494
FXUS61 KBOX 250003
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
803 PM EDT Mon Jun 24 2024

.SYNOPSIS...
A disturbance aloft over the Northern Adirondacks moves
southeastward tonight, bringing evening cloudiness, northwest
breezes and a drier air mass to Southern New England. Warmer
temperatures then return for Tuesday but humidity levels remain
comfortable. Increasing humidity levels on Wednesday with the risk
for showers and thunderstorms, and some could become strong. Drier
and less humid to end the workweek, although summerlike warmth and
humidity return by this weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...

8pm Update: No changes made to the forecast as the forecast
remains in good shape, previous forecast discussion follows...

So for tonight, shortwave disturbance aloft and its cool pocket
of air aloft will be moving through the interior Northeast and
offshore through midnight. The approach of this disturbance
should at least maintain cloud cover if not increase it a bit.
Think cloud cover should trend more partial to mostly cloudy. An
outside chance (20% or less) of a sprinkle or light shower as
the shortwave moves through. Am a little skeptical the coverage
will be as numerous as some of the high res models indicate with
drier air moving into the lowest hundred or so mb of
atmosphere. Carried a mention of isolated showers but with nil
QPF over northern and northeast portions of Southern New
England, but many areas however stay dry. Should also see more
northwesterly breezes for the evening and overnight, which will
continue to usher in lowering dewpoints and a more comfortable
air mass. Humidity levels should be low enough tonight to give
fans/ACs a break for more open-windows. Lows tonight in the mid
50s to lower 60s, with mid 60s out over Cape Cod.

&&

.SHORT TERM /TUESDAY NIGHT/...
Brief shortwave ridge and weak high pressure will bring very
pleasant weather again tomorrow. Mid level winds turn SW
Tuesday afternoon allowing for 850mb temps to warm from +13C to
+17C. This will bring high temperatures back into the upper 80s
to low 90s. With westerly surface winds, dewpoints will remain
in a comfortable range in the upper 50s. Skies should remain
mostly sunny through the day with subsidence aloft helping
suppress diurnal cumulus. Late in the day, mid to high level
cirrus clouds may bring some filtered sunshine ahead of a weak
shortwave moving through overnight.

Surface winds turn southwest overnight, brining moisture rich
flow into the region. This will bring dewpoints back into the
low to mid 60s. Winds overnight also turn gusty at 15-20mph as
the pressure gradient tightens ahead of the next system for
Wednesday. This will keep overnight temps quite warm in the
upper 60s to low 70s near urban centers.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Highlights:

* Wednesday is hot, muggy, and late day thunderstorms. A few showers
  could linger into Thursday morning across southeastern parts of
  southern New England.

* A post-frontal airmass provides relief from the heat and muggies
  late this week, along with drier conditions.

* Upcoming weekend looks splits, with the unsettled conditions
  likely on Sunday.

Rain and thunderstorm chances increase the second-half of Wednesday
with a mid-level trough and shortwave passage. For now, most of the
daylight hours Wednesday appear dry. Deep southwest flow ahead of
the approaching front advects a warm/moist airmass into southern New
England. Likely a hot and muggy day with highs in the upper 80 to
lower 90s, with dew points near 70F, courtesy of PWATs nearing the
two inch mark. Combination of heat and humidity provides instability
for storms late day. Best forcing at this time comes around late
afternoon and evening and exits during the overnight hours. The
discussion earlier stated a remnant EML from the upper Midwest could
be in the vicinity late in the day, 21z-ish, but latest 12z model
guidance suggests this feature could be over us by 12z/15z. There is
still some uncertainty with how strong and widespread these storms
could become. But there are signs for a few stronger storms, SHREF
has surface based CAPE around 1,000 to 1,500 J/kg, along with modest
wind shear, 30 to 40 knots. Additionally, the 12z CSU machine
learning probs for severe weather/winds did back off slightly across
the northeast, though maintained the greatest risk for severe
weather across the Mid Atlantic states. Did maintain the greatest
pops between 00z and 10z, though there could be lingering showers on
Thursday morning as the front is slow to exit the coastal waters.
Places like Cape Cod and the Island could see a few showers up until
lunch before improving.

It`s important to note, those seeking a bit of relief from the heat
and muggy conditions at the ocean, there is a chance for stronger
rip currents. While there are no headlines, yet, future updates may
include a statement or advisory for this hazard.

Comfortable conditions Thursday with a post-frontal airmass due to
surface surface high moving down out of central Canada into northern
Great Lakes region. Drier weather to follow the rest of Thursday
into Friday, daily highs in the upper 70s and low 80s, dew points
are in the low 60s on Thursday and 50s on Friday.

Heading into this coming weekend, potentially a split weekend with
drier weather on Saturday with showers and thunderstorms on Sunday.
Model guidance suggests a system developing across the northern
Great Lakes with a trailing cold front. Still too early to get into
the details, but looks as if the later half of the weekend could be
unsettled.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:

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

00z TAF Update:

Tonight: High confidence.

BKN-OVC VFR bases 035-050 to start tonight, with an outside
chance (20% or less) of a sprinkle or light unrestricted shower
00z thru 04z but will leave out of the TAFs due to low prob. NW
to NNW winds around 12-15 kt with gusts low 20s kt range thru
midnight, then becoming NW around 8-12 kt, highest east.

Tuesday and Tuesday Night: High confidence.

VFR with increasing mid/high clouds arriving later Tue night.
NW winds 5-10 kt ease a bit and shift to W/WSW by aftn.

KBOS TAF...High confidence in TAF. VFR with WNW winds around
10-15 kt with gusts up to 25 kt today. Low (< 15%) chance of an
unrestricted-visby shower tonight with winds shifting to NW
around 15 kt overnight. Winds then shift back to WNW/W Tue AM with
decreasing speeds, becoming SW late in the day on Tue.

KBDL TAF...High confidence in TAF. VFR. W winds around 10-15 kt
become NW/N late this aftn and tonight at similar speeds. Winds
then shift early Tue to W and then SW later Tue aftn.

Outlook /Wednesday through Saturday/...

Wednesday: VFR. Breezy. Chance SHRA, isolated TSRA.

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

Thursday: VFR. Chance SHRA.

Thursday Night through Friday Night: VFR.

Saturday: VFR. Breezy. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Tonight...
High pressure begins to move in allowing winds to turn north and
weaken to 10-15 knots. Seas also decrease 3-6 feet.

Tomorrow...

Mainly clear conditions with winds turning SSW. Gusts begin to
ramp up again in the southern waters to 20-25 knots. Seas
decrease to 2-4 feet

Tomorrow night...

Southwesterly winds continue to ramp up across all the waters
with gusts up to 30 knots again. Seas ramp back up to 3-6 feet.
Small Craft Advisories will likely be needed for the this
period.


Outlook /Wednesday through Saturday/...

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

Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas. Rain showers likely,
isolated thunderstorms.

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

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

Friday through Saturday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 3 AM EDT Tuesday for ANZ232>235-237.
     Small Craft Advisory until 3 PM EDT Tuesday for ANZ254>256.

&&

$$

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