469
FXUS61 KBOX 041754
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
154 PM EDT Tue Jun 4 2024

.SYNOPSIS...

Weak high pressure will bring mainly dry conditions through
Wednesday, with cooler temperatures near the coast. Our weather
pattern then changes to a cloudy and more unsettled outlook by
Thursday and into the weekend. Thursday looks to be the wettest
day with showers and storms capable of localized downpours,
with more hit or miss showers or thunderstorms for Friday into
the weekend. Temperatures trend a little cooler than normal.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

915 AM Update...

* Beautiful day with just scattered diurnal clouds & perhaps an
  afternoon spot shower or two towards the Berks this afternoon

* Highs lower-middle 80s inland, upper 60s/70s near the coast

Previous forecast is on track. Ridge of high pressure slowly
slides to our south today. We do expect some scattered diurnal
clouds to develop by afternoon...but still expect partly sunny
skies through the afternoon. Onshore flow/sea breezes will hold
high temps in the upper 60s to the lower 70s on the immediate
coast. Not too far inland from the immediate coast...highs
should reach the upper 70s to near 80. Further back in the
distant interior...850T near +14C should yield highs in the
lower to middle 80s with the warmest of those readings in the CT
River Valley.

Mainly dry today as height rises are indicating large scale
subsidence, but all the CAMs are showing a few convective showers
developing this afternoon in western MA where marginal instability
develops with decent low level lapse rates. A closer look at the
forecast soundings show environment is mostly uncapped in the
Berkshires where there is a low risk for an isolated t-storm. But
further east, the presence of a mid level cap will limit updraft
strength.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...

Tonight...

Mainly dry conditions but can`t rule out an isolated shower spilling
south across northern MA as a weak mid level shortwave rotates south
along the east side of the ridge leading to weak height falls.
Otherwise, partly cloudy skies with some stratus possible over
Cape/Islands and portions of south coast. Lows will be mostly in the
50s.

Wednesday...

High pres south of New Eng will drift further south with increasing
SW flow developing. Partial sunshine and warming low level temps
will lead to highs reaching well into the 80s, but 70s closer to the
south coast where SW winds will keep it cooler. Looks mainly dry
again as best moisture and instability will be across northern New
Eng where convection chances are higher.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

Thursday through Monday

A broad cyclonic flow pattern settles over The Northeast by late
week beginning an extended period of unsettled weather in southern
New England. Thursday will feature widespread persistent
precipitation and possibly a few thunderstorms as a frontal wave
moves over the region. Rather robust PWATs on the order of 1.75
inches should allow for 0.5 to 1 inches of rainfall across most of
southern New England during the day Thursday. As the associated
surface cold front shifts east on Friday, the region drys out for a
brief period, but persistent broad cyclonic flow and a cold pool
aloft will support daily showers chances through early next week.
Temperatures will be near normal with daily highs/lows in the mid to
upper 70s and upper 50s/low 60s respectively. Expect more clouds
than sun during this time period.

&&

.AVIATION /18Z TUESDAY THROUGH SATURDAY/...

Forecast Confidence Levels:

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

18z TAF Update...

This afternoon and tonight...High Confidence except low
confidence near the south coast, Cape and Islands tonight.

VFR conditions will persist tonight in most locations, but a spot
shower or even a t-storm is possible near the Berks this
evening. A few spot showers can not be ruled overnight across
the rest of the region...but dry weather dominates. The main
uncertainty revolves around the potential for some low stratus and
fog to impact areas near the south coast, Cape and Islands
tonight. This remains uncertain given marginal low level
moisture...but greatest risk is our Nantucket terminal
so will need to monitor this closely. Sea breezes come
to an end early this evening...otherwise light S winds
becoming SW tonight.

Wednesday...High Confidence.

Any low clouds/fog patches should burn off Wed morning across
the Cape and Islands. Otherwise...VFR conditions with winds
SW at 10 to 15 knots.

Wednesday night...Moderate Confidence.

Low end MVFR-IFR ceilings and possibly reduced vsbys will
overspread the region from south to north...but specific timing
remains uncertain. The evening will mainly be dry...but a
cluster of showers and perhaps an embedded t-storm or two may
begin to overspread the region from southwest to northeast
towards daybreak. Light S winds.

KBOS TAF...High confidence in TAF.

KBDL TAF...High confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Mainly VFR, with local IFR possible. SHRA
likely, isolated TSRA.

Thursday: Mainly MVFR, with areas IFR possible. SHRA likely,
isolated TSRA.

Thursday Night: Mainly VFR, with local IFR possible. Chance
SHRA, isolated TSRA.

Friday: Mainly VFR, with local MVFR possible. Chance SHRA,
isolated TSRA.

Friday Night: VFR. Slight chance SHRA.

Saturday: Mainly VFR, with local MVFR possible. Chance SHRA,
isolated TSRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

High confidence through Wednesday.

Tranquil boating conditions through tonight. Generally E-SE winds up
to 10 kt today becoming SW tonight. Increasing SW winds developing
Wed with gusts up to 20 kt. Seas below SCA.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Winds less than 25 kt. Chance of rain showers,
isolated thunderstorms.

Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.
Rain showers likely, isolated thunderstorms.

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

Friday through Saturday: Winds less than 25 kt. Areas of seas
approaching 5 ft. Slight chance of rain showers.

&&

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

&&

$$

SYNOPSIS...KJC/RM
NEAR TERM...Frank/KJC
SHORT TERM...KJC
LONG TERM...RM
AVIATION...Frank/RM
MARINE...KJC/RM