791
FXUS61 KBOX 081928
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
328 PM EDT Sat Jun 8 2024

.SYNOPSIS...

Weak low pressure will bring a period of showers Sunday, with
improving conditions in the afternoon from west to east. 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 8 PM THIS EVENING/...
330 PM...

Tonight...

* Cool and dry tonight, then a chance of rain towards morning across
  western MA/CT

Short wave trough moving across ME/NH late this afternoon is
triggering isolated showers across eastern MA. This feature exits
offshore quickly with subsidence and dry air advecting across the
region through this evening. Hence, dry weather this evening and
overnight, along with temps 3-5 degs cooler than normal, with lows
in the 50s. Temps level off overnight or perhaps rise a few degs
towards morning, as cloud shield arrives from the west, as next
short wave exits the Great Lakes. Thus, increasing clouds late from
west to east with a chance of showers toward morning across western
MA/CT. Gusty WSW winds late this afternoon, diminish with sunset and
thereafter.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM SUNDAY/...
330 PM update...

Sunday...

* Widespread showers Sunday AM into early/mid afternoon
* Clearing west to east in the afternoon

Fairly robust mid level short wave, accompanied by a 100 kt upper
level jet streak and a strengthening low level jet up to 40 kt.
Impressive for early June. In fact, some of the guidance has a weak
surface wave developing on the boundary, a reflection of the strong
forcing for ascent. This will combine with modest moisture advection
with PWATs climbing to about 1.5 inches, yielding a large swath of
showers Sunday morning and into the early to mid afternoon from west
to east. Its a progressive system, so expecting showers to enter
western MA/CT around 12z-ish and then exiting eastern MA/Cape Cod
20z-22z. As the system races eastward, sunshine will develop from
west to east across the region. Modest rainfall totals of 0.25 to
0.50 inches possible across northern MA, with lower amount through
CT/RI. Chance of thunder fairly low given cold pool and steeper mid
level lapse rates tracking across northern New England.

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 and mid
70s later in the afternoon, as clouds give way to some sunshine.
Fairly light winds with weak surface wave tracking across the
region, although SW winds 15-20 kt possible across the south coast,
especially Nantucket.

Sunday night...

Dry weather behind the departing frontal wave and seasonably cool
with lows in the 50s. Light west winds.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Highlights:

* Few showers for Monday and Tuesday, with seasonable temperatures.

* Signs of a warm-up starting Wednesday though at least Friday.

* Turning unsettled Friday into Saturday.

Looking forward to the upcoming week, there are a couple chances for
rain, albeit low chances on Monday and Tuesday. With the next chance
for active weather, potentially, late next week. Overall, synoptic
setup shows an anomalous mid-level trough and low over the northeast
on Monday through the first-half of Wednesday, followed by mid-level
ridging late Wednesday into Friday. Beyond Friday, global guidance
suggests another mid-level trough with a return of active weather as
early as late-Friday into Saturday, with a drying trend into Sunday,
Father`s Day. Something to keep watching as many might be looking to
book a tee time for Dad next weekend.

As mentioned, both Monday and Tuesday have chances for isolated to
scattered rain showers, but think Tuesday features the best chance
due to higher PWATS and stronger shortwave passage. PWATs on Monday
are low, compared to the climatological normal, roughly 75% or less
of normal, which is between 2/3 and 3/4 inch. PWATs do increase the
following day, Tuesday, to around an inch. Overall, no major changes
for these days, though have removed mention of thunder from the
forecast grids do to very minimal CAPE and wind shear. While low-
level lapse rates are steep, thanks to the cold pool aloft, this
will likely yield more in the way of diurnal clouds. Highs both days
range from 75-80 with lows 55-60.

In general this period is rather quiet and dry, best forcing for any
showers should remain north in northern New England Thursday and
Friday. Increasing temperatures middle week through Friday, as mid-
level ridging and warm southwesterly flow develops in the lower
levels. This will help transport warmer and more humid air to
southern New England. In fact, the 6-10 day temperature outlook from
CPC shows a 70-80 percent probability for above average temperatures.
Warming to the low and mid 80s Wednesday afternoon, then middle to
upper 80s Thursday and Friday. In addition, nightly lows are
expected to be in the 60s - coupled with increasing dewpoints,
likely to be a warmer and more humid end to the week.

Forecast does trend more unsettled late-Friday into Saturday, as a
cold front approaches from the west. While this is towards the end
of the forecast, hard to speculate whether or not it will bring
storms, but, global models do show some modest values of CAPE on
Friday, perhaps if the front makes it to SNE by the afternoon a few
storms could be possible.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
Forecast Confidence Levels:

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

18Z TAF update...

Thru 00z...high confidence for VFR cloud bases with just
isolated brief -shra. Otherwise, dry weather and gusty west
winds 15-20 kt, gusting up to 25-30 kt at times. Winds more SW
along the south coast and Islands.

After 00z...High confidence.

VFR, with lowering cigs late across interior MA and CT as
showers move in from the west. Gusty west winds early this
evening become W-SW wind 5-10 kt late evening and overnight.

Sunday...Moderate confidence.

Areas of MVFR cigs and vsbys developing as a period of showers
move across the region. Arriving around 12z western MA/CT and
then exiting eastern MA/Cape Cod/ACK 20-22z. Mostly SW wind
5-15 kt but could see N-NE winds across northeast MA if surface
wave develops along the front.

Sunday night...high confidence.

VFR, dry weather and west winds 5-15 kt.

KBOS TAF...High confidence through tonight, then some
uncertainty on exact timing of MVFR conditions, arrival and
departure.

KBDL TAF...High confidence.

Outlook /Sunday Night through Thursday/...

Sunday Night: VFR.

Monday: VFR. Slight chance SHRA.

Monday Night: VFR.

Tuesday: VFR. Slight chance SHRA.

Tuesday Night through Wednesday Night: VFR.

Thursday:

&&

.MARINE...
Forecaster Confidence Levels:

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

High confidence through Sunday night...

WSW winds 15-20 kt with gusts up to 25 kt at times, then diminishing
after sunset. Any isolated showers late afternoon dissipate with
sunset as well. Dry overnight along with good vsby.  Then Sunday,
weak surface wave moves SW to NE across New England with a band of
showers in the morning into early/mid afternoon. Vsby may lower to 1-
3 miles at times across the northern MA waters.  Drying trend late
in the day from west to east. Fairly light winds as weak wave
traverses southern New England. Although, SW winds 15-20 kt possible
across the waters near Nantucket and points south and east. As the
surface wave exits late in the day, dry weather Sunday night along
with good vsby and light west winds.

Outlook /Sunday Night through Thursday/...

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 Thursday: Winds less than 25 kt.

&&

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

&&

$$

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