254
FXUS61 KGYX 130238
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1038 PM EDT Sun May 12 2024

.SYNOPSIS...
High pressure gradually builds in and moves offshore through
tomorrow. A warm front stalls through central New England on
Tuesday, then a slow moving cold front stalls on Wednesday. Low
pressure passing south of New England spreads moisture and
showers in from late Tuesday into Thursday. Conditions dry out
late in the week as New England sees a period between systems,
and then likely turns unsettled again by late next weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
0238Z Update... Temperatures continue to fall through the 40s
in most areas, albeit at a slower rate than the last several
nights. Patchy fog will likely develop later tonight, however
its extent will be driven by the amount of cloud cover over the
region.

Patchy fog will mainly be confined to the northern mountains
tonight, somewhat different than the last couple chilly nights
over southern areas.

Update...Showers continue over the forecast area as of 2130Z
per latest radar imagery and surface observations. However, with
large surface dew point depressions, some of the echoes are not
reaching the ground with plenty of dry air in the mid levels in
the latest GYX sounding. In any case, have upped pops across
portions of the region, especially in Maine. In western Maine,
the latest HRRR has showers expanding through about 00Z before
dissipating overnight.

Have nudged temperatures downwards for the overnight lows,
especially in the Midcoast region where clear skies may allow
for temperatures to drop into the 30s. Have introduced patchy
frost into the forecast for the early morning and early
afternoon hours.

Will continue with patchy fog and may need to expand to areas
that receive rainfall this evening.

Prev Disc...
Weak sfc high just tour S, with cool upper level closed low
overhead, and very weak forcing in the mid levels, has allowed
for some showers to develop, mainly over the mtns early this
afternoon, but they will move S during the mid to late
afternoon. I think calling them sct or isolated is probably the
best way to describe them, and they are all light, producing
generally a few hundredths of an inch at best. I do think some
of the clouds clear out tonight, but also with mid level
forcing, I dont think they clear out completely until late, and
Tds are higher than Sat night. So frost is not expected in
activated zones. Otherwise lows will drop into the upper 30s in
the mtns and mostly the low 40s in the S.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
On Mon, we manage to squeeze into weak ridging at all levels
above the sfc, with a more SW flow at the sfc, as we sit between
systems. We should a mainly sunny morning, with more clouds in
the afternoon, but still a fair amount of sun. The SW flow is
weak, so so coastal zones S of Casco Bay will likely a partial
onshore component to the wind, but won;t be that much cooler
than inland except near the midcoast. Highs range from around 60
on the mid coast to the low mid 60s inland, and near 70 in S NH.
Monday night will see clouds and showers move in during the
evening and overnight as a warm front moves in. Mins will be
milder and mostly in the 40s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Overview...

A warm front brings warm temperatures to parts of the forecast
area on Tuesday. A cut off low gradually moves through the Ohio
River Valley and south of New England Wednesday and Thursday. A
short wave ridge passes through on Saturday, and then another
system approaches New England by next Sunday.

Details...

As a cut off low lingers across western Quebec, the warm front
associated with the low makes progress into New Hampshire and
parts of western Maine on Tuesday. The front likely stalls
somewhere near central Maine without fully clearing the area
during the daytime. With this, temps warm into the 70s to near
80 across southern New Hampshire, while parts of the MidCoast
and northwestern zones may fail to make it past the upper 50s.
This forecast holds with the NBM temps for now, but the gradient
is likely to be a little stronger than what it currently being
shown. The big question is just how far northeastward the front
makes it, with the MidCoast, Central Maine, and all northern
areas standing the best chance for the front not to make enough
progress for warmth.

A cold front sags southward late Tuesday through Wednesday,
with showers expanding along this front as a slow moving low
tracks south of the area and sends moisture northward. Showers
become likely by the afternoon across northern areas on Tuesday,
and gradually increase as the front moves southward into
coastal areas by Wednesday. The bulk of the moisture stays south
of the region, but the slowing front serves to focus shower
activity on Wednesday, and possibly into Thursday as well. The
front stalls, likely through the middle of the forecast area
from east to west. There will be wet periods during this
timeframe into Thursday, but coverage looks to gradually lessen
as the forcing weakens. Some showers still can`t be ruled out on
Friday as the low tracks out to sea.

A quick shortwave ridge likely passes through on Saturday, but
the next system will be quick on it`s heals with moisture
spreading in from the southwest. It`s still unclear whether this
ridge will pass through during the day on Saturday, or if it
moves through a bit more quickly and allows showers to move in
by the afternoon hours. We`ll need to wait a little longer to
iron out these details, but that looks like the set up at this
point.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Short Term...VFR will persist through Monday and into Monday
evening, but cigs and vis will drop in ?SHRA overnight, at least
to MVFR, and maybe some periods of IFR.

Long Term...VFR conditions are expected across southern and
western terminals on Tuesday, but some MVFR conditions are
likely across coastal terminals during the day, especially at
RKD where IFR conditions are possible in marine fog. Ceilings
lower at all terminals with showers Tuesday night, with MVFR
conditions likely and periods of IFR possible. These conditions
continue on Wednesday, and then gradually improve into the day
on Thursday. VFR likely doesn`t return fully until Friday and
lasts into Saturday. Restrictions likely return again with
showers Saturday night and Sunday.

&&

.MARINE...
Short Term...Winds/seas stay below SCA criteria into Monday, but
could approach weak SCA winds by Mon evening.

Long Term...A cold front slowly approaches the waters on
Tuesday, and stalls near the coast by Wednesday. A slow moving
low pressure system passes south of the waters Wednesday and
Thursday. These two features bring freshening southerly flow,
becoming easterly by Wednesday and Thursday, with SCA conditions
possible during this time frame. This system slowly moves
eastward on Friday, with waves likely lingering near 5ft on
Friday.

&&

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

&&

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