531
FXUS61 KBOX 141752
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
152 PM EDT Fri Aug 14 2026

.WHAT HAS CHANGED...
Risk for scattered showers and storms have increased this
afternoon into early tonight, mainly in interior Southern New
England.

&&

.KEY MESSAGES...

- Scattered showers and t-storms mainly for interior Southern
  New England this afternoon through sundown. A couple could
  produce small hail and gusty winds.

- Pleasant weekend with seasonably cool temperatures and
  comfortable humidities.

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

&&

.DISCUSSION...
KEY MESSAGE 1...Scattered showers and t-storms mainly for
interior Southern New England this afternoon through sundown. A
couple could produce small hail and gusty winds.

Main concern for the rest of the afternoon into early tonight
revolves around low-topped showers and thunderstorms. A rather
potent shortwave disturbance is visualized in water vapor
imagery early this afternoon near Ottawa ON, forecast to move
southeast through New England into early tonight.
Modest instability given dewpoints falling into the mid 50s is
present across most of New England, but stronger forcing and the
cool pocket of air aloft due to the shortwave is contributing
to scattered convective showers across NY and VT. BUFKIT soundings
show strong 925-700 mb lapse rates as well as strong mid-upper
level flow aloft, but with low equilibrium levels around 25-28k
and wetbulb zero heights on the order of 9000 ft. Have seen some
lightning strikes in eastern Ontario, and anticipate some of
these showers could blossom into scattered t-storms. With the
cold profiles aloft, even stronger showers could produce
graupel/"dippin` dots" hailstones, with deeper t-storms capable
of hail up to 1" diameter with locally strong/gusty winds. The
severe weather risk level has increased to a Level 1 of 5, but
still think the risk storms become severe is on the low side. The
best chance for storms is mainly from a FIT- ORH- PVD line
south and west, with showers more likely into eastern MA.
Showers/storms are expected to dissipate into the early-mid
evening hours associated with sundown and passage of the
shortwave disturbance.

Clearing skies overnight, which will bring a risk for patchy
river valley fog as winds go light northerly. A big airmass
change comes in tonight with much lower humidity levels and lows
in the mid 50s to around 60, so a good night to crack open the
windows!

KEY MESSAGE 2...Pleasant weekend with seasonably cool
temperatures and comfortable humidities.

Beautiful weekend shaping up as a 1024 mb high pressure
establishes itself over Southern New England Saturday, then
begins to move offshore into Sunday. Full sun, light northerly
winds and dewpoints falling into the 40s Saturday will bring a
taste of early-autumn, with highs in the mid 70s to around 80 as
850 mb temps run around +7 to +10C. Very strong radiational
cooling setup Saturday night, with widespread 50s for lows as
ridge of high pressure centers itself overhead, to go along with
patchy river valley fog. A bit more of an increase in cloud
cover Sunday, with risk for showers developing late in the day
on Sunday in western New England at earliest, but most of the
daytime hours are dry.

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

Sunday starts off under mid-level ridging with heights falling
through the day ahead of an approaching shortwave trough in the
flow. This will keep conditions dry most of the day Sunday with
temperatures in the upper 70s/low 80s. There is general agreement
across most guidance in rain arriving Sunday night, spreading from
west to east. Expect batches of showers to continue through Monday.
Can`t rule out an embedded storm or downpour with marginal
instability around. With PWATs 1.5-1.8", brief heavier rain rates
are possible. Mid-level winds will be strong enough to keep any
heavier showers or storms moving if there are any. This should help
minimize the risk for flash flooding. Can`t rule out isolated
instances of flash flood impacts in poor drainage/urban areas given
the potenial for embedded heavier downpours. This has been reflected
in the WPC ERO as a Marginal Risk (Level 1 of 4). For total amounts,
ensemble guidance shows a range of 0.25" to 0.50" across southern
New England. Localized higher amounts are possible, especially
within any downpours.

A cold front moves through the region by Tuesday with a drier
airmass advecting into southern New England behind it. Conditions
remain generally dry Tuesday and Wednesday with zonal flow aloft.
Temperatures will likely be in seasonable ranges in the upper 70s to
low 80s with dewpoints in the low to mid 60s keeping humidity
leaning toward the more comfortable side. Ensemble guidance signal
for a trend toward unsettled weather by late-week with chances for
rain returning to the forecast.


&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

18z TAF Update:

Through 00z Saturday: High confidence.

VFR generally governs. SCT low-topped SHRA/TS now developing
across NY and western New England are stilll anticipated to
to move SE into western portions of Southern New England through
sundown, and these could bring MVFR- IFR visby, small hail and
localized strong wind gusts mainly for BDL and ORH south and
west, with less of a shot at PVD and BOS. NW winds around 5-10
kt, with occasional sub-20 kt gusts.

Tonight: High confidence.

SHRA/isolated TS to move offshore and/or weaken by 02z with
mainly VFR conditions. Latest guidance seems more favorable for
MVFR-IFR patchy mist/fog development toward daybreak in
interior river valleys (e.g. BDL) and perhaps at BED too. Light
north winds.

Saturday and Saturday Night: High confidence.

VFR. North winds 5-10 kt, with seabreezes near the coast during
the daytime hours. Patchy river valley fog with IFR visbys
overnight.

KBOS Terminal...High confidence in TAF. Main risk for a few
brief showers in the vicinity of the terminal will be after
21z/22z until about 02z. Low risk for a rumble of thunder too.
Odds favor sea breeze remaining offshore this afternoon...but
we do expect one to develop on Sat.

KBDL Terminal...High confidence in TAF. Better chance for TSRA
after 19z thru sundown.

Outlook /Saturday Night through Wednesday/...

Sunday: VFR. Breezy. Slight chance SHRA.

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

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

Monday Night through Tuesday Night: VFR.

Wednesday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Saturday Night: High confidence.

Winds and seas remain below small craft advisory criteria
through Saturday night. NW winds 10-15 kt decrease and become
northerly around 10 kt tonight into Saturday. Risk for showers
and thunderstorms with small hail and brief strong gusty winds
over mainly southern waters this afternoon and tonight.
Otherwise, good visibility expected Saturday.

Outlook /Saturday Night through Wednesday/...

Sunday: Winds less than 25 kt.

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas locally approaching 5 ft. Chance of
rain showers, slight chance of thunderstorms.

Monday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Seas up to 5 ft. Chance of rain showers, slight
chance of thunderstorms.

Monday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain showers.

Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.

Tuesday Night through Wednesday: Winds less than 25 kt.

&&

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

&&

$$

DISCUSSION...Loconto/Mensch
AVIATION...Loconto/Mensch
MARINE...Loconto/Mensch