385
FXUS61 KBOX 311112
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
712 AM EDT Sun May 31 2026

.WHAT HAS CHANGED...

No significant changes to the forecast into this afternoon.

&&

.KEY MESSAGES...

- Dry start to the day today with scattered showers and
  isolated thunderstorms developing in the afternoon. Near-
  seasonable temperatures.

- First half of next week dominated by cooler temperatures and
  off- and-on showers.

- Confidence decreases in forecast for late-week. More likely
  leaning dry and warm. Still monitoring in potential for a
  coastal system to bring showers late Thursday and Friday.

&&

.DISCUSSION...

KEY MESSAGE 1...Dry start to the day today with scattered showers
and isolated thunderstorms developing in the afternoon. Near-
seasonable temperatures.

Brief period with weak high pressure in place will bring a dry start
to the day today with a mix of sun and clouds. Temperatures aloft
warm a few degrees from yesterday allowing temperatures to recover
back to more seasonable values in the upper 60s and low 70s. Clouds
increase in the afternoon as the next shortwave approaches. This
shortwave trough will drop southward bringing a slight uptick in
moisture to support scattered showers developing in the afternoon.
The morning sunshine and warmer temperatures should also help build
marginal instability to support a few brief downpours or an isolate
weak storm.

Showers continue early tonight gradually decreasing in coverage
through the overnight period as the remainder of the system shifts
across the region.

KEY MESSAGE 2...Unsettled conditions for the first half of the week
with periods of isolated to scattered showers.

Another push of cold air gets ushered into the region Monday behind
the Sunday night`s system. This will bring cool day with cooler than
normal highs in the upper 50s and 60s. Expect warmer temperatures in
the CT Valley in the mid to upper 60s while onshore flow keeps the
east coastal areas on the cooler side struggling to get into the low
60s. A weak trailing piece of shortwave energy drops south during
the day Monday. Not much moisture to work with, but there is a low
chance (< 30%) to support isolated/pop-up showers in the afternoon.

Tuesday, the core of lower 500mb heights shifts east although
souther New England still remains under a trough aloft. With the
slight moderation in heights, temperatures aloft follow by warming a
few degrees from Monday. This should support a more seasonable day
with high temperatures in the low to mid 70s with local sea breezes.
Coastal areas may end up a bit cooler in the upper 60s where the sea
breeze sets up. There are indications across model guidance for
another weak piece of shortwave energy shifting southward across the
region resulting in another shot for some pop-up showers in the
afternoon.

KEY MESSAGE 3...Confidence decreases in forecast for late-week. More
likely leaning dry and warm. Still monitoring in potential for a
coastal system to bring showers late Thursday and Friday.

Uncertainty grows in the forecast as we head into late-week.
Ensemble guidance shows a general consensus with an amplified upper
level trough nudging east into the region. A chunk of solutions
indicate that a closed low develops at the base of the upper trough
near the Carolinas then tracking in a north/east Thursday into
Friday. Ensemble means are currently favoring this closed low to
track well offshore of the region resulting in dry conditions.
However, there have been individual solutions across deterministic
and ensemble guidance that indicate a closer pass to the 40N/70W
benchmark which may bring showers to the eastern portions of the
region. If it does end up dry, there is a signal for a strong ridge
aloft to bring an anomalously warm airmass into the region. This may
support summer-like temperatures in the low to mid 80s, perhaps
nearing 90s in the Valleys.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...

Forecaster Confidence Levels...

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

12z TAF Update...

Today...High Confidence.

Any lingering localized fog patches burn off by 13z.
Otherwise...VFR today outside of scattered showers and an
isolated t-storm or two expected to develop after 18z especially
across central and eastern MA into RI. Given cold temps
aloft...a bit of graupel is possible with any of the heavier
showers too. WNW generally near 10 knots...But brief localized
sea breezes possible for a time near the immediate coast this
afternoon.

Tonight...High Confidence.

Mainly VFR outside any scattered showers and isolated t-storm
risk with the main threat coming to an end by midnight.
Potential for MVFR ceilings to push in after 10Z for the east
coast/Cape terminals. This as light NW flow turns N-NE towards
12z Monday and increase to between 8 and 14 knots.

KBOS...High confidence in TAF. Main concern is after 18z for
scattered showers with the low risk of an isolated t-storm in
the vicinity of the terminal into this evening. Also...a brief
sea breeze possible this afternoon.

KBDL...High confidence in TAF.

Outlook /Monday through Thursday/...

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

Monday Night: VFR.

Tuesday: VFR. Slight chance SHRA.

Tuesday Night through Thursday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today and Tonight...High Confidence.

NW winds continue to decrease across the water early this
morning, less than 25 kts by 12Z. SCAs remain in place for outer
coastal waters for 5-6 ft seas. Cape Cod Bay/Nantucket sound and
Mass Bay falls below 5 ft this morning followed by the norther
outer coastal waters by this evening. Seas stay around 5 ft
through late tonight for the southern outer coastal waters.

Outlook /Monday through Thursday/...

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

Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft

Tuesday through Tuesday Night: Winds less than 25 kt.

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

Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 11 AM EDT this morning for ANZ231-
     232-251.
     Small Craft Advisory until 8 PM EDT this evening for ANZ250.
     Small Craft Advisory until 11 PM EDT this evening for
     ANZ254>256.

&&

$$

DISCUSSION...Mensch
AVIATION...Frank
MARINE...Mensch