010
FXUS61 KGYX 010655
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
255 AM EDT Tue Jul 1 2025

.SYNOPSIS...
A cold front will approach the region today, with warm and humid
conditions ahead of it and a chance of showers and thunderstorms
with its passage. A strong storm or two cannot be ruled out but
the coverage of storms is low confidence. A brief break on
Wednesday will give way to another cold front on Thursday. A
similar threat of showers and thunderstorms will accompany that
boundary as well. Then drier conditions are expected into the
holiday weekend.

&&

.NEAR TERM /THROUGH TODAY/...
Fog forecast on track this morning and well visualized on
nighttime microphysics channel as high clouds have yet to move
in over most of the forecast area. Fog will most be confined to
western ME...along the coast and pushing up into the I-95
corridor around the Capital Region. Fog will scatter out from
southwest to northeast this morning after sunrise...but moist
advection may keep low ceilings around Penobscot Bay into the
afternoon.

As for precip this morning...guidance is focusing mainly on the
northern zones. Convection to the south around NYC is forecast
to dissipate as it moves northeast and largely stay south of the
forecast area. Warm advection showers to the north are forecast
to continue in the mtns. While the southern end of those showers
may increase a bit in intensity...the cooling effect of precip
and clouds in this area should limit the afternoon severe
weather threat across the north.

To the south over much of the rest of the forecast area the
Storm Prediction Center still has a marginal risk for severe
weather. This is driven primarily by the threat for wind gust.
Based on forecast soundings I do not disagree with that
assessment. Skinny CAPE profiles with an area of drying in the
700 to 500 mb layer would support precip loading and downburst
potential. We also should have more than enough shear to
organize the updrafts. The limiting factor will be coverage of
convection. Current CAMs are fairly scattered thru the day and
by the time the front really arrives in the forecast area it is
after dark and we are rapidly losing instability. I did remove
the severe wording from the grids given the overall uncertainty.
It is possible that once we see how morning precip evolves that
more targeted areas could be added back to the forecast. I did
also add heavy rain wording to thunderstorms for the afternoon.
PWATs will be near 2 inches...and HREF max QPF in 6 hours late
this afternoon is pushing 3 inches.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
As the front nears the coast this evening showers and storms
will be riding northeast along the boundary. Given that the
threat for severe weather is expected to be tied mostly to
elevated cores...as we increase CIN the threat should decrease
pretty quickly. However some torrential rain will remain
possible as the near 2 inch PWATs will not be pushed south of
the local area until well after midnight.

Some marine fog will also be possible...but my current thinking
is that southwesterly wind direction and rain outflow will help
to keep that in the Gulf of ME vs onshore.

Wed will feature a similarly warm day but slightly less humidity
and weaker overall forcing. But diurnal heating alone may be
enough to pop off some isolated showers or thunderstorms. These
would mainly be tied to heating of the higher terrain and will
tend to dissipate as they leave that heat source and drift
east/southeast.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Key Message: Another front will cross the area Thu with the
threat of showers and storms. This will be followed by high
pressure and generally dry and pleasant weather thru the
weekend.

Impacts: Various convection allowing models (CAMs) and ensembles
are hinting at a threat for strong to severe storms Thu. This
will be highly dependent on timing of the front...as it may
already be near the coast at peak heating however.

Forecast Details: A reinforcing cold front is forecast to drop
out of Quebec and cross New England Thu. CSU machine learning
severe probabilities indicate that a marginal to low end slight
risk severe threat is possible given the set up. Forecast
soundings show both sufficient CAPE and shear to support that
thinking. In addition ECMWF EFI also has an elevated CAPE/shear
overlap...especially for southeast half of the forecast area.
That also means that we have a narrow spatial window for this
threat given the current forecasts of frontal timing. If the
boundary speeds up it will already be in the Gulf of ME by the
time peak heating occurs.

After the front high pressure builds in from the west. The ridge
axis is not forecast to cross the forecast area until sometime
Sat. This will mean largely west to northwest flow Fri and
little in the way of moisture advection. That will mean a warm
4th with refreshing dewpoints.

Sat into Sun humidity will start to creep back up again with the
next frontal passage possible Mon or Tue.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Short Term...Marine fog is making the push inland at this
hour...with IFR or lower conditions developing along the western
ME coast and inland to the I-95 corridor. This will linger thru
sunrise where fog scatters out to VFR for most areas. IFR or
lower conditions will take the longest to clear out across the
Midcoast and Penobscot Bay areas. Coverage of convection with
the approaching cold front is low confidence. Any SHRA/TSRA will
bring the possibility of MVFR or lower conditions...and at this
time these look to be mostly confined to the afternoon hours
into the evening. Depending on the coverage of rainfall
today...some radiation fog is possible tonight. Subsequent
shifts will be able to get a better handle on that threat as the
convective situation evolves today.

Long Term...Largely VFR conditions expected thru the extended.
The exception will be with another frontal passage around the
Thu timeframe. Some redeveloping coastal fog will be possible
and threaten IFR conditions for coastal terminals. The frontal
passage will bring increasing chances for SHRA/TSRA with local
MVFR or lower conditions possible.

&&

.MARINE...
Short Term...Areas of fog are developing as moisture continues
to increase across the coastal waters. Some of this fog may be
locally dense thru daybreak. A the frontal boundary nears the
waters tonight the southwest winds will increase...and a few
gusts near 25 kt are possible. In addition any convection that
survives over the trip into the Gulf of ME may also contain
gusty winds and torrential rain.

Long Term...Winds and seas generally expected to remain below
SCA thresholds thru the weekend. Another frontal boundary will
cross the waters around Thu. Will have to watch for the
redevelopment of coastal fog along with the threat of convection
bringing gusty winds to the waters.

&&

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

&&

$$

Legro