-- Discussion containing changed information from previous version are highlighted. --
377
FXUS61 KBOX 232300
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
700 PM EDT Thu May 23 2024

.SYNOPSIS...
Much drier air moves in tonight followed by warm and less humid
conditions Friday into Saturday as high pressure builds into the
region. A frontal system may bring a few showers and isolated
thunderstorms Saturday night into Sunday. Turning cooler and more
seasonable early to mid next week, with a better chance of
showers.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Showers and t-storms assocd with an MCS are moving to the east
of New Eng with partial clearing moving in from the west. The
challenge for the rest of the afternoon is the potential for
isolated convection redeveloping. Atmosphere has been worked
over across much of the region, except interior northern and
western MA where not much convection occurred. With clearing
moving in from the west, expect destabilization and agitated CU
is developing in western MA. Can`t rule out an isolated
shower/t-storm developing in the interior but much of the
region should be dry.

Much drier air moves in from the north tonight behind the weak cold
front. Expect a fair amount of cirrus so overall mostly clear to
partly cloudy skies. Exception will be along the immediate south
coast and especially the Cape/Islands where stratus and fog expected
to develop. Lows will be in the 50s, except around 60 in urban
centers.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Friday...

Northern stream trough passes well to the north with attendant cold
front dropping south across northern New Eng. Wedge of dry air and
subsidence will prevail across SNE leading to abundant sunshine. It
will be a warm day with 925 mb temps 19-20C supporting highs 80-85
with less humidity as dewpoints drop through the 50s and into the
40s, especially northern MA. It will become a bit breezy as deep
mixing will result in W-SW gusts to 20-25+ mph developing in the
afternoon, especially in northern MA.

Friday night...

The secondary cold front moves south of the coast with high pres
building in from the north. Clear skies and light winds will result
in good radiational cooling with lows dropping into the low-mid
50s, with some upper 40s across western MA.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Highlights

* Warm and dry Saturday

* Scattered thunderstorms possible Sunday

* Unsettled for the first half of next week

Saturday and Sunday

A mid-level ridge builds over southern New England on Saturday
supporting dry/sunny conditions across the forecast area. Temps will
be warm across the interior in the upper 70s to low 80s, but sea-
breezes will keep the coastal locations cooler in the upper 60s to
low 70s. As the mid-level ridge shifts east Saturday night into
Sunday, return flow from the south will support increasing
dewpoints/moisture for Sunday afternoon. Model guidance is resolving
a subtle upper-level short-wave/mid-level low moving over the region
early Sunday. With a few hundred J/kg of CAPE and 30 to 40 knots of
deep layer shear, this disturbance may be enough to trigger a few
scattered thunderstorms on Sunday. With instability values on the
modest side, there is no signal for any potential storms to become
strong to severe at this time. Aside from thunderstorm potential on
Sunday, it looks to be a quiet second half of the weekend with
seasonable temperatures and a mix of sun and clouds.

Next Week

A broad upper-low builds over the eastern US early next week. This
feature is expected to support unsettled weather through mid to late
week with substantial precipitation expected Monday night into
Tuesday. Temps look to be seasonable with daily highs/lows in the
mid 70s and mid 50s respectively. A cold front may bring another
round of precipitation and cooler temperatures by the end of next
week. Details are vague at this time range so stay tuned for more
details.

&&

.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --
Forecast Confidence Levels:

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

00Z TAF Update

Tonight...Moderate Confidence.

IFR-LIFR stratus and fog over the Cape/Islands, possibly
reaching the immediate south coast. Otherwise VFR. Winds
becoming light W.

Friday and Friday night...High confidence.

VFR. W wind 10-20 kt Fri with 25 kt gusts possible north of the
MA Pike. Diminishing wind Fri night becoming light N-NW.

KBOS TAF...High confidence in TAF.

Showers and a few t-storms exiting by 19z then VFR. SW wind
10-15 kt becoming W this evening. W gusts to 20 kt developing
Fri afternoon

KBDL TAF...High confidence in TAF.

Outlook /Saturday through Tuesday/...

Saturday: VFR.

Saturday Night through Sunday: VFR. Slight chance SHRA,
isolated TSRA.

Sunday Night: Mainly VFR, with local MVFR possible.

Memorial Day: Mainly VFR, with areas MVFR possible. Chance
SHRA, isolated TSRA.

Monday Night: MVFR/IFR conditions possible. Chance SHRA,
isolated TSRA.

Tuesday: Mainly VFR, with local IFR possible. Breezy. Chance
SHRA, isolated TSRA.
-- End Changed Discussion --

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Friday night...High Confidence.

SW winds become light W tonight behind a weak front, then increasing
SW-W wind 15-20 kt during Fri. Winds become light NW-N Fri night as
another front moves through. Seas below SCA thresholds.

Outlook /Saturday through Tuesday/...

Saturday: Winds less than 25 kt.

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

Sunday Night: Winds less than 25 kt.

Memorial Day: Winds less than 25 kt. Slight chance of rain
showers, isolated thunderstorms.

Monday Night through Tuesday: Winds less than 25 kt. Seas up to
5 ft. Chance of rain showers, isolated thunderstorms.

&&

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

&&

$$

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