Area Forecast Discussion
Issued by NWS Caribou, ME-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCAR 190158
Area Forecast Discussion
National Weather Service Caribou ME
958 PM EDT Tue Oct 18 2016
A warm front will move across the area this evening followed by a
cold front later tonight. High pressure will build across the
region Wednesday through early Thursday. Strong low pressure will
lift north across the region Friday into Saturday.
.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --940 PM Update: Not much chg made to going fcst. latest radar ref
imagery still shows some additional shwrs movg W to E from Ern QB
into Nrn ME. Otherwise, fcst hrly temps and dwpts thru the ovrngt
were updated based on erly to mid eve obs to unchgd fcst lows
posted at 8 am. Hrly fcst temps are still xpctd initially rise
in the ovrngt before falling behind a a late ngt erly Wed morn
cold frontal passage. Lastly, used msly higher trrn wording for
areas of fog ovrngt across the N hlf of the FA due to the advctv
nature of the fog.
Prior Disc: Lowered pops early this evening with radar showing
the region rain free. Still expecting showers to move into the
area, mostly across the north, later this evening as the front
pushes in. Also lowered temps early this evening. Expect mixing to
raise temps overnight as southwesterly breeze increases.
The warm front continues to make slow progress into the forecast
area this afternoon. The heaviest rain associated with the front
is currently in Aroostook County and will exit by late afternoon.
This will leave areas of light rain and drizzle for the remainder
of this evening under a frontal inversion. The air in the warm
sector is very humid with dew points likely to reach over 60F in
the Downeast region tonight. This means that temperatures will
tend to rise most of the night and that fog/drizzle will form for
many areas...especially towards the coast and in higher upslope
The cold front will arrive in the Crown of Maine this
evening and slowly slink southward during the night. Most of the
precip will be in Aroostook County where up to a quarter inch
could fall in the Saint John Valley. Have added isolated thunder
this evening in the north half of the forecast area...mostly north
of a line from Greenville to Houlton where elevated instability
will be sufficient. The line currently in Quebec has been
impressive this afternoon and continuity alone prompts mention of
thunder. As the front moves south later in the night, little if
any precip is expected...especially south of Houlton. The fog will
be eroded in northern zones, but will probably hang around until
morning for much of Hancock and Washington counties. Lows tonight
will be near 50F north and upper 50s for Bangor and the Downeast
For Wednesday, high pressure will build through the day. Cooler
air will be slow to advect southward. As a result, the elevated
overnight temperatures will serve as a springboard to highs in the
60s and 70s. It will probably be one of the nicer days left in
this fall season. Morning clouds from residual moisture to tend to
dissipate by late morning into early afternoon as dry air with the
high advects into the forecast area. It will be windy with gusts
in the 20 to 25 mph range.
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.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
High pressure will cross the region Wednesday night with mostly
clear skies. High pressure will exit across the maritimes Thursday
while low pressure lifts across the Ohio River Valley. A trof will
extend northeast from the low, toward New England. Clouds will
increase early Thursday. Moisture will increase along the trof
through the afternoon which will bring a chance of rain to the
forecast area during the afternoon. The low will track toward
western New England Thursday night, with the trof across northern
Maine. Moisture convergence along the trof will support rain
across northern portions of the forecast area Thursday night, with
rain likely Downeast. An upper level trof will approach from the
west Friday which will support the development of a secondary low
across New England. The approaching upper trof and developing
surface low will draw tropical moisture north across the region.
Isentropic lift, upper level divergence in advance of the
approaching trof and moisture convergence will support rain
across the region Friday. Temperatures will be at slightly above
normal levels Thursday/Friday.
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A deep trough of low pressure will be moving in from the Great
Lakes on Friday as a series of disorganized surface lows move
north toward our region from the south. A weak low associated with
a tropical depression, well off the southeast coast, will be
lifting north northeast as the trough moves in. Latest guidance is
suggesting this low will track well south and east of our region
as the trough nears. However, a frontal low further north, off the
New England coast, will be able to tap into some moisture from
this tropical wave as it lifts north through our region Friday
night. This has the potential to bring significant rain to the
area Friday night before it lifts north of the area on Saturday as
the trough nears. Drier air circulating through the trough will
swing into the area on Saturday. Moisture pooled in the upper
trough will then circulate back into our region late Saturday
night into Sunday as the upper trough lifts to our north. Some
showers are likely Sunday and boundary layer temps may be cold
enough for snow showers over the higher elevations in western
areas. Chilly conditions with snow or rain showers will persist
across the north in wrap around moisture Monday into Tuesday while
Downeast has partial clearing. Wednesday will remain chilly as the
upper trough to our north continues drawing cold air in from the
northwest and Canadian high pressure begins building in from
central Canada. Stratocumulus clouds will likely persist over the
north Wednesday with some sunshine favored Downeast.
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: As the warm front crosses this evening, the trend will
be all sites going to IFR and LIFR due to ceiling and vis. The
poor conditions will be exacerbated by LLWS. Southeasterly winds
up to 60 to 70 kts will be found between FL030 to FL050. Even at
2000 ft, 40 to 50 kt winds are forecast. Most of these winds will
not mix to the surface although FVE could see gusts over 30 kts
this evening. The cold front will tend to remove the IFR ceilings
later tonight in favor of MVFR ceilings. VFR conditions are
expected for all sites by mid to late Wednesday morning and will
continue through Wednesday evening.
SHORT TERM: VFR conditions are expected Wednesday night through
early Thursday, with MVFR conditions starting to develop Thursday
afternoon. IFR/LIFR conditions are expected Thursday night
through early Saturday, with MVFR conditions later Saturday. MVFR
conditions are expected to persist across northern areas Sunday,
with occasional MVFR conditions possible Downeast.
NEAR TERM: The SCA will remain in place with winds and seas
continuing to trend upward this afternoon with some gusts to 35
kts possible. The winds will become more steady through the night
around 25 kts. Seas will increase this evening to nearly 7 feet.
SHORT TERM: Conditions are expected to be below small craft
advisory levels Wednesday night into early Thursday night. Small
craft advisory conditions are then expected later Thursday night
into Friday. Visibilities will be reduced in rain and fog
Thursday night into Friday.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ050>052.