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916
FXUS61 KGYX 120127
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
927 PM EDT Sat May 11 2024

.SYNOPSIS...
A cool and unsettled pattern continues through the weekend as a
longwave trough with multiple cut off low pressure system gradually
crosses the area. Isolated afternoon showers continue this
weekend, with some lingering into the evening hours. Below
average temperatures are expected, with a trend warmer into
early week. A more widespread period of showers and rain is
likely beginning Monday night into Wednesday. Conditions dry
out late in the week as New England sees a period between
systems, and then may turn unsettled again by next weekend.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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0125Z Update...
Mid level clouds continue to dissipate as they move south across
portions of Maine and New Hampshire. Mainly clear skies remain
over westernmost Maine and eastern New Hampshire. Have lowered
temperatures in this region where radiational cooling will be
prominent again tonight. Frost advisories have been issued for
portions of western Maine and southeastern New Hampshire until
8 AM.

Update...
Latest satellite imagery continues to show quite a bit of cloud
cover over eastern and northern portions of the forecast areas
as of 2242Z as well as western New Hampshire. Mainly clear skies
will continue in-between in an area of weak ridging. Have made
minor adjustments to temperatures and dew points for the near
term portion of the forecast. A frost advisory will remain for
portions of the interior into early Sunday morning as
temperatures drop through the 30s once again tonight.

Prev Disc...
The weather pattern remains largely the same as it was last
night, so I`m not expecting tonight to be terribly different in
terms of sensible weather. In the low-levels, we remain in a col
between low pressure centers east of Nova Scotia and over
western New York... meanwhile aloft, shortwave ridging separates
the upper level reflections of these features. The result is
another calm night with diurnally driven cumulus cover today
dissipating this evening, and temperatures cooling into the 30s
to near 40.

Now that we consider the growing season to be active outside of
Coos Co NH and the Western Maine mountains, the big question
will be if we dip to near or below freezing... and where. Like
last night, and today, the multiple (weak) flow regimes in play
through the column will lead mixed cloud decks which will make
it tough to determine where those ideal cooling conditions will
occur. The best guess right now is an outcome similar to last
night, where locations near the ME/NH border and along the coast
are most likely to radiate out at least early in the overnight.
Dew points are creeping up in onshore flow, which gives me
pause... however a slightly warmer/more humid trend would still
produce areas of frost vs the freeze last night. The HREF shows
some mid/higher clouds crossing into the area from the west
after midnight... but they may not reach this area in time
before temperatures dive. Overall it`s marginal, but a Frost
Advisory has been posted for portions of the Androscoggin, Saco,
and Piscataqua River Valleys.
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&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
A bit of a funny synoptic picture develops Sunday, with an
upper level low dawdling across New England atop building high
pressure extending south from Labrador... coming into phase with
broad high pressure over the southeast US. The result is fairly
similar to today, with diurnally driven showers and clouds
although likely a little more widespread given the support from
the upper level low. Strong mixing will bring about steep lapse
rates and some instability, with offers further support for
convective showers however the 700 mb cap remains so there is a
ceiling to how vigorous they could be.

Wash, rinse, repeat for Sunday night... light flow and clearing
skies, along with pressure rises behind the departing upper
low, will allow temperatures to cool again into the 30s to near
40. Like tonight, will have to keep an eye on forecast trends in
case widespread frost is a possibility.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Overview...

The week starts off with New England situated between three
separate cut off low pressure systems. One moves closer Monday
night and Tuesday, spreading showers and rain into much of the
area at times into at least Wednesday. The system moves away on
Thursday, with a dry day looking most likely on Friday before
another system moves toward the area on Saturday.

Details...

The week starts off dry with seasonable temps on Monday as
three separate cut off lows linger near New England, one
offshore near Bermuda, another to the north near James Bay, and
another across the Southern Plains. By Monday night and Tuesday,
moisture drawn northward by the southern system begins to
interact with a cold front associated with the Canadian low
pressure system. Showers expand across northern and western
areas Monday night and Tuesday, but likely won`t expand into
southern and coastal areas until Tuesday night and into
Wednesday as the front sags southward.

The low passes well to the south on Wednesday, with the
northern edge of the rainfall near or into southern forecast
areas. Wednesday and Wednesday night are trickier forecasts,
with the chance that the rain remains to our south most of the
day. Rain looks more likely than not at this point, but it would
only take a little more of a southward jog of this system to
leave Wednesday mostly dry. However, if it does trend more
northward, periods of showers or rain would likely linger into
Thursday.

With this slow moving pattern and multiple cut off low pressure
systems, it looks likely to raining somewhere in our CWA for
several days from Monday through Wednesday, but not everywhere
at once. There are likely to be breaks in the rain and clouds,
similar to what we`ve seen the last couple of days, but are
difficult to time out at this point.

Friday looks like the next chance for a mostly dry day as New
England has its next best chance to be between systems. But then
by next weekend, it looks like another cut off low will
gradually spin northwestward, spreading moisture toward New
England. High pressure across the Canadian Maritimes will
attempt to thwart this system toward the southwest, but there
are too many other low pressure systems to get through first
before the details of this one become more clear.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Short Term...Mainly VFR through tomorrow with light winds (calm
during the overnights and turning onshore in daily seabreezes)
and a chance for brief, light rain showers. Best chances for
restrictions comes with brief MVFR CIGs, most likely near the
coast overnight and with SHRA activity.

Long Term...VFR prevail through Monday, and then showers likely
accompany MVFR ceilings Monday night and Tuesday across
northern and western terminals. These restrictions spread to the
remaining terminals late Tuesday and Tuesday night. Showers and
MVFR ceilings likely linger across coastal and southern
terminals on Wednesday, with some improvement across northern
and western terminals more likely. Conditions gradually improve
toward VFR everywhere by Thursday, and linger through at least
Friday night.

&&

.MARINE...
Short Term...Light southeast flow today turns light and variable
overnight before returning out of the south on Sunday... then
southwest by the end of the day. Winds are forecast to remain
below 10-13 kts by and large, with similarly quiet seas mainly
2-4 ft.

Long Term...A slow moving low pressure system and cold front
approach the waters Tuesday and Wednesday, with SCA conditions
possible on Tuesday with southwesterly flow. This low passes
south of the waters Wednesday and Thursday, with the front
likely crossing slowly Wednesday and Wednesday night.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
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ME...Frost Advisory until 8 AM EDT Sunday for MEZ012-018>020-033.
NH...Frost Advisory until 8 AM EDT Sunday for NHZ004-006-010.
MARINE...None.
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&&

$$