628
FXUS61 KBOX 131124
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
724 AM EDT Thu Aug 13 2026

.WHAT HAS CHANGED...
Monitoring early morning shower and embedded thunderstorms
across southern New England, though storms aren`t anticipated to
become severe.

&&

.KEY MESSAGES...

- Scattered showers and thunderstorms remain possible today and
  Friday.

- Dry, seasonable, and comfortable weather returns for the
  weekend.

- Rain chances return late Sunday into Monday, followed by
  quieter weather into the middle of next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Scattered showers and thunderstorms remain possible
today and Friday.

Monitoring a cluster of showers with embedded thunderstorms south of
I-90 early this morning, mainly impacting Connecticut as of 0530Z.
While storms remain sub-severe, they are producing lightning and
localized wind gusts up to 40 mph. This complex of showers and
storms will move east toward Rhode Island and southeastern
Massachusetts prior to sunrise, leading to a wet start for the early
morning commute. However, multiple runs of the HRRR overnight have
shown the potential for a secondary cluster of showers and embedded
thunderstorms to redevelop across eastern Connecticut, Rhode Island,
and southeastern Massachusetts from 09Z to 12Z. Otherwise, expect a
cloudy start to the day.

Clouds disperse this afternoon with daytime heating and mixing
within the boundary layer, allowing temperatures to warm into the
lower to middle 80s. Storm coverage this afternoon remains limited.
As mentioned by the previous forecaster, the mid-levels are dry with
northwest flow. Outside of a few hit-or-miss showers, the afternoon
is largely dry as the better forcing remains associated with the mid-
level trough and shortwave across northern New England. By late this
evening, the first cold front moves offshore, with a secondary surge
of drier air reinforcing on Friday. CAMs try to initiate a few pop-
up storms along the edge of this boundary, but given the dry air in
place, don`t expect anything more than isolated coverage of garden-
variety thunderstorms. The vast majority of southern New England
remains dry, with lower humidity and highs in the lower 80s.

KEY MESSAGE 2...Dry, seasonable, and comfortable weather returns for
the weekend.

Quiet weather-wise this weekend as an area of high pressure
originating from northern Canada settles across the Northeast for
Saturday and the first half of Sunday. PWATs lower quite
dramatically, with values between 0.5 and 0.7 inches, or nearly one
standard deviation below normal. Thus, little to no humidity is
expected Saturday, and conditions may actually feel quite dry, with
almost fall-like humidity. Temperatures remain near seasonable
levels, ranging from the upper 70s to lower 80s. Saturday night into
Sunday morning, clear skies and light winds provide favorable
conditions for effective radiational cooling. Lows tumble into the
mid-50s, while urban centers hover near 60 degrees. On Sunday, high
pressure exits as a low pressure system approaches from the Great
Lakes region. Warm air advection ushers moisture northward from the
southwest with the passage of a warm front, resulting in increasing
cloud cover through the afternoon. Temperatures remain seasonable
and similar to Saturday, though dew points increase to near 60
degrees.

KEY MESSAGE 3...Rain chances return late Sunday into Monday,
followed by quieter weather into the middle of next week.

The next opportunity for rainfall comes during the second half of
Sunday into Monday. However, there remains uncertainty regarding
rainfall amounts, as the best forcing is associated with the surface
low and track variability makes it difficult to pin down where the
greatest rainfall will occur. This is worth monitoring, as global
guidance is in agreement that PWATs may exceed 2 inches, indicating
the potential for heavy rainfall. This is also supported by a
Marginal Risk (level 1 of 4) for excessive rainfall. Global
ensembles highlight areas north of I-90 as having the greatest
likelihood for measurable rainfall, with a 40-60 percent probability
of at least a half inch of rain between Sunday evening and Monday
evening. That said, if rainfall becomes more convective, localized
totals could be higher. One positive is that this system appears
progressive, with the cold front clearing east of New England on
Monday. Drier air then advects in from the northwest, leading to
another dry stretch from the latter half of Monday through Tuesday
and Wednesday as surface high pressure builds back into the region.
During this time, temperatures are expected to remain seasonable,
with highs in the lower to middle 80s and tolerable humidity as dew
points remain in the lower 60s.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

Today...Moderate confidence.

Leftover SCT/BKN VFR/MVFR decks should begin to scatter out
between 15-17Z, increasing the risk for SHRA/TS, mainly north of
the Mass Pike, as a sfc cold front moves through. Coverage
looks spotty but will need to monitor with later updates. Winds
SW to W under 10 kt, then shifting to WNW/NW at 5-10 kt after
20Z.

Tonight...High confidence.

Any lingering SHRA dissipates early, with VFR conditions prevailing
thereafter. NW winds 5-10 kt.

Friday...High confidence.

VFR. Low probability of an isolated afternoon thunderstorm across
interior southern New England; otherwise, dry. NW winds 8-12 kt.

KBOS Terminal...High confidence.

KBDL Terminal...High confidence.

Outlook /Friday Night through Monday/...

Friday Night through Saturday Night: VFR.

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

Sunday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SHRA, slight chance TSRA.

Monday: VFR. Breezy. Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Friday...High confidence.

Early morning showers and embedded thunderstorms across the southern
waters off the coasts of Rhode Island and southeastern Massachusetts
today will clear by mid to late morning. SW to SSW winds are
expected today, with gusts around 20 kt. Winds shift to the NW
tonight at 10-15 kt and continue through Friday, along with dry
conditions. Seas will remain below 3 ft throughout the forecast
period.

Outlook /Friday Night through Monday/...

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

Saturday through Saturday Night: Winds less than 25 kt.

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

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas. Chance of rain showers,
slight chance of thunderstorms.

Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Chance of rain showers, slight
chance of thunderstorms.

&&

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

&&

$$

DISCUSSION...Dooley
AVIATION...BW/Dooley
MARINE...Dooley