906
FXUS61 KBOX 112324
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
724 PM EDT Sun Aug 11 2024

.SYNOPSIS...
Mild days, cool nights and comfortable humidity by August standards,
will be the weather theme for much of the week ahead. Mainly dry
weather too, with just a few showers possible Monday and again
Thursday. A frontal system moving in from the Great Lakes could
bring our next chance for more widespread showers next weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
720 PM Update:

* Dry, cool/comfortable tonight.

This evening and overnight...

A beautiful evening in progress, with clearing skies. Temps
mainly in the mid 70s at this hour, but very comfortable with
dew pts in the 50s. Winds mainly SW 10-15 mph. High amplitude
closed low over southern Ontario and Quebec, with a vigorous
short wave rotating through the eastern Great Lakes, which is
kicking off thunderstorms across Lake Ontario into western NY.
This short wave will traverse across northern NY/VT/NH/ME
tonight. Therefore, the bulk of any convection will track north
of MA/CT/RI. However, can`t rule out a brief shower across
northwest MA this evening. Otherwise, dry and very pleasant
weather prevails. Given dry airmass, diminishing winds and
mostly clear to partly cloudy conditions tonight, radiational
cooling will support lows in the 50s overnight outside the urban
areas and coastline, where lows there will range between 60-65.
Followed the cooler MOS guidance given the above setup. Very
comfortable by early to mid August standards. Not expecting much
fog if any overnight, as dew pts are lower than the avg min
temps for this time of year. Hence, its a dry airmass.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Updated: 3:50 PM

* Mild days and cool nights continue
* Scattered afternoon showers Monday

Monday...

Lead short wave over ME Monday morning, departs northeast into the
maritimes, leaving behind a reinforcing shot of cool, dry air across
SNE. This promotes dry weather Monday morning along with sunshine.
Cool morning lows in the 50s and 60s quickly jump into the 70s by 11
am. Trailing short wave ejects eastward from the NY state and this
will yield building diurnal clouds. Not much moisture in advance of
this feature, with surface dew pts in the 50s. This will limit SB
instability, but 500 mb temps cooling to -16C will provide steep mid
level lapse rates. Although, the lack of mid level moisture will
preclude the full magnitude of this instability from being realized.
Thus, just expecting scattered low top showers (low EQL) with a low
probability (~10%) of an isolated thunderstorm. Given the cold air
aloft, worst case scenario would be an isolated gusty thunderstorm
with small hail. However, most of the convection will just be low
top showers.

Otherwise, many hours of dry weather with any shower/thunderstorm
very brief in duration. Cool air aloft will yield slightly lower
highs than today, with max temps Monday in the upper 70s and lower
80s, mid 70s high terrain.  WSW winds 10-15 mph.

Monday night...

Another reinforcing shot of cool/dry air behind departing short
wave. Any lingering shower activity dissipates around or shortly
after sunset. Thus, dry weather remainder of the night. NW winds
behind departing short wave provides weak CAA, yielding another
night with lows in the 50s.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
350 PM update...

Key Points

* Seasonable and mainly dry conditions for much of the work week

* Low chance for an isolated shower/T-storm Thursday afternoon.

* Tropics are beginning to heat up and will be watched closely
  over the coming days and weeks.


High pressure over the Great Plains continues to extend east into
southern New England bringing dry and pleasant weather for much of
the week. Northerly flow will keep temperatures and dewpoints in
check this week staying in the low 80s for highs and low 60s for
lows. Dewpoints also stay in the upper 50s to low 60s much of the
week. Only chance for showers this week looks to be Thursday into
Thursday night as a closed upper level low retrogrades back to the
southwest into New England. SBCAPE values look rather meager at this
point with 300-500 J/kg, limiting the severe threat. Bufkit profiles
do however show show tall and skinny CAPE profiles which could lead
to some heavy downpours with some showers or thunderstorms.

Heading into next weekend and early next week, considerable
uncertainty exists with how the forecast evolves. Guidance brings a
shortwave trough out of Great Lakes, but large differences in timing
and amplitude exists among the different guidance sources. Either
way, next weekend looks like the best potential for a widespread
wetting rain.

We continue to monitor developments of tropical systems in the
Atlantic. The National Hurricane Center maintains an area of high
likelihood for tropical cyclone development near the Lesser
Antilles. For the latest on this potential, refer to tropical
weather outlooks from the NHC. At the very least, long-period swells
propagating well ahead of any tropical cyclone that may develop,
following great circle tracks, would increase the risk for rip
currents later next weekend or early in the following workweek.
Otherwise, it is still too early at this point to provide specifics
on where this potential tropical cyclone will track with much degree
of confidence, but is something we`ll be monitoring.

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
Forecast Confidence Levels:

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

00z update...

This evening & overnight...high confidence.

VFR tonight. Any remaining gusts should diminish after sunset.

Monday...High Confidence.

VFR cloud bases. Dry in the morning, then scattered brief
afternoon showers, therefore VCSH in most terminals, except Cape
Cod and the Islands. Very low prob (5-10%) of isolated thunder,
but too low to include in the TAF. WSW winds 10-15 kt.

Monday night...high confidence.

VFR, dry weather and WNW winds 5-15 kt.

KBOS TAF...High confidence. SW winds 10-15 kt thru the
period.Dry thru Monday morning, then VCSH for the afternoon,
especially 18z-22z.

KBDL TAF...High confidence. Mainly SW winds 5-15 kt and dry
weather through Monday morning. Then VCSH Mon afternoon, mainly
18z-22z.

Outlook /Tuesday through Friday/...

Tuesday through Wednesday Night: VFR.

Thursday: VFR. Slight chance SHRA, isolated TSRA.

Thursday Night through Friday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Updated: 3:45 PM update...

Through Monday night...High Confidence.

Tranquil boating weather with persistent SW winds 5-15 kt through
Monday, then shifting to WNW Monday night. Dry weather with the
exception of a few brief showers, an isolated thunderstorm Monday
afternoon, dissipating with sunset.

Outlook /Tuesday through Friday/...

Winds less than 25 kt.

&&

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

&&

$$

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