347
FXUS61 KBOX 311838
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
238 PM EDT Fri May 31 2024

.SYNOPSIS...
High pressure over the Ohio Valley Friday builds slowly east this
weekend and crest over New England Sunday. This will provide dry
weather along with warm days and cool nights.  The next chance of
showers, albeit very low, is late Sunday, Sunday night and into
Monday, as low pressure tracks south of the region.  Then high
pressure reinserts itself much of next week, with warm but dry
weather returning, along with cool nights.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...

Tonight...

230 PM update...

* Another chilly night ahead

Scattered to broken diurnal clouds will dissipate with sunset and
give way to mostly clear conditions, setting the stage for good
viewing conditions tonight for the possible aurora.  Visit
swpc.noaa.gov for more information regarding the possible magnetic
storm. Dry NNW flow aloft will maintain a very dry airmass across
SNE, with dew pts in the 30s and 40s. This combined with mostly
clear conditions and a weak NW pressure gradient, will support
another night of chilly temps. Thus, we will lean toward the cooler
MOS guidance to derive lows tonight, mainly in the mid to upper 40s
in the suburbs. Low to mid 50s elsewhere, including the city of
Boston and the high terrain, where winds will likely not decouple.
Don`t think we will see much if any patchy fog tonight given the dry
airmass, with dew pts as low as the mid to upper 30s at 2 pm.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY NIGHT/...

230 PM update...

* More fabulous weather, sunshine and warm but low humidity

Saturday...

As we flip the calendar to June 1st (opening day for hurricane
season), our dry, pleasant weather continues. This is courtesy of
closed low over the Maritimes combined with ridge axis over the
eastern Great Lakes, continuing to provide a dry NNW flow/airstream
across SNE. Almost a rinse and repeat weather pattern from today.
Hence, lots of sunshine and another nice temp recovery from morning
lows in the 40s and 50s, warming into the upper 70s and lower 80s,
along with comfortable humidity (dew pts in the 40s!). Another day
of spectacular weather. Only wrinkle to the forecast is possible
afternoon seabreeze for eastern MA. As closed low exits the
maritimes and dives southward, shallow cool air spreads across the
Gulf of ME and westward toward MA. This cooler air just offshore
combined with a weakening pressure gradient supports seabreeze/cool
maritime air to come onshore. Thus, could have temps falling through
the 70s and into the 60s during the afternoon along the coast.
Otherwise, another gorgeous day on tap for MA/RI/CT.

Saturday night...

Deep layer ridge crest over the region Saturday night into Sunday
morning, continuing our dry and cool weather pattern. Not as chilly
as previous nights but still cool for early June. Followed the
cooler MOS guidance to derive mins, with forecast lows mainly in the
50s, but a few upper 40s in the normally cooler suburbs. Dew pts not
quite as low as today, therefore patchy fog is possible.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...

Key Points...

* High pressure supports warm/dry weather through mid to late next
  week

* Low chance for some afternoon showers across western MA/CT Sunday
  afternoon

Details...

Quiet and mostly dry weather is the story for most of the extended
forecast period thanks to expansive mid level ridging over southern
New England on Sunday which rebuilds on Tuesday/Wednesday. This
broad ridge and associated surface high will keep widespread rain
chances out of the forecast through at least mid week. The one
exception will be Sunday night into Monday as a weak shortwave drops
into the northeast bringing a plume of moisture and associated rain
showers with it. Thinking continues to be that high pressure will
steer this disturbance southwest of the region, so the best rain
chances will be over CT and coastal RI. Beyond that, our next
widespread rain chances come around Thursday or Friday as the ridge
begins to break down with the arrival of a trough which digs into
the Great Lakes during the latter half of the week. Confidence on
when this rain arrives and who sees the most is low at this distance
in time. Temperature-wise the airmass overhead will remain
essentially unchanged with 850mb temps on either side of 10C which
will correlate to highs in the upper 70s/low 80s and lows in the
50s.

&&

.AVIATION /19Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:

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

18z update...

This evening and overnight...High confidence.

SCT-BKN VFR cloud bases this afternoon gives way to SKC after
sunset. Modest NW winds 10-15kt gusts up to 20 kt at times,
slackens after sunset.

Saturday... High confidence.

VFR and dry. NNW winds less than 10 knots will give way to afternoon
seabreezes along the coast.

Saturday night...high confidence.

VFR, dry weather and light/variable winds. MVFR in patchy fog
possible.

KBOS TAF...VFR, dry and NW winds 10-15kt with gusts up to 20 kt at
times, diminishing after sunset. Rinse and repeat for Saturday,
except seabreeze will develop late morning and afternoon.

KBDL TAF... VFR, dry and NW winds 5-15 kt.

Outlook /Sunday through Tuesday/...

VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

230 PM update...

Through Saturday night...

Very pleasant boating conditions, with weak high pressure over the
OH Valley late Friday, slowly building east and cresting over New
England early Sunday. This will provide light winds, locally onshore
along with dry weather and excellent vsby to the horizon. The only
negative, is that water temps remain chilly, only 55-60 degs.

Outlook /Sunday through Tuesday/...

Winds less than 25 kt.

&&

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

&&

$$

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