942
FXUS61 KGYX 031951
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
351 PM EDT Mon Jun 3 2024

.SYNOPSIS...
Weak high pressure builds in from the north through Tuesday for
mostly fair weather outside of a few afternoon showers both
days. Temperatures will run above normal through mid week with
afternoon sea breezes bringing cooler conditions to the coast. A
trough approaches from the west Wednesday and will linger near
New England through the weekend with unsettled conditions.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
More instability and a better moisture profile has lead to a pretty
robust cumulus field from the foothills northward across western ME
and also into northern NH, but dry air aloft has limited precip
to only a few light showers thus far. Over the next 2-3 hours,
expect coverage of showers to increase somewhat (with perhaps a
storm or two) over these areas as more boundaries come
together, but with the dry air aloft aloft I kept limited PoPs
to 20-30%. Northerly steering flow aloft could bring some of
this activity farther south, but at the same time it`s cooler
and much more stable to the south where the seabreeze has gone
through.

Convection diminishes by sunset with dry conditions expected
overnight. Skies will range from partly to mostly cloudy with
patchy fog developing in some areas.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
High pressure will be overhead to start Tuesday morning but will
gradually sink south through the day. The weak pressure gradient
will again allow for quick development of the seabreeze, keeping the
coast a bit cooler while the interior again warms into the mid 70s-
lower 80s, perhaps reaching the mid 80s across western and northern
NH.

A pocket of dry air aloft will keep most dry, but more instability
and the depth of the low-level moisture will be more favorable
across western and northern NH for isolated-scattered afternoon
showers. Following the diurnal cycle, showers will diminish by
sunset or so.

Going into Tuesday night, the upper ridge axis will be centered west
of the area, and models are showing weak PVA entering northern New
England on the eastern periphery of the ridge. With this source of
lift and a small amount of elevated instability, additional
showers could develop during the course of the night with this
looking to be mainly across northern NH. Outside of any precip
that develops, sky will be generally partly cloudy with patchy
fog possible with lows in the 50s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Overview: Rain chances improve during the long term. Expansive
low pressure will slowly slide east from the Great Lakes,
bringing periods of showers. The lows residence time will keep
unsettled conditions in the region at least through the weekend.


Details: Surface high pressure will be pulling SE off the New
England coast Wednesday, with slight boundary draped across many
northern New England states. Return flow from the low will
enhance onshore component of wind, leading to packing of
temperature gradient fairly far inland. Amid the increase in
convergence and instability, will see shower chances jump in the
afternoon for much of the interior and mountains.

The environment does bear some analysis here. Long, skinny CAPE
is presented in soundings, with PWAT values progged to surpass
the 75th percentile in the region and improving. So, precip
efficiency in any showers or storms would be decent...but mid
level RH is fleeting with a warm cloud depth that just gets
around 8 to 10 kft. Storm motion also looks marginal initially
with slow cloud layer winds but speedier up and downshear winds.
The concern here is a marginal environment becoming more potent
if developed storms interact with a boundary that forms from
seabreeze or terrain. We saw this a couple times last year that
lead to localized flash flooding. Considering the dry antecedent
conditions, this isnt a large concern at this time. But, storm
modes in models are starting to resolve single cells that
produce over an inch of rain in isolated areas. This seems to be
focused across the foothills and mountains of ME and NH, while
also including parts of interior ME.

Wednesday night, surface instability falls off with some
elevated instability remaining. This could prolong some showers
into the evening, but coverage should be on the downtrend.
Surface dewpoint depression closes across much of the interior
overnight. This could result in fog developing for much of the
interior. New developing low over the eastern Great Lakes will
hoist a warm front into southern New England Thursday morning.
This will lead to more synoptic forced rain moving into the
region slowly Thursday. While this surface low is expected to
pass off the coast, upper low and occluded front to the west
will prolong shower chances into the afternoon and evening
hours. This system will continue the unsettled pattern for a
greater portion of the extended forecast through the weekend.

A chance of rain runs into early next week in the forecast, and
unfortunately due to the upper low, it will be difficult to
provide much more resolution in timing and coverage at range.
One hedge would be the chance for showers to increase during the
day and afternoon as daytime heating enhances avail instability.
The upper low will slowly move northeast through early next
week.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Short Term...VFR the rest of the day with a few showers, mainly
away from the coast and closest to HIE and AUG. Should these
pass over any terminal, brief VFR restrictions are possible, but
these will dissipate by 00Z. For tonight, light onshore flow
will lead to the possibility of patchy fog/low stratus and MVFR
to IFR restrictions. Conditions return to VFR through Tuesday
morning, which will again prevail through the day with coverage
of showers again much too low for VCSH in the TAFs. Patchy fog
will be possible again Tuesday night.


Long Term...SHRA for interior terminals Wednesday, but
restrictions should be minimal. Patchy fog may develop
overnight, with trend to IFR ceilings is expected through
Thursday. Thurs will also feature invading SHRA/RA through the
afternoon. With unsettled weather expected through late week and
the weekend, restrictions will be likely at times amid fog,
showers, and lowered ceilings.

&&

.MARINE...
Short Term...Winds and seas continue to remain below SCA levels
through Tuesday night. Light east to southeast flow becomes
northeasterly tonight and then returns to more southerly Tuesday
afternoon with the seabreeze and high pressure sinking south of the
Gulf of Maine. High pressure becomes centered just to the southeast
of Cape Cod Tuesday night and will result in a southwest wind at or
below 10 kt. Patchy fog is possible tonight through Tuesday
night.

Long Term...Below SCA conditions expected, although with a humid
airmass arriving, fog development over the waters is expected
from mid week through the weekend. This could reduce visibility
at times for portions of the coastal waters. Broad, upper low
pressure will slowly track towards the region during this time,
lifting north early next week.

&&

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

&&

$$


NEAR TERM...Combs
SHORT TERM...Combs
LONG TERM...Cornwell