Forecast Discussion for BOX NWS Office
405
FXUS61 KBOX 302358
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
758 PM EDT Sun Aug 30 2026
.WHAT HAS CHANGED...
No significant changes.
&&
.KEY MESSAGES...
- Scattered showers possible tonight and dry during the day
Monday, though cooler with few clouds following a backdoor
cold front.
- Unsettled Monday night through Thursday, with several
opportunites for showers and thunderstorms. Timing which days
may have better storm chances is still low-confidence.
- Mix of clouds and sun with diurnally driven spot showers
Friday into the early part of Labor Day Weekend, but drier
weather most of the time. Dry and seasonable Sunday and on the
Monday holiday, with onshore breezes.
&&
.DISCUSSION...
KEY MESSAGE 1...Scattered showers possible tonight and dry during
the day Monday, though cooler with few clouds following a backdoor
cold front.
Cloud cover continues to build in today as high pressure continues
to push eastward and eventually offshore. Weak low pressure tracks
near the region tonight as well, increasing chances for some
scattered showers towards CT, RI, SE MA, Cape Cod, and the Islands.
Not anticipating any washouts with any that move through tonight,
and these should clear the region heading into Monday morning. Lows
tonight will generally fall into the upper 50s and low to mid 60s.
A backdoor cold front is expected to make its way across southern
New England late tonight into tomorrow morning, clearing skies and
ushering in drier air. Winds aloft shift more N then NE after
midnight, reaching the surface after daybreak. This onshore flow
will also aid in keeping eastern parts of the region slightly
cooler; highs closest to the coast will generally be in the low 70s.
Still, much of the region can expect a less humid day with highs in
the upper 70s. Heading into Monday evening/night, high pressure
shifts full offshore, which will introduce the start of a more
unsettled pattern.
KEY MESSAGE 2...Unsettled Monday night through Thursday, with
several opportunites for showers and thunderstorms. Timing which
days may have better storm chances is still low-confidence.
We still look to enter into a cloudy and unsettled weather pattern,
as a stalled frontal boundary in the vicinity of Southern New
England or just to our southwest focuses several opportunites for
showers and storms Monday night through Thursday. The wavy frontal
boundary separates hot, humid and conditionally unstable air to our
southwest, with more seasonable and less humid air over
northern/eastern New England, with strong NW flow aloft. It likely
won`t be raining the whole period of time, but in a pattern governed
by convection and hard-to-time shortwaves in the NW flow aloft,
timing which period(s) and the location of showers and storms is
still subject to change and is low-confidence, with poor run-to-run
consistency across the model suite.
Right now the two periods that appear to have the best chance of
showers and storms looks to be Monday night and into the first part
of Tuesday, and again later Wednesday afternoon into part of
Thursday. Tried to introduce higher PoPs (high Chance to Likely) for
these days, but a general slight chance to chance governs the Monday
night thru Thursday period. It looks like the potential for storms
to become strong to severe looks limited, but a slightly better
chance exists later Wednesday into Thursday as a stronger, more-
coherent shortwave aloft allows for at least some of the more
unstable warm sector to work its way in. Temperatures were kept in
the 70s to low 80s Tue thru Thurs, with rather mild lows in the mid
60s (climo low temperature values are in the upper 50s/around 60).
KEY MESSAGE 3...Mix of clouds and sun with diurnally driven
spot showers Friday into the early part of Labor Day Weekend,
but drier weather most of the time. Dry and seasonable Sunday
and on the Monday holiday, with onshore breezes.
Stalled frontal boundary finally moves offshore Thursday, although
cyclonic flow aloft will keep our weather pattern somewhat unsettled
with a mix of clouds and sun. Spot showers are possble Friday and
Saturday afternoon but should be drier much of the time. Broad high
pressure then works in from the north Sunday into Labor Day, leading
to an onshore flow but with sunny and dry conditions.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update:
Tonight: High confidence.
VFR; spotty rain showers working their way through Southern New
England are falling into drier air. These should pass offshore
between 02-04z. Thereafter, winds shift from SW around 10-15 kt
to WNW/NW around 5-10 kt.
Monday: High confidence.
VFR. A backdoor cold front moves westward through Southern New
England, starting around 11-13z in NE MA and not til 18-20z at
BDL. This will flip winds to NE around 5-10 kt, a little
stronger for the eastern coastal terminals.
Monday Night...Moderate confidence.
MVFR with pockets of IFR possible further in the interior.
Rain chances increase from W to E after 00z Tuesday. Some
embedded thunder possible as well.
KBOS Terminal...High confidence. P6SM -SHRA thru 02z mentioned
in TAF given SWly winds around 10-13 kt. Winds become NW
overnight, then a backdoor cold front brings a windshift to NE
around 11-13z with FEW-SCT Cu deck.
KBDL Terminal...High confidence.
Outlook /Tuesday through Friday/...
Tuesday: MVFR/IFR conditions possible. SHRA likely, slight
chance TSRA.
Tuesday Night: Mainly VFR, with local IFR possible. SHRA
likely, slight chance TSRA.
Wednesday: Mainly VFR, with local IFR possible. Chance SHRA,
slight chance TSRA.
Wednesday Night: Mainly VFR, with local IFR possible. SHRA
likely, slight chance TSRA.
Thursday: Mainly VFR, with local MVFR possible. Chance SHRA,
slight chance TSRA.
Thursday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Friday: VFR. Slight chance SHRA, slight chance TSRA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Through Monday Night...High confidence.
SW winds continue over the waters as high pressure continues
shifting offshore. Brief Small Craft Advisory-level gusts are
expected over the nearshore waters of the Cape and Islands
through midnight tonight at the latest. Showers and some
embedded thunder with them are possible tonight, particularly
towards the southern waters.
A backdoor front moves over the waters from N to S late tonight
into Monday morning, shifting winds more NE initially, then more
S heading into the evening hours. Light S winds over the waters
Monday night, along with more chances for showers and
thunderstorms.
Outlook /Tuesday through Friday/...
Tuesday: Winds less than 25 kt. Chance of rain showers,
isolated thunderstorms.
Tuesday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain showers, slight chance of thunderstorms.
Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain showers, isolated thunderstorms.
Wednesday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers, slight chance of
thunderstorms.
Thursday: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.
Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers.
Friday: Winds less than 25 kt. Seas up to 5 ft. Slight chance
of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ231>234.
&&
$$
DISCUSSION...Loconto/Hrencecin
AVIATION...Loconto/BW/Hrencecin
MARINE...Loconto/Hrencecin
NWS BOX Office Area Forecast Discussion
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