Area Forecast Discussion
Issued by NWS Caribou, ME-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCAR 240431
Area Forecast Discussion
National Weather Service Caribou ME
1231 AM EDT Sat Sep 24 2016
High pressure will slowly build toward the region through Monday
as low pressure over the eastern maritimes slowly moves east into
the open north Atlantic. Low pressure from the great lakes will
then slowly approach the region Monday night and Tuesday.
.NEAR TERM /THROUGH TODAY/...
-- Changed Discussion --Update: Mainly clear skies continue across the region early this
morning. Temperatures have already fallen into the low to mid 30s
across parts of northwest Maine so the frost advisory looks good.
Some patchy river valley fog is also being observed and the going
forecast has this handled nicely. Bottom line is no significant
changes to going forecast.
Orgnl Disc: As skies have begun to clear up north, temps in the
northern part of the CWA have actually increased post-cold front.
However, this will be short-lived, and a significant drop in temps
is expected overnight. Patchy frost is likely in the North Woods
tonight, and it may extend east toward the St. John Valley and
northeastern Aroostook. However, did back off on the frost a touch
and bumped up expected lows by a degree or two up north due to
very strong 925mb winds and possible patchy cloud cover, both of
which could act to limit inversion strength, decoupling, and
decrease in the winds. Valleys and other protected locations stand
the best chance of decoupling and having temps drop low enough for
The frost potential was the most challenging part of the forecast,
and will need to be monitored closely. Temps will be a good deal
cooler than normal tonight thru Sat. Lows will range from mid-30s
in the North Woods to the mid-40s at the coast, and highs Sat will
be from the low 50s up north to the low 60s Downeast. Otherwise,
high pres building in from Canada should bring dry weather and
partly to mostly sunny skies to the state.
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.SHORT TERM /TONIGHT THROUGH MONDAY/...
Broad cyclonic flow over the state for this period with northwest
flow firmly established. Temperatures will run below average with
850mb temps running close to freezing for most of this period.
Saturday night will be cold again with lows down into the 30s and
low 40s. It could be colder but it looks like a low-level stratus
deck with advect in across the region capping radiational cooling.
Sunday that low level stratus deck will remain in place across the
north, with partly cloudy skies closer to the coast on Sunday. It
will be a brisk day though with gusty northwest winds dropping the
wind chill down into the 40s north and 50s Downeast. There could
be a few sprinkles across the Northwoods and the County during the
afternoon, but it will remain mostly dry. Another cold night on
Sunday night with clouds diminishing in area coverage. This should
allow some Northern locations to get down into the lower 30s with
upper 30s across Interior Downeast and the Penobscot valley
region. Monday looks like a nice fall day with shortwave ridging
at all levels developing. High clouds will be streaming in towards
the end of the day with highs rebounding back towards normal.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Ridging across the area will bring a mostly clear and tranquil night
Monday night with some patchy valley fog likely by early Tuesday
morning. Our focus will then be on a rapidly approaching occlusion
running out ahead of a low in the great lakes. Clouds will increase
Tuesday morning and a band of rain will likely cross the area during
the midday and afternoon. However, the latest ECMWF has the front
moving through earlier in the day Tuesday so the timing remains
uncertain. The occlusion may slow down as it reaches the eastern
part of our region on Wednesday. This could prolong rainfall in
eastern areas on Wednesday. Otherwise, Wednesday will be cloudy to
partly sunny following the frontal passage. A large ridge of high
pressure is then expected to build into the area going into the
latter part of the week. This should bring mostly sunny and dry
weather Thursday, Friday, and possibly into the weekend.
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: After a very challenging environment with low stratus,
rain, and mist playing havoc with TAFs for much of the day, dry
air moving in is leading to improvement at all sites. A few sites
are still holding on to MVFR CIGs as of publication time, but all
sites are expected to shift to VFR conditions by the evening.
Anticipate VFR conditions at all sites thru Sat evening.
SHORT TERM: Some MVFR cigs possible across the northern TAF sites
on Sunday afternoon, but no impacts to KBHB/KBGR. Winds could be
gusty on Sunday afternoon out of the northwest, but gusts will
remain below 25mph. Monday looks to be an excellent aviation day.
NEAR TERM: N-NW`ly winds will remain a bit elevated early tonight
as cooler air filters in behind the recent front. Wind gusts may
exceed 20kts at times, but based on 925mb winds, expect gusts to
remain below SCA limits. Conditions calm down later tonight into
SHORT TERM: Winds will be offshore Saturday night through Sunday
night with gusty NW winds. Gusts should remain below 20kts
through the period, with waves building close to 5 feet across the
outer portions of zone 051 and 051 on Sunday. Winds will subside
along with seas during the day on Monday.
-- Changed Discussion --ME...Frost Advisory until 8 AM EDT this morning for MEZ001-003-004.
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