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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCAR 201403
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1003 AM EDT Wed Mar 20 2019

.SYNOPSIS...
High pressure will slide south of the area through today then
move east into the open Atlantic tonight. Low pressure will
develop off the Mid-Atlantic coast on Thursday and track north
to our region on Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
10 am Update... After a rather chilly morning temperatures are
starting to rebound late this morning. Surface high will
continue to move offshore setting up a return southwest flow
today with moderating temperatures. Highs are expected to rise
into the mid to upper 30s north and lower 40s central and
downeast this afternoon. Just minor tweaks to hourly temps/dew
points otherwise no other significant changes.

previous discussion
High pressure will move off to the east today with a
southwesterly flow developing on the back side of the high with
temperatures rising to near 40. Expect milder temperatures in
the flow behind the high. Expect clouds to increase during the
day. Skies will become mostly cloudy tonight, as low pressure
approaches from the south, with low temperature in the 20s to
lower 30s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Return flow wl hv kicked in on wrn periphery of high as it builds
into the Atlantic. S/wv dropping thru the Great Lks at the start of
the short term wl phase with wv currently mvg thru the Plains. This
wl serve to pump up the upr lvl ridge axis ovr the state with pcpn
rmng to the north and west of CWA into Thu evng.

By 00z Fri wv that is currently ovr Northwest Territories in nrn
Canada wl swing into the Great Lks and phase with the energy mvg off
of the Carolina coast. This interaction wl intensify sfc cyclone
acrs the northeast but where and when it does rmns up in the air.

Guidance has all trended inland with track of sfc low while 00z EC
has slowed significantly. If the EC were to be realized could be
looking at fairly significant snow across the north in the trowal as
the storm stalls along the coast.

Very low confidence continues to exist regarding ptypes for the end
of the week with most confidence of all rain for Downeast on Friday
with around 1 inch expected. This wl lkly lead to ponding of water
on area roadways on Friday.

NAM indicating cold air damming acrs cntrl zones Friday morning with
snow mixing with sleet and eventually frzg rain in the mrng bfr
transitioning to all rain in the aftn. NAM has greatest surge of
warm air ahd of low keeping entire CWA all rain in the aftn bfr
mixing snow back in acrs the far nw in the aftn.

As previously stated confidence in fcst is about as low as it gets
with multiple wvs phasing over the next 24-48 hours. For the time
being expect that there wl be a light glaze of ice acrs cntrl areas
Fri mrng as warm advection results in frzg rain. Snow totals look to
range fm 3-5 inches acrs the far northwest with rainfall amnts of
around 1 inch ovr Downeast.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Snow showers continue on Saturday acrs the north as low exits into
the Maritimes. Gusty winds are expected on Sat in wake of system. A
cold front wl cross the area Sun night into Mon morning with
possible snow showers acrs most of the area. 00z GFS is most bullish
with pcpn ahead of the front with EC and CMC bringing front thru
mostly dry. A reinforcing shot of cold air wl move into the area for
the early half of next week.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: VFR conditions are expected today and tonight.

SHORT TERM: VFR expected on Thu before lowering to IFR and LIFR
Thu night through Sat morning. Conditions will be a combination
of clouds, snow and rain. Gradual improvement expected Sun
morning.

&&

.MARINE...
NEAR TERM: 10 am Update...Winds/seas will remain below SCA
levels through tonight. Visibility is expected to be unlimited
through tonight/

previous discussion
Have used the Nam to initialize winds. Southwesterly wind wave
will be the primary wave system across the Gulf of Maine Today
with seas 1-2 feet/4 seconds today building to around 3 feet
tonight. Will initialize wave grids with 0600Z NWPS. Total Water
Level: Total water level is expected to remain around +0.10
Today and Tonight. Expect surge to develop in southeasterly flow
as low pressure approaches the Gulf of Maine Thursday Night
into Friday. Surge guidance suggest storm surge around +1.0
feet. Have initialized the surge grids with the ESTOFS which has
show good past history but will increase Base Tide anomaly by
+0.50 feet Friday. Significant reverse surge is expected over
the weekend as a strong off-shore flow develops behind the low.
In Bangor ice induced anomaly persists at low tide. Will adjust
the anomaly such that the lowest tide will be at a minimum of
4.5 feet MLLW for the next several days.

SHORT TERM: SCA will be needed Thur night with seas on Friday
ahead of strengthening coastal running between 8-12 feet. Gale
force winds will be possible on Saturday in wake of departing
system.

&&

.HYDROLOGY...
The combined amount of rainfall and snowmelt may be enough to
lift ice and generate ice jam potential in the southern half of
the forecast area. River rises are progged at 2 to 4 feet which
should be sufficient to break up some ice.  Further north,
existing snowpack will likely absorb the rainfall without
issues. The combined T/Td thawing degree hour index is still not
indicating any caution signals as the period of warmer temps
and dew points is relatively brief.

Along the coast, high astronomical tides and storm surge at
Friday morning`s high tides seem likely to cause minor issues at
some of the usual trouble spots such as the Deer Isle Causeway,
Seawall Road, and Machias.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.

&&

$$

Near Term...Duda/Mignone
Short Term...Farrar
Long Term...Farrar
Aviation...Duda/Mignone/Farrar
Marine...Duda/Mignone/Farrar
Hydrology...