208
FXUS61 KBOX 200024
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
824 PM 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. Hurricane Erin will
pass well southeast of Nantucket on Friday, with the only
impacts being limited to southeast coastal New England. High
surf and dangerous rip currents along with beach erosion are
anticipated on south- facing beaches, dangerous marine
conditions from gale force wind gusts and high offshore waves,
and potential minor coastal flooding on the Islands are the main
impacts as Erin passes well offshore. Dry weather for this
weekend. Another chance for rain returns heading into the start
of next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Key Messages:

* Another day of cooler temperatures and lower humidity.

An expansive high pressure over northern Quebec continues to move
east, bringing northeast flow to southern New England. Wind off the
ocean is helping to mitigate temperatures along the eastern coast,
and a dry airmass is helping to keep the humidity at bay. High
temperatures this afternoon likely in the low to mid 70s across the
area, with the eastern shores struggling to reach much above 70.
Dewpoints slightly higher than yesterday... low to mid 50s, except
high 40s across the interior. Clouds continue to build in throughout
the afternoon and evening, leading to slightly warmer temperatures
tonight... in the mid to high 50s.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Key Messages:

* Rain chances return midweek, although exact rainfall totals
  are still uncertain.

A quick shortwave moves through New England Wednesday, bringing rain
chances to the area. Guidance is still struggling to come to an
agreement on exact placement, but generally thinking south of the
Mass Pike will see the heaviest rainfall. The ECMWF, NBM, and
Canadian all favor roughly 1" QPF/24 hours across southern CT and
RI, the GFS favors 1.25" QPF/24 hours across northern CT, and the
NAM stays the furthest north with a swath of 1.5" QPF/24 hours
across interior MA. 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.

High temperatures Wednesday will likely be in the low 70s across
eastern MA as easterly winds continue. Slightly cooler temps with
highs in the mid 60s and down into the upper 50s in the higher
elevations of the western parts of the region with continued cloud
cover.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Messages:

* Erin passes well offshore of Nantucket Fri. Impacts to Southern
  New England include high surf and dangerous rip currents through
  late this week, beach erosion on south-facing beaches, dangerous
  marine conditions with gale-force wind gusts, and a risk for minor
  coastal flooding for Nantucket and Martha`s Vineyard during the
  Thurs and Fri night high tides.

* Away from the southeast coast, mainly dry weather with cooler than
  normal temps and modest northeast breezes.

* Warming trend for late in the weekend into early next week with
  next chance for rain around Sun/Mon.

Details:

Hurricane Erin is still forecast to pass well southeast of Nantucket
out over the open Atlantic Ocean Thurs into Fri. For the latest on
Erin, refer to the current advisories issued by the National
Hurricane Center. For the vast majority of Southern New England,
mainly dry weather, cooler than normal temps and modest northeast
breezes are anticipated. Fringe impacts locally should be primarily
confined to southeast coastal New England, and we`ll touch upon
this impacts below...

Enhanced Northeast Winds for Southeast Coastal New England: Mostly
cloudy weather with steadily increasing northeast winds/gusts are
expected Thurs into Fri, with gusts around 25-35 mph for the south
coast, Cape Cod, with gusts perhaps nearing 40 mph over Martha`s
Vineyard and especially Nantucket Thurs night into Fri. While
pretty breezy, minimal if any adverse impacts are expected from
wind gusts of this magnitude.

Dangerous Marine Conditions: We`ve opted to hoist a Gale Watch for
much of the southern waters for Thurs and into a good part of
Fri, which extends into Fri night out in the far southeast
waters. The combination of northeast to north wind gusts of
35-40 kt and offshore seas of 15 to 20 ft will lead to dangerous
boating conditions for mariners starting Thurs but especially
Thurs night through Fri.

High Surf/Dangerous Rip Currents: Large breaking waves in the surf
zone from southerly swell will lead to a threat of dangerous rip
currents and high surf on south-facing beach exposures. We`ve opted
to extend the High Surf Advisory into Friday, and we may need to
extend Nantucket and Barnstable Counties into a high surf advisory
for Saturday too, as Erin pulls away and the swell direction changes
from an easterly direction.

Coastal Flooding/Beach Erosion: Swells from Erin and wave action
will most likely result in dune and beach erosion on south-facing
beaches Thurs into Fri. This is especially the case for Martha`s
Vineyard and Nantucket, which have experienced significant erosion
due to nor`easters over the past several cold seasons. Although the
majority of the coastline should remain spared from coastal
flooding...due to 1-2 ft storm surge with some wave action with as
much as 8 ft waves in Nantucket Sound, minor or up to pockets of
moderate coastal flooding could materialize on Martha`s Vineyard and
on Nantucket around the high tide periods late-Thursday-evening and
especially late-Friday-evening as winds turn northerly. Coastal
Flood headlines could be needed in the coming day(s).

For Sat into the weekend...dry weather should prevail into Sat with
significantly lighter winds. By Sun, temps warm back up to
seasonable levels with rising humidity levels. A threat for showers
and thunderstorms around Sun into Mon as a cold front moves eastward
from the Gt Lakes. Don`t see too much in the way of severe weather
potential with this cold front but there is time to reassess that
over the coming days.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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. ESE winds 5 to 10 knots.

Wednesday and Wednesday Night...High confidence in trends, low
confidence in timing and placement of SHRA.

VFR maintained through 15-17z. Periods SHRA then break out
18-20z western airports which move east/southeast after 21z.
Ceilings decrease to at least MVFR with visbys 2-6 SM in SHRA.
It remains uncertain where the steadiest (heaviest?) rain may
fall, although seems to be near ORH-BAF-BDL area. SHRA then
slips south/west for overnight, although ceilings still likely
to be low. NE winds around 5-10 kt.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday: VFR. Windy with local gusts up to 30 kt. Slight
chance SHRA.

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

Friday: VFR. Strong winds with local gusts up to 40 kt.

Friday Night through Saturday: VFR. Breezy.

Saturday Night: VFR.

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

&&

.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 /Thursday through Sunday/...

Thursday: Low risk for gale force winds with gusts up to 35 kt.
Rough seas up to 15 ft. Slight chance of rain showers.

Thursday Night: Low risk for gale force winds with gusts up to
40 kt. Rough seas up to 18 ft. Slight chance of rain showers.

Friday: Low risk for gale force winds with gusts up to 40 kt.
Rough seas up to 18 ft.

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Rough seas up to 14 ft.

Saturday: Winds less than 25 kt. Rough seas up to 11 ft.

Saturday Night: Winds less than 25 kt. Rough seas up to 9 ft.

Sunday: Winds less than 25 kt. Areas of rough seas. Slight
chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory until 8 AM EDT Saturday for MAZ020>024.
RI...High Surf Advisory until 8 AM EDT Saturday for RIZ006>008.
MARINE...Gale Watch from Thursday morning through late Friday night for
     ANZ231-232-254-255.
     Gale Watch from Thursday morning through Friday afternoon for
     ANZ233>235-237-256.
     Small Craft Advisory until 8 AM EDT Thursday for ANZ254>256.

&&

$$

SYNOPSIS...Loconto/McMinn
NEAR TERM...McMinn
SHORT TERM...McMinn
LONG TERM...Loconto
AVIATION...Loconto/BW/McMinn
MARINE...Loconto/BW