985
FXUS61 KBOX 190746
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
346 AM EDT Tue Aug 19 2025

.SYNOPSIS...
Below normal temperatures with low humidity remain in the region for
much of this week before a warming trend kicks in at the end of the
week. A shortwave moving through Wednesday will increase cloud cover
and bring rain chances to southern New England, but amounts are
still uncertain. Breezy conditions across the region prevail
Thursday and Friday, with winds possibly reaching gale-force over
the Cape and Islands. Another chance for rain returns heading into
the start of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Messages:

* Calm conditions and comfortable temperatures with low humidity

Another beautiful day ahead across southern New England. High
temperatures expected to be in the 70s once again with light winds
gradually becoming more SE as the day goes on. Low humidity with dew
points primarily in the 40s and 50s. Cloudy skies build in as the
day goes on.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Key Messages:

* Another unseasonably cool night, though remaining dry

* Increasing cloud cover with rain chances returning for midweek

Cloud cover continues to increase overnight tonight ahead of a
disturbance that will move through the region Wednesday. In terms of
rainfall amounts, guidance is still far apart on totals. The NAM and
GFS are notably higher than other models, and ensemble probabilities
are mainly favoring 24 hour totals less than a quarter of an inch
(except for the ECMWF ENS, which is noting totals in CT and RI up to
and slightly over 0.5"). PWAT values are approaching 2" in parts of
CT and RI Wed afternoon, which will be something to monitor for the
possibility of some isolated heavy downpours. The latest HREF
guidance has mainly scattered showers across the region through the
afternoon Wednesday with low probs for thunder in western MA into
CT. The chance for a widespread soaking rain remains lower at this
time.

Lows tonight are expected to be cooler than normal once again,
settling into the 50s across the region. Highs Wednesday will likely
be in the low 70s across eastern MA as easterly winds continue.
Slightly cooler temps with highs in the 60s and down into the upper
50s in the higher elevations of the western parts of the region with
continued cloud cover.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Key Messages:

* Large southerly swell from distant Erin will bring high surf and
  dangerous rip currents to south-facing beaches through the latter
  part of this week

* Northeast winds intensify over the Cape and Islands
  Thursday/Friday and could reach gale-force

* Another chance for some rain arrives Sunday along with a weekend
  warm-up

The main story for this period of the forecast is the dangerous to
life-threatening surf and rip current risk across our south-facing
beaches. This elevated risk is due to the passage of Hurricane Erin
far to our southeast by Friday, which will be churning up
significant swell that will eventually make its way to our coasts;
waves south of Nantucket may reach up to 20 ft. Along with elevated
surf, the gradient between Erin and the Canadian high pressure
settled over southern New England will lead to amplified NE winds
over the Cape and Islands that could reach gale-force strength.
Model guidance is indicating winds at 850 mb approaching 50 kts over
the Islands by Friday morning and even up to 55 kts at 925 mb. Aside
from the Cape and Islands, the rest of southern New England can
expect a generally breezy Thursday and Friday before the gradient
slackens with Erin`s influence diminishing as it moves further into
the Atlantic.

Through the rest of the week, high and low temperatures remain
relatively consistent. Lows remain in the 50s and low 60s and highs
remain in the 70s before a warming trend kicks in for the weekend.
More seasonably normal temperatures can be expected heading into the
weekend as highs return to the low 80s. The next chance for some
rain arrives sometime Sunday as another disturbance moves into the
region as part of a trough settled over much of Ontario into
Quebec.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

06z TAF Update:

Rest of Tonight: High confidence.

VFR. Winds remain light and variable through 12z.

Tuesday and Tuesday Night...High confidence.

VFR. ESE winds 5 to 10 knots.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Mainly VFR, with local MVFR possible. Breezy.
Chance SHRA.

Thursday: VFR. Breezy. Slight chance SHRA.

Thursday Night: VFR. Windy with areas of gusts up to 35 kt.

Friday: VFR. Windy with gusts up to 35 kt.

Friday Night: VFR. Windy with local gusts up to 30 kt.

Saturday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Wednesday...High confidence.

Large southerly swell from major hurricane Erin will result in
seas at or above 5 feet for portions of our southern waters
today, ramping up through mid-week. For this reason, Small Craft
Advisories will remain in effect across the southern waters for
an extended period. A High Surf Advisory also goes into effect
this morning for southern coastal areas, including the Cape. Rip
currents will become a significant concern as the week goes on
with this elevated surf.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Winds less than 25 kt. Areas of rough seas.
Chance of rain showers, slight chance of thunderstorms.

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 14 ft. Slight chance of
rain showers.

Thursday Night: Strong winds with gusts up to 40 kt. Rough seas
up to 18 ft. Slight chance of rain showers.

Friday: Moderate risk for gale force winds with gusts up to
40 kt. Rough seas up to 17 ft.

Friday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 12 ft.

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Rough seas up to 10 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory from 8 AM this morning to 8 PM EDT Thursday
     for MAZ020>024.
RI...High Surf Advisory from 8 AM this morning to 8 PM EDT Thursday
     for RIZ006>008.
MARINE...Small Craft Advisory until 8 AM EDT Thursday for ANZ254>256.

&&

$$

SYNOPSIS...Hrencecin
NEAR TERM...Hrencecin
SHORT TERM...Hrencecin
LONG TERM...Hrencecin
AVIATION...Hrencecin
MARINE...Hrencecin