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564
FXUS61 KGYX 071606
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1206 PM EDT Fri Jun 7 2024

.SYNOPSIS...
An upper low approaches from the west bringing chances of
showers and few thunderstorms this afternoon and Saturday
afternoon. A second upper low moves over the area Sunday into
the upcoming workweek keeping shower chances going into the
middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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1205 PM Update...Quick update just to bring thunder into
the forecast a couple hours earlier along the Connecticut River
Valley as some storms have already developed.

1035 AM Update...Scaled back PoPs again as showers only remain
in central Maine. Also tried to get a better handle on the
clearing in New Hampshire. At the moment much of the state is
mostly clear with only the southeast still holding on to clouds,
but even there it looks like it will clear in the next hour or
two. The inherited forecast remains on track with these clearing
areas being the focus for thunderstorm development this
afternoon.

635 AM Update...Have trimmed back PoPs across much of NH into SW
Maine as a band of rain showers has lifted to the north. Have
also prolonged fog in the valleys of western NH based on
satellite trends.

Previously...

An elongated trough/upper low will remain to the west of New
England through today. This system will spread forcing for
ascent over the forecast area with models suggesting a couple
surface troughs will rotate through late morning into tonight.
This will lead to showers and possibly a few thunderstorms
developing from early this afternoon into this evening with the
best chances focused in the mountains. However, the 00Z HREF
suggests a few cells could track all the way to the coast.

The forecast challenge is how well skies clear and the resultant
instability. As of early this morning much of the area is socked in
with low ceilings and fog, although there are breaks in the clouds
across far SW NH back across western New England and Upstate NY.
Winds look to remain predominantly onshore through the day with
cloud cover and the marine influence limiting the instability along
the coast into central Maine. West to southwest flow develops across
across New Hampshire into interior western Maine that will lead to
periods of insolation. CAMs suggest MU CAPE builds to 500-1000 J/kg
across these areas with possibly an axis of higher CAPE near the
NH/ME border. Deep layer shear will be quite strong with 0-6 km
shear approaching 60 kts. This magnitude of shear may actually act
to squelch updrafts, especially as mid level lapse rates will be
poor around 5C/km. Therefore, the threat for storms to become strong
is low. The overall forecast thinking for today is for clouds to
linger longest near coastal and central Maine with a mix of sun
clouds across New Hampshire and western Maine. Highs will range from
the mid 60s across central Maine to the low 80s across southern NH.
Much of the area looks to remain precipitation free through mid day
with PoPs increasing early this afternoon through the evening.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Shower chances will continue through tonight as the upper low makes
eastward progress. Light westerly flow looks to push into western
Maine tonight with somewhat drier air moving in by Saturday morning.
This should limit fog development tonight with the greatest
potential for fog near the Mid Coast. Lows tonight will drop into
the low to mid 50s.

The upper low moves overhead during the day Saturday. This will
steepen mid level lapse rates and likely leads to self
destructive sunshine as solar heating in the morning leads to CU
developing by mid day. This will also lead to some afternoon
showers across the interior towards the Mid Coast where an area
of convergence will help with lift. Saturday will be cooler
than today with highs in the 60s north to 70s south. Steady west
to southwest winds will inhibit a sea breeze with coastal areas
reaching the same warmth as the interior.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
The overall pattern across the northeast in the extended will
consist of moist cyclonic flow due to upper level low pressure
lingering across the northeast US and southeast Canada. This
will lead to unsettled weather at times. But at this time it
does not look like there will be any washouts, just mainly
chancy to low likely PoPs for showers and thunderstorms at
times, peaking in the afternoons with diurnal heating. This will
be mainly true Saturday through Monday before a period of
ridging takes hold thereafter. Highest PoPs each day are in the
mountains, with lesser PoPs in southern NH where it could be
dry most of the time.

Temperatures each day will be in the 70s for most folks, with
60s in the mountains. A warming trend will take place Tuesday
and Wednesday with highs returning back into the 80s.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
Short Term...IFR/LIFR conditions in low cigs and fog likely
persist until around 12Z for most TAF sites. Conditions then
improve across interior NH TAF sites with VFR likely by mid
morning. Coastal sites and KAUG will likely see IFR to MVFR
conditions through this morning with cigs lifting this
afternoon. Scattered SHRA this afternoon may bring brief
restrictions. Coastal sites and KAUG likely see IFR conditions
again tonight in low cigs while dry air moving into the NH will
limit flight restriction there. VFR likely prevails Saturday,
although scattered after SHRA will be possible.

Long Term...Outside of scattered showers and an isolated
thunderstorm, or two, ceilings will be mainly VFR through
Tuesday. Winds also remain on the lighter side, generally less
than 10 kt with westerly gusts possibly 20 to 25 KT Saturday and
Sunday afternoons.

&&

.MARINE...
Short Term...Winds and seas remain below SCA thresholds through
Saturday. Dense marine fog continues this morning and erodes
from SW to NE this afternoon while the Mid Coast may hang onto
fog through tonight. Scattered showers and thunderstorms
forming over land may track into the waters before weakening
this afternoon. Winds eventually turn westerly around Saturday
morning limiting the fog potential over the waters.

Long Term...Conditions hazardous to small craft are not
expected through Tuesday. Seas will generally be 3-4 ft with
winds 10-15 kts with gusts to 20kts.

&&

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

&&

$$

UPDATE...Baron
NEAR/SHORT TERM...Schroeter
LONG TERM...Ekster