876
FXUS61 KBOX 181729
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
129 PM EDT Wed Sep 18 2024

.SYNOPSIS...
High pressure continues to support warm and mainly dry weather
through this afternoon. We`ll have our next chance for
measurable precipitation later tonight. Greatest chances should
be confined to Cape Cod and the Islands. Otherwise, mainly dry
with mostly cloudy conditions and blustery NE winds this weekend
into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

Another mild say with highs in the upper 70s to low 80s and
increasing mid-high clouds south of I-90. Expect more sun than
clouds for areas north of I-90 away from the coast. Winds become
more easterly during the afternoon which should support
cloudiness along the east coastline. Some patchy areas of
drizzle possibly this morning as well. An area of low- pressure
moving north along the mid- Atlantic coast will result in
increased rain chances this evening over the south coast Cape
and Islands, but showers likely don`t move over the region until
the overnight hours.

&&

.SHORT TERM /THURSDAY/...
Tonight and Tomorrow

Aforementioned area of low pressure slowly moves north and east
overnight into tomorrow morning, but eventually begins to
meander in response to blocking high pressure over The Canadian
Maritimes. Expect showers to develop over the south coast, Cape,
Islands, and southeastern MA overnight into tomorrow morning.
Winds become northeasterly tomorrow afternoon supporting
overcast skies across the region. High temps will be much cooler
on THursday in the upper 60s to low 70s, but elevated dewpoints
in the mid 60s will support a muggy feel to the atmosphere
tomorrow. Some uncertainty in how much rainfall will accumulate,
but latest HREF run supports 0.5 to 1 inch of rain across
southeastern MA and The Cape with as much as 1.5 inches over The
Islands.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Not much change in the latest guidance suite compared to the
past couple of days. Broad agreement continued, but there also
remained significant uncertainty in the details. Trended the
forecast with this update towards the consensus solution,
without making large changes just yet.

Overall, expecting a mid level trough to be nearby late this
week into early this weekend. At the surface, southern New
England should be between two features; a large high pressure to
the north, and a low pressure approaching from the south.
Ensembles showed most of the uncertainty was more east-west in
nature rather than north- south. Thus, still have the greatest
confidence in this low pressure center passing near or just SE
of the 40N/70W benchmark Thursday night into Friday. This timing
is highly uncertain, and could change with later forecasts,
even at this relatively closer time range.

Another aspect which will need to be monitored closely with this
low pressure is coastal flooding. Astronomical tides are rather
high later this week. A slow-moving low pressure with persistent
winds with at least some onshore component for the south coast
of New England may result in pockets of coastal flooding issues
late this week.

High pressure should then build into our region from the N this
weekend into early next week, leading to more dry weather.

Temperatures anticipated to trend below normal by this weekend,
and continue into early next week.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Forecast Confidence Levels:

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

Rest of Today...Moderate Confidence

VFR north of the MA pike, while south of the MA pike has some
lingering MVFR with IFR cigs closer to the Cape and Islands.
Although guidance does show improvements this afternoon, with
higher dewpoints streaming in, am a bit skeptical if the Cape
and Islands will be able to go and maintain VFR.


Tonight...Moderate Confidence

Winds turn NE this evening, which will bring CIGS down to
IFR/LIFR east of the I-95 corridor, while to the west, CIGS
should remain VFR with pockets of MVFR possible. LIFR cigs are
most likely for the Cape and Islands, but could work into BOS
and PVD. Light rain begins to work its way from south to north
overnight, mainly just affecting the Cape and Islands northward
to BOS. ORH and BDL should stay mainly dry.

Tomorrow...High Confidence

IFR continues as winds increase from the NE at 10-15 knots
inland, and 15-30 knots near the waters. Rain becomes moderate
to heavy for the Cape and Islands. The extent that rain reaches
inland remains uncertain, but should remain light outside of the
Cape. Western terminals may see no rain with MVFR/VFR conditions
tomorrow afternoon.

Tomorrow Night... Low confidence

Guidance tries to show some improvements in CIGS, but am rather
skeptical given the continued on shore NE winds. The low stalls
south of the Cape and Islands, but rain could still continue for
eastern terminals, esspically the Cape and Islands.


KBOS TAF...Moderate Confidence

VFR this afternoon with east winds. Winds turn NE overnight,
bringing in IFR CIGS by 00-02z. CIGS could go LIFR late
overnight, but confidence is low at this time. light rain is
possible early Thursday morning, possibly lasting into Friday
morning

KBDL TAF...High confidence in TAF.

VFR today with light winds. Mainly VFR overnight and tomorrow,
but pockets of MVFR possible. Expecting the rain to stay east
of the CT river valley

Outlook /Thursday Night through Sunday/...

Thursday Night: Mainly VFR, with local IFR possible. Windy with
local gusts up to 30 kt. Chance SHRA.

Friday: Mainly VFR, with local IFR possible. Breezy. Slight
chance SHRA.

Friday Night: Mainly VFR, with areas IFR possible. Breezy.
Slight chance SHRA.

Saturday: Mainly VFR, with local IFR possible. Windy with local
gusts up to 30 kt. Slight chance SHRA.

Saturday Night through Sunday: Mainly VFR, with local MVFR
possible. Breezy.

&&

.MARINE...
Forecaster Confidence Levels:

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

Marine

Today through Tomorrow

Low-pressure approaches the coastal waters this evening and
overnight. This result in winds increasing out of the northeast
into tomorrow morning when 25+ knot wind gusts will be possible
over the coastal waters. Seas will build as well with wave
heights rising to 4 to 6 feet over the outer marine zones. A
Small Craft Advisory remains in effect for the the south
coastal waters through Thursday.

Outlook /Thursday Night through Sunday/...

Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 8 ft. Chance of rain
showers.

Friday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Rough seas up to 8 ft. Chance of rain showers.

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Rough seas up to 9 ft. Slight chance of rain
showers.

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 10 ft. Slight chance of
rain showers.

Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 25 kt. Rough seas up to 10 ft. Slight chance
of rain showers.

Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Rough seas up to 10 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 8 AM to 8 PM EDT Thursday for
     ANZ232>235-237.
     Small Craft Advisory from 5 PM this afternoon to 8 PM EDT
     Thursday for ANZ254>256.

&&

$$

SYNOPSIS...Belk/RM
NEAR TERM...Belk/RM
SHORT TERM...RM
LONG TERM...Belk
AVIATION...RM/KP
MARINE...Belk/RM