FXUS61 KCAR 171719

Area Forecast Discussion
National Weather Service Caribou ME
1219 PM EST Sun Dec 17 2017

High pressure will build across the region today and move east
tonight. A weak area of low pressure will cross the region

1215pm update...
Winds will quickly diminish after mid-afternoon and set the
stage for plummeting temperatures this evening. Have made
adjustments to further lower temperatures this evening. Most of
the area...except the coast...will drop below zero. Some of the
normally colder northern locations may even drop as low as
-20F before higher clouds increase later tonight. Have entered
lows around 4am rather than 7-8am due to the clouds. For
tomorrow's weak shortwave, have refined the snow forecast with
most activity south of a line from Bangor to Calais. Snowfall
may reach just over an inch south of that line by Monday

Previous discussion...
High pressure will build across the region today with abundant
sunshine and continued below normal temperatures. Afternoon
highs today will range from the low to mid teens north and low
to mid 20s central and down east. High pressure will continue to
build across the region tonight. This should allow for decent
radiational cooling conditions, with light winds and mainly
clear skies expected this evening. Temperatures will fall off
rather quickly after sunset under clear skies and light winds.
However, high clouds will begin to increase across the region
after midnight. Despite the increasing high clouds, lows tonight
are expected to fall to 5 to 10 below across the north and zero
to 10 above across down east areas.

A weak s/wv movg ese from Cntrl QB will bring msly Downeast and
Cntrl ptns of the Rgn lgt sn Mon aftn/erly eve aft increasing
cldnss Mon morn with max snfl upwards of an inch alg the
Downeast coast. Hi Temps will remain sig below avg, but behind
the s/wv Mon ngt, with a lack of llvl cold air and cont'd cld
cvr, ovrngt low temps will be milder.

Another s/wv on the heels of Mon's system will bring the next
opportunity of lgt snfl to msly Nrn ptns of the FA by Tue aftn,
cont into eve, with Downeast and perhaps eve Cntrl ptns of the
Rgn mixing with or even chgng to lgt rn as strong llvl warm
advcn develops with the sfc low tracking well N of the Rgn into
Ern QB. Colder air behind the sfc low then arrives Wed
morn/aftn with brisk NW winds msly Nrn sct sn shwrs and
possible sn squalls.

Much colder and dry conditions will follow for Wed ngt thru Thu
ngt as mdt residence arctic air prevails. Winds will diminish
Thu ngt for some radiational cooling, which will likely be
somewhat lmtd by the presence of hi cldnss.

Many 00z varying dtmnstc model runs have now trended N with the
sfc low(s) xpctd to impact the Rgn later Fri into the weekend.
Of these model runs, we prefer the 00z CanGem attm, with a more
srn track of the low from Srn QB on Fri into Nrn Washington
county by Sat aftn. This solution better matches CPC's outlook
of fcst 500mb ht anomalies in the 6-10 day outlook and
respective sfc temp/precip anomalies impacting our FA durg this
tm in addition to the track record of antecedent events that
occurred with as much llvl cold air in advance ovr our Rgn.
Subsequently, precip types across our FA Fri aftn thru Sat
showing sn N and mixed precip and or rn Cntrl and Downeast
better correspond best to the CanGem solution. With potential
sig equiv precip amts with this event, we will need to monitor
the potential of at least wntr wx advs for ptns of the FA
receiving wintery precip as this event gets closer to the near
term later this week.

NEAR TERM: VFR conditions expected through tonight.

SHORT TERM: VFR conditions Mon morn will lower to MVFR or even
IFR ovr Downeast sites in a pd of lgt sn Mon aftn in erly eve
while Nrn TAF sites remain VFR. All sites will then remain VFR
Mon ngt into Tue morn. Nrn TAF sites will then lower to MVFR or
IFR in intermittent lgt sn Tue aftn into Tue ngt while Downeast
sites lower to low VFR or MVFR in lgt mixed precip, rn , or
rn/sn shwrs. Downeast sites recover to low VFR on Wed while Nrn
TAF sites cont with MVFR SC cld clgs with flurries and isold sn
shwrs. All sites then recover to VFR for Wed ngt and Thu.

NEAR TERM: Conditions will generally remain below small craft
advisory levels through tonight. There will be a few gusts early
this morning up to 25 kt.

SHORT TERM: Initially no hdlns, then winds and seas increase to
SCA later Tue and cont so thru Wed ngt before subsiding below
SCA on Thu. Went with blended WW3/NWPS guidance for fcst wv hts.


Near Term...Duda/MCW
Short Term...VJN
Long Term...VJN
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