175
FXUS61 KGYX 152247
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
647 PM EDT Thu Aug 15 2024

.SYNOPSIS...
Thunderstorms are moving through NH this afternoon, with more
storms developing soon. These storms may contain gusty winds
and small hail. Storms clear the region late tonight with areas
of fog popping up across the region tomorrow morning. Tomorrow
should be drier than today but a few thunderstorms can`t be
ruled out north of the mountains. Hurricane Ernesto moves
parallel to the Gulf of Maine Sunday night bringing high seas
and swell to the coast, with no other impacts from Ernesto
expected. The weather after Sunday looks unsettled with showers
and storms possible through much of early next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
645 PM Update...Showers and a few thunderstorms continue across
the forecast area, mainly over western NH. These will wane in
the next 1-2 hours with the loss of daytime heating. Otherwise,
most of the rest of the area should remain dry.

Previously...

A mature upper-level low over the Canadian Maritimes continues
to bring cooler and moist conditions into NH and ME. Current
observations shows overcast and temperatures in the 70s across
western Maine with much warmer temperatures observed over the
CT river valley. This upper-level low will interact with a
right jet-exit region in an environment with 1400J of CAPE and
low-level wind shear, allowing for the development of more
strong thunderstorms this afternoon. Any developing storms will
move south through the evening, with gusty winds and small hail
remaining possible with some of the stronger storms that
develop. Once the sun sets this evening, energy will be lost
quickly and not long after storms will start to fizzle out.

The calm winds after the storms tonight will allow for easy
development of fog as temperatures cool down within a remnant
moist environment overnight. Areas of fog will overspread the
region tomorrow morning with the aforementioned upper-level low
heading off to sea. &&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Maine should expect to see slightly warmer temperatures
tomorrow with similar temperatures expected in New Hampshire.
Some destabilization around daybreak tomorrow will allow a few
storms to pop-up north of the mountains. More calm winds
tomorrow night, within a drier environment than tonight`s will
allow for some patchy fog to form tomorrow night, though less
fog than what is expected tonight. Winds will start picking up
from the south/southeast as a cold front associated with an
upper-level low in the Great Lakes approach the region

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
At 500 MB, the weekend will start will a small area of ridging
over New England as we sit between upstream and downstream
trough and Ernesto to our SE. By Monday that trough shifts over
the NE CONUS. And 500 MB flow on the downstream side tightens
up a bit as it runs into ridging and absorbs Ernesto to our E,
which makes Monday the day with the most dynamic forcing and the
best chance for rain. The trough, and likely associated cold
front swings through on Tuesday, with cooler and less humid air
moving in for the middle of the week. However, will have that
500 MB trough lingering, which means a chance for some showers.
By late week, should see some sfc ridging move in beneath NW
flow aloft.

Models seem a little more optimistic about the weekend, given
the relative ridging overhead. Still cannot rule out a few
SHRA/TSRA, especially if a greater amount of sun leads to
increased instability, although Saturday seems better capped
than Sunday, so slightly lower chances then. Highs on Saturday
will be in the upper SS to lows 80, while on Sunday, with
better onshore flow and more clouds, mainly run in the 75-80
range. Itll be more humid with Tds running in the mid to upper
60s, and overnight lows in the low to mid 60s.

On Monday,, as that upper level trough starts to deepening a
bit and a wave lifts out of the base of it, will see more in the
way of SHRA/TSRA, and it`ll be more cloudy as well. Also
humidity will be up with tds in the mid 60s N to the upper 60s
and low 70s S. Highs will be closer to the mid 70s than 80 on
Monday as well. SHRA/TSRA continue into Mon evening, but should
start to wane somewhat after midnight, and the cold front may
make into the mtns late so lows range from the upper 50s there
to the low to mid 60s in the S.

Tuesday and Wed will be cooler and drier as 950 temps drop below
+10C, so highs will generally be in the 70s both days. The
cooler air aloft and the 500 MB trough overhead will be enough
for scattered daytime showers to develop, and perhaps a couple
TSRA as well. Overnight lows will be more comfortable and range
from the low 50s in the mtns to the mid to upper 50s in the S.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Short Term...
Currently, scattered thunderstorms are ongoing across
southern NH, including CON, MHT, PSM. Storms are just starting to
develop over LEB and HIE, with VFR likely over AUG and RKD. Storms
this evening will continue to impact airports across NH and PWM.
Areas of fog early tomorrow morning will likely bring most sites
down to LIFR. Most fog tomorrow should mix out by 9 AM. Scattered
storms tomorrow afternoon may impact HIE, but no other impacts are
expected tomorrow. Patchy fog may return for Thursday morning.
Long Term...
While VFR is expected to prevail through the
weekend, cannot rule out some brief flight restrictions due to
SHRA/TSRA and then patch fog at night. Late Sunday night into
Monday could some low stratus and numerous SHRA, plus a few
TSRA, and will likely see MVFR with some periods of IFR through
the day, with possibly some LIFR into Monday night. Expecting a
return to mainly VFR Tuesday morning.

&&

.MARINE...
Short Term...
Light southeasterly flow expected tonight with less than 3
ft seas. Showers and thunderstorms this afternoon/evening over the
Gulf of Maine may impact any marine operations. Thick fog is
possible tomorrow morning over the Gulf, but otherwise tomorrow will
feature light southeasterly flow and 2-3 ft seas. Seas increase a
little tomorrow night and into Saturday morning. No SCAs are
expected over the next 2 days.
Long Term...
Winds will not be an issue this weekend into early
next week, but seas will increase, especially on Sunday and peak
on Monday in long period swell from Ernesto. Seas away from the
coast could push to almost 10 ft, while near shore waves could
reach to around 6 ft. The seas will begin to subside late Monday
night and Tuesday.

&&

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

&&

$$

SYNOPSIS...Palmer
NEAR TERM...Ekster/Palmer
SHORT TERM...Palmer
LONG TERM...Cempa
AVIATION...
MARINE...