674
FXUS61 KGYX 170815
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
415 AM EDT Sat Aug 17 2024

.SYNOPSIS... High pressure near the Gulf of Maine will maintain
onshore flow and mostly dry conditions through the weekend. A
frontal system approaches late Sunday and crosses the area Monday
into Tuesday bringing the next chance for widespread rainfall.
Meanwhile, Hurricane Ernesto will be tracking north through the
western Atlantic and staying well out to sea. Long period swell from
Ernesto will start to arrive tonight and peak around Monday
bringing high surf and a rip current risk. High pressure then
builds in around the middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The persistent upper low in the Canadian Maritimes will lift out
into the Atlantic today with a mid level ridge axis sliding across
the forecast area. At the surface, an area of high pressure is
centered over southern Nova Scotia and will slowly drift east
through the day. Moist onshore flow beneath an inversion has led
to widespread low clouds and areas of fog to develop early this
morning. While deep layer ridging will keep the forecast area
mostly dry today, mesoscale models suggest low clouds will be
stubborn to scatter out this morning. As low clouds do scatter
out late this morning some mid to high level clouds associated
with a trough to the west of New England will start to spill
into the area. Additionally, there will still be some wildfire
smoke aloft over the area, but this smoke will eventually pull
east of the area as the upper low moves into the Atlantic. This
will lead to some filtered sunshine this afternoon after a
mostly cloudy start to the day.

Long period swell from well offshore Hurricane Ernesto will start to
enter the Gulf of Maine later today, although the greatest swell
will not arrive until late Sunday and Monday. Nevertheless, there
will be an increasing rip current risk late today as the swell first
approaches the Mid Coast. Highs today will generally be in the mid
70s along the coastal plain. Highs increase farther inland to the
upper 70s across the north and low 80s along the CT Valley away from
the marine influence.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
A trough over the Great Lakes will slowly slide east tonight with
high pressure offshore providing moist onshore flow again tonight.
This will bring low clouds and potential for fog along the coastal
plain with chances for showers increasing west to east towards day
break Sunday. Lows tonight will generally be in the upper 50s to low
60s.

The 00Z model suite suggests the trough over the Great Lakes makes
little progress eastward Sunday as Ernesto tracks north through the
western Atlantic. This will keep the best forcing for ascent to the
west of the area and have generally kept slight chance to low chance
PoPs (15 to 30 percent) in the forecast. High pressure offshore will
maintain onshore flow with highs slightly cooler than today.
Long period swell from Ernesto will still be on the increase
approaching 5 feet at 15 seconds towards the Mid Coast first
then spreading towards southern beaches late Sunday. Have gone
with a High Surf Advisory first starting along the Mid Coast to
coastal Cumberland County starting early Sunday morning with the
High Surf Advisory not going into affect for areas south of Cape
Elizabeth until late Sunday. Both Advisories will run through
Monday as that is when the swell and surf look to peak before
subsiding into mid week.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
500 MB pattern goes from not quite zonal weakly amplified flow,
to Omega block by Monday, with trough situated over the CWA to
becoming less amplified again by the end of the week. So,
initially we deal with deepening closed low to our W Sunday into
Monday, which will mean the best chance for precip, then the
closed low sits over New England through the middle of the week,
as it fills, and slowly shift NE by Friday. After the initial
round of showers Sunday-Monday, itll turn much less humid and
cooler through the middle week, with maybe some some isolated
afternoon showers as we sit beneath a cold pool aloft, then
possible a warm trend Friday into next weekend.

Expect showers to become more numerous and frequent Sunday
night, especially after midnight. Light ESE flow and increasing
Tds, should be favorable for fog in many spots as well.
Otherwise, mins should mostly be in the low to mid 60s. By
Monday morning, should see widespread showers and perhaps some
periods of light rain. TSRA are possible as well, especially
away from the coast, and some convection could produce
torrential downpours. Given the onshore and rain cant see maxes
varying too much across the CWA, but the warm tropical air mass
should allow for max temps of 70-75 in most spots. Coolest along
the mid coast. The showers and storms continue into Mon evening
before, the cold front moves through and winds switch to the W,
probably around or after midnight. Mins range from the upper
50s in the mtns to the low 60s in the S.

Tue-Thu will be somewhat similar as the cooler air in the trough
moves overhead. There will be the possibility of a few showers
Tue and Wed afternoon given the cooler air aloft and the closed
low overhead, and this will lead to partly sunny conditions as
well, but the more part it should be dry with highs in the upper
60s to around 70 in the mtns and in the mid to upper 70s in the
S. Overnight lows range from the upper 40s to low 50s in the N,
to the mid 50s in the S. Still dry and maybe a little warn by
Friday.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Onshore flow beneath an area of subsidence will
continue a tricky aviation forecast through this morning as low
cigs and fog periodically impact some TAF sites. On the whole, the
combination of low cigs and fog will continue mostly IFR
conditions through this morning with both periods of MVFR and
LIFR depending on the behavior of cigs. Cigs look to lift later
this morning for improving conditions into the afternoon.
Onshore flow continues tonight for another round of likely
IFR/LIFR conditions while similar to last night there could be
some sites that see periods of MVFR/VFR. Conditions likely
improve during the day Sunday.

Long Term...It looks like all terminals drop to IFR or lower in
fog and low cigs Sunday night, with only minor improvement
during the day on Monday with showers as well. IFR or lower
expected Monday night before a return to VFR by midday Tuesday.

&&

.MARINE...
Short Term...Long period Swell from Hurricane Ernesto that is
forecast to pass well SE of the Gulf of Maine will arrive later
today. Building swell will generate seas greater than 5 feet by
tonight with a SCA likely Sunday into Monday due to seas. Winds
will remain steady onshore with gusts generally less than 20
kts.

Long Term...Seas continue to be the main issue into early next
week. Seas will peak on Monday in long period swell from
Ernesto. Seas away from the coast could push to around 9 ft,
while near shore waves could reach to around 6 ft. The seas will
begin to slowly subside late Monday night and Tuesday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...High Surf Advisory from 5 PM Sunday to 8 PM EDT Monday for
     MEZ023.
     High Surf Advisory from 2 AM Sunday to 8 PM EDT Monday for
     MEZ024>028.
NH...High Surf Advisory from 5 PM Sunday to 8 PM EDT Monday for
     NHZ014.
MARINE...Small Craft Advisory from 8 PM this evening to 8 PM EDT Monday
     for ANZ150>152.
     Small Craft Advisory from 2 PM Sunday to 8 PM EDT Monday for
     ANZ153-154.

&&

$$


NEAR TERM...Schroeter
SHORT TERM...Schroeter
LONG TERM...Cempa