455
FXUS61 KBOX 071940
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
340 PM EDT Fri Jun 7 2024

.SYNOPSIS...
Cooler tonight, then mainly dry and seasonable conditions
Saturday. Scattered showers on Sunday with diminishing rain
chances through Tuesday. Warming and drying trend Wednesday
and Thursday, before unsettled conditions return to round out
the weekend.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Some pop-up showers developed beneath a cold pool aloft. These
were mainly across NY state and northern New England. Another
band of showers developed across portions of RI and eastern MA,
but required help from seabreeze boundaries to overcome the less
favorable instability towards the coast. While these showers
were locally heavy, they were still not tall enough to be
concerned about thunderstorms. These showers are expected to
dissipate as they move onto the ocean side of the seabreeze
boundaries. The risk for showers should continue through
midnight.

Main concern tonight will be the return of stratus and fog along
portions of the coast. Drier air will try to push SE across
southern New England overnight, but it will take time to reach
the coast. The most likely areas will be the Cape and islands
again. An east wind this afternoon also brought some stratus and
fog into portions of the east coast of MA. As long as the wind
remains from the east, it is unlikely this will dissipate or
move out. Currently thinking winds become southerly towards
sunset, which will begin that process.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Trending less humid for Saturday, but still the low risk for a
spot afternoon shower. The greater risk will be towards northern
New England. A stronger west wind should keep the seabreeze at
bay, meaning high temperatures along the immediate east coast.

Clearing for a brief time Saturday night. More clouds and a risk
for showers could arrive late Saturday night ahead of another
weak low pressure. Above normal temperatures continue.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Highlights

* A mix of showers and sunshine on Sunday

* Some spot showers possible Monday/Tuesday before what looks to
  be a drying trend mid week

* Unsettled conditions possibly return late next week with
  trough developing in the vicinity of the northeast


Sunday...

Sunday is shaping up to be the wettest day of the long term
period with cutoff low quasistationary in southern/central
Quebec. Southwest surface to 925mb flow will allow
PWATs/dewpoints to surge back above 1.25"/mid 60s. More robust
shortwave, at least compared to what we`ve seen the last few
days, will scoop across the northeast beginning Sunday morning,
but is rather slow to move seaward so should produce showers for
the better part of the day. Still, the day doesn`t look like a
washout, but anyone with outdoor plans may want to pack an
umbrella.

Thunderstorm potential remains low on Sunday with modest CAPE,
between 400-600J`kg, but as is often the case here in SNE, mid
level lapse rates are lackluster, perhaps just touching 6.5C/km.
So, while we can`t rule out a few rumbles of thunder in the
strongest cold pool convective showers, we do not anticipate
severe weather.

Monday and Tuesday...

Upper level cutoff shifts northeast of the region to start the
work week, but lagging shortwave trough will yield scattered
shower activity for Monday and Tuesday, particularly across
northern Massachusetts, with lingering cold pool aloft (850mb
temps may drop as low as 0C across upstate NY late Monday). Cold
pool showers will be fighting against a drying column as PWATs
again drop to 0.75", so overall expect shower activity to be
much more sparse compared to Sunday. Expecting more sun than
clouds both days with diurnal cumulus developing each afternoon.
Even with cold pool aloft, W/NW downsloping should support
temperatures slightly above to near normal, in the mid to upper
70s, perhaps touching 80F in the warmest locations.

Mid to Late Week...

Very persistent trough/cutoff upper low finally relinquishes
its grasp on southern New England by Wednesday as ridging builds
in from the southwest. There remains uncertainty in how strong
ridging will be, but it should provide a brief lull in unsettled
conditions as high pressure settles in the vicinity of the
region through Thursday. Temperatures also look to trend in a
warmer direction as we progress through the week as southwest
winds develop behind the departing trough. Global guidance shows
another trough sliding southeast from the Great Lakes/southern
Ontario to round out the work week/start next weekend, but
remains varied in timing and strength of the feature. So, while
it looks like unsettled conditions will return by
Friday/Saturday, specific details won`t be sussed out for
several days.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
Forecast Confidence Levels:

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Mainly VFR for most of or region this afternoon. Isolated
showers across southern New England this afternoon. Showers
along the east coast should dissipate by 21Z. Showers farther
west may linger longer into this evening as a cold pool aloft
moves across northern New England.

IFR/LIFR in stratus and fog near ACK and along portions of the
east coast of MA should become more widespread this evening, at
least until winds turn SW to W and drier air overspreads our
region. The most likely impacted region will be across SE MA and
portions of RI.

Mainly VFR Saturday and Saturday Night. Can`t rule out brief
MVFR in spotty showers Saturday afternoon.

KBOS TAF...Moderate confidence. Fog bank just to the east of the
terminal will threaten the field with LIFR conditions as long
as there is an E wind. Still expecting winds to turn S this
evening, but current timing in the TAF may be too fast.

KBDL TAF...High confidence.

Outlook /Sunday through Wednesday/...

Sunday: Mainly MVFR, with areas VFR possible. Breezy. Chance
SHRA.

Sunday Night: Mainly VFR, with local MVFR possible. Breezy.
Chance SHRA.

Monday: Mainly VFR, with local MVFR possible. Breezy. Slight
chance SHRA.

Monday Night: VFR.

Tuesday: Mainly VFR, with areas MVFR possible. Slight chance
SHRA.

Tuesday Night: VFR.

Wednesday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.

High confidence through Saturday.

SW to W winds develop overnight. Before that happens, areas of
poor visibility in fog around the Cape and islands. Improving
visibility late tonight through Saturday night. A few gusts up
to 25 kt possible Saturday afternoon. Otherwise, expecting seas
to gradually subside tonight. Small Craft Advisory continues for
marginal 5-foot seas across the outer southern coastal waters.

Outlook /Sunday through Wednesday/...

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers.

Sunday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.

Monday: Winds less than 25 kt. Seas locally approaching 5 ft.

Monday Night: Winds less than 25 kt.

Tuesday: Winds less than 25 kt. Slight chance of rain showers.

Tuesday Night through Wednesday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 4 PM EDT this afternoon for ANZ254.
     Small Craft Advisory until 5 AM EDT Saturday for ANZ255.
     Small Craft Advisory until 10 PM EDT this evening for ANZ256.

&&

$$

SYNOPSIS...Belk/KS
NEAR TERM...Belk
SHORT TERM...Belk
LONG TERM...KS
AVIATION...Belk/KS
MARINE...Belk/KS