Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 121437

Area Forecast Discussion
National Weather Service Caribou ME
1037 AM EDT Mon Apr 12 2021

Canadian high pressure will build south into the area today
through Thursday. Low pressure from the mid Atlantic states will
then begin to track well south of the region on Friday.

1020AM update...Moist NE flow continues with cloudy conditions
for most of the area. That limits highs for today and will cap
lows tonight to the upper 30s to lower 40s. The stronger NE flow
will be mostly over Downeast Tuesday...where it will be cooler
and cloudier. Further north and west, some afternoon clearing
will likely generate highs closer to 60F on Tuesday.

Previous Discussion...
NE flow continues today as a backdoor cold front slides
through. Temperatures wont see a notable drop off, rather
conditions will remain humid with drizzle ending in the morning.
Shallow dry layer at the surface will limit drizzle from
becoming too widespread, and rules fog out. The saturated layer
between 850 and 950mb will be the source of cloud cover through
the day across the north into the Central Highlands. In the mid-
afternoon, enough drying through this layer is expected to
provide the coast and portions of Downeast with some sun. This
may quickly cause a rise in afternoon temperatures into the mid
to upper 50s.

Wind will be tricky to determine today. Typical diurnal mixing
wont be the main driver given the cloud cast for much of the
area and steady sfc temps, but low level lapse rates will be
elevated and eastern Maine will be at the exit region of a
rather unique 40-50 kt NE LLJ coming out of the Maritimes.
Forecast soundings bring mixing levels up to 900/925, which
would tap into some of this jet, 25-32 kts. Momentum transfer
brings the chance for a few gusts near 30 mph during the morning
through noontime, before the divergent quad moves south over
the waters this evening.

Clouds remain over the area tonight. Another warm night may be
on tap, but that will depend on how deep the cloud layer is to
trap remaining daytime heat. Did keep temps moderate, but cooler
than Sun night.


Very strong upper lvl/high latitude blocking will cont ovr the
N Atlc and Ern Can, with swrd displaced strong upper lvl wrlys
and jet core/streaks ovr the Cntrl and Srn U.S. This pattern
will initially keep our FA from any organized precip thru all of
the short term and at least the beginning of the long term.

On Tue, llvl 950-800mb moisture from the Can Maritimes will be
holding over the FA, keeping bkn-ovc ST/SC cld cvr ovr Ern ptns
of the FA and keeping hi temps from getting abv lower to mid
50s. Drier llvl air then arrives from the N Tue ngt, likely
holding thru Thu with clr to ptly cldy skies and milder aftn hi
temps due to greater sunshine.


Upper lvl low pres advc ESE from the midwest will induce a
secondary low off the Mid Atlc states coast Thu eve. This
secondary low will rapidly become captured by the the upper low
by Fri eve, which will slow the NE advc of deeper mid to llvl
moisture into our FA. Clds will begin to increase spcly ovr
Cntrl and Downeast areas Thu ngt with rnfl holding off until Fri
ovr these areas as the cld canopy xtnds into Nrn ptns of the FA.

The consensus of longer range models keep the best potential of
rnfl ovr Cntrl/Downeast areas Fri aftn into Sat morn, with
possibly enough nocturnal cooling and dynamic cooling from alf
for rn to mix with and perhaps chg to wet sn ovr inland areas
late Fri ngt into Sat morn, with lmtd accumulation possible. The
nrn most precip, most likely in the form of lgt rn could make a
run briefly alg the NB border as far N as NE ME Sat aftn if the
00z dtmnstc GFS and ECMWF models are correct, but this
uncertain. In fact, with the sfc low tracking well S of NS prov
on Sat, we really couldn`t go much higher then maximum hi chc
PoPs with this event Fri Ngt into Sat morn even alg the Downeast
coast, and we are going abv WPC PoPs attm. Hi temps Fri and Sat
will be cooler with cld cvr and/or precip arnd, but should rise
well abv frzg both days, making wet snfl outside of late ngt
and erly morn hrs nearly impossible outside of very hi trrn.

Following the departure of the low Sat ngt, skies should
partially clr with ptly sunny skies and milder aftn high temps.


NEAR TERM: MVFR clgs through the morning. Patchy drizzle tapers
by noon at all terminals. Winds NE with gusts up to 25 kt
through noon, becoming 10-15 kts.

SHORT TERM: Tue Morn...MVFR cigs likely. Lgt winds

Tues Aftn - Fri Morn...VFR. Lgt winds

Fri Aftn...MVFR clgs/vsbys with rn Downeast sites. VFR Nrn TAF
sites. Lgt to Mdt ENE winds.


NEAR TERM: NE winds will increase to 25 kt this morning through
early afternoon with a SCA. There will be a brief lull in winds
early this evening, before shifting N and increasing to around
25 kt overnight on the coastal waters. Drizzle this morning may
limit visibility, before becoming sunny this afternoon.

SHORT TERM: SCA conditions will likely continue Tue and Tue ngt
mainly ovr outer MZs050-051. After a pd of below SCA winds/seas
for Wed and Thu, the next potential of SCA or greater winds and
associated seas will Fri thru Sat as low pres from the mid Atlc
states tracks well S and E of our waters. Kept close to blended
model guidance for fcst wv hts with wvs mainly composed of two
spectral groups; a SW propagating 4 to 7 sec short fetch group
and a N propagating 10 sec open Atlc background swell.


MARINE...Small Craft Advisory until 8 AM EDT Tuesday for ANZ050-051.



Near Term...Cornwell
Short Term...VJN
Long Term...VJN
Marine...Cornwell/VJN is the U.S. government's official web portal to all federal, state and local government web resources and services.