656
FXUS61 KBOX 271913
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
313 PM EDT Thu Jun 27 2024

.SYNOPSIS...
Dry and pleasant conditions through Friday as a high pressure
briefly builds in. Still looking to be an active weekend in
store as a slow moving frontal system brings showers and
t-storms with localized downpours, especially Saturday afternoon
into Sunday night. Drier weather then returns for early next
week with seasonable temperatures.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Post cold front air mass settles into the region with breezy
conditions overnight from the northwest. A rouge spot shower is
possible this afternoon, but not anticipated to be anything more
than light and brief. Diurnal cu cloud cover will dissipate
overnight, but winds are likely to remain strong enough to
preclude any radiational cooling. Never the less, a great night
for sleeping with windows open as the low temperature drops into
the low 50s and upper 40s away from the coastal plain. Near the
coast a few degrees warmer in the middle to upper 50s.

A side note: NWS Boston/Norton is conducting a storm survey in
the communities of Cumberland/Lincoln, Rhode Island and in North
Attleborough, Massachusetts. We will share our findings later
this afternoon.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Surface high pressure and mid-level height rises will lead to a
wonderful day across southern New England. One challenge will
be how strong the winds become, building surface high could lead
to weaker winds and potentially a sea breeze, which have lower
confidence in, if it were to happen, it would occur by early
afternoon. Otherwise a dry and comfortable day with low humidity
and highs in the middle and upper 70s with the lower CT River
Valley near 80F. Mostly sunny with scattered diurnal cu
developing the late morning through the afternoon hours.

Mainly dry overnight into early Saturday morning, though a few
spot showers are possible with the passage of the mid-level
shortwave. As for lows, slightly warmer than tonight, mid 50s to
low 60s.

&&

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

* Periods of showers and t-storms associated with a slow moving
  frontal system starting late in the day Sat and into Sun. Heavy
  downpours capable of producing street flooding are possible,
  although the risk for severe storms appears low.

* Gradually improving conditions Mon.

* Dry and seasonable weather for Tue and Wed with high pressure in
  control.

Details:

Friday:

Saturday and Sunday:

Still looks to be an active period of weather for the weekend as
today`s models and ensembles continue to advertise a frontal system
moving in from the Great Lakes region later Sat aftn and continuing
into Sunday. This frontal system looks to interact with an anomalous
plume of moisture (PWATs 2-2.25"!) and favor several chances for
showers and t-storms.

Seems to be a slower trend in the guidance as far as timing goes, so
think there is a decent chance the morning to early-aftn Sat is dry,
but with increasing cloud cover. PoPs then steadily increase during
the 2nd half of the daytime hrs into the Chance/lower Likely range,
with Categorical PoPs (70-90%) Sat evening and continuing into
Sunday, with the best chances on Sunday in southeast New England
with indications for a stalling cold front. There are some signals
that showers could linger into early on Mon in eastern and
southeast New England, consistent with a slowing frontal boundary.

While there may be some stronger storms at times, it is looking as
though given an unfavorable time of day for destabilization, the
main potential hazard is primarily heavy rainfall capable of street
flooding. It`s still too uncertain which area(s) are most at risk to
see flooding; hydrologically, more urbanized areas are typically
more vulnerable, and portions of the CT Valley and along the reach
of the Massachusetts Turnpike have seen significant rainfall in
recent days. We also want to emphasize it won`t be raining
everywhere at all times, but the potential exists for heavy rainfall
this weekend, mainly Sat evening into Sunday.

Temps are seasonable with readings in the upper 70s to mid 80s, but
both Sat and Sun look to be quite muggy with dewpoints rising into
the upper 60s to mid 70s.

Monday:

Gradually improving conditions on Mon as surface ridge tries to
build in from the northwest. Still looks as though eastern MA could
see more hit-or-miss scattered showers as upper trough moves through
during the morning hrs in vicinity to a slow-moving surface front.
However improving conditions into Mon aftn and also turning MUCH
less humid. Highs mid 70s to low 80s and lows mid 50s/around 60.

Tuesday through Wednesday:

Sprawling high pressure settles over New England for Tue and Wed,
favoring dry weather and temps around or slightly above normal.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
Forecast Confidence Levels:

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

Through 00z... High confidence.

VFR. Low chance of a spot shower, though the vast majority of the
afternoon is dry. West/northwest wind 10 to 14 knots and occasional
gusts 20 to 25 knots.

Tonight... High confidence.

VFR. Dry. Northwest to north/northwest, winds 5 to 10 knots, with
winds of 10 to 13 knots for terminals on Cape Cod and islands.

Friday... Moderate confidence.

VFR, scattered cu around 5-7 all though dry. High pressure settles
in with variable wind conditions while the flow is out of the west,
there is a chance for winds to become south during the late morning
with low confidence in sea breeze development. Will reassess this
afternoon/evening update.

Friday Night... High confidence.

VFR. Perhaps a spot shower across western MA/CT prior to sunrise
with southwest winds less than 10 knots.

KBOS TAF... Moderate confidence in TAF after 12z Friday.

VFR. Dry. W to NW wind tonight into early Friday, low confidence in
a local sea breeze developing by late morning. Will reassess during
the 00z TAF issuance.

KBDL TAF... High confidence in TAF.

Outlook /Saturday through Tuesday/...

Saturday: VFR. Breezy. Slight chance SHRA.

Saturday Night: MVFR/IFR conditions possible. Breezy. SHRA,
slight chance TSRA.

Sunday: Mainly MVFR, with local IFR possible. Breezy. SHRA,
slight chance TSRA.

Sunday Night: VFR. Breezy. Chance SHRA, slight chance TSRA.

Monday: VFR. Breezy. Slight chance SHRA.

Monday Night through Tuesday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Tonight through Saturday morning...

Cold front moves off shore and high pressure moves in from the west
which will ease seas and wind gusts. Dry conditions prevail during
this time with patchy areas of marine fog possible southeast of
Nantucket.

West to northwest winds between 10 to 20 knots overnight, becoming
lighter from the north by daybreak. Friday, there is a low chance of
onshore winds developing during the afternoon along the south coast,
eventually going south to southwest overnight into Saturday morning.

Residual seas at 5 ft for the outer southern waters this afternoon
and settles around 2-3 ft off shore and 1-2 ft near shore Friday
into Saturday morning.

Outlook /Saturday through Tuesday/...

Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.

Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 25 kt. Seas up to 5 ft. Rain showers, slight
chance of thunderstorms.

Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Seas up to 5 ft. Rain showers, chance of
thunderstorms.

Sunday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers, slight chance of thunderstorms.

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

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

Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft.

&&

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

&&

$$

SYNOPSIS...Loconto/Dooley
NEAR TERM...Dooley
SHORT TERM...Dooley
LONG TERM...Loconto
AVIATION...Loconto/Dooley
MARINE...Loconto/Dooley