Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 171439

Area Forecast Discussion
National Weather Service Caribou ME
1039 AM EDT Tue Sep 17 2019

Canadian high pressure will build across the region through
Wednesday night, then slowly settle south over the Gulf of
Maine Thursday through Saturday.


1020 AM Update: A large channel of clrg has opened up in the SC
cld deck ovr N Cntrl areas late this morning in addition to SE
ptns of the FA, both of which is experiencing a little more
enhanced downslope from upstream highland areas ovr the Gaspe
Peninsula and Nrn NB highlands, respectfully. A little band of
shwrs ovr NB prov is movg SW toward Ern Downeast areas, but the
trend should be toward weakening as they cross the Ern ME
border, do for now will keep isold shwr mention ovr Downeast
areas into the aftn.

Otherwise, we will cont to show a slowly decreasing cld cvr
trend from N to S across the FA this aftn into eve. lastly, fcst
hrly temps/dwpts have been updated into the aftn from trends
seen in latest sfc obs with no chgs to fcst aftn hi temps attm.

Orgnl Disc: A surface trough and associated low-level moisture
will continue to push southward today while colder and drier air
arrives in northern zones this morning and sinks southward
through tonight. The surface trough will maintain cloudy skies
in the southern half of the forecast area and a few afternoon
sprinkles towards Washington and Hancock counties. Hard to
envision more than a hundredth of an inch anywhere with a modest
unstable layer near 850mb yielding less than 50 J/kg of CAPE.
The colder air working its way south will bring dew points
dropping into the 30s and 850mb temps dropping towards 0C
tonight. It`s the coldest air mass of the season to date. The
1028mb high will be dropping due south from northern Quebec.
Skies will be clear to start the evening towards northern
Aroostook County and the clearing will spread southward to the
coast tonight. The existing Freeze Watch area continues to have
the longest duration of clear skies and light winds and there`s
a real threat of temperatures dropping as low as the mid to
upper 20s in the normally colder spots of Aroostook, northern
Penobscot and northern Piscataquis counties. Will continue the
Freeze Watch to highlight the most vulnerable areas and let the
day crew finalize the exact areas covered by advisories or


High pressure will remain across the region Wednesday through
Thursday night with mostly clear skies. Favorable conditions
for radiational cooling will support the chance of frost across
much of the forecast area Wednesday night, including Downeast
areas. Sub-freezing temperatures are also possible, particularly
across the normally colder locations of northern Maine.
Temperatures will be at below normal levels Wednesday, with near
normal level temperatures Thursday.


High pressure will remain across the region Friday into Sunday,
with mostly clear/partly cloudy skies. A cold front will begin
to approach later Sunday with increasing clouds in advance of
the front. Could also have a slight chance of showers late,
mostly across northwest portions of the forecast area. The cold
front should then cross the region Monday with showers.
Temperatures will be at above normal levels Friday through


NEAR TERM: Prevailing condition will be VFR outside of some
morning MVFR cigs possible from PQI southward to the coast.
There`s also the risk of shallow patchy valley fog near sunrise
Wednesday morning.

SHORT TERM: Wednesday through Saturday...Generally VFR.
However, variable conditions possible with any patchy valley fog
Wednesday night.


NEAR TERM: A few northeasterly gusts may reach up to 20 kt this
morning as colder air moves over the relatively warmer waters.
Winds will tend to decrease later today into tonight and become
more easterly. Seas will remain around 2 ft or less with a mix
of locally wind-driven waves and a longer period south swell.

SHORT TERM: Winds/seas will remain below small craft advisory
levels Wednesday through Thursday night. Seas will then build
to 5 to 8 feet in southeast swell Friday into Saturday.


ME...Freeze Watch from late tonight through Wednesday morning for



Near Term...VJN
Short Term...Norcross
Long Term...Norcross
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