170
FXUS61 KBOX 281757
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
157 PM EDT Mon Sep 28 2026

.WHAT HAS CHANGED...
Flood watch has been cancelled. Small craft advisories for
Boston Harbor and Narragansett Bay have also been taken down as
conditions begin to improve.

&&

.KEY MESSAGES...

- Slowly improving weather overnight and Tuesday as the
  nor`easter weakens and moves away

- Warm and Dry conditions arrive Wednesday through Friday
  followed by a chance for rainy and unsettled conditions this
  weekend

&&

.DISCUSSION...
KEY MESSAGE 1...Slowly improving weather overnight and Tuesday as
the nor`easter weakens and moves away.

Although the low level swirl around the center of the nor`easter
south of Long Island looks impressive on satellite imagery, the
storm is quickly weakening as it`s starting to move more quickly to
the northeast. Still a good amount of moisture, wrapped around the
circulation, producing a fairly large area of light rainfall.
However as the dynamics weaken, the rainfall intensity is also on a
downward trend. Expect most areas will see less than 1/2" of
additional rainfall from this point forward. Models are all in good
agreement in taking the low across the Cape overnight and then into
the Gulf of Maine on Tuesday. Surface winds will slowly transition
from NNE to NNW and then NW by Tuesday morning - except across our
southern coastal waters and Nantucket, which will see winds go from
the SE to SW and eventually W since the low center will pass north
of those areas. Model forecast cross-sections indicate low level
moisture will be slow to leave tomorrow, so expect a generally
mostly cloudy day. Better chances for some afternoon sunshine will
be across western areas. There is no blob of cold air that will come
in behind the nor`easter, and in fact 925mb temperatures will be a
little warmer than they were today. So given that and some breaks of
sunshine, temperatures will be in the mid to upper 60s for most, and
a few locations - especially in the CT River Valley - could hit
70F.

Also, given the downward trends in rainfall, have gone ahead and
cancelled the Flood Watch. Although some minor flooding is still
expected along portions of the Taunton River, we don`t
anticipate any increase in risk for flooding across the area.


KEY MESSAGE 2...Warm and Dry conditions arrive Wednesday through
Friday followed by a chance for rainy and unsettled conditions this
weekend.

A mid-level ridge builds across the southeastern CONUS this week,
while surface high pressure settles south of the region Wednesday
through Friday, leading to a stretch of quieter and warmer weather.
Guidance hints at a weak northern-stream shortwave Wednesday night
into early Thursday, followed by a secondary shortwave Thursday
night into Friday. PWATs Wednesday night into Thursday remain below
1.2 inches and do not align particularly well with the best forcing.
Outside of a brief light shower, would anticipate more clouds than
anything. PWATs increase to around 1.5 inches Thursday night with
the passage of the secondary weak shortwave, when a few light
showers could brush the region. No significant impacts are
anticipated with either disturbance. Temperatures trend warmer
through the middle and latter half of the week, though the latest
guidance has trended somewhat cooler compared to previous runs.
Highs generally return to the lower and middle 70s, with Thursday
potentially the warmest day as temperatures reach the middle to
upper 70s. No notable cold is expected overnight, with lows
generally falling into the 50s.

Forecast becomes a bit more interesting by late next week as a
strong continential high pressure system arrives from SE Canada.
Guidance shows a rather sharp drop in temperatures with 850 temps
falling from +15-17C Friday to +4-6C on Saturday. Beyond this front,
guidance is beginning to come into better agreement with depicting a
strong area of low pressure across SE Canada on Sunday. There
remains a variety of solutions with the GFS/ICON depicting secondary
cyclogenesis along a frontal boundary near the Carolinas and the
ECMWF/CMC leaning more towards a strong frontal boundary. In any
case, the second half of the weekend looks wet and unsettled. Behind
this feature, guidance depicts a much colder airmass moving in from
Canada with 850mb temps falling below zero later Monday through
Wednesday. These mid-level temps would support highs in the 40s and
50s with nighttime lows possibly falling into the 30s depending on
radiational cooling.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

18z TAF Update...

Overall moderate confidence.

IFR to occasionally LIFR conditions will continue through the
evening and much of the overnight. Although areas of -RA and -SHRA
will slowly wind down later this evening, low ceilings and BR will
persist in most areas. Probably some -DZ mixed in as well. The
timing of the -SHRA and lower visibility/ceiling conditions are just
estimates.

As we get into Tuesday morning, we should see improving conditions
to at least MVFR in most areas, and perhaps VFR conditions
developing by early afternoon across western areas. Guidance
suggests low level moisture will remain in place, resulting in
widespread ceilings of 2000-2500ft for most areas much of the day.
Basically what you see this afternoon across western NY and PA will
be what is over our area tomorrow.

VFR conditions should build in Tuesday night.

KBOS Terminal...Moderate confidence in TAF. Should continue to see
NNE winds occasional gust 20-25kt through 00z before wind diminish a
bit and start to transition to NW.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Wednesday through Saturday/...

Wednesday through Wednesday Night: VFR.

Thursday through Thursday Night: VFR. Breezy.

Friday: VFR. Slight chance SHRA.

Friday Night: VFR. Chance SHRA.

Saturday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Overall high confidence.

The nor`easter is weakening and beginning to move more quickly
to the northeast. The center will pass over Cape Code overnight
and then move into the Gulf of Maine for tomorrow. As that
happens, winds will continue to diminish. Seas will also
continue to subside, but that process will take a bit longer
than the winds, especially for the outer waters off the eastern
MA coasts. High pressure does move across the region later
tomorrow, and then will set up off the US east coast and provide
an extended period of SW winds for the middle through end of the
week.

Outlook /Tuesday Night through Saturday/...

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

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: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Coastal Flood Advisory until midnight EDT tonight for MAZ007-
     015-016-019-022>024.
RI...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ230-
     236.
     Small Craft Advisory until 8 PM EDT this evening for
     ANZ231>235-237.
     Small Craft Advisory until 2 PM EDT Tuesday for ANZ250-251.
     Small Craft Advisory until 8 AM EDT Tuesday for ANZ254.
     Small Craft Advisory until 2 AM EDT Tuesday for ANZ255-256.

&&

$$

DISCUSSION...FT/Nash
AVIATION...FT/Nash
MARINE...FT/Nash