NWS Caribou, Maine Area Forecast Discussion



000
FXUS61 KCAR 161011
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
611 AM EDT Fri Apr 16 2021

.SYNOPSIS...
Low pressure will cross southern New England today then continue
south of the Gulf of Maine tonight through Saturday. High pressure
will cross the area Sunday into Monday then slide south of the
region on Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
600 AM Update: Only chg from the prev update was fcst hrly
temps/dwpts based on trends seen from current sfc obs with an
estimated obsvd ovrngt low temp across the FA from the trend of
last ngt`s obs. No chgs were made to fcst aftn hi temps attm.

Prev Disc: Models have been amazingly consistent over the lat 2
to 3 days with the xpctd scenario tdy and tngt with the low
movg toward the Srn Gulf of ME from the mid Atlc states. Namely,
they indicate rn entering far SW ptns of our FA by mid to late
aftn, then contg to slowly pivot nwrd into Cntrl areas this eve
and eventually to most of the N late tngt. With Hi temps xpctd
to reach at least into the lower to mid 40s before the arrival
of precip, initially the blyr will be to warm for snow, but
initial evaporational and nocturnal cooling combined with
dynamic cooling from aloft with greater precip rates with any
left ovr banding should transition precip to all sn within 2 to
3 hrs after sunset Downeast or later onset Cntrl/Nrn areas. Hi
temps across the FA will be sig cooler tdy and inverted, with
far Nrn areas nearing 50 degrees this aftn due to partial
sunshine thru thinner cld cvr before thicker cld cvr arrives
late in the day.

With the sfc low xpctd to exit ESE to S of NS prov by Sat morn,
banding looks to fizzle out in the pre-dawn hrs before reaching
far Nrn areas, where its not certain whether St John vly will
receive any measurable liquid equiv precip by erly Sat morn.
Where the precip band remains intact ovr interior Downeast and E
Cntrl areas, about a 50 mile wide corridor of max snfl
potential of 2 to 3 inches looks possible with lcly higher amts
ovr higher trrn by Sat morn before steady precip tapers to sct
rn-sn shwrs. Sn totals will be diminished alg the immediate
coast with warmer sfc-blyr temps harder to overcome and ovr the
N where there will be little QPF for sn production. Still cannot
completely rule a wntr wx adv tngt for parts of the Rgn, spcly
late, where the best sn banding sets up ovr interior Downeast/E
Cntrl areas, but models still vary widely with liq equiv precip
amts ovrngt, with some solutions relatively lgt cntrd ovr
downeast areas and others more robust with heavier amts as far N
as Cntrl ptns of the FA, with all agreeing that a sharp cut-off
of precip will occur ovr the N.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
Low pressure sliding south of the Gulf of Maine on Saturday will
push a band of moisture north across the area. This will produce
some light wet snow inland and rain along the coast Saturday morning
with just some light rain and wet snow showers during the day
Saturday. A light accumulation of wet snow is possible over east
central areas early in the morning. Any slushy snow on road surfaces
will melt by late morning. As the moisture reaches the north it will
thin out leaving only some light rain and wet snow showers with
little or no snow accumulation. The low will continue to weaken as
it tracks south of Nova Scotia Saturday night with only spotty
showers of rain or wet snow lingering across the area. Sunday will
remain mostly cloudy but dry as the low continues away but some
residual moisture will linger in its wake. Very weak surface high
pressure will build in Sunday night. However, some moisture will
continue to linger across the area bringing a mostly cloudy night. A
spotty rainshower is possible, mainly in western areas. Otherwise,
Sunday night will be dry.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
High pressure building over will allow for more breaks in the
overcast on Monday. However, the high is very weak and will not be
able to advect much dry air into the region so clouds will continue
to linger. Weak upper ridging will build over allowing for some
moderation with inland temps well into the upper 50s across the
area. Tuesday will continue to be mild as both upper ridging and
surface high pressure build nearby to our south. A return
southwesterly flow behind the surface high will allow temperatures
to push into the low 60s across the area. A cold front will approach
on Wednesday. The gradient between the approaching cold front and
surface high pushing off to the southeast will bring a southerly
wind. Some showers, and possibly an organized band of rain, may
push across the area ahead of the front late Wednesday into
Wednesday night. Low pressure may develop along the front,
possibly across our area if the ECMWF is right, or just north of
the region if the Canadian and GFS are right. Moderately cooler
weather with stratus clouds and wind will then follow for
Thursday.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: Tdy...Msly VFR with patchy MVFR SC clgs Nrn TAF sites
til mid morn then Downeast sites lowering MVFR clgs/vsbys later
this aftn in rn. Mdt ENE winds.

Tngt...Downeast sites IFR clgs/vsbys in rn and wet snow. Nrn TAF
sites VFR clgs in the eve, becmg MVFR clgs/vsbys late tngt in
lgt snow with KHUL becmg IFR clgs/vsbys in sn. MDT ENE winds
becmg NNE by daybreak.

SHORT TERM: Saturday: IFR to MVFR. NNE wind.

Saturday night: MVFR, possibly improving to VFR Downeast. N wind.

Sunday: Possibly MVFR north early. Otherwise, VFR. N wind.

Sunday night: VFR, possibly lowering to MVFR north. NW wind.

Monday: VFR, NW to W wind.

Monday night: VFR. W wind.

Tuesday: VFR. W to Sw wind.

&&

.MARINE...
NEAR TERM: E to NE winds will cont to ramp up to gale force
gusts by aftn, contg thru much of the ngt before dmnshg back to
SCA by daybreak Sat. Wv Hts will reach arnd 10 ft ovr the open
waters late tdy thru the ovrngt before beginning to subside by
erly sat morn. Kept close to blended model guidance for fcst wv
hts with wvs mainly composed of two spectral groups; W
propagating 3 to 5 sec short fetch group and an increasing NW to
W propagating 8 to 10 sec open Atlc swell/storm wv group which
will become the main single wv group by this aftn.

SHORT TERM: NE Winds will remain SCA and possibly marginal gale
Saturday, diminishing to SCA then below SCA Saturday night.
Winds are then expected to remain below SCA through Monday
night, and may increase to gale on Tuesday in S winds.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Gale Warning until 4 AM EDT Saturday for ANZ050>052.

&&

$$

Near Term...VJN
Short Term...Bloomer
Long Term...Bloomer
Aviation...VJN/Bloomer
Marine...VJN/Bloomer

NWS CAR Office Area Forecast Discussion