Area Forecast Discussion
Issued by NWS Caribou, ME

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565
FXUS61 KCAR 181939
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
339 PM EDT Wed Apr 18 2018

.SYNOPSIS...
Low pressure will continue to slowly move northeast away from
the region across the Maritimes tonight. A new area of low
pressure will develop to our south on Thursday and track across
Nova Scotia Thursday night and the northern Maritimes on Friday.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
Currently surface and upper low pressure remains just to the
north of Northern Maine and slowly drifting to the east and
northeast. This system has been generating snow and rain showers
across northern and eastern areas today however expect this
activity to slow diminish going into the evening. Low pressure
is then expected to develop to the south of New England Thursday
Morning then move northeast across the outer Gulf of Maine
Thursday Night. This will result in a snow or rain across much
of the area. The precipitation type will be mostly diurnally
driven. Will use the precipitation type from thickness tool run
on a 50/50 blend of the Nam and Gfs. Snow accumulation form snow
ratio.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Whats left of steady lgt sn erly Fri morn will taper to sct
rn/sn shwrs late Fri morn and then sct rn shwrs Fri aftn as sfc
low pres moves ENE away from the region alg the S shore of Nova
Scotia and the upper low crosses the Rgn. Little in the way of
sn accumulation is xpctd durg the morn as Sfc-BL layer temps
rise abv fzg and strong late Apr background insolation keeps lgt
sn rates from amounting to much on surfaces, spcly roadways
which will likely only be wet durg this tm. Whats left of any rn
or rn/sn shwrs Fri eve will msly end late Fri ngt, leaving msly
cldy skies across the Rgn Sat as the upper trof only slowly exits
the FA. Skies will then slowly clr from W to E across the FA
Sat ngt with a contd NW breeze as sfc hi pres ovr Wrn QB begins
to exert more influence ovr our Rgn.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
With more in the way of sunshine on Sun, aftn hi temps will
begin a slowly recovery to more spring like values of mid to
upper 40s N to lower 50s Downeast, albeit under still somewhat
breezy conditions. More substantial improvement in temps with
lgtr winds then occurs Mon and again on Tue as mdtly strong
upper ridging from Cntrl Can and great lakes begins to apch our
FA with contd msly clr skies. By Tue, most low trrn lctns N of
the immediate coast will be near or just abv 60 deg F for aftn
hi temps, with coastal areas cooler due to a sea breeze.
Wed will cont be quite mild, cldnss will begin to increase from
the SW durg the aftn as low pres and associated s/wv begin to
apch from the OH vly, with rn movg into the Rgn from SW to NE by
late Wed ngt.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
NEAR TERM: Expect MVFR/IFR conditions tonight into Thursday
Night.

SHORT TO LONG TERM: MVFR clgs and ocnl vsbys with sn and rn
shwrs will prevail across our TAF sites Fri into Fri eve with a
brief pd of IFR vsbys in steady lgt sn possible across Nrn TAF
sites Fri morn, then improve SW to NE across the Rgn to VFR
late Fri ngt into Sat morn and then cont VFR all TAF sites thru
Mon.

&&

.MARINE...
NEAR TERM: Have used a 50/50 blend of the Nam and Gfs for
sustained winds. Waves: Primary wave system is long period
southerly swell From Monday storm event(8 feet/9 seconds) with a
secondary southwesterly wind wave. Expect the southerly swell
system to slowly subside Tonight into Thursday Morning with wave
heights falling to below SCA by 1500Z so will remove inter-
coastal zone from SCA and keep outer waters in SCA. Have used
the 1200Z NWPS run to initialize the wave grids. Boundary
conditions for NWPS look reasonable. For Total Water Level: Post
surge still significant, was around 1 foot from last high tide
cycle so will adjust and slowly decrease surge model bias over
next 2 to 3 days using the anomaly grid.


SHORT TO LONG TERM: Initially winds and seas will be just below
SCA thresholds Fri ovr our outer MZs050-051...but will cont to
subside further below SCA thresholds ovr the weekend and cont
below SCA thresholds for all our waters into early next week.
Went with a blend of WW3 and NWPS guidance for fcst wv hts for
these ptns of the fcst. Primary wv pds will initially be arnd 10
sec on Fri and Fri ngt with SE swell, diminishing to arnd 5 sec
durg the day Sat and contg so into erly next week.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 11 AM EDT Thursday for ANZ050-051.

&&

$$

Near Term...VJN
Short Term...Mignone
Long Term...Mignone
Aviation...VJN/Mignone
Marine...VJN/Mignone



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