Bath, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

579
FXUS61 KGYX 121907
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
307 PM EDT Wed Mar 12 2025

.SYNOPSIS...
A shortwave will cross New England tonight bringing clouds and
slight chances for flurries. High pressure then returns for the
end of the week with temperatures rising above normal Friday
and Saturday. A frontal system approaches late in the weekend
bringing chances for widespread rain and posing an elevated risk
for ice jam flooding.


&&

.NEAR TERM /THROUGH TONIGHT/...
Satellite imagery currently shows some patchy clouds across
southern New Hampshire moving eastward. These clouds are ahead
of a shortwave that will move across the region tonight. Some
snow showers develop, but persistent dry air at the surface
should allow most snowflakes to evaporate. Some flurries are
expected tonight, especially across southern and western New
Hampshire. Strengthening high pressure to the east should limit
any snowfall from occuring tonight.

Winds will remain calm this evening as a low-level inversion
develops, inhibiting stronger winds in the lower levels from mixing
down to the surface. Clearer skies up north should allow for some
radiational cooling north of the mountains tonight, as calm winds
and clearer skies become present.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
A partly cloudy day is expected tomorrow, with some stratus
expected to move across NH and southern Maine through the day. A
swath of developing mid-level vorticity associated with the
aforementioned shortwave should allow for the development of a
mid-level cloudbank stretching from upstate New York, through
the Gulf of Maine. These clouds will start scattered in the
morning and spread across much of New Hampshire and Maine
through the afternoon. No precipitation is expected with these
clouds, with the low-level and surface air far too dry for
snowfall. These clouds will keep high temperatures suppressed
for the day, with most places struggling to reach 40F.

Skies clear out as the swath of mid-level vorticity slides to the
south tomorrow evening. Clearing skies along with calm winds will
allow for more pronounced radiational cooling Thursday night across
the region, with many valley sites expecting to see lows in the
teens.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Pattern Overview: A significant 500mb closed low develops in
the Central CONUS on Friday, but becomes more of an open wave as
it reaches our area at the end of the week. Latest guidance
suggests much of the initial energy splits north of New England,
with the trough lagging until Monday night. This would trend
QPF slightly downward for Sunday/Monday. The pattern quiets
again Tuesday as zonal 500mb flow returns.

Impacts and Key Messages:
* An elevated risk for ice jam flooding exists on Sunday night
  and Monday as a warm system will bring rain and rapid snowmelt
  to the region, contributing to river rises which will break
  up and move river ice. Further details can be found in the
  dedicated hydrology section below.

Details: Friday: Friday may start with some patchy valley and
coastal fog as moist flow raises dewpoints. We will then be well
mixed so it should clear out early on, with much of the
forecast area under fairly clear skies by mid-morning. Global
models continue to suggest 925mb temperatures either side of +4C
which would amount to highs in the upper 40s and low 50s. We
are also back to having to consider seabreezes, so expect that
at least the immediate coast may fall short. Onshore flow
continues into the night so marine fog could move onshore early
with more widespread fog developing overnight. Low temperatures
look to end up just either side of freezing.

Saturday and Sunday: Saturday looks to be a pretty soggy day as
areas of fog, and maybe drizzle at times, persist through the
day. 925mb temperatures look to be around +6-8C through the peak
heating period, so locations that get breaks of sun could see
some quick heating to near 60. Otherwise, heating likely gets
stunted with many locations again in the low 50s. The approach
of a warm front Saturday evening only exacerbates things with
widespread fog and low clouds taking hold again for Saturday
night. Low temperatures hold in the 40s. Sunday morning starts
with fog and drizzle as the forcing from the warm front
continues through, this will transition to light rain later in
the day as a cold front approaches. Guidance is beginning to
suggest that the energy associated with the initial trough
ejection from the significant system in the central CONUS will
largely split to the north of New England, no longer coinciding
with the axis of moisture moving through. For this reason QPF
has trended down a bit with this system. Interior locations may
end up more around 0.50" or less, with southern New Hampshire
and the coastal plain more poised to be within the 0.50"-0.75".
There also remains a signal for locally higher amounts, near an
inch, in the White Mountains. There may still be uncertainty in
QPF, but one thing is certain and that is that we will see river
ice break up and move as a result of this systems rainfall and
snowmelt. This will pose an elevated risk of ice jam flooding
beginning Sunday night.

Monday-Wednesday: Rain comes to an end from northwest to
southeast on Monday, but clouds hang around until a secondary
cold front crosses and clears them out overnight. With this
being said temperatures look to also be dropping through
freezing during this time so any showers still hanging on would
become wintry, staring in the mountains Monday evening and
progressing to the coast overnight. This would be very light on
the back end of the system, so wouldn`t expect too much out of
them. We return to quieter weather for Tuesday and Wednesday.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Short Term...
Mostly VFR expected through tomorrow morning. Some low-level
stratus may poke into New England tomorrow afternoon, with
isolated MVFR possible by the end of the day tomorrow. After
that, skies should clear, bringing VFR restrictions back through
Friday morning.

Long Term...Increasing moisture brings about the risk for some
morning IFR valley and coastal fog Friday, but it will quickly
mix out to VFR by mid morning. IFR conditions return as coastal
fog moves in again Friday evening, with more widespread fog
developing as the night goes on. Not much improvement should be
expected through early Sunday morning as low clouds and fog will
persist. Ceilings may raise to MVFR later on Sunday as fog and
drizzle transition to light rain, but periods of IFR are still
possible in heavier rain showers Sunday night. Monday will start
improvements toward VFR as precipitation exits the area but it
may be slow. Sunday afternoon and evening remains the window for
wind gusts 25- 30kts with the passing of a cold front.

&&

.MARINE...
Short Term...
Light northerly winds at 6-12kts expected, with 2-4ft seas overnight
tonight. Winds shift to southeasterlies by daybreak tomorrow at the
same magnitude and will continue through Friday morning. No changes
to seas are expected through Friday morning. SCA issuance not
expected.

Long Term...Conditions stay below SCA criteria
through the day Saturday before wind gusts and seas ramp up
overnight. Winds will be southerly with a period of gales
possible Sunday night with the passing of a cold front. Winds
gusts slacken below 25kts on Monday. However, seas will be
building to 6-10ft on Sunday night and the swell will be slow to
exit, so SCAs will likely be needed through at least Monday.

&&

.HYDROLOGY...
Ice jam flooding concerns are growing for the rain-on-snow
event early next week. Routine river flooding is not expected at
this time unless otherwise impacted by ice. A gradual ripening
of the area snowpack will continue into the weekend, with snow-
eating fog/drizzle Saturday and a more rapid release/melt Sunday
night. The energy from this system will be lessening when
crossing the area, limiting the overall rainfall potential to an
inch or less for most areas. The high dewpoints and southerly
winds will be the primary drivers in melting the snowpack, which
could release between 1 to 3 inches of water over the weekend.
River responses will start as early as Saturday, with more rapid
rate of rise Sunday night with the arrival of more widespread
moderate rainfall. The cumulative runoff will be sufficient to
raise most streams and rivers with some nearing bankfull, but
flooding is not expected at this time. Again the main factor
will be any ice jam development. Much of the ice in southern
rivers will rot and flush prior to the Sunday night event, but
central and northern rivers should anticipate further break-up
and shifting of ice into early next week posing a risk to
downstream communities. The ice jam flood risk will linger until
the flows recede or the ice flushes out.

&&

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

&&

$$


NEAR/SHORT TERM...Clair/Palmer
LONG TERM...Baron
HYDROLOGY...Jamison