854
FXUS61 KBOX 040709
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
309 AM EDT Thu Sep 4 2025

.SYNOPSIS...
Very pleasant weather continues today. Warm front brings a few brief
showers very late tonight through early Friday morning. Warm and
humid conditions Friday afternoon and Saturday afternoon, ahead of
an approaching cold front late Saturday. The cold front brings the
risk of scattered showers and thunderstorms late afternoon through
the evening hours, with rain showers overnight through early Sunday
morning. Drier weather returns late Sunday into Monday behind the
cold front with slightly below normal temperatures into middle part
of next week

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Messages:

* Patchy morning fog will erode by midmorning, giving way to another
  gorgeous late-summer day across southern New England.

A bit of deja vu on this Thursday with below than normal temperatures
and patchy morning fog to kick off the morning. Forecast does remain
on track this afternoon, sunshine with fair weather clouds and mild
temperatures. 00z BUFKIT sounding show a bit deeper mixing as well
and will have a steady S/SSW wind. Similarly, today`s afternoon high
temperatures return to the lower 80s and upper 70s, though the S/SSW
wind keep the southern shoreline communities closer to mid-70s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Key Messages:

* Scattered showers overnight into early Friday morning.

* Becoming warm and muggy Friday afternoon with the low chance of an
  isolated rain shower in far northern Massachusetts border towns.

Clouds are on the increase overnight in response to an shortwave and
mid-level warm front lifting across southern New England. PWATs are
on the rise, increasing to 1.6", adequate for showers activity around
midnight through early Friday morning. There are lower probabilities
for thunder overnight with elevated instability, MUCAPE of 200-300
J/kg and marginal mid-level lapse rates of 6C/km. Thinking these are
scattered showers, so not every community will see one, with the
greatest chance in western communities of Massachusetts and northwest
Connecticut. Rainfall remains light, HREF mean rainfall overnight
are less than 0.25" with areas in eastern Massachusetts and Rhode
Island receiving less than 0.10". If there were to be a more robust
convective shower, a quick hit of 0.5" to 0.75" would not be out of
the question. Temperatures are seasonable with overnight lows
between the upper 50s and lower 60s.

Outside of a lingering shower on Friday morning, rest of the day is
shaping up to be a dry one. A few warm advection showers cannot be
ruled out for areas north of Route 2 in northern Massachusetts, as
the best forcing is across northern New England. Otherwise, it`s a
warm and muggy afternoon, a blend of clouds and sun. Temperatures
reach the low to middle 80s, the south coast remains less warm with
highs in the upper 70s to 80F. Dew points are noticeably higher and
range between the low 60s across interior locations with middle to
upper 60s for the coastal plain. Additionally, have breezy S to SSW
winds 10-15 mph and gusts up to 25 mph.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Key Messages:

* A dry start for Saturday, showers and thunderstorms are possible
  during the late afternoon through the evening hours.

* Trending drier with a fall-like feel starting Monday and through
  the middle part of next week.

Heading into Saturday,will need to remain weather aware, especially
those seeking to spend the day outdoors. A mid-level trough and cold
front approaches from the west and ahead of the front a few storms
could develop. After several days of comfortable temperatures and
humidity, Saturday will feel more summer like with highs in the low
to middle 80s! And dew points climb well into the upper 60s to
perhaps as high as 70F. This will make it feel sticky and as if the
air temperature were 2-4 degrees warmer.

There is potential for a few strong storms, adequate instability of
800-1000 J/kg and 30-40 knots of shear. The challenge here, the best
forcing approaches late afternoon across western New England. Timing
remains difficult as the window of time in question does fall
outside the CAMs forecast period, although the global ensembles are
favoring late afternoon to early evening arrival time. FWIW, the
experimental RRFS, which typically runs "hot" as it comes to
convection does hint at a few isolated storms in western parts of
southern New England between 4-6pm, with a fine line of convection
nearing the I-95 corridor between 8-10pm. This is something to
monitor given numerous outdoor events Saturday afternoon and
evening. Shower activity does continue overnight into Sunday
morning.

Sunday, the cold front extends over the coastal waters and will be
slow to move. This will allow for rain chances Sunday, with the area
with greatest risk being Cape Cod and the islands. Otherwise more in
the way of clouds than sunshine. Much cooler post frontal airmass
with high temperatures in the low 70s and upper 60s.

Surface high pressure and rising mid-level heights Monday into the
middle part of next week. Dry fall-like conditions are anticipated
as highs only reach the lower 70s and upper 60s and overnight lows
in the low 50s to upper 40s.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

Through 12z... High Confidence.

VFR. Some fog patches and low clouds may impact the typically prone
terminals very late tonight. Winds becoming calm/light SSW to SW
tonight.

Today... High Confidence.

VFR. Increasing mid-level clouds, west to east during the afternoon
ahead of a front. S wind 8-12 knots, gusts up to 20 knots are
possible.

Tonight... Moderate Confidence.

VFR conditions early but deteriorate to MVFR from west to east
overnight from low clouds with the returning low level moisture.
Some localized IFR conditions are also possible after midnight
across parts of the interior. In addition, a few more advection
showers possible late with the greatest risk across interior
southern New England. S winds 5-10 knots.

Friday... High Confidence.

Becoming VFR. Breezy, SSW wind 10-15 knots, gust to 25 knots.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night: VFR. Breezy.

Saturday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA, chance TSRA.

Saturday Night: Mainly MVFR, with areas VFR possible. Breezy.
SHRA likely, slight chance TSRA.

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

Sunday Night: VFR. Chance SHRA.

Monday: VFR. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Friday... High Confidence.

Area of high pressure moves east of the coastal waters today with
increasing S to SE winds of 10-15 knots with occasional gusts less
than 25 knots. Seas today are increasing 3-4 feet. A few showers are
possible overnight into Friday morning and areas or marine fog.

Wind shifts to the SSW for Friday, sustained winds are 15-20 knots,
with gusts 25-28 knots. Seas on the outer waters are building 4-5
feet and near shore waters are 3-4 feet. Conditions are marginal for
a Small Craft Advisory, no headlines will be issued now, but could
be issued during subsequent forecast updates.

Outlook /Friday Night through Monday/...

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft.

Saturday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Slight chance of rain showers.

Saturday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Rain showers likely.

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Rain showers likely.

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

Monday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$
Dooley