Area Forecast Discussion
Issued by NWS Caribou, ME-- Remove Highlighting --
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FXUS61 KCAR 220506
Area Forecast Discussion
National Weather Service Caribou ME
106 AM EDT Thu Sep 22 2016
High pres will continue to bring fair conditions into Thursday.
Low pres from central Canada will move across the region Thursday
night into Friday bringing rain to the region. Colder air is
expected for the first full weekend of Autumn as another
Canadian high pressure builds in behind the low.
.NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --107 AM Update...
Adjusted the hrly temps/dewpoints to match the
latest conditions as cooling ongoing. Daycrew`s overnight low
temperatures look good. Decided to add fog for the river valleys
right around sunrise. Bufkit soundings support this w/some
radiational cooling. IR satl imagery showed some clouds across
northern Quebec dropping se. This is in response to a weak cold
front as seen on the meso analysis moving across the St. Lawrence
River. Given the trajectory of the cloud shield, expecting most of
this to remain n of the border.
A dry secondary cold front will slowly cross the region with
little even in the way of cldnss. This front, which will stall
near the Downeast coast on Thu, will provide a track for low pres
from the upper great lks to track alg aft this pd.
Meanwhile, aft a ngt which will feature diminishing winds, fair
conditions, diminishing winds and cooler ovrngt lows, Thu will
begin with msly sunny skies. Increasing cldnss will follow for
Thu aftn with the leading edge of rain reaching far NW ptns of
the region late in the aftn as the low from the great lks begins
to apch. Between cooler fcst aftn 925-850mb temps and increasing
aftn cldnss, hi temps Thu will be 5 to 8 deg cooler than this
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.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Rain will spread into the forecast area Thursday night as low
pressure treks across the forecast area. The low will move into
New Brunswick Friday morning and drag a cold front across Maine in
its wake. Much drier air will follow the front, so expect the rain
will taper to showers by Friday afternoon with the bulk of the
activity shifting toward Downeast and the coast. There` still some
model spread as to where exactly the low will track, which will
have a direct impact on exactly where the heaviest rain will fall.
For now, have stayed closer to the NAM, GFS, and Canadian as the
ECMWF looks to be a southern outlier. This would place the
heaviest rain along and north of a Houlton- Greenville line. These
areas would get a half to three-quarters of an inch, with some
higher amounts possible. South of this line, rainfall totals would
be a quarter to a half of an inch, less than a quarter inch along
the immediate coast.
As mentioned above, much drier and cooler air will spread into the
area late Friday and Friday night. Clearing skies will allow
temperatures to drop into the mid and upper 30s across much of the
northern half of our forecast area, with some 20s possible in the
usual cold valley locations in the North Woods. Central and Downeast
areas will bottom out in the upper 30s to lower 40s. A party to
mostly sunny day follows on Saturday. It`ll be cool side though,
ranging from the lower 50s across the Saint John Valley to the lower
60s Downeast. Winds will be breezy out of the northwest as well,
adding to the brisk feel of the day.
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The model guidance is in good agreement through the period. An
upper level low over eastern Quebec and a high pressure ridge over
the eastern half of the USA into central Canada will be the
dominate weather features through most of the period. The upper
level low will slowly drift southeast and will finally move south
of the area Tuesday evening. The high pressure ridge at this time
is forecasted to block a new frontal that will dominating the
weather through the southeast and upper midwest. The high pressure
ridge will remain across Maine through the end of the period.
Loaded a blend to smooth out the minor differences in the models.
Loaded NAWAVE4 for seas in the coastal waters. Loaded windgust by
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
NEAR TERM: Contd VFR is xpctd all TAF sites overnight and thru 00z
SHORT TERM: Rain will spread across the state Thursday night into
Friday morning, resulting in prevailing MVFR conditions, locally
lower to IFR at times. A cold front will cross the area Friday
afternoon, bringing rain to an end and improving conditions to VFR
at all sites by 00z Sat. VFR will then prevail through Saturday
night. Scattered showers and MVFR ceilings will develop over the
northern terminals Sunday afternoon and again Monday afternoon.
NEAR TERM: No hdlns xpctd, with long pd 10 sec swell will
continue ovr our waters tngt into Thu, with wv hts 2 to 3 ft ovr
outer coastal zones, and 1 to 2 ft alg the immediate coast. Kept
close to WW3 wv guidance for fcst wv hts.
SHORT TERM: Low pressure will move north of the waters Thursday night
into Friday morning. Winds and seas are expected to increase as a
result and may briefly approach Small Craft levels before subsiding
behind a cold frontal passage Friday afternoon/evening. No
headlines have been issued at this point, but they may be needed
as model trends become more clear. High pressure will then build
over the waters, along with quiescent conditions, through the