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599
FXUS61 KBOX 011933
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
333 PM EDT Wed May 1 2024

.SYNOPSIS...
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A weak low pressure system will bring scattered showers near
the coast Thursday. High pressure north of the region will bring
dry and seasonable weather Friday and most of Saturday with
onshore winds. An approaching front should bring showers late
Saturday into Sunday. Dry and warmer weather is expected early
next week.
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&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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4pm Update

Mainly dry the rest of today with a low chance for an isolated
shower across the Berkshires and CT river valley this afternoon as
100-200 J/kg of SBCAPE builds with some sunshine. Low clouds and
pockets of fog form again overnight as surface winds turn south and
bring in low level moisture. Overnight lows again stay in the mid to
upper 40s with low cloud cover and weak warm air advection.
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&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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Tomorrow:

Shortwave trough and associated surface low drops south
from northern New England. An area of light showers associated with
a cold front move through tomorrow morning, however, guidance is
mixed on the extent south and intensity of these showers. The best
forcing for showers looks to mainly stay confined to northeast MA.
Later in the afternoon, the center of the low pressure and core
of shortwave energy passes over eastern MA. At this point,
100-200 J/kg of MUCAPE will be able to build, allowing for
isolated convective showers to form across eastern MA, with the
best chance over northeast MA again. With the low amount of
instability, there is a low chance for a rumble of thunder with
any showers tomorrow afternoon. Confidence was not high enough
to include mention in the forecast database at this point.

High temperatures have trended warmer tomorrow with SSW flow, and
increasing chances for sunny to partly sunny skies across western MA
and CT. Stuck with the NBM for temperatures tomorrow with highs in
the mid to upper 70s in the CT river valley, and upper 60s to low
70s in RI and Eastern MA away from the coasts.

Tomorrow night:

Winds shift NE overnight as the center of the low moves south off
shore and high pressure builds in to the north. This will bring all
the low clouds and fog back onshore, eventually pushing west over
much of the region. This keeps low temps mild once again only
dropping into the upper 40s to low 50s. Rain and shower chances
quickly decrease as the low exits and upper level ridge builds in.
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&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...

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Key Points:

 * Overall quiet weather pattern ahead
 * Scattered showers late Saturday into Sunday
 * Warmup early next week

Still have the greatest confidence in dry weather persisting through
most of Saturday. Still some disagreement in when showers could
arrive late Saturday into Sunday. Both the 01/12Z GFS and CMC
suggest at least a risk for showers along the east coast of MA late
Saturday afternoon, while the larger NationalBlend ensemble
maintains dry weather for the same time frame. Given the synoptic
pattern, with a high pressure just to the east of New England,
favoring the drier NationalBlend solution into Saturday night. This
still pushes the focus for weekend showers into Sunday.

Trickier forecast for earlier next week. Latest guidance suite still
exhibited some timing and amplitude differences with the evolution
of a mid level longwave trough near the Rockies. This will
eventually impact our weather downstream. Our proximity to a surface
front will be critical to our forecast outcome. At present, thinking
this front will be pushed far enough south where mainly dry weather
prevails Monday and Tuesday, before returning north as a warm front
some time Tuesday night into Wednesday.

Near normal temperatures expected through Saturday, before briefly
trending below normal Sunday. Likely to see above normal
temperatures early next week.
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&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
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Forecast Confidence Levels:

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

Rest of Today: Moderate Confidence

IFR ceilings continue to persist across NE MA. Expecting IFR
CIGS to continue while winds remain ENE. Should see
improvements to MVFR once winds shift SSW later this evening.
Ceilings continue to lift across SE MA, RI, but confidence on
VFR vs MVFR is low. VFR for the CT river valley with a low
chance for a isolated shower this afternoon.

Tonight: Moderate Confidence

VFR/MVFR becoming IFR/LIFR late overnight before sunrise.

Tomorrow: Moderate Confidence

Slow improvements of IFR to MVFR in the morning. A passing low
could bring light rain esspically to NE terminals tomorrow
morning into the afternoon. Western terminals will see CIGS
reach VFR tomorrow afternoon, while eastern terminals,
esspically Cape Cod and the Islands, could get stuck with
MVFR/IFR.

Thursday Night: VFR/MVFR in the west, with IFR/LIFR filling
back in the east.

KBOS TAF...Low confidence

Guidance is really struggling to maintain the IFR status deck
thats been hanging around all day. With an ENE wind, not
expecting much improvements to MVFR/VFR outside a brief breaks
in the clouds. Winds should turn around to the SSW this evening
which should help push CIGS back up into the MVFR range, but
confidence is low to moderate at this time. Higher confidence at
IFR/LIFR CIGS working back in overnight before sunrise, lasting
into the late morning. A passing low could bring light showers
tomorrow morning into the afternoon, but confidence was only
high enough to include VCSH in the TAF at this time.


KBDL TAF...Moderate confidence.

The IFR status deck has cleared BDL, however stratocumulus are
starting to form which may bring brief periods of MVFR this
afternoon. There is a low chance for an isolated light shower
this afternoon, but confidence was not high enough to include a
VCSH in the TAF. Expecting CIGS to drop back to MVFR then IFR
again overnight and improving again tomorrow morning with VFR
again by tomorrow afternoon.

Outlook /Friday through Monday/...

Friday: Mainly VFR, with local MVFR possible.

Friday Night: VFR.

Saturday: Mainly VFR, with local MVFR possible.

Saturday Night: Mainly VFR, with local IFR possible. Slight
chance SHRA.

Sunday: MVFR/IFR conditions possible. Chance SHRA.

Sunday Night: Mainly VFR, with areas IFR possible. Chance SHRA.

Monday: VFR.
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&&

.MARINE...
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Forecaster Confidence Levels:

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

Tonight: Winds shift south tonight remaining 10 knots or less
with calm seas.

Tomorrow:

Weak low pressure system brings scattered showers and a low
chance for a rumble of thunder mainly across the northern
waters. Winds remain south at 10-15 knots gusting 20 knots.
Light seas of 1-3 feet.

Tomorrow night: Low clouds and fog possible overnight. Winds
turn ENE again at 5-10 knots and seas remain 1-3 feet.


Outlook /Friday through Monday/...

Friday through Saturday: Winds less than 25 kt.

Saturday Night: Winds less than 25 kt. Slight chance of rain
showers.

Sunday: Winds less than 25 kt. Chance of rain showers.

Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain showers.

Monday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers.
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&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

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