Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 172302
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
602 PM EST Fri Nov 17 2017

.SYNOPSIS...
Low pressure will continue to exit across the Canadian
Maritimes overnight as high pressure builds across from the
west. The high will move east on Saturday. Another low will
track toward the area Saturday night through Sunday.

&&

.NEAR TERM /THROUGH SATURDAY/...
540 PM Update: Latest sat imagery is showing the back edge of SC
cld cvr progressing a little more slowly then prev anticipated,
so we adjusted cld cvr to delay clrg ovr NE ptns of the FA til
late tngt. Latest radar ref imagery is also showing weak St
Lawrence sn flurry bands affecting xtrm NE ptns of the Rgn,
which we now include in wx grids for the next few hrs.

Otherwise, only minor chgs to fcst hrly temps/dwpts/ovrngt fcst
lows based on trends seen from latest avlbl sfc obs.

Orgnl Disc: Surface and upper level low pressure will continue
to exit through the Canadian maritimes overnight to be replaced
by surface and upper level ridging by Saturday morning. The
gusty northwest winds will continue into this evening as a tight
pressure gradient remains in place across the area. However,
the wind will begin to subside toward daybreak Saturday as the
gradient weakens and the high builds across from the west.
Expect mainly cloudy skies this evening to give way to partial
clearing overnight. Lows tonight will generally range from the
mid teens to around 20 across the north and lower 20s across
central and downeast. After a mainly sunny start to the day,
Saturday will see increasing high and mid clouds by afternoon in
advance of the next low tracking toward the region from the
west. However, it will remain dry as any precipitation
associated with the next system holds off until after dark
Saturday. Highs on Saturday will range from the mid to upper 30s
north and lower 40s central and down east.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Precipitation will spread from SW to NE over Sat night.
Depending on how cold the lowest levels get Sat PM and early
overnight hours, overrunning warm air could lead to some early
snow and then mixed precip overnight. Any mixing would be mainly
north of a Greenville-Houlton line between 00z and 06z Sun, with
all rain expected by daybreak Sun. As of now, the NAM appears to
be the strongest on mixed precip potential, but the GFS is not
too much warmer, so it seemed prudent to include the mix
potential.

Gusty S-SE`ly winds will pump warmer air into the CWA after 12am
Sun, and pretty widespread rain is expected into Sun afternoon
as low pressure moves NE down the St. Lawrence Valley. There is
some disagreement on the path of the main low and whether or not
a coastal low will develop, and for now the forecast reflects
the main low passing just north of the state Sun afternoon with
no significant coastal low development. As the low passes to the
north, rainfall will diminish from S to N Sun eve, with just
some lingering snow showers expected across the Crown of Maine
and western North Woods through early Mon morning.

Regarding possible headlines in the short term, at this point am
not convinced of the need for any wind headlines. Typical
parameters we look for to get advisory level winds for Downeast
are not met later Sun or Sun night. That said, will need to
watch for high winds in the Central Highlands and Quebec border
(mainly zones 3, 4, and 10) behind the cold front. A Gale Watch
seems quite likely, once the current marine headlines expire.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Weak ridging likely to bring dry weather Mon night into Tue
morning. A weak shortwave moving through Canada may push a front
across the area Tue night or Wed AM. There will likely be some
rain/snow showers with this front across the north and west
zones, but kept POPs to low- end Chance for now due to
disagreements on timing and also uncertainty on the coverage.
Expecting a break in the weather Wed into Thu. All models point
to the potential for a trough and associated surface low
crossing the area Fri and Fri night, though there are
significant disagreements on how deep the trough will be and the
strength of the surface low and coverage of precip. Did lean
toward the stronger CMC/ECMWF solution, but kept POPs to Chance
or less for now.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MVFR ceilings late this afternoon will give way to
VFR and decreasing clouds overnight. Northwest winds will gust
up to 35 kt this evening and then diminish overnight. Light
winds and VFR conditions can be expected on Saturday.

SHORT TERM: VFR conditions Sat eve will quickly deteriorate to
IFR and even LIFR conditions late Sat night into Sun AM, with
these reduced conditions expected to continue into early Sat
afternoon. Improvement back to MVFR or VFR conditions are
expected later Sun eve into Sun night, though local IFR
conditions are possible in any lingering snow showers for KPQI
to KFVE through 12z Mon. VFR conditions then expected Mon and
Tue, with another round of rain and/or snow showers Tue night
into Wed AM bringing possible MVFR or IFR conditions.

&&

.MARINE...
NEAR TERM: Small craft adv conditions are expected the
remainder of the night. Winds/seas will remain below small craft
advisory levels early Saturday before increasing by later
Saturday afternoon.


SHORT TERM: Borderline SCA criteria onshore winds are expected
Sat night into early Sun AM, with gale force gusts expected
later Sun morning into Sun night as winds shift SW-W`ly. Winds
will decrease some during the day Mon, but likely to remain well
above SCA criteria. Seas initially 3-6 ft Sat eve will build to
10-14 ft for offshore waters Sun afternoon through Sun night.
Seas will decrease some Mon as winds turn offshore, but remain
5-9 ft further from the coast.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 4 AM EST Saturday for ANZ050>052.

&&

$$

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



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