596
FXUS61 KBOX 291401
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1001 AM EDT Fri Aug 29 2025

.SYNOPSIS...
Cold front will bring a round of showers and thunderstorms on
today, with small hail and gusty winds possible with a few of
the strongest storms. Pockets of heavy rain could impact this
afternoon`s commute. Otherwise, dry and very pleasant weather
pattern should prevail over most of the Holiday Weekend into
most of next week with just a low risk for a few brief showers
on Labor Day.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Updated 10 AM Fri:

Key Messages:

* More numerous storms develop in central MA/eastern CT around
  midday and head east during afternoon/evening.

* Impacts to the PM commute/holiday weekend travel from
  localized street flooding and poor visibility in downpours.

* Brief strong wind gusts and small hail possible in strong
  storms, but most storms will be sub-severe.

Few showers/storms popped up this morning in E CT and E MA where
we have some weak instability and one in Griswold, CT reported
1/4" hail per CoCoRaHS observer. We should see a few more
showers or storms develop in these areas through midday but
coverage will be fairly sparse.

Meanwhile, more showers were entering western New England ahead
of cold front. Latest high-res models continue to point toward
more numerous storm development around midday, especially in
central MA and eastern CT, before storms probably merge into a
line and head eastward during afternoon and evening, meaning
less of a thunderstorm risk for western MA/western CT.

Timing looks to be:
 - Central MA/Eastern CT 12-3 PM
 - Greater Boston/Providence 3-7 PM
 - South Coast, Cape Cod, Islands 5-9 PM

Severe threat remains fairly low given limited instability, weak
shear, and marginal mid level lapse rates, but given colder air
aloft we can`t rule out small hail or brief wind gusts (30-ish
mph). It`s not out of the question that we`ll need to issue a
SVR or two but overall this does not look like a big severe
weather day.

Also need to be aware of brief downpours given increasing
PWATs (up to 1.2") but none of the moisture parameters are off
the charts, and forecast soundings are not overly impressive.
Still, any downpours in urban areas during PM rush hour (and
holiday weekend travel) could result in localized street
flooding and poor visibility at times.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
305 AM Update:

Key Messages:

* Clearing/drying behind the cold front Fri night. Lows in the upper
  40s to lower 50s.

* Other than a few clouds during the day, the weekend is tranquil,
  dry and slightly cooler than normal. Highs in the 70s, with cooler
  nights in the mid/upper 40s to the mid 50s.

Details:

Tonight Through the Weekend:

Cold front will have pulled offshore by late this evening with drier
northwest flow working in for the overnight. We`ll become governed
by cyclonic flow aloft from a closed upper low expected to
meander around northern New England for the weekend. At surface,
high pressure will build into New England tonight into
Saturday, then move offshore on Sunday.

Overall tranquil/dry weather with no hazardous weather will rule
across Southern New England this weekend. There may be some
diurnally-driven cloud cover, with better chances over northern MA
closer to the upper low. Wouldn`t rule out a spotty shower but the
vast majority of the weekend ends up dry. Cool temperatures aloft
will favor temps running cooler than normal, with highs in the 70s,
and lows in the 40s to lower to mid 50s.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Key Messages:

* Dry weather continues through midweek, and while the coasts will
  be touch cooler with onshore flow, a gradual warming trend is
  expected.

* Next chance for rain may hold off until late next week.

Details:

High pressure will remain anchored offshore through at least the
middle of next week. This will maintain dry weather, with seasonable
temps and cooler nights. Onshore flow/seabreezes near the coasts,
too. Temps should follow a warming trend into the mid to upper 70s,
perhaps nearing 80 in the CT Valley.

After the anticipated rains today, it`s an extended stretch of dry
weather. At this point it doesn`t look like we`ll see our next
chance for more widespread rain until late next week. Early
indications are that it could be a decent rainmaker, but confidence
in the details is low.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

12z TAF Update:

Today...High confidence.

VFR conditions dominate today, but we do expect briefly lower
conditions which we will explain below. A few spot showers
early-mid morning near the I-95 corridor. Otherwise...the main
concern is showers and scattered t-storms especially from ORH
eastward to BED-PVD-BOS this afternoon and particularly in the
18-23z time frame. There is the potential for a brief solid
line of storms to develop along this cold front. Brief strong
wind gusts, small hail, lightning and heavy downpours are
possible with the strongest storms. Across western MA/CT still
expect scattered showers with isolated t-storms later
today...but the threat for more widespread thunderstorms is
likely to be further east. Winds becoming S-SW at 5 to 15 knots.

Tonight: High confidence.

VFR. W to WNW winds 5-10 kt.

Saturday and Sunday: High confidence.

VFR through the period. W/NW winds near 10 kt Sat, becoming
light overnight. Light north winds on Sun, with seabreezes along
the coast.

KBOS TAF...High confidence in TAF. Cluster of brief showers with
a downpour or two in the vicinity of the terminal through 1230z
or so. Biggest concern though is later today when showers and
scattered t-storms are anticipated...greatest risk is between
19z and 23z.

KBDL TAF...High confidence in TAF. Scattered showers expected mainly
this afternoon with isolated t-storms possible mainly after
16z.

Outlook /Monday through Tuesday/...

VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Friday night...High confidence.

Winds and seas to be below small craft criteria today, but south
to southeast winds may reach 20 kt. Main concern for boaters
today is with a line of strong t-storms capable of small hail,
brief strong wind gusts, lightning and heavy rain between 5-9
PM.

Tranquil conditions then expected tonight through the weekend,
with W winds around 10-15 kt and seas less than 4 ft all waters.

Outlook /Monday through Tuesday/...

Winds less than 25 kt.

&&

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

&&

$$

SYNOPSIS...Loconto
NEAR TERM...JWD
SHORT TERM...Loconto
LONG TERM...Loconto
AVIATION...Frank/Loconto
MARINE...Loconto