310
FXUS61 KGYX 220721
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
321 AM EDT Sat Jun 22 2024

.SYNOPSIS...
A cold front will stall over Southern New England through
tonight as weak waves of low pressure ride along it. This will
result in a showery morning today with highs today below normal
at most locations. A warm front will attempt to move northward
through the forecast area on Sunday with a chance of showers and
thunderstorms. A few thunderstorms may be severe across New
Hampshire. Another front will then cross on Monday with
additional unsettled weather before high pressure builds towards
the middle of next week bringing warmer weather.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A weak short wave trough and falling heights early this morning
has aided in triggering showers across the region, mainly north
of a KLEB-KPWM line. These will gradually move southeastward
this morning as the attendant short wave trough moves
southeastward as well. The threat for excessive rainfall has
seemed to diminish fairly substantially as forcing for ascent
and elevated instability remains quite weak. The PWATS are
relatively high however, so some heavy downpours with local poor
drainage flooding still isn`t out of the question as long as
precipitation takes on a more convective appearance.

This main batch of showers will continue southeastward and exit
the coast near PWM by noontime. However, continued scattered
showers are expected across northern and central zones
throughout much of the day. Of course the clouds and showers
and east winds will keep temperatures down today, with lots of
highs in the 60s expected.

The exception may be southwesternmost NH where heating may be
sufficient for a few strong thunderstorms this afternoon as
indicated by a few CAM runs. Gusty winds and torrential
downpours would be the main threats with these storms. However
this is conditional upon SFC heating.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
WAA, at least aloft, continues tonight with forcing for ascent
sufficient for more showers, some potentially heavy given the
high PWATS. A few thunderstorms will be possible overnight as
well as marginally unstable conditions develop aloft. Fog,
especially along the coast is probable as well.

Warm front attempts to make northward headway into our forecast
area on Sunday. Models tend to overforecast the northward
advancement of warm fronts in northern New England. However, an
anomalously strong southwesterly LLJ will be present and this
should help it move through at least central and western NH by
Sunday afternoon. North and east of there, it will likely
remain more stable with highs again in the 60s, especially into
many of our Maine zones except perhaps York County and portions
of Cumberland County. However, this could change depending on
speed and strength of parent low pressure to our north.

The SPC has placed a good portion of NH in a slight risk for
severe thunderstorms on Sunday. This is mainly driven by the
convective wind threat due to the strong LLJ, but also note the
5% tornado risk as well. A few models show impressive hodographs
in NH. Will continue to monitor as the threat remains fluid and
conditional upon warm front disposition and speed of
approaching cold front (timing could be off).

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...

Key Messages -

   * Any strong storms come to an end Sunday night with
     unsettled/showery conditions through Monday.

   * Dry and warmer Tuesday and Wednesday.

   * Strong cold front arrives Wednesday night with showers and
     a few thunderstorms before cooler temperatures arrive for
     the end of the week.

--Pattern and Summary--

Troughing moves overheat Sunday night in to Monday with shortwave
ridging quickly building in it/s wake as we move towards the midweek
ahead of Canadian troughing that will be digging into the Great
Lakes region. This second trough looks to arrive to end the
week. Thus...the forecast looks to open unsettled before turning
warmer and drier through midweek. The most impactful weather
will arrive Wednesday night into Thursday as the reinforcing
trough arrives with it/s associated cold frontal boundary with
temperatures falling to end the week.

--Daily Details--

Unsettled conditions look to continue behind any convection Sunday
night into Monday as shortwave trough and associated mid level
forcing for ascent arrives from the west. The guidance suite
differs on the eventual track of low pressure Sunday night and
Monday with the arriving trough causing the low to slow...and
potentially cross the CWA through Monday. Thus...expect showers
to remain in the forecast with some potential for some isolated
thunderstorms with temperatures near or a bit below seasonal
norms depending on shower coverage.

High pressure builds in for Tuesday-Wednesday with T8s rebounding to
around +15C on Tuesday...and then up another 1-2C for the day
Wednesday.  This should allow widespread 80s for highs on Tuesday
with highs south of the mountains building into the upper 80s to
potentially near 90 on Wednesday. Dewpoints in the 60s will prevent
heat indices from moving much above high temperature values...so
do not expect heat headlines for Wednesday.

Next cold front arrives Wednesday night which will take
temperatures back closer towards seasonal norms to end the
forecast period Thursday and Friday. A quicker frontal passage
would introduce severe weather potential late Wednesday...with
an overnight passage still bringing thunder...though a much
lower threat for any severe weather.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...

Short Term...Today through Sunday...
MVFR to local IFR conditions are expected today, in low clouds
and showers/isold thunder. A few breaks to VFR will be possible
later this morning and this afternoon, especially at northern
terminals. CIGS lower to IFR with areas of LIFR tonight in low
clouds and showers, with some restrictions due to fog also. CIGS
and VSBYS improve to VFR from south to north Sunday afternoon
as a warm front moves northward. However, KAUG and KRKD will
likely remain low. Showers and thunderstorms are expected
Sunday, especially late afternoon and evening and some could be
strong, with strong SFC wind gusts. LLWS possible later tonight
and Sunday with strong southwesterly LLJ developing.

Long Term...After evening thunderstorms Sunday...MVFR/IFR
restrictions are likely for the overnight as fog develops given
moist low level conditions. Showery conditions continue on
Monday with MVFR restrictions possible. Improvement to VFR is
expected for Tuesday and Wednesday.

&&

.MARINE...
Short Term...Easterly flow continues through today, with
conditions remaining below SCA levels. Patchy dense fog is
possible as a warm front lifts across the waters. Winds turn
more southerly later tonight as a warm front begins to lift
across the region. Southwesterly winds possibly increase to SCA
levels on Sunday.

Long Term...Residual SCA conditions possible Sunday night...esp
for the outer waters with diminishing winds/waves Monday as low
pressure tough moves overhead. Southerly winds strengthen
Wednesday with SCAs possible by late in the day.

&&

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

&&

$$

NEAR TERM...Ekster
SHORT TERM...Ekster
LONG TERM...Arnott