-- Discussion containing changed information from previous version are highlighted. --
260
FXUS61 KBOX 081035
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
635 AM EDT Sat Jun 8 2024

.SYNOPSIS...
Mainly dry and seasonable conditions today, with just a chance
of a spot shower. Weak low pressure will bring a period of
showers late tonight into Sunday, with improving conditions in
the afternoon. Still unsettled early next week with a chance of
showers, then a warming and drying trend Wednesday and Thursday.
Another frontal system will bring increasing risk for showers
and thunderstorms for the end of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Upper level trough moves across New Eng today with core of
coldest air aloft through 18z before temps aloft begin to
moderate as the trough lifts out. Modest moisture in the
850-700 mb layer combined with steep low level lapse rates will
support a few showers today, with greatest chance north of the
MA Pike closest to cold pool. Otherwise, a mix of sun and
clouds today as sct-bkn diurnal cu develops later this morning
into the afternoon. Instability is meager with CAPES less than
500 J/kg and it is confined to low levels with a cap above so
not much vertical development to cu field. Cooling 850 mb temps
will result in a cooler day today, with highs mostly in the mid
70s which is close to normal, and humidity levels will be low.
It will become fairly breezy later this morning through the
afternoon as soundings show a well mixed boundary layer
supporting westerly gusts 25-30 mph.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Tonight...

Weak shortwave ridging will allow for clearing skies this evening,
before clouds increase overnight ahead of next shortwave
approaching from the Gt Lakes. An area of showers will develop
ahead of the shortwave which may move into western MA/CT toward
daybreak. Otherwise, dry for much of the night with lows mid-
upper 50s.

Sunday...

Fairly robust mid level trough and shortwave moves through with a
weak wave possibly developing on the surface front across SNE. Deep
moisture plume and decent forcing for ascent will result in a wet
morning with a period of showers, especially north of the MA Pike
but do expect some showers further south. Thunder chances are low as
best instability will be to the north where mid level lapse rates
are more favorable. As the shortwave exits in the afternoon
subsidence and pretty good drying moves in from the west so expect
improving conditions during mid to late afternoon with partial
sunshine developing. It will be a cool morning with the showers,
with temps mostly in the upper 50s and 60s, but temps should recover
into the lower 70s later in the afternoon as clouds give way to some
sunshine.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Highlights

* Seasonable temperatures Monday and Tuesday with slight chances for
  spot showers each afternoon

* Trending warmer by mid-week

* Unsettled weather possibly returning late week

Monday and Tuesday

Persistent upper-low and associated cold pool aloft remain in the
vicinity of southern New England to start the week. Embedded in the
larger flow, a series of short-wave disturbances will traverse over
The Northeast allowing for showers chances on both Monday and
Tuesday. Showers on Monday should be isolated in nature as there
won`t be a whole lot of moisture in the column with PWATs around
0.75 inches. Aside from a spot shower or two, we can expect a mix of
sun and diurnal clouds Monday afternoon with seasonable temps in the
70s. By Tuesday, model guidance takes the coldest temps at 500 hPa a
bit further south than previous days which will introduce steeper
mid-level lapse rates and some elevated instability. Moisture
increases as well with PWATs climbing to around an inch. This will
result in slightly higher shower/thunderstorm chances on Tuesday
afternoon, but with virtually no shear beneath the center of the
upper-low over southern New England, any thunderstorms would be sub-
severe and short-lived. Tuesday will also feature a mix of sun and
diurnal clouds with highs in the mid to upper 70s.

Wednesday

The quasi-stationary upper-level low over The Northeast finally
ejects east of southern New England Tuesday night into Wednesday.
Heights rise behind the departing upper-low as a mid-level ridge
axis builds in from the west. This will be accompanied by warmer
temperatures than previous days with highs likely in the 80s on
Wednesday afternoon. Given heights rising, Wednesday should be a
mainly dry day across the forecast area.

Thursday and Friday

A warming trend ensues to end the week as return flow from the south
should advect a warm/moist air mass into The Northeast. Thus, we may
be in store for more summer like conditions with highs in the 80s
and dewpoints in the mid to upper 60s. There is a good amount of
spread in the model guidance at this time range, but there is chance
for some more unsettled weather to end the week as another upper-
level disturbance will be digging over The Great Lakes Region toward
the Northeast. Stay tuned for more details...

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Forecast Confidence Levels:

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

12Z TAF update...

Today...High confidence.

VFR. Sct-bkn cu around 5k ft developing 14-17z with a brief
shower possible, mainly north of the MA Pike. W wind gusts to
25-30 kt developing by midday, winds more SW over Cape/Islands.

Tonight...High confidence.

VFR, with lowering cigs late across interior MA and CT as
showers move in from the west. W-SW wind 5-10 kt.

Sunday...Moderate confidence.

Areas of MVFR cigs developing as a period of showers move across
the region. Improving condiitons later in the afternoon. Mostly
SW wind 5-15 kt.

KBOS TAF...High confidence.

KBDL TAF...High confidence.

Outlook /Sunday Night through Wednesday/...

Sunday Night: VFR.

Monday: VFR. Slight chance SHRA.

Monday Night: VFR.

Tuesday: VFR. Slight chance SHRA.

Tuesday Night through Wednesday: VFR.
-- End Changed Discussion --

&&

.MARINE...
Forecaster Confidence Levels:

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

High confidence through Sunday

Increasing W-SW winds today with gusts to 25 kt developing this
afternoon, especially over nearshore waters and SCA is in effect for
most waters. Winds quickly diminish this evening with mostly SW
winds 10-20 kt Sunday. Good vsbys today and tonight, lowering Sunday
as some showers move through, especially over the waters north of
Cape Cod.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft.

Monday through Monday Night: Winds less than 25 kt.

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

Tuesday Night through Wednesday: Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from noon today to 7 PM EDT this evening
     for ANZ230>235-251.
     Small Craft Advisory from noon today to 10 PM EDT this evening
     for ANZ254>256.

&&

$$

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