042
FXUS61 KBOX 110951
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
551 AM EDT Tue Jun 11 2024

.SYNOPSIS...

Pleasant temperatures again today and tomorrow with a low chance
for an isolated shower. High pressure moving off the coast will
allow warmer temperatures for Thursday and humidity by Friday.
An approaching cold front will bring the risk for scattered
showers and thunderstorms Friday afternoon and evening. High
pressure builds in for the weekend bringing beautiful dry
weather with pleasant temperatures and low humidity.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

550 AM Update...

* Diurnal clouds developing later this morning & afternoon, but
  with nothing more than a few brief spot showers later today

* Highs mainly in the lower to middle 70s

Previous forecast is on track. Plenty of diurnal CU develop
later this morning and afternoon underneath cold pool
aloft...but with nothing more than a few spot showers. Earlier
discussion below.

Upper level closed low remains centered over Southern New England
today with high pressure building in from the west. Diurnal
cumulus will quickly form this morning with 850mb temps around
+8C leading to convective temps only around 70F. With diurnal
cumulus forming in the early to mid morning, high temperatures
will likely be cooler then yesterday, only reaching the low to
mid 70s. Closer to the coasts, sea breezes should form in the
mid to late morning capping high temps in the upper 60s to low
70s. Dewpoints remain in the lower to middle 50s today making
it feel very comfortable outside. Despite the clouds...dry
weather dominates but do expect a few diurnally driven spot
showers during the afternoon/early evening.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...

Tonight:

Diurnal cumulus will dissipate quickly with sunset allowing for
mainly clear skies overnight. Winds will also remain light overnight
allowing for good radiational cooling. Overnight lows drop into the
mid to upper 50s again.

Tomorrow:

Upper level closed low begins to move NE, but remaining under
cyclonic flow for much of the day. Wednesday will ultimately be very
similar to Tuesday with diurnal cumulus forming mid to late morning
and low chance for isolated low topped showers. Thinking the best
chance for these showers on Wednesday will be near the sea breeze
front providing a little bit extra convergence and forcing.
High temps look to be just a bit warmer Wednesday in the mid to
upper 70s with WSW flow. Dewpoints begin to climb into the upper
50s making it feel a bit more humid then Tuesday.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

Key Points...

* Dry but warm Thu with highs mainly middle to upper 80s
* Warm & Humid Fri with afternoon/eve scattered showers & t-storms
* Beautiful next weekend with low humidity & temps a tad below normal

Details...

Thursday...

Ridge of high pressure slides off the coast allowing warmer
southwest flow of air to develop across the region by Thu. 850T
warming to between +14C/+15C should allow afternoon highs to reach
the middle to upper 80s in many locations. Southwest winds will
result in somewhat cooler temps near the south coast...where 70s to
lower 80s will be more common. Humidity looks to remain in check Thu
and given mid level ridge axis crossing the region...dry weather
will prevail.

Friday...

Shortwave trough and an associated cold front will approach from the
west on Friday. Timing still somewhat uncertain...but expect
humidity to return ahead of an approaching shortwave/cold front.
Highs should reach well into the 80s to near 90 as long as we
receive enough solar insolation with dewpoints climbing into the
60s. Thinking at least some modest instability with 0-6 KM
shear increasing to between 40 and 50 knots. Enough forcing with
the shortwave should generate the development of scattered
showers & t-storms. Timing still uncertain this far out. We can
not rule out some elevated activity in the morning...but main
risk for scattered showers & thunderstorms will be during the
afternoon/evening hours. Given the parameters in place...we will
need to watch the risk for severe weather and localized heavy
rainfall with the activity. That being said...it is too early to
assess at this point but something to watch.

This Weekend...

Large Canadian high pressure builds in for the weekend. This brings
beautiful/dry weather for the weekend with low humidity and temps a
tad below normal. Highs will be 70s to near 80 with overnight lows
mainly in the 50s with even some upper 40s possible.

Monday....

High pressure moves off the coast on Monday...allowing for a return
southwest flow of warmer air to begin moving into the region. Upper
level ridging building north should result in dry weather continuing
too.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...

Forecast Confidence Levels:

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

12z TAF Update...High Confidence.

Today: VFR. Localized sea breezes forming mid morning,
otherwise light WNW winds. A few brief spot showers possible
during the afternoon/early evening hours.

Tonight: Mainly VFR. Calm/light & variable winds. Patchy ground
fog may develop late in the typically prone locations and
perhaps parts of the Cape/Islands.

Wednesday: VFR. Localized sea breezes form again, otherwise
light WSW winds. Low chance for an isolated afternoon shower
again.

KBOS TAF...High confidence in TAF. VFR. Sea breeze should
develop by 14-15z. Sea breeze kicks out between 01z-03z.

KBDL TAF...High confidence in TAF. VFR. Light WNW winds.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: VFR.

Thursday through Thursday Night: VFR. Breezy.

Friday: Mainly VFR, with local IFR possible. Breezy. Scattered
SHRA, scattered TSRA.

Friday Night: Mainly VFR, with areas MVFR possible. Breezy.
Chance SHRA, isolated TSRA.

Saturday: VFR.

&&

.MARINE...

Forecaster Confidence Levels:

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

Today:

Tranquil boating weather with light WNW winds turning southerly
in the afternoon. Seas 1-3 feet.

Tonight:

Areas of fog possible especially east of the Cape and Islands.
Light southerly winds. Seas 1-2 feet.

Tomorrow:

Fog may linger east of the Islands, otherwise another pleasant
day. Winds remain light and southerly. Seas 1-2 feet.


Outlook /Wednesday Night through Saturday/...

Wednesday Night through Thursday: Winds less than 25 kt.

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

Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Scattered rain showers.

Friday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain showers, isolated thunderstorms.

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

&&

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

&&

$$

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