845
FXUS61 KGYX 081037
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
637 AM EDT Mon Jul 8 2024

.SYNOPSIS...
High pressure will maintain mostly dry conditions through Monday
with very warm and humid conditions continuing for much of the
week. A stationary front wavering over the Northeast will
provide a focus for showers and storms Tuesday afternoon into
Wednesday. A trough will approach from the west Wednesday
transporting remnant moisture from Beryl into the region
Wednesday into Thursday. Thunderstorms are again possible Friday
as a stalled remains over the region.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
635 AM...Just a few tweaks to temps/sky based on current conds,
but overall should be mainly sunny and very warm day, with some
relief along the coast from the sea breeze.

Previously...Any morning fog along the mid coast or in the
sheltered valleys should diminish by 8 AM again this morning.
Weak sfc high moves across the CWA between zonal flow aloft,
with a slight anticyclonic bend to it, and this should keep
things generally sunny and dry today. It will be another very
warm day, but the W flow slackens and shifts a little more to
the S. This should allow the sea breeze to show earlier in the
day and move a little more inland as flow will be more onshore
than along shore. Still it wont prevent all but the immediate
coastline to get into the 80s but should see highs limited to
80-85 in the coastal zones. While the rest of the CWA will make
it to 85-90 again, with low 90s in srn NH. The W flow should
keep Tds in the low to mid 60s where temps are the highest,
which will prevent apparent temps form reaching advisory levels.
Given the sfc instability can;t rule out a shower or two this
afternoon in ME, probably along the sea breeze boundary, but
strong capping at ~700 MB should prevent any convective showers
from producing lightning.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Skies are mainly clear tonight with just some cirrus, but will
have to watch for coastal stratus/fog moving in this evening.
Given the more direct onshore flow today, theres a better
chance fog approaches the shore late in the day and moves
onshore once heating diminishes. The best chance for this is
mainly from somewhere in York county NE through the mid-coast
and this where mins are generally in the low to mid 60s, along
with the mtns which should see lows in the lower 60s in many
spots. In central and southern NH low will be limited to the
upper 60s to around 70 in many areas.

Fog may linger a little longer into the morning along the mid
coast on Tuesday, but an increasing SW flow should clear it out
and also limit the sea breeze somewhat along the entire coast in
the afternoon. Increasing low level moisture and very warm
temps aloft will push temps across much of the area into the
upper to lower 80s. This along with high Tds may require a heat
advisory, especially over parts of S NH on Tuesday. The cooler
will be the mtns where more clouds are possible and the
immediate coast where highs will likely be limited to around 80.
Some uncertainty remains for the tempos though as a weak 500 MB
trough wave moves through and pulls a very weak cold front into
the far nrn zone by Tuesday evening. This could set off some
SHRA/TSRA across the CWA, mainly in the afternoon into Tuesday
evening. If storms fire up earlier could produce anvil cirrus
which will limit max temps to some degree.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
The 500 mb pattern across North America will feature a pronounced
ridge along and west of the Rockies, a downstream trough, and a
ridge in the western Atlantic to start the long term period. A
warm and humid airmass will be in place with a stationary front
wavering over the area providing a focus for showers and storms
into Wednesday. The main story in the long term period will be
the poleward transport of deep tropical moisture from Beryl
within the aforementioned trough over the central US. Global
models and ensembles are in decent agreement that the ridge in
the western Atlantic will hold firm while the trough over the
central US gradually moves east through the end of the week. The
eastward migration of this trough will start to transport some
of this deep moisture into the Northeast with increasing forcing
for ascent Thursday and Friday. The pattern de-amplifies next
weekend suggesting a drying trend while disturbances aloft will
maintain low PoP in the forecast through the end of the period.

Tuesday will be very warm and humid with highs into the upper 80s to
low 90s with dewpoints near 70 degrees south of the mountains. This
will bring heat index values into the mid 90s for portions of
southern NH and interior SW Maine. The forecast challenge for
Tuesday is the amount of cloud cover as there is a large spread in
both global models and CAMs with some showing mostly cloudy skies
for much of the day and others showing mostly sunny skies
through Tuesday morning. This cloud cover will have implications
for both high temperatures as well as instability for
thunderstorms. Most model solutions suggest there will be
scattered afternoon thunderstorms, while those with less in the
way of cloud cover suggest a few strong to severe storms cannot
be ruled out with ample SB CAPE and decent deep layer shear. A
short wave rotating through Quebec will act to shift the
stationary front offshore for a drying trend Tuesday night into
Wednesday morning.

The trough over the central US will lift northeastward towards
the Great Lakes Wednesday. By this time Beryl will be a post
tropical low with the trough advecting a plume of anomalous
PWATs towards the Northeast. This moisture will lead to mostly
cloudy skies Wednesday with PoPs increasing Wednesday afternoon.
Global models are in decent agreement that the plume of highest
PWATs will be on the order of 2 to 2.5 inches while the
northward extent of this plume remains somewhat in question.
Nevertheless, ensembles suggest that PWATs will likely exceed
the 90th percentile across much of the area Wednesday night
through Thursday night. All the while forcing for ascent will
increase with the approaching trough and the right entrance
region of a jet streak sliding overhead. While much will need to
be ironed out over the coming days, there is a growing signal
for heavy rain impacting the region centered on Thursday.

The trough will linger west of the region Friday maintaining
chances for for showers and storms. This trough eventually
weakens and lifts northeast of the area going into Saturday with
PoPs decreasing through the weekend.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Short Term...Early morning valley and coastal fog fog should
burn off by around 8 am again today with VFR expected though
about sunset everywhere. A better chance for coastal fog/stratus
tonight especially at KPWM/KRKD coming in early in the evening,
and may see stratus spread inland to KAUG. Valley fog at
KHIE/KLEB expected after midnight. The coastal fog may take
longer to burn off Tue morning, but should see VFR by mid
morning. TSRA will be possible mid to late afternoon and
evening.

Long Term...There will be chances for showers and
storms most days Wed through Friday with restrictions likely in
this activity. Thursday will likely have the most widespread
activity and resultant flight restrictions. A humid airmass in
place will also bring the threat for fog most nights.

&&

.MARINE...
Short Term...Fog builds back over the waters today as light
becomes onshore, and should thicken late today and overnight.
Flow becomes more SW on Tuesday, so fog may become more patch
during the day but should return Tue evening. Winds/seas stay
below SCA levels through Tuesday.


Long Term...High pressure in the western Atlantic will maintain
southerly flow over the waters for much of the week while gusts
look to remain at or below 20 kts. Seas also look to remain
below SCA thresholds through the period. A humid airmass will
remain over the Northeast bring the threat of marine fog over
the waters most nights.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...Cempa
SHORT TERM...Cempa
LONG TERM...Schroeter
AVIATION...
MARINE...