacted locations.  Overall looks to be a relatively minor
event. This should be the only tidal cycle that a flood threat
exists for and not expecting any inundation flooding in coastal
areas.
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&&

.CAR WATCHES/WARNINGS/ADVISORIES...
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ME...Winter Weather Advisory from 5 AM to noon EDT Monday for
     MEZ010-015-016-029-031.
     Wind Advisory from 2 PM Monday to 5 AM EDT Tuesday for MEZ029-
     030.
     Coastal Flood Advisory from 10 PM Monday to 2 AM EDT Tuesday
     for MEZ029-030.
MARINE...Gale Warning from 8 AM Monday to 6 AM EDT Tuesday for
     ANZ050>052.
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&&
$$

Near Term...MCW
Short Term...Norcross
Long Term...Norcross
Aviation...MCW/Norcross
Marine...MCW/Norcross
Hydrology...Norcross
Tides/Coastal Flooding...Dumont