Area Forecast Discussion
Issued by NWS Caribou, ME-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCAR 220216
Area Forecast Discussion
National Weather Service Caribou ME
1016 PM EDT THU JUL 21 2016
A cold front will approach Thursday night and cross the region
on Friday. Another secondary cold front with an upper level low will
approach from the northwest on Saturday and cross the area Saturday
.NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --1015 pm update...
S/wv conts to mv thru wrn Quebec at this time. 00z raob showed
favorable profile fr storms near Montreal with instability still
present along with favorable shear. However, latest radar and
lightning trends indicate storms are having a tough time holding
together tonight. Thus hv lowered pops acrs nrn Maine to just
isolated thru 07z tho this may be a little too optimistic and may
need to be lowered further.
This wl eventually impact svr wx potential for tomorrow. If
showers/storms fizzle out bfr they mv into nrn Maine, entire area
wl be at risk for strong-svr storms tomorrow along pre-frontal
trof depending on sfc htg. 00z NAM is similar to RUC in weakening
showers until aft 12Z Fri with CAPE values ranging anywhere btwn
1000-2000 J/kg. 0-6km shear progged to be btwn 25-35kts acrs the
north late mrng ahd of pre-frontal trof with 30-40kts in the aftn
acrs srn zones. As of now it looks as tho best chc for organized
svr wx wl be drg the aftn in Downeast zones.
No chgs needed with this update other than to lwr pops by svrl
more hrs tonight.
Prev discussion blo...
Strong thunderstorms possible on Friday.
Decaying MCS is forecast to move across the New England region
overnight into Friday morning. Showers and possible thunderstorms
are expected to move into western areas this evening and then move
east overnight into Friday morning. Elevated instability is there
w/MU CAPE of around 500 joules w/0-6km shear of 35 kts. PWATS
increase to 1.3+ inches overnight. Therefore potential for some
strong storms is there but the offsetting items are high
convective inhibition and a stable llvls. Thinking is the activity
will breakup and weaken as it pushes east overnight and decided
against any enhanced wording attm. Some storms could contain brief
heavy rainfall given the high PWATS. Increasing humidity overnight
w/mins staying in the 60s.
Attention turns to Friday afternoon as the cold front apchs from
the west. Activity in the morning looks like it will stabilize
portions of northern and western Maine w/clouds. Plus lapse rates
drop off from west to east. Instability appears to set up further
east and south mainly from a line of say Mars Hill southwest
through Mt. Katahdin on south into the Central Highlands and
interior Downeast including the Bangor region. This is not saying
that NE Aroostook County(Caribou-Presque Isle) could not see some
strong storms. SPC has kept most of the New England region
including all of Maine in a Sight Risk for Severe Thunderstorms
w/the main threat being strong wind gusts(55+ mph) and hail. Heavy
rainfall is also possible. SB/MU CAPES from the NAM and GFS hit
values of 1500-2000 joules w/0-6km shear of 30+ kts. Low/mid
levels lapse rates are progged to be 6.5+ c/km which is good
enough to help w/initiation. Plus, 35-40 kt at 700-500mbs will
aid in the forcing. Plus, this region has the best potential to
heat up w/temps hitting the 80s. Kept enhanced wording in the
forecast. Later shifts can decided on whether to upgrade the
wording overnight for the threat. The Hazardous Weather Outlook
will be updated this afternoon. Further north, clouds will keep
daytime maxes back in the upper 70s to lower 80s.
-- End Changed Discussion --
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
An upper level trough of low pressure will be slowly pushing over
the area Friday night as a weak surface trough moves across the
region. Thunderstorms early Friday evening may contain some gusty
winds or heavy rainfall early. Otherwise, the thunderstorms should
taper off Friday night. Lingering showers will likely remain over
the region as heights lower. A weak secondary shortwave trough
will slide into the area late Friday night into Saturday. The
surface trough on Saturday will be just off the coast as winds on
the surface become northwest. Showers will be likely, and a few
thunderstorms are still possible, mainly resulting from the
cooling aloft. Otherwise, Saturday will remain mostly cloudy. The
upper level trough will slowly move east of the region on Sunday.
Low heights and some cool air aloft may produce a few showers in
eastern areas, mainly early Sunday. Otherwise, Sunday will bring
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Skies will clear Sunday night as high pressure begins to build into
the region. This will be followed by plenty of sunshine and a warm
day on Monday. A fast moving shortwave trough will approach Monday
night bringing increasing clouds and possibly a thundershower in
western areas late at night. Tuesday will then be partly cloudy
and warm. Weak surface troughing may spawn a thundershower or two
around the area Tuesday. High pressure should then push down from
central Canada on Wednesday to bring sunshine and drier
conditions. The dry weather will likely last through Thursday as
the high builds over.
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: VFR expected next 24 hours. Any terminal that receives
strong storms will briefly drop to MVFR/IFR but confidence remains
too low to include in forecast at this time. Expect srly winds
arnd 10kts, occasionally gusting to nr 20kts in the afternoon.
SHORT TERM: MVFR conditions are likely Friday night into Saturday
with locally IFR conditions in any heavier showers or lower
stratus clouds. MVFR Conditions may continue Saturday night but
should improve to VFR on Sunday as skies partially clear. VFR
conditions are likely Monday into Monday evening, possibly
lowering to MVFR late Monday night as a new trough of low pressure
moves in. MVFR to VFR conditions are expected on Tuesday.
NEAR TERM: Seas will gradually come up this evening into Friday
hitting 3-5 ft over the outer zones by late in the day. Further
inland, seas around 2 ft. There will be a moderate risk for rip
currents given the ssw fetch. Winds 10 to 15 kts in Friday w/some
gusts to 20 kts ahead of the apchg cold front.
SHORT TERM: A few wind gusts may reach 20 kt Friday evening over
the offshore waters. Seas up to 5-6 feet over the offshore waters
will require an SCA for hazardous seas Friday night. Winds and
seas are expected to be below SCA Saturday through Monday.
MARINE...Small Craft Advisory for hazardous seas from 8 PM Friday to 8
AM EDT Saturday for ANZ050-051.