Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 010031
Area Forecast Discussion
National Weather Service Gray ME
831 PM EDT WED AUG 31 2016
A slow moving cold front will continue to sag south through New
England tonight and will push offshore on Thursday. High
pressure will gradually build in from the west Thursday night
through Friday. High pressure will crest over the region early
Saturday before shifting offshore. Although confidence is low...
sub-tropical low pressure will move north along the east coast
Saturday night and Sunday and may affect southern New England
Sunday night into Monday.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --830 PM Update...Forecast remains on track. Scattered showers and
thunderstorms across Coos County NH will gradually work eastward
and likely gradually weaken with the loss of diurnal heating as
they move through the western ME mountains.
545 PM Update...Just a few minor adjustments to the forecast for
this evening and overnight based on latest trends in radar and
mesoscale model data. Showers and thunderstorms across
northernmost VT and southern Quebec should move into Coos County
NH and the western ME mountains over the next couple of hours. The
activity will probably weaken from it/s present state but still
expect some heavy downpours and occasional lightning strikes.
Otherwise, further south, expect dry weather except for perhaps a
Current 500 mb trough approaching from the west showing a little
disorganizations with weak waves rotating just south of the closed
low over Quebec and anther wave lagging a bit zonally and
crossing into PA/NY this afternoon. First wave to the north will
pass thru late this afternoon and evening and is currently setting
off sct convection in srn Quebec and along the intl border of NY.
This will track thru the far nrn zones between 21z and 01z and
will see a few sct SHRA and maybe a TSRA. Then later tonight,
after mid night will see another threat for showers in the
southern zones associated with the wave to the south. These are
less likely to have any lightning. OVernight lows will range from
the upper 50s in the mountains, where the front should cross
before daybreak, and the mid 60s in the south, which will see a
surge in low level moisture ahead of the front, producing some
fog as well.
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.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
As upper level wave flattens early Thu, the front will slow to a
crawl as it hits srn NH and the coastal plain of ME, this will
keep a fair amount of clouds around and linger the threat for
SHRA/TSRA in these areas into at least early afternoon on Thu. The
front should eventually move offshore with some clearing, from N
to S, during the mid to late afternoon. Highs will range from the
upper 70s to around 80 in the south to only around 70 in the north
behind the front. Will also a reduced rip risk at least for
Thursday night will see better clearing, but low level moisture
will linger closer to the coast. It will be cooler everywhere with
lows near 50 in the north to around 60 on the coast.
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
High pressure building in from the west on Friday will produce
a mix of sun and clouds and seasonable temps across the region.
High temps will range from the mid 60s to lower 70s north and
in the lower to mid 70s south.
High pressure will crest over the region Friday night. Clear
skies and light winds will allow for good radiational cooling
with lows ranging through the 40s north and lower to mid 50s
High pressure will slide offshore on Saturday. Expect the
majority of the day to feature abundant sunshine with highs
generally ranging through the 70s from north to south.
Forecast confidence drops off at this point as remains of TD 9
heads up the east coast. Still some differences in timing and
track of this system with the new GFS hugging the east coast and
weakening as it moves north to the vicinity of Long Island by
Monday morning. After another nice day Sunday this would bring
some light rain into southern zones late Sunday night into Monday.
New ECMWF has been trending toward the GFS solution for the
past several days and this trend continues this afternoon...
although the ECMWF track remains just offshore over the warmer
waters north of Hatteras on its trip northward maintaining a
slightly lower central pressure. This solution would also bring
clouds and a little light rain into coastal and southern interior
zones on Monday.
In any case...expect upper level ridging building in from
the west on Tuesday to finally push this weakening system
eastward. Expect both days to be sunny and warm with highs
pushing well into the 80s by Wednesday.
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
Short Term...A period of IFR or lower is expected during the pre-
dawn at KHIE/KLEB/KAUG. Could see MVFR fog at other terminals, but
confidence not high enough for TAF inclusion. VFR is expected Thu
into Thu night, with the exception of valley fog.
Long Term...VFR Friday through Sunday. Some MVFR/IFR ceilings
possible in coastal and southern interior zones on Monday.
Short Term...Swell heights are dropping off a bit tonight and
Thursday, and winds will remain below SCA levels as well.
Long Term...SCA`s may be needed late Sunday into Monday.