675
FXUS61 KBOX 072344
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
744 PM EDT Sat Jun 7 2025

.SYNOPSIS...
A cold front will bring showers and isolated thunderstorms with
pockets of heavy rainfall this afternoon with conditions drying
out this evening. Dry weather expected Sunday with pleasant
temperatures. A few showers are possible on Monday, but the bulk of
the rain with the next system will hold off until Tuesday. Dry and
warmer weather follows for Wednesday and Thursday

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Key Messages...

* Showers and a couple embedded thunderstorms through this
  evening. Some capable of localized heavy rainfall.

* Rain exits this evening followed by dry conditions tonight and
  Sunday.

* Patchy fog possible overnight.

Details...

Fairly active afternoon weatherwise as a batch of rain pushes
from west to east across southern New England. A few embedded
thunderstorms and convective showers have brought pockets of
heavy rainfall bringing localized flooding impacts to areas this
afternoon. Heavy rain threat will continue through around 8 PM
this evening followed by lingering lighter rainfall as the bulk
of the rain exits to the east. The front will over several hours
shifting winds north.

Conditions dry out this evening, continuing overnight. There is
a chance for patchy fog in areas this evening and tonight with
and after the front moves through. Otherwise quiet weather
tonight with low temperatures in the mid 50s to low 60s.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
A brief ridge of high pressure builds into the region for
Sunday. This will bring in drier air to allow for breaks in the
clouds by the afternoon. High temperatures on Sunday will be in
the 75 to 80 degree range. Onshore flow will keep it cooler
along the east facing coastline in the 60s to near 70.

A round of showers are possible Sunday night into early Monday
as a low pressure system moves in from the south. Still some
uncertainty on exact track which will influence the
amounts/location of higher probs. Overall a quick moving system
bringing chances for light precipitation.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Key Messages:

* Spotty shower activity on Monday. A better chance for rain and a
  few thunderstorms on Tuesday with a cold front passage. Trending
  drier mid to late week.

* Slightly cooler to start the week, followed by a warming trend
  with increased humidity.

There are opportunities for additional rain heading into next week,
but should be focused to the first-half of the week. A weak area of
low pressure or open wave passes south of the region on Monday, this
leads to scattered light rain, in addition to easterly flow off of
the relatively "cooler" ocean waters will keep temperatures cooler.
Will follow this up with a warm frontal passage, lifting over the
region early in the day on Tuesday. With increasing PWATs to roughly
two inches, chance for warm advection showers Tuesday morning and
the afternoon. A trailing cold front swings through later Tuesday
afternoon /evening with potential of downpours and embedded thunder.
The trend is for drier conditions Wednesday into the end of next
week as mid-level ridging and surface high pressure build in.

Temperature-wise, the first-half of the week will be cooler, as
mentioned above, the easterly flow on Monday suppresses afternoon
highs at the upper 60s and lower 70s. Will be somewhat warmer away
from the influence of the on shore flow, Connecticut River Valley
tops out in the mid 70s. No big change in the air mass on Tuesday
will have similar temperatures. Followed by increasing temperatures
aloft Wednesday to Friday, deep mixing to 850mb, and able to tap
into the +13C to +15C. Result are highs in the low to middle 80s.
Dewpoints are elevated in the low 60s, leading to humid conditions.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

00z TAF Update...

Tonight...Low confidence.

Low confidence forecast tonight as conditions try to clear
behind the front, however with dewpoints still in the 60s,
clearing skies will only lead to fog development overnight
esspically with the residual moisture from this afternoons rain.
Guidance is not hitting the fog hard tonight, but there is a
noticeable low level inversion around 200-300 feet across much
of the region tonight with little cloud obstruction above. If
fog does form, expecting more MVFR/IFR CIGS.

The Cape and Islands will likely remain on the wrong side of the
front tonight, keeping conditions IFR/LIFR tonight with
scattered showers.

Sunday...High confidence in trends but lower confidence in timing.

Lingering MVFR-IFR conditions Sunday morning improving to VFR
between 11-13z. Will likely take a bit longer for the Cape and
Islands. Diurnal cumulus around 030 to 040. E winds generally
at 5 to 10 knots.

BOS TAF...Moderate confidence in TAF.

Despite the VFR conditions at Boston around the 00z hour, not
confident those will last as MVFR/IFR clouds drop down from
northern New England. Low chance for sunrise fog tomorrow
morning.

BDL TAF...Moderate confidence in TAF.

MVFR/VFR tonight with overnight fog possible.

Outlook /Monday Night through Thursday/...

Monday Night: Mainly VFR, with areas IFR possible. Slight
chance SHRA.

Tuesday: MVFR/IFR conditions possible. Chance SHRA, isolated
TSRA.

Tuesday Night: Mainly VFR, with local IFR possible. Chance
SHRA.

Wednesday: VFR. Breezy.

Wednesday Night: VFR.

Thursday: Breezy.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today through Sunday...High confidence.

However....a wave of low pressure and its associated southerly
swell will be enough to generate 4 to 5 foot southerly swell
later today into tonight across our southern outer-waters.
Therefore...we have hoisted a small craft advisory for those
waters later today into tonight but conditions should drop back
below criteria for Sunday. The biggest issue for mariners will
be areas of fog...some of which will be locally dense especially
over our southern waters during the overnight and morning
hours.

Outlook /Monday Night through Thursday/...

Monday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain showers.

Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Chance of rain showers, isolated thunderstorms.

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

Wednesday through Thursday: Winds less than 25 kt. Areas of
seas approaching 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 4 AM EDT Sunday for ANZ254>256.

&&

$$

SYNOPSIS...Dooley/Mensch
NEAR TERM...Frank/Mensch
SHORT TERM...Mensch
LONG TERM...Dooley
AVIATION...KP
MARINE...Dooley/Mensch