513
FXUS61 KGYX 140753
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
353 AM EDT Wed Aug 14 2024

.SYNOPSIS...
Comfortable temperatures and valley fog this morning will give
way to increasing clouds and showers and thunderstorms this
afternoon. Especially across western Maine, a few of these
storms could be strong and contain small hail and gusty winds.
Another round of showers and storms is expected Thursday before
some improvement Friday. After Friday, more unsettled weather
is possible through this weekend and potentially even into early
next week. Hurricane Ernesto passes offshore late this weekend
and early next week, bringing an increasing swell and dangerous
rip currents by late this weekend and early next week.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Valley fog this morning will lift shortly after sunrise with
daytime mixing. It will be another warm day with sun early. An
approaching S/WV trof will help increase clouds and convection
by this afternoon. Storms will develop along the higher terrain
and drift south with the S/WV. Forecast soundings still show
decent lapse rates aloft and ample CAPE for stronger storms.
Lack of shear will preclude a widespread severe weather
threat...but an isolated storm with small hail and gusty winds
will be possible. I have not included that wording in the
forecast grids at this time since the coverage of severe weather
threat is not anticipated to be that great. Subsequent updates
may put that wording in...mainly from the mtns into most of
western ME.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM THURSDAY/...
CLearing skies will allow for radiational cooling and valley fog
once again. Given the increased chances of rain today I do have
more widespread coverage of fog tonight. Thu will also remain
under the influence of the upper trof...giving us another
afternoon of increasing convection. Showers and storms should
focus midday to early afternoon in the mtns...and drift south
thru the afternoon and evening. Still cannot rule out a stronger
storm or two...with machine learning guidance showing a low
probability of small hail.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Overview...

A series of troughs move through the Northeast late this week
and through the weekend, bringing multiple chances for showers
and storms, as well as near average to seasonably cool
temperatures. Tropical storm Ernesto is expected to strengthen
into a Hurricane and pass offshore this weekend and early next
week, bringing an increasing swell and dangerous rip currents
starting this weekend.

Details...
A weak shortwave ridge moves through on Friday, bringing a
brighter and relatively drier day. However, with the cutoff low
and cold pool aloft still nearby, some scattered showers are
still possible Friday afternoon, especially across northern and
eastern areas.

By Saturday, the next trough begins to dig in through the Great
Lakes. This brings an increasing chance of showers late in the
day, especially across western and northern areas. These
continue to spread eastward overnight as low pressure develops
through the Great Lakes and slowly drifts eastward. A ridge
develops and remains nearly stationary across Atlantic Canada
over the weekend. This slows and nearly stalls the system in the
Great Lakes from making much eastward progress, allowing
eastern areas to stand a better chance at remaining drier. This
pattern continues through Monday, with another reinforcing
shortwave transiting the trough going into Tuesday.

While all this is going on across the Northeast, Ernesto is
expected to become a hurricane and pass offshore this weekend
and early next week, likely passing close to Bermuda this
weekend. An increasing swell from the system is expected to
begin arriving by Saturday, with waves gradually building
through Monday, and then slowly lowering from Tuesday through
midweek next week. There remains some question as to how much
the trough across the Northeast will interact with Ernesto and
affect its track. While it`s expected to remain offshore, this
interaction will determine how close Ernesto will pass by to
New England, and the angle that it will be tracking while
offshore. These factors impact how large the waves will build
to, and the strength of the rip currents. Regardless, the long
period swell begins to arrive by Saturday, likely starting as a
2ft swell with a 16 second period, and then gradually build
through Monday. To how large remains in question and dependent
on the track distance and direction, which will be the main
question to solve over the next few days. Regardless, rip
currents begin to strengthen by Saturday and remain a concern
through at least midweek next week.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Local LIFR conditions in the CT River Valley will
linger until just after sunrise then VFR. SHRA/TSRA develop by
mid afternoon and drift south thru the evening hours. Local MVFR
or lower conditions are possible in any convection, and some may
contain gusty winds and small hail. After showers dissipate
local LIFR conditions will once again by possible in valley fog
tonight. Another round of local MVFR or lower conditions will be
possible Thu in SHRA/TSRA.

Long Term...Mainly VFR conditions are expected, but periods of
MVFR ceilings and showers are likely at times through early
next week, especially across interior terminals during the
afternoon and evening. Nighttime valley fog is also likely at
LEB and HIE each night.

&&

.MARINE...
Short Term...Winds and seas are expected to remain below SCA
thresholds. Later this evening showers and storms may drift over
the coastal waters with locally gusty winds possible.

Long Term...Weak pressure patterns prevail as broad high
pressure gives way to broad low pressure late this week through
the weekend. Hurricane Ernesto likely passes east of the Gulf of
Maine late this weekend and early next week, bringing an
increasing southeasterly swell starting by Saturday. The swell
may build to greater than 5ft by Sunday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$

SHORT TERM...Legro