384
FXUS61 KBOX 240612
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
212 AM EDT Mon Jun 24 2024

.SYNOPSIS...
Scattered showers and thunderstorms this evening come to an
end, except along the south coast, where storms may linger
overnight. A cold front moves offshore Monday, giving way to
mainly dry weather and not quite as hot or humid as Sunday. Dry
and very warm weather is on tap for Tuesday but with comfortable
humidity. Hot and humid weather returns later Wednesday.
Another round of showers and thunderstorms is possible later
Wednesday, perhaps lingering into Thursday. Otherwise...drier
weather with lower humidity returns by Friday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...

2 AM Update:

Cold front still to the northwest of Albany, NY and widely
scattered showers with isolated thunderstorms continue to fire
in the warm sector across SNE. More widespread showers and
storms are offshore south of New England in the deeper
moisture/instability axis. By sunrise, shower threat should be
confined to the south coast, with drier conditions northwest.
Very warm night/predawn hours currently across SNE and breezy
with anomalous low level SW jet over southeast MA. This wind
anomaly will begin to move offshore toward daybreak. Hence, not
as windy as daybreak approaches. This low level jet and
accompanying WAA is keeping temps in the 70s, quite warm for
this time of night/early morning. Humid as well with dew pts in
the upper 60s and lower 70s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...

Key Points

* Less heat and humidity
* Weak afternoon showers, but no severe weather

Tomorrow:

Shortwave trough and cold front moves through much of New
England in the afternoon, but with limited moisture and
instability, we finally break the daily severe weather chances.
There will still be scattered low topped showers with strong
cyclonic vorticity overhead and low amounts of SBCAPE at 100
J/kg or less. Behind the cold front, 850mb temps will drop to
10C allowing the region to finally get a break from the
excessive heat and humidity from the past week. High
temperatures tomorrow range from the upper 70s in NW MA, to
upper 80s in SE MA. Dewpoints also drop into a more comfortable
range in the low 60s.

Monday night:

Secondary cold front moves through overnight, but with a drying
column, no precipitation is expected. This cold front will
continue to bring dewpoints down into the 50s overnight. With
clear skies and low dewpoints, temps should be able to drop down
into the low 60s to even upper 50s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...

Key Points...

* Dry & very warm Tue with tolerable humidity
* Humid with showers/t-storms later Wed which may linger into Thu
* Dry & seasonable Fri
* Humidity increases next weekend with risk of showers/t-storms Sun

Details...

Tuesday...

Shortwave ridging briefly builds across the region on Tue. This will
result in abundant sunshine and a very warm afternoon...but with
tolerable humidity. Highs Tue should mainly be in the middle to
upper 80s.

Wednesday and Thursday...

The next shortwave trough will slide southeast across the Great
Lakes Wed. This will induce southwest low level flow and increasing
humidity. The amount of solar insolation will determine the high
temps Wed...but currently thinking upper 80s to lower 90s away from
the south coast.

Diurnal heating along with increasing dewpoints will likely allow
for modest instability to develop Wed. The bigger question remains
the timing of the shortwave and associated cold front.
While...timing is uncertain...the threat for showers & t-storms will
increase late Wed into Wed night. It is too early to assess the
severe weather potential...but given that a remnant EML looks to be
in place with modest effective shear will have to watch this closely.

Not sure if Thu will turn out dry or the threat for a few showers/t-
storms will continue. The current guidance seems to favor a more
drier solution Thu...but that certainly is subject to change.

Friday...

High pressure builds in behind the cold front and should result in a
very nice end to the work week. Plenty of sunshine expected on Fri
with highs in the upper 70s to the middle 80s along with
low/comfortable humidity.

Next Weekend...

The high pressure system moves east of the region on Sat...but
current indications favor mainly dry weather with a gradual increase
in humidity. It is a long way off...but by Sunday it looks like it
may be rather humid and the threat for some showers & t-storms will
increase ahead of the next shortwave trough/cold front.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Forecast Confidence Levels:

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

06z update...

Through 12z...Moderate to high confidence on trends, but some
uncertainty on areal extent of IFR/MVFR early this morning.

Mainly VFR cloud bases with isolated showers thru 12z. Patchy
areas of MVFR/IFR developing across southeast MA. Uncertainty
how much this area will expand, possibly into RI and eastern MA.
Gusty SW winds 15-25 kt with gusts near 30 kt at times will
gradually ease toward 12z. Until then, this will yield marginal
LLWS over southeast MA.

After 12z...high confidence.

Any IFR/MVFR cigs at 12z along with scattered showers will be
confined to Cape Cod and the Islands. Gradually improving to VFR
by mid to late morning, along with dry weather. Elsewhere, VFR
at 12z will prevail today with VFR cloud bases this afternoon
and just the chance of an isolated shower/sprinkle. Gusty SW
winds 15-25 kt at 12z, will ease to 10-20 kt and shift to the
west this afternoon.

Monday night...High confidence.

VFR cloud bases with an isolated shower/sprinkle possible during
the evening. West winds 10-20 kt in the evening, shifting to NW
10-15 kt after midnight.

Tuesday...high confidence.

NW winds 10-15 kt in the morning, becoming SW 10-15 kt in the
afternoon.  VFR and dry runways.

KBOS TAF...Moderate confidence in TAF.

Only uncertainty is a brief period of MVFR possible through 12z,
along with an isolated shower. Otherwise, VFR cloud bases with
dry weather today, just low risk of an isolated shower/sprinkle
this afternoon/evening. SW winds gusting up to 25 kt thru about
09z, then slowly easing and becoming west later this morning and
continuing into the afternoon.

KBDL TAF...Moderate confidence in TAF

Other than an isolated shower thru 12z, VFR cloud bases and dry
weather. SW winds early this morning, becoming west late morning
in the afternoon.

Outlook /Tuesday Night through Friday/...

Tuesday Night: VFR. Breezy.

Wednesday: Mainly VFR, with areas MVFR possible. Breezy. Chance
SHRA, chance TSRA.

Wednesday Night: Mainly MVFR, with areas VFR possible. Breezy.
SHRA likely, isolated TSRA.

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

Thursday Night: VFR.

Friday:VFR

&&

.MARINE...
Forecaster Confidence Levels:

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

*** SCA remains in effect Sunday afternoon into Monday ***

Tonight...

Showers and thunderstorms likely tonight after 06z through 12z.
Winds continue to be strong out of the SW gusting up to 30
knots, possibly higher at times. Seas 5-10 feet.

Monday...

Showers and thunderstorms should move well out to sea by 12z.
Winds remain out of the SW and remain gusty to 25 knots. Seas
4-8 feet.

Monday Night...

Clear conditions with decreasing winds turning NW at 15-20
knots. Seas decrease to 3-6 feet.


Outlook /Tuesday Night through Friday/...

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

Wednesday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft. Slight chance of rain
showers.

Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers,
isolated thunderstorms.

Thursday: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers.

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

Friday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory until 7 PM EDT this evening for MAZ020>024.
RI...High Surf Advisory until 7 PM EDT this evening for RIZ006>008.
MARINE...Small Craft Advisory until 8 AM EDT this morning for ANZ231.
     Small Craft Advisory until 5 AM EDT Tuesday for ANZ232>235-237.
     Small Craft Advisory until 9 AM EDT this morning for ANZ236.
     Small Craft Advisory until 9 PM EDT this evening for ANZ250.
     Small Craft Advisory until 5 AM EDT early this morning for
     ANZ251.
     Small Craft Advisory until 9 AM EDT Tuesday for ANZ254>256.

&&

$$

SYNOPSIS...Frank/KP
NEAR TERM...Nocera
SHORT TERM...KP
LONG TERM...Frank
AVIATION...Nocera/KP
MARINE...Frank/KP