329
FXUS61 KGYX 142311
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
711 PM EDT Wed Aug 14 2024

.SYNOPSIS...
Isolated showers and storms dissipate this evening. Another
round of showers and storms is expected Thursday before some
improvement Friday. By this weekend, periods of more unsettled
weather are possible through the weekend into early next week.
Hurricane Ernesto passes offshore late this weekend and Monday,
bringing an increasing swell and dangerous rip currents by
Saturday through midweek next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
7 PM Update...One strong/severe storm in southwestern Somerset
County ME continues to move southward and is currently
weakening. The rest of the region is dry. However, we cannot
rule out a few more storms this evening with another short wave
trough moving southward in the cyclonic flow regime aloft.

Previously...

Isolated showers and storms have developed this afternoon. At
time of publishing, these are mostly over central and southern
Maine. The cu field has been slow to show much deeper growth
through the afternoon, perhaps stunted by earlier smokey cast
deterring some solar insolation through the first half of the
day. There should remain instability off the surface however as
upper low stalls over Nova Scotia/New Brunswick. Embedded
shortwave will be forcing that taps into this instability into
the evening and early overnight to keep showers and some thunder
possible.

With the low shear and dry low levels, will continue to have
some of these storms produce gusty winds through the early
evening. This shouldn`t be a widespread impact unless a cluster
of storms forms a uniform outflow, but the deeper/stronger
storms will be capable of these winds.

A few pockets of showers may continue up to midnight, but a
general clearing trend is forecast. This will again bring in fog
chances for the CT River Valley late. HREF vis and ceiling
guidance has also hinted at a low deck of clouds advancing along
the coast and interior from the east overnight. Probabilities
aren`t the highest, but patchy fog could form over damp areas as
the night cools.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
A similar setup possible for Thursday where a chance for
afternoon showers and thunderstorms exists. Shear parameters are
again marginal compared to available instability. Theoretically
gusty winds and small hail would again be possible in stronger
cells. Will continue to assess how this trends, and how this
afternoon plays out to increase confidence. HRRR Smoke/RAP
models do portray additional high level smoke passing through
the region, and this may further impede afternoon convection.

Surface temps may be a couple degrees cooler as more morning
cloud cover is possible and the upper low retrogrades west.
While highs topped out around 80 today, highs may only make it
into the mid to upper 70s for ME and the northern half of NH
Thursday.

A similar evening trend is anticipated as daytime heating wanes
and clearing begins. At this time, overnight showers look less
likely compared to Wed night.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Overview...

A series of troughs affect New England this weekend and into
early next week. Generally cool and showery conditions are
expected, with some brighter periods in between. Hurricane
Ernesto passes offshore late this weekend and early next week,
bringing building surf and increasing rip currents.

Details...

A weak shortwave ridge passes through New England, bringing a
relatively drier and brighter day on Friday. Scattered showers
are still likely during the afternoon hours across the higher
terrain, but don`t look to be as widespread as on Thursday.

By Saturday, the ridge passes and a trough begins to deepen
through the Great Lakes, with low pressure developing across the
Great Lakes as well. The low is very slow to make any eastward
progress over the following few days as the ridge stalls and
builds across Atlantic Canada through the weekend. With this
pattern, showers and scattered thunderstorms likely begin to
move into western areas late in the day Saturday, and make slow
progress eastward overnight Saturday. The progress mostly stalls
by Sunday, with western areas seeing a greater chance for
showers than eastern areas. There remains some question as to
just how far east it will progress, but at this point the coast
stands the best chance to see the driest conditions.

By Monday, a shortwave dives in and deepens the trough, while
also causing it to become more amplified and help the pattern
begin moving along again. With this, the greatest chance for
rain and showers in the forecast arrive late Monday as the low
progresses east. The trough continues to transit through on
Tuesday and possibly into Wednesday, keeping the chance for
scattered showers around.

While all this is going on, Hurricane Ernesto is expected to
pass near Bermuda on Saturday, and making it`s closest pass to
Nova Scotia on Monday. Ernesto helps to amplify the ridge
across Atlantic Canada, aiding in the slow down of the trough
progression, while also bringing it`s own effects. Building surf
and increasing rip currents remain the biggest concerns from
Ernesto, with a southeasterly swell building by Saturday. The
swell builds through Monday, and then will be slow to subside
through Wednesday. Rip currents become increasingly more
dangerous by Sunday, and continue through at least Tuesday. High
astronomical tides are also occuring early next week, so some
splashover is also possible. The track is favorable overall for
a long duration swell event, with the storm tracking mostly
northward for two days around Bermuda.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
Short Term...VFR this afternoon, with some SHRA/TS developing
this afternoon and early evening. MVFR ceilings may develop late
along coastal and interior terminals in ME. This may be
accompanied by patchy fog to reduce vis as well. This lifts
Thursday, with another round of SHRA/TS in the afternoon.

Long Term...Mainly VFR conditions are expected on Friday, with
brief showers possible across interior terminals. VFR conditions
prevail more often than not Saturday through early next week,
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...Below SCA conditions expected. Stacked upper low
over New Brunswick and Nova Scotia will slowly retrograde west
over the next few days. This should give little wind at the
surface outside of daytime sea breeze that turn onshore in the
afternoon. Some marine fog is possible tonight.

Long Term...Weak pressure patterns prevail as broad high
pressure builds across Atlantic Canada into this weekend.
Hurricane Ernesto passes east of the Gulf of Maine late this
weekend and early next week, bringing an increasing
southeasterly swell starting on Saturday. The swell builds to
greater than 5ft by Sunday, and continues through midweek next
week.

&&

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

&&

$$