712
FXUS61 KBOX 101926
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
326 PM EDT Sat Aug 10 2024

.SYNOPSIS...
A cold front moving offshore will provide dry and comfortable
weather tonight. A weak wave of low pressure develops on the
offshore front Sunday, yielding increasing clouds across southern
New England, however dry weather will prevail. Most of the upcoming
workweek will feature generally dry weather with a mix of clouds and
sun, seasonable temperatures and low humidity levels. Monday and
Thursday could offer enhanced cloudiness and better chances for hit
or miss showers, but no significant impacts are expected.

&&

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

330 PM Update:

* Much less humid and cooler tonight

This Evening...

Cool front/wind shift line to about the Cape Cod Canal at 2 pm,
however showers have moved offshore, no longer impacting KACK.
Thus dry weather prevails across all of SNE. Post frontal
airmass continues to spill across the region, with a west breeze
10-15 mph advecting lower dew pts into the 60s and now 50s
across western MA! Hence, much less humid trends the rest of
today and into tonight. Although, still warm at 2 PM with plenty
of sunshine warming temps up to 88 degs at OWD/TAN/EWB and PYM!

For south coastal beaches, SW winds will become west with the
frontal passage later this afternoon. Keep in mind high surf
advisories remain posted for this area. Received a surf report
from Horseneck beach in Westport, MA of 3-5 ft surf and strong
rips. Exercise caution if heading down to a south facing ocean beach
this afternoon in RI and southern MA.

Overnight...

Beautiful weather tonight as the post frontal airmass continues to
advect across the region, with dew pts falling into the 50s regionwide!
This drier airmass combined with mostly clear conditions and light
west winds, will provide radiational cooling conditions. Given
this setup, we will derive min temps from the cooler MOS datasets,
supporting lows overnight in the mid to upper 50s for most locations!
The exceptions will be the coastline, Cape Cod, Islands and the
urban areas of Boston, Providence, Hartford and Worcester, where
mins will be in the 60s, but feeling cooler given dew pts in
the 50s. As for the risk of patchy fog, given diurnal drying
this afternoon combined with dew pts falling into the 50s, this
combination should preclude much if any radiational fog development.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...

Updated: 3:30 PM

Sunday...

Closed low over Ontario today traverses eastward and ejects a modest
short wave toward New England Sunday. This yields mid/upper level
WAA across SNE, with sunshine at daybreak giving way to increasing
clouds thereafter into the afternoon, yielding filtered sunshine.
This short wave also induces a weak surface wave on the offshore
front, tracking south of New England. However, with the column being
so dry, not expecting any precip, just an abundance of mid level
clouds, that should thin for some late day sunshine. Not as warm
tomorrow given less sunshine and less humid too, as core of drier
air will be over the region Sunday. Nonetheless, very pleasant
conditions with highs in the low 80s, upper 70s high terrain and
along the south coast, along with dew pts in the 50s! Southwest
winds 10-15 mph, except southeast winds along the Plymouth
coastline.

Sunday night...

As weak surface wave south of New England exits east of our
longitude, cool/dry air get replenished on the backside of the
wave into SNE. Thus, another dry, cool night with comfortable
humidity. Given mostly clear conditions, light winds and a dry
airmass, followed the cooler MOS guid to derive mins, which
yields another night in the mid to upper 50s, except 60-65 along
the coast and islands, including the urban areas of Boston,
Providence and Hartford.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...

Updated: 3:45AM

Highlights:

* Tranquil weather for most of the upcoming workweek, with a mix of
  sun and fair weather clouds on most days.

* More focused periods of showers for Mon and again on Thurs, but
  nothing impactful.

* Seasonable temperatures (upper 70s to mid 80s) with low levels of
  humidity.

Details:

Overall no significant changes compared to prior forecasts for this
period, with good overall agreement in the 00z ensembles. Broad
cyclonic flow aloft will continue to govern our weather pattern for
much of the forecast period; though there are a couple of days where
we could see a more focused period of showers, all in all, it is a
relatively quiet, tranquil weather regime.

Initial rather potent shortwave disturbance aloft over the eastern
Gt Lakes moves into the Northeast states on Mon. Notable edits were
made to NBM in the Mon to early Mon evening timeframe. It`s a pretty
strong shortwave that moves in and with ensembles indicating some
shallow convective instability in conjunction with broader vertical
motion associated with the shortwave, expect Mon to at least feature
increasing cloudiness toward a partly to mostly cloudy look. Models
are showing some spotty QPF in this period too, although fcst
soundings show a well mixed PBL that could keep shower coverage more
isolated. Not a washout by any means but expect increasing
cloudiness and hit-or-miss showers during the daytime hrs Mon,
decreasing in coverage later in the day as shortwave moves east and
diurnal heating wanes. Besides Monday, the other day that looks to
feature diurnal showers is around Thurs, with GFS and ECMWF
indicating another vort maxima in broader cyclonic flow digging
southward. Shower coverage here should also take on a diurnal trend
with more clouds/off-and-on showers during the daytime, then
decreasing after sundown. But between these two days, no significant
or impactful weather is expected, and instability looks meager
enough to limit thunder.

When it comes to temperatures and humidity levels...expect pleasant
midsummer weather with seasonable temperatures through the period.
Should see highs in the mid 70s to around 80 for Monday, then adding
a degree or two each day toward the low to mid 80s by late in the
week. With broader cyclonic flow and NW flow aloft, humidity levels
should be comfortable through the period.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Forecast Confidence Levels:

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

18z TAF Update: high forecast confidence through the period.

This evening and overnight...

VFR, dry weather and west winds 10-15 kt, gusting up to 20 kt
diminishing with sunset. South coast, SW winds 10-15 kt this
afternoon shifting to west late this afternoon, then diminishing
with sunset.

Sunday...

Dry runways and VFR. Southwest winds 10-15 kt, which should be
sufficient to preclude a sea breeze for eastern MA terminals,
including KBOS.

Sunday night...

Continued VFR, dry weather and light winds.

KBOS TAF...High confidence. SW winds should be sufficient to
hold off a seabreeze.

KBDL TAF...High confidence for VFR, dry runways and modest west
winds this afternoon, then light/variable winds tonight before
becoming SW Sunday afternoon.

Outlook /Monday through Thursday/...

Monday: VFR. Isolated SHRA, isolated TSRA.

Monday Night through Wednesday Night: VFR.

Thursday: VFR. Slight chance SHRA, isolated TSRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Updated: 3:30 PM

Thru Sunday night...High Confidence.

Leftover southerly swells will slowly subside tonight. WSW winds
tonight yield dry weather and good vsby. Weak surface wave
tracks south of New England Sunday, but precip shield will
remain well offshore. Just a thin overcast with good vsby and SW
winds. More of the same Sunday night, light winds, dry weather
and good vsby.

Outlook /Monday through Thursday/...

Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents until 8 PM EDT this evening for MAZ007-
     015-016-019.
     High Surf Advisory until 8 PM EDT this evening for MAZ020>024.
RI...High Surf Advisory until 8 PM EDT this evening for RIZ006>008.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ235-237.
     Small Craft Advisory until 8 AM EDT Sunday for ANZ254>256.

&&

$$

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