655
FXUS61 KGYX 271843
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
243 PM EDT Thu Jun 27 2024

.SYNOPSIS...
High pressure builds toward our area overnight bringing cool and
quiet weather conditions to region. The high will slide
offshore Saturday allowing a warm front to lift north across
our region, followed by a cold front Sunday. This will support
increasing clouds Saturday followed by numerous showers and
locally heavy rain Saturday night into early Sunday. High
pressure then arrives for Monday and Tuesday before weakening
and sliding offshore Wednesday with seasonable temperatures.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...

High Impact Weather Potential: Isolated thunderstorm possible from
the Capitol region to the Midcoast through late afternoon...then
minimal.

Pattern: Early afternoon GOES 16 water vapor imagery shows this
morning/s deep moisture plume now east of the region with a compact
shortwave trough diving towards the region out of southern Quebec.
Ahead of this feature is a secondary cold front that is crossing the
forecast area from northwest to southeast.  Much drier air is
arriving behind this feature which will focus the near term forecast
on cloud trends as well as overnight low temperatures.

Through this evening: Shower activity ahead of secondary cold front
continues to push east with winds shifting to the northwest in it/s
wake. Temperatures begin their fall by 8pm in the mountains with
readings in the 50s...with temps across SE NH and the coast of ME
still near 70.

Tonight: Canadian high pressure settles into New York state
overnight with northwesterly cold air advection pushing T8s into the
single digits above freezing across the forecast area. A rather
substantial low level gradient will remain in place across the
forecast area overnight with 1000 mb geostrophic wind values of 20
to 30kts suggesting that most locations outside of the deepest
valleys will see a breeze continue through the overnight hours.
Arriving PWATs of 0.25" will push into the area as dewpoints fall
through the 40s.  Thus...expect clearing skies and despite the
breeze...it will be a much cooler night than on previous nights with
lows generally in the 40s...with a few lower toward the coast /esp
over the urban centers/.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...

High Impact Weather Potential: None.

Pattern: High pressure crests just south of the region on Friday
before pulling south and east of New England Friday night with a
developing return flow.  Thus...a very quiet period of weather is in
store to end the week with primary forecast concerns centered on
temperatures and cloud cover Friday night as the next system over
the Great Lakes begins to approach.

Friday: Pretty potent mid level subsidence moves overhead during the
day with surface dewpoints in the upper 30s to around 40.  This
suggests very little in the way of cloud cover and the CU rule
agrees...with perhaps a few Cu popping from the mountains north but
clear skies elsewhere outside of a few wisps of cirrus from
precipitation over the Great Lakes.  Northwesterly gradient will
keep a breeze from this direction through the day...generally 10-15
mph.  T8s around +6C with some downslope assistance under light
northwesterly flow should allow temperatures into the low/mid 70s
south and east of the mountains...with highs stuck in the upper 60s
to around 70 in the north.

Friday Night:  Mid level flow backs as the next shortwave and
associated low pressure system moves into the western Great Lakes
with positive temperature and moisture advection developing in the
return flow overnight.  This will commence the top down saturation
process with increasing upper and mid level clouds during the
overnight.  Thus...temperatures will be warmer than on Thursday
night with lows in the upper 40s to mid 50s expected from north to
south with no significant weather impact expected overnight.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
An unsettled weather pattern returns for the weekend. High
pressure on Saturday will drift offshore as an area of low
pressure near the upper Great Lakes approaches from the west.
This will help push a warm front and an eventual cold front
through the area Saturday afternoon and night. Clouds will
increase on Saturday with rain developing west to east starting
in New Hampshire in the afternoon then reaching Maine by late
afternoon/evening. Rain continues overnight before tapering to
showers by daybreak on Sunday. There will be plenty of moisture
to work with so locally heavy rainfall is possible during this
period. Attention will be paid to the position of the frontal
boundary and track of the surface low, which could support a
swath of heavy rain. WPC has the area in a marginal risk with
the window of concern late Saturday night through daybreak
Sunday. On Sunday an upper level trough approaches the area
which will help to initiate scattered showers and thunderstorms
throughout the day. A few showers may linger into Monday as the
upper level trough crosses the area although most of the day
should be dry. As the upper level trough enters the Gulf of
Maine indications are that low pressure will form. However,
models continue to show the area of low pressure forming east of
the area which will keep any additional showers offshore and
allow high pressure to build eastward from the Ohio Valley
Tuesday and Wednesday bringing dry and seasonable conditions to
the area.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...

Short Term...

Summary: A secondary cold front pushes through the terminals this
afternoon with high pressure building overhead tonight and through
Friday with quiet weather conditions.  Mid and upper level clouds
increase Friday night as high pressure passes south of the region.

Restrictions: A brief shower at PWM-AUG-RKD in the 18-20Z timeframe
may bring a brief MVFR restriction...otherwise expected VFR
conditions to dominate through Friday night.

Winds: Northwest winds 14g22kts will diminish to 5-10kts for the
overnight before strengthening to 10g18kts for the day on Friday.
Winds will diminish to calm/light-variable Friday night.

LLWS: No LLWS is expected through Friday night.

Lightning: Very low potential for an isolated thunderstorm AUG/RKD
through 20Z then no additional lightning potential through Friday
night.

Long Term...Numerous showers and thunderstorms with locally
heavy rain Saturday night into Sunday morning will result in
sub-VFR conditions.


&&

.MARINE...
Short Term...Southwest winds 10G18kts this afternoon will shift
to the northwest behind a departing cold front tonight with a
few wind gusts 20-25kts overnight through early morning Friday
before slowly diminishing through the day turning to the
southwest Friday night.

Long Term...Small Craft Advisory conditions probable as
southerly flow increases ahead of a cold front Saturday night.
Showers and thunderstorms may produce locally gusty winds.

Monday...The conditions are anticipated to be below Small Craft
Advisory criteria as winds subside, however some choppy seas
could approach 4 ft on the outer waters.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
Southwest winds
10G18kts this afternoon will shift to the northwest behind a
departing cold front tonight with a few wind gusts 20-25kts
overnight through early morning Friday before slowly diminishing
through the day turning to the southwest Friday night.
&&

$$

SYNOPSIS...Jamison
NEAR TERM...Arnott
SHORT TERM...Arnott
LONG TERM...Doughty