952
FXUS61 KGYX 081924
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
324 PM EDT Mon Jul 8 2024

.SYNOPSIS...
High pressure offshore will maintain very warm and humid
conditions 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. A few more
scattered showers and storms are expected over the weekend.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Strong surface heating has allowed for CU fields to blossom
across the interior while onshore flow has pushed some stable
air into the coastal plain resulting in less clouds just inland
from the coast. Latest satellite and area webcams show that
onshore flow has allowed marine fog to encroach upon the
immediate coast and this fog will push inland tonight. A few
isolated showers have also developed over the mountains with hi
res guidance suggesting additional isolated showers will be
possible along the mountains to the Capital District of Maine
through this evening. The loss of surface heating will allow CU
and any shower activity to dissipate around sunset.

In addition to marine fog pushing inland along the coastal plain
there will also likely be valley fog developing later tonight.
It will remain warm and humid tonight with lows in the 60 to
near 70 degrees.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Another very warm day is expected Tuesday with similar high
temperatures to today. What will make it feel even hotter than
today resulting in a Heat Advisory being issued for southeastern
NH is that deep moisture will be on the increase and dewpoints
are forecast to remain elevated into the upper 60s and low 70s
south of the mountains. This will bring heat index values above
95 degrees for zones in a Heat Advisory and low 90s elsewhere
south of the mountains.

A short wave embedded in cyclonic flow over eastern Canada will
send a glancing blow of forcing for ascent near the area Tuesday
afternoon. Diurnal heating will bring SB CAPE near 2000 J/kg by
early afternoon across southern NH into the coastal plain of
Maine with little in the way of a capping inversion. The
approaching short wave will also increase deep layer to 40-50
kts, which will be enough for organized convection. The 12Z CAM
suite shows some variance in storm coverage with the HRRR/FV3
showing more widespread strong storms across the southern two
thirds of NH into the coastal plain of Maine while the ARW/NSSL
show more isolated storms. Overall timing is consistent with
storms initiating over NH between 2-4 PM and tracking eastward
into southern Maine. SPC has placed the southern two thirds of
NH and the coastal plain of Maine in a Marginal Risk for severe
storms with the primary threat being strong winds with inverted
V profiles. High freezing levels and marginal CAPE within the
hail growth zone will limit the potential for hail while PWATs
climbing to around 2 inches will make torrential downpours
possible. Storm motion looks swift enough to mitigate the flash
flood potential while there could be some training of storms
that could lead to isolated instances of flooding.

Thunderstorm activity will diminish around sunset while the
warm and humid airmass will remain in place Tuesday night. Lows
will likely struggle to drop below 70 degrees for much of the
area south of the mountains. Ample low level moisture will also
likely lead to fog across much of the area.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A deep moisture supply in and around the remains of Beryl will
continue to stream east, northeast on Wednesday. Showers will
enter the region during the day. Very high PWATs can be expected
over the region as values rise to over two inches by late in the
day across much of the region. This moisture, the remnants of
Beryl and some jet dynamics interplay will allow for locally
heavy showers during the day. As the atmosphere destabilizes
Wednesday afternoon with temperatures climbing into the 80s some
sunshine and surface dew points in the lower 70s, expect a few
thunderstorms as well.

These conditions will continue Wednesday night as the complex
systems continue to approach from the west. Currently, latest
12Z models and ensemble solutions continue to focus on a stripe
of high QPFS, mainly across northern and perhaps central areas.
In this region, two to four inches of rain are certainly a
possibility where localized flooding or flash flooding remains
possible. Less precipitation can be expected at this time
further to the south, however this will need to be monitored
with time as small shifts the rainfall axis can be expected as
the atmosphere remains loaded with moisture.

Thursday`s forecast will be changeable. Somewhat of a dry slot
crosses through the region during the day as evident by lowering
of PWATs with time after some early morning rains. However,
models soundings keep surface dew points on the high side once
again. Therefore, scattered thunderstorms can be expected once
again, but not nearly as widespread as Wednesday and Wednesday
night.

Very warm and muggy conditions will continue during the period
Friday through the weekend as a large ridge of high pressure off
the Eastern Seaboard continues to pump moisture in the region.
Weak short waves crossing through the forecast area will allow
for more scattered showers and thunderstorms in the region.

Fog...fog may be persistent during the nighttime periods
especially Thursday night onwards. Fog will occur both over the
interior valleys as well as the coastline.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Short Term...Marine fog encroaching upon the coast will likely
bring IFR/LIFR conditions to KRKD, KPWM and KAUG tonight through
day break Monday. Valley fog will also likely bring IFR/LIFR
conditions to KLEB and KHIE for a few hours later tonight while
remaining terminals likely see prevailing VFR. Conditions
improve to VFR for most sites Tuesday morning while fog may
linger at KRKD. Scattered showers and thunderstorms will develop
across NH around 18Z and track into southern Maine around 20Z
and most TAF sites stand a chance of seeing a passing TSRA
before activity diminishes around 00Z Wednesday. Fog and low
cigs will likely bring periods of IFR/LIFR to most TAF sites
Tuesday night.

Long Term...LIFR and IFR conditions expected in widespread showers
and thunderstorms Wednesday and Wednesday night along with
patchy fog. Conditions improve to just IFR at times in scattered
showers and storms Thursday and through the weekend. Patchy fog
will continue especially at night.

&&

.MARINE...
Short Term...Southerly flow will prevail over the waters tonight
through Tuesday night while winds and seas remain below SCA
thresholds. The humid airmass in place will likely continue
areas of marine fog that could become locally dense tonight
through Tuesday night. Thunderstorms developing over land
Tuesday afternoon will also have the potential to track into
the waters with storm diminishing around sunset.

Long Term...Winds will generally remain out of the south during
the long range portion of the forecast but stay below SCA
thresholds. Patchy to areas of fog may become persistent over
the coastal waters, especially during the nighttime hours.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...Heat Advisory from noon to 8 PM EDT Tuesday for NHZ010-012-013.
MARINE...None.
&&

$$
NEAR/SHORT TERM...Schroeter
LONG TERM...Cannon