Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 241650
Area Forecast Discussion
National Weather Service Gray ME
1250 PM EDT Mon Oct 24 2016
Low pressure meandering over the maritimes will keep a strong
west to northwest flow over the region through Tuesday, with
upslope snow accumulations expected in the mountains. High
pressure will build in from the northwest Wednesday and Wednesday
night. Low pressure will approach from the west on Thursday and
will cross the region Thursday night and Friday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --1248 PM...Minor ESTF update to reflect the current mesonet and
satellite trends in near term grids.
840 AM...for this ESTF update I made adjustments to near term
grids that reflect both radar and satellite trends and the current
mesonet. I expect cloud cover to expand south and east out of the
higher terrain today with cool cyclonic flow and daytime heating.
500 mb trough and associated sfc low are tracking
across srn new England this morning. With dry air in place, and
best dynamics moving south of the CWA, the precip will pass to our
south. Cannot rule out a sprinkle moving along the NH/MA border
thru about 12Z, but other than it will be dry. Will also see some
clouds moving through with the 500mb trough, but these should
clear out by mid- morning, too. Behind this wave winds will pick
up again and another shot of colder will filter in this afternoon.
The winds will not be as strong as Sunday but gusts of 25-30 mph
will be possible, especially this afternoon. Upslope should get
going again this afternoon in the mountains, but best chance for
accums will be overnight. highs today will range from around 40 in
the mountains, to around 50 on the coast and in southern NH.
-- End Changed Discussion --
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
NW flow continues tonight and another wave will move through the
500mb trough, so any clearing in the south will become partly to
mostly cloudy by evening. This should also help enhance the
upslope flow overnight and could see an inch or two of accums up
to 2500 feet, and 2-4 inches above that. Winds will diminish, but
should keep going at around 10-15 mph in many spots, which will
deter rad cooling in all but the most sheltered areas. Overnight
lows will range from around 30 in the north to the mid 30s in the
Tuesday will get breezy again, although a little less so than
Monday. While upslope SHSN will diminish somewhat in coverage and
intensity, they will continue thru the day, with some accums still
possible in the higher terrain. Some sun can be expected in the
downslope on the coastal plain with highs a couple degrees cooler
than Monday, mostly on the coastal plain, and temps will range
from round to near 50.
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Cyclonic flow will continue over the region Tuesday night and
Wednesday as upper low slowly pulls off to the east. Looking
for mostly cloudy skies Tuesday night with lows in the mid
20s to mid 30s. Clouds will hang tough in the mountains on
Wednesday with downsloping winds producing a mix of sun and
clouds to the south. Highs on Wednesday will range from the
upper 30s to upper 40s.
High pressure building by to the north will bring diminishing
clouds Wednesday evening as upper low pulls away to the east.
Good radiational cooling will allow temps to bottom out in the
upper teens to mid 20s north and upper 20s to near 30 south.
Shortwave approaching from the west on Thursday will bring the
potential for a messy mix of wet snow...sleet and rain over
higher terrain in interior sections of the forecast area
as cold air dams up east of the mountains. Still some timing
diffs between ECMWF and GFS but precip looking more likely to
begin Thursday afternoon in southern New Hampshire and will spread
northeast Thursday evening.
Depending on the track of the surface low expect warmer air to
gradually erode cold air over the region Thursday night as strong
onshore flow sets up ahead of approaching low. Expect mixed precip
in inland areas to gradually change to rain overnight.
Rain will continue on Friday as low pressure crosses the region
and will be tapering off in the afternoon as low pressure heads
into the maritimes. Axis of heaviest precip will likely set up
along the front range of the Whites in good upslope flow with
models showing 1 to 2 inches in these areas. Models also
indicating a fair amount of shadowing northwest of the
Friday night will bring a break in the action as low pressure
pulls away to the east. Models diverging quite a bit for the
weekend so forecast confidence rather low for Saturday and
Sunday. Will likely stay close to super blend pops for days
6 and 7.
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Short Term...VFR expected at all terminals into Tue. W-NW will
gust from 20-25 kts today, especially in the afternoon. KHIE could
see MVFR to IFR flight restrictions tonight, mainly in SHSN.
Long Term...VFR Tuesday night and Wednesday with areas of MVFR
ceilings in the mountains. VFR Wednesday night. MVFR /IFR Ceilings
developing Thursday Afternoon. IFR/LIFR ceilings/vsby Thursday
night and Friday.
Short Term...HAve dropped the gales for SCA outside of the bays,
as W-NW winds will pick up a bit today and persist into Tue
morning, at least.
Long Term...SCA`s likely Tuesday night and Thursday Night.
MARINE...Small Craft Advisory until 8 AM EDT Tuesday for ANZ150-152-154.