277
FXUS61 KGYX 071909
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
309 PM EDT Sun Jul 7 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 into Wednesday. A
trough will approach from the west during the second half of the
week transporting deep moisture into the region as well as
bringing more widespread showers and thunderstorms Thursday and
Friday.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A stalled front continues to sit just offshore this afternoon,
and will remain nearly stationary through the overnight. This
keeps dew points higher closer to the coast, while western and
northern areas see more mixing and dew points dropping into the
low to mid 60s. Some isolated pop up showers are showing up
across the higher terrain, but these are expected to quickly
tapper off around sunset. Closer to the coastline, fog is likely
to move onshore again through the evening hours across the
MidCoast, and may also do so along the southern coastline after
midnight. Radiation and valley fog is expected to develop again
tonight across interior locations as skies remain mostly clear.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Tomorrow looks quite similar to today overall, except for a
slightly stronger sea breeze along the coastline. A ridge axis
crests the area in the early morning, allow for the sea breeze
to more easily develop by the late morning hours, keeping highs
confined to the 70s to low 80s near the coast. Away from the
coast and outside of the higher terrain, temperatures warm back
into the upper 80s to low 90s again under mostly sunny skies.

A weak mid level trough swings through during the afternoon
hours, and is likely to kick off some isolated showers across
the higher terrain and parts of Central Maine tomorrow.
Otherwise, conditions look fairly quiet for tomorrow.

Clouds and some leftover shower activity begin to drift into
southwestern NH late tomorrow night as moisture begins to
increase across the area. Lows bottom out near 70 across
southern NH, while most other locations dip into the 60s. Patchy
fog is likely to develop again tomorrow night as our pattern
remains fairly consistent

&&

.LONG TERM /TUESDAY 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 Tuesday 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 /19Z SUNDAY THROUGH FRIDAY/...
Short Term...VFR conditions likely give way to IFR and LIFR in
fog at RKD and AUG again tonight, with valley fog bringing LIFR
to LEB and HIE again tonight. PWM and PSM likely see
restrictions from fog as well, but this is lower confidence and
may be more intermittent. VFR returns tomorrow morning for the
day, and then fog likely returns again tomorrow night to the
same terminals.

Long Term...There will be chances for showers and storms most
days Tuesday 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...A stalled front keeps locally dense fog ongoing
across the waters, especially toward the MidCoast and farther
east. Intermittent fog likely continues into tomorrow night as
moisture increases again on southerly flow as a weak area of
high pressure moves east of the waters.


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.

&&

$$


NEAR TERM...Clair
SHORT TERM...Clair
LONG TERM...Schroeter