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-- Discussion containing changed information from previous version are highlighted. --
610
FXUS61 KCAR 220222
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1022 PM EDT Thu Sep 21 2017

.SYNOPSIS...
Tropical Storm Jose will remain southeast of Cape Cod
and will slowly weaken through this weekend while High
pressure both at the surface and upper atmosphere builds
across the region from the west.

&&

.NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --
10pm Thursday Update...
No changes needed other than to copy in current temperatures,
dewpoints, and wind. Quiet night. Temperatures falling fast
central/northern areas due to light winds, mostly clear skies,
and dry air. Slower cooling down this evening near the coast
thanks to somewhat thicker clouds and a bit of a breeze.

Previous Discussion...
Strong high pressure will persist over the region tonight into
Friday then weaken later in the day Friday. Some clouds from
Jose are possible along coastal areas tonight into Friday but
not rain is expected from the storm. The north will remain
mostly clear Tonight and Friday.

A High Surf Advisory in effect through Friday afternoon for the
coast. More on this in the Tides/Coastal Flooding section
below.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
Unseasonably warm conditions expected this weekend...

What`s left of any hi cldnss from slowly weakening and departing
Maria in the open Atlc SE of Cape Cod will dissipate Fri ngt
into Sat morn. Otherwise, xpct, msly clr skies and lgt winds Fri
ngt. Cannot rule out late ngt patchy fog for parts of the area,
but milder ovrngt lows compared to tngt and antecedent dry
ground conditions will be lmtg factors, so we so not show any
fog in our fcst grids for Fri ngt attm.

Sat will be msly sunny and sig warmer with msly lgt west winds
as high pres alf conts to build, xcpt aftn sea breeze for
Downeast areas. A weak s/wv movg E across Cntrl QB could bring
some hi cldnss to Nrn ptns of the FA late Sat ngt and Sun morn.

Otherwise, most model guidance shows an additional surge of
warmer and somewhat more humid air movg into the Rgn from the W
by Sun aftn. The only lmtg factor to area wide record hi temps
Sun aftn may be the amt of sunshine across NE ptns of the Rgn
which will be in the NE quadrant of a very large and
unseasonably strong upper ridge. If the 12z GFS model and
supporting ensm run is correct, however, the hi temp fcst of
lower 80s for low trrn lctns N will be conservative by 3 to 5
deg F. Other models like the 12z ECMWF show a delay of the
arrival of the warmest air until nearly eve, and the 12z CanGem
model, interestingly enough shows a back door cold front sliding
across the Rgn on Sun. Given past trends of CPC guidance
regarding the strength of the upper hi, we have discounted the
12z CanGem model attm. Sun ngt will be mostly clear to partly
cloudy and quite mild for this tm of season.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Mon will cont to be ptly to msly sunny and unseasonably warm
across the Rgn, with most models advertising a back door cold
front beginning to move Swrd into Nrn ME from Ern QB by aftn.
Subsequently, Hi temps may be a little cooler across the far N.
We tried to split the difference with the tmg of the cold front
passage from the faster GFS and slightly slower ECMWF. Both
models bring the front to near the Downeast coast by Tue morn.
With little in the way of frontal cnvrg and very stable lapse
rates alf, we do not xpct much in the way of shwrs with this
feature, with only some cldnss.

Additional s/wvs will continue to flatten the NE U.S. upper
ridge and will bring the Rgn better shwr chcs from late Wed thru
Thu with perhaps appreciable rnfl amts for the Rgn Wed ngt into
Thu. Hi and low temps Tue thru Thu will be cooler, but still
sig abv seasonal norms with ovrngt lows Thu ngt behind a
strongercold front closer to seasonal avgs.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: Generally VFR next 24 hours. One exception is right
along the coast where an MVFR ceiling should develop Friday
morning. Other exception is patchy shallow valley fog from KHUL
north late tonight.

SHORT TO LONG TERM: Mainly VFR xpctd area wide from Fri ngt
through Tue with perhaps a pd of MVFR cldnss across Nrn
most TAF sites late Mon ngt into Tue morn.

&&

.MARINE...
NEAR TERM: Have used the NAM to initialize the wind grids,
however there is still a strong inversion resulting from the
relatively cold sea surface temperature. Therefore have reduced
the wind speeds from the NAM by 20 percent to adjust for high
bias. For Waves: Currently long period swell from Jose (7-8
feet/12 seconds) is still entering the Gulf of Maine. This wave
system will subside tonight into Friday but due to additional
waves being generated by the weakening storm the process will be
slow. A secondary northeasterly wind wave system has also
developed across the Gulf of Maine but this wave group will also
subside tonight as high pressure builds down from the north.
Will use the Nearshore Wave Prediction System (NWPS) to
initialize the wave grids but will lower model wave heights by 1
foot to adjust for high bias resulting from cold sea surface
temperature.

SHORT TO LONG TERM: SCA seas from long pd swell from slowly
weakening Jose will still be continuing Fri ngt into Sat.
Following this, there may be a break in from SCA conditions
Sun and Mon before wv hts increase back into the SCA range by
midweek from long distance swell radiating from Maria as it
tracks well SE of our waters. Kept close to WW3 wv guidance for
fcst wv hts. Wv pds will be exceptionally long, ranging from 12
to 16 sec, with the longest pd swells erly next week from
Maria.

&&

.TIDES/COASTAL FLOODING...
Currently long period swell from Jose which is running at 12
seconds/7-8 feet continues to enter the Gulf of Maine. Waves are
expected to to slowly subside Tonight and Friday. Have extended
the high surf advisory into Friday afternoon. Concern is that
long period waves high impact in the surf zone, and can run up
much higher on the shore than shorter period waves resulting in
the danger of spectators being washed into the ocean. Dangerous
Rip Currents are also expected.

Some minor beach erosion is possible. However, runup,
splashover, flooding due to storm surge are not expected.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...High Surf Advisory until 6 PM EDT Friday for MEZ029-030.
MARINE...Small Craft Advisory until 6 PM EDT Friday for ANZ050>052.

&&

$$

Near Term...Foisy/Mignone
Short Term...VJN
Long Term...VJN
Aviation...Foisy/Mignone/VJN
Marine...Foisy/Mignone/VJN
Tides/Coastal Flooding...Mignone