341
FXUS61 KBOX 241805
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
205 PM EDT Tue Sep 24 2024

.SYNOPSIS...
Weak high pressure will build over our region today, but
continued onshore winds should keep cloudiness in place, especially
near the coast. Rain chances return late Wednesday into Thursday as
a front moves through the area. Dry and warmer weather looks to
follow through the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
9 AM update...

Low level moisture below a stout inversion will result in
strato-cu developing and increasing across SNE today. While
there will be lots of strato-cu, expect clouds to mix with some
sunshine. May also see a few brief sprinkles in eastern MA and
RI as radar is showing some light returns backing in from the
ocean. Highs will top out in the mid-upper 60s, perhaps a few
locations in the CT valley near 70.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Upper-level ridge axis begins to move east with deep
upper-level SW flow and shortwave energy moving toward the region.
Surface high pressure will take longer to move out, keeping the flow
onshore at the surface.  This will result in mostly cloudy to
overcast skies for much of the region tonight through Wednesday.
Cloud cover should keep tonight`s lows in the 50s, with upper
40s possible in northwestern MA. High temps Wednesday will again
be in the low to mid-60s with continued onshore easterly winds
at 10- 15mph. Rain chances don`t creep into the forecast until
late Wednesday when better moisture and forcing arrive.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Wednesday night and Thursday Deepening northern stream trough will
interact with energy from the cutoff southern stream trough over the
south-central US.  Strengthening warm air advection will bring
showers from west to east from late Wednesday into Thursday. Despite
PWATs over 1.5 inches, not expecting heavy rain or large amounts of
QPF due to marginal upper-level forcing.  There is still quite a bit
of spread in the ensembles, with the 25th percentile showing less
than a tenth of an inch, while the 75th percentile shows up to 0.75
inches.  Most global deterministic guidance shows roughly a half
inch with isolated spots of 1+ inches.  There could be a rumble or
two of thunder overnight Wednesday and Thursday with low amounts of
elevated instability.  Rain showers could linger into Thursday night
as the upper level closed low swings south into SNE. However, a cold
front ahead of the upper-level trough will bring in much drier air,
with PWATS falling near 0.5 inches.  Lows Thursday night drop into
the low to mid-50s

Friday - Monday Upper-level closed low moves offshore to the east
while another blocking ridge settles in for Friday through the
weekend.  High temperatures begin to rebound to more seasonable
levels in the upper 60s to low 70s with dry conditions and sunny
skies.  With good radiational cooling conditions, overnight lows
will drop into the upper 40s to low 50s.  Patchy radiation fog is
possible with the longer nights and dewpoints in the mid to upper
50s

&&

.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:

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

Through Wednesday...Moderate confidence.

Mainly VFR cigs into this evening should trend to MVFR
overnight, but specific timing is uncertain. Patchy late night
fog possible in the CT valley. A mix of MVFR and VFR cigs Wed. E
wind 5-15 mph.

Wednesday night... Moderate Confidence

MVFR trending to IFR overnight as widespread showers develop and
move into the region.

BOS TAF...Moderate Confidence in TAF.

Mainly VFR with periods of MVFR possible, trending more to
MVFR overnight into Wed. Specific timing uncertain. Persistent E
winds 5-15 kt.

BDL TAF...Moderate Confidence in TAF.

Mainly VFR, trending to MVFR overnight into Wed. Specific timing
uncertain.

Outlook /Thursday through Saturday/...

Thursday: Mainly VFR, with areas IFR possible. Chance SHRA.

Thursday Night: VFR. Slight chance SHRA.

Friday through Saturday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today through Wednesday...High Confidence.

Small Craft Advisories remain in effect for all outer open
water zones along with the northern near coastal waters for seas
of 5-6 feet. Winds will stay just below small craft criteria
gusting up to 20 knots from the east through Wednesday.

Rip Current Statement remains in effect for both the southern
and eastern coasts. Seas of 5-7 feet with continued east winds
at 10-20mph will create dangerous rip currents today.

Outlook /Wednesday Night through Saturday/...

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

Thursday: Winds less than 25 kt. Local rough seas. Chance of
rain showers, isolated thunderstorms.

Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers.

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

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

Saturday: Winds less than 25 kt. Seas up to 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents until 8 PM EDT this evening for MAZ007-
     019-020-022>024.
RI...High Risk for Rip Currents until 8 PM EDT this evening for
     RIZ006>008.
MARINE...Small Craft Advisory until 8 PM EDT Wednesday for ANZ250-251-
     254>256.

&&

$$

SYNOPSIS...KP
NEAR TERM...KJC
SHORT TERM...KJC/KP
LONG TERM...KP
AVIATION...KJC/KP
MARINE...KP