200
FXUS61 KBOX 190527
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
127 AM EDT Fri Jul 19 2024

.SYNOPSIS...
Broad area of high pressure to build into Southern New England
through Friday evening. This will bring significantly lower humidity
levels compared to the past several days, along with dry weather and
seasonable temperatures. Chances for showers and storms along
with increased humidity return next week with timing still
uncertain.

&&

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

10PM Update:

Surface high pressure continues to build in behind the cold
front that brought all the showers and thunderstorms last
evening. Dewpoints are already dropping into the upper 50s to
low 60s for much of SNE. With clear skies and calm winds
overnight, low temps are still on track to drop into the upper
50s to low 60s.

315 PM Update:

Drier NW flow is starting to take root across Southern New England.
Although still pretty humid over the Cape and Islands (e.g.
dewpoints in the upper 60s to low 70s) with a few showers dotting
the southern nearshore waters, look across western and central MA
and most of northern CT and you`ll find dewpoint temperatures
crashing into the upper 50s to lower 60s. Thus, a FAR more
refreshing airmass is gradually filtering into the entirety of
Southern New England as high pressure is ridging in from the west.

Tranquil evening in store for Southern New England, and overall a
really nice midsummer evening is on tap. Dewpoints should commonly
dip into the 50s (which many individuals would describe as
comfortable on the humidity scale, and it`s been a long time coming
over where we`ve been for the past week-plus). We could see a bit of
a freshening to NW breezes early tonight but should settle in around
5-10 mph for the late evening and overnight. While decent
radiational cooling is anticipated under clear skies and though many
areas saw rain yesterday, the combo of falling dewpoints and enough
of a northwest breeze should mitigate fog or mist development. Lows
tonight in the upper 50s/around 60 in the interior, with lower to
mid 60s for eastern MA and RI.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
315 PM Update:

High pressure remains in control of our weather to close out
the workweek. Full sun, dry weather, seasonable temps and
comfortable humidity levels are on tap, setting the stage for a
spectacular midsummer day to kick off the weekend. Easing NW
winds on Friday gives way to seabreezes along both coasts
following the typical start timing climatology around late
morning to early afternoon. Clear skies and light winds for the
evening could allow for patchy fog development Friday night in
the favored river valleys, and there is some increase in
moisture levels along the immediate south coast Friday night so
areas along the south coast could be another potential
development spot.

Highs on Friday in the mid 80s inland, upper 70s near the coast.
Lows in the mid 50s to lower 60s on Friday evening. But certainly
far more tolerable from a humidity perspective.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
The weekend continues to look dry and pleasant with high
temperatures in the mid to upper 80s across the area. Dewpoints
through the weekend are expected to remain in the 60s. Not much in
terms of rain or storm chances through Sunday, but CAPE values of
100-200 J/kg in northern and northwestern MA could help encourage
some very isolated showers. Saturday looks relatively cloudy with
skies mostly clearing going into Sunday afternoon. Winds over the
weekend look mostly calm with a possible seabreeze moving in Sunday
afternoon across Boston and NE MA. Winds on Monday and Tuesday look
pretty calm but variable throughout the day with another chance at a
seabreeze in the afternoons for the same areas.

SW flow aloft looks to return going into next week, bringing with it
increased moisture and chances for showers and storms. Guidance is
suggesting greater chances for showers and storms from Wednesday
night into Thursday, though there isn`t much confidence in the
timing just yet due to the spread between the ensembles and
deterministic models still present. CSU ML probs currently have SNE
under a 0.05-0.15 chance for severe on Wednesday and Thursday, so
this will be something to continue to monitor. Temperatures
throughout the week are looking to remain in the 80s for most of the
area, aside for a slight dip into the upper 70s for parts of central
into eastern MA and most of RI.

Even past this, there are possible severe chances on Thursday into
Friday; the GFS in particular has a trough progressing from the
Great Lakes into Vermont and New Hampshire, bringing with it CAPE
values from 120-400 J/kg across SNE and continued strong SW flow.
The ECMWF keeps this trough in the Great Lakes region through the
end of this period for the time being.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:

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

06Z update...

Today and tonight...High confidence.

VFR. Easing NW winds during the day. Localized sea breezes
developing 15-17Z. Winds light and variable overnight.

Saturday...High confidence.

VFR. SW winds 5-10 kts.

KBOS TAF...High confidence in TAF.

VFR through the period. Seabreeze Fri starting 15-17Z.

KBDL TAF...High confidence in TAF.

VFR through the period.

Outlook /Saturday Night through Tuesday/...

Saturday through Monday: VFR.

Monday Night: VFR. Slight chance SHRA, isolated TSRA.

Tuesday: VFR. Chance SHRA, isolated TSRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through tonight: High confidence.

Winds diminishing, SW becoming NW then N Thu night behind the
front. Seas over south coastal waters will be 5-6 feet today,
diminishing overnight. Showers and a few t-storms continue
into the early afternoon, especially southern waters.

Friday: High confidence.

Winds 5-10 kts. Seas 2-4 feet.

Outlook /Saturday Night through Tuesday/...

Saturday through Monday: Winds less than 25 kt.

Monday Night: Winds less than 25 kt. Slight chance of rain
showers.

Tuesday: Winds less than 25 kt. Chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for
     ANZ254>256.

&&

$$

SYNOPSIS...Loconto/Hrencecin
NEAR TERM...Loconto/KP
SHORT TERM...Loconto
LONG TERM...Hrencecin
AVIATION...Loconto/BL/Hrencecin
MARINE...BW/KP