Area Forecast Discussion
Issued by NWS Boston, MA

Home |  Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
538
FXUS61 KBOX 291122
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
722 AM EDT Tue Sep 29 2026

.WHAT HAS CHANGED...
Coastal Flood Advisories have expired, but Small Craft
Advisories remain for the eastern waters through this morning. A
Flood Warning also remains in effect for the Taunton River.

&&

.KEY MESSAGES...

- Conditions continue to improve today as the low finally
  pushes offshore and into the Gulf of Maine.

- Above seasonal temperatures arrive mid-week followed by
  unsettled conditions for the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Conditions continue to improve today as the low
finally pushes offshore and into the Gulf of Maine.

Damp conditions are slowly beginning to improve as the low
slowly moves across Cape Cod and offshore into the Gulf of Maine
today. Winds have already begun to transition west-southwest
across interior southern New England, but the coastal plain will
remain misty through sunrise and overcast throughout the day. A
warming trend starts today as a warm airmass settles over New
England... surface temperatures today warming to the mid to
upper 60s, perhaps to just above 70 across the interior where
there will be more breaks of sunshine.

KEY MESSAGE 2...Above seasonal temperatures arrive mid-week
followed by unsettled conditions for the weekend.

Surface high pressure and a mid-level ridge begin to build in,
bringing a warmer and drier airmass to southern New England by
mid- week. This will enhance the warming trend throughout the
week, allowing temperatures to climb into the mid to upper 70s
by Thursday, possibly near 80 by Friday. The caveat being a low
pressure system moving across Ontario and Quebec Thursday and
Friday. A trough axis and trailing cold front looks to then
sweep through New England sometime Friday, bringing the
potential for rainy and unsettled conditions for the weekend.
Once the low moves through Quebec, a rather strong continental
high pressure system will build over Ontario, sinking those +4C
to +6C 850mb temperatures down into New England and sharply
dropping surface temperatures through the weekend. The question
remains when exactly the cold front move through. If it arrives
earlier Friday, afternoon high temperatures could be mitigated
by the colder airmass dipping in from Canada.

Towards the second half of the weekend and into early next
week, ensemble guidance is suggesting the potential for a
deepening low to sweep across the James Bay, bringing a
secondary shot of even colder air to New England. 850mb
temperatures could drop to near 0C by the start of the next work
week, supporting surface highs in the 40s and 50s with
nighttime lows possibly falling into the 30s depending on how
far south the low tracks.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

12z TAF Update...

Today...High confidence in trends. Moderate confidence in
timing.

Low CIGS and VISBYs with lingering BR/-DZ as the low moves
offshore through the morning. Conditions improve through the
morning to at least MVFR, potentially VFR across the interior.
Guidance suggests low level moisture will remain in place,
resulting in widespread ceilings of 2k-2.5kft for most areas
much of the day, although there may be patchy 3k CIGS at times.

Tonight...High confidence in trends. Moderate confidence in
timing.

MVFR conditions continue to improve to VFR throughout the
evening and overnight period. NW winds back to W/WSW as the low
continues to push offshore.

Wednesday...High confidence.

VFR. Light WNW winds, though ESE winds for eastern coastal MA
and SW wind for southern RI and the Islands.

KBOS Terminal...Moderate confidence in TAF. NW winds 5-10 kts
with gradual improvement to MVFR by the afternoon. Will likely
not improve to VFR.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: VFR.

Thursday: VFR. Breezy.

Thursday Night: VFR.

Friday: VFR. Breezy.

Friday Night through Saturday: VFR. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Overall high confidence.

The center of the low pushes offshore and towards the Gulf of
Maine later today after passing over Cape Cod. Winds will
continue to diminish through the early morning hours. Seas will
also continue to subside, but the eastern waters linger around 4
to 5 feet through the morning. High pressure begins to build in
later tonight into Wednesday, providing an extended period of
SW winds through the end of the week.

Outlook /Wednesday Night through Saturday/...

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

Thursday Night through Friday: Winds less than 25 kt. Seas up
to 5 ft.

Friday Night through Saturday: Winds less than 25 kt. Areas of
seas approaching 5 ft. Slight chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ250-
     251.
     Small Craft Advisory until 8 AM EDT this morning for ANZ254.

&&

$$

DISCUSSION...McMinn
AVIATION...Dooley/McMinn
MARINE...McMinn