783
FXUS61 KBOX 110716
AFDBOX

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

.SYNOPSIS...
Mild 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 /THROUGH TODAY/...

Today:

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 low 50s today making it feel very
comfortable outside. Hi-res guidance is quite mixed on the
chance for showers today esspically with a mid level warm nose
around 700mb. With HREF mean CAPE values around 100 J/kg,
isolated low topped showers are possible in the afternoon.

&&

.SHORT TERM /TONIGHT 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 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 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 /06Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:

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

Tuesday: VFR. Localized sea breezes forming mid morning,
otherwise light WNW winds. Low chance an isolated shower in the
afternoon.

Tuesday night: VFR. Light and variable winds. IFR fog possible
for the Cape and 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
21-22z.

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