297
FXUS61 KBOX 281409
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1009 AM EDT Fri Jun 28 2024

.SYNOPSIS...
Pleasant weather today with seasonable temperatures and
comfortable humidity. Still dry for much of Saturday, but there
could be some isolated to scattered showers/storms sliding into
the interior late. Temperatures still seasonable, but will see
increasing humidity levels. A slow moving frontal system brings
showers and t-storms with localized downpours, especially
Saturday night into Sunday night. Drier weather then returns
for early next week with seasonable temperatures.

&&

.NEAR TERM /THROUGH TONIGHT/...

10am - No changes to the forecast this morning, as forecast
remains on track.

Highlights

* Overall a very pleasant day with near to slightly cooler than
  seasonable temperatures, with comfortable humidity levels. A
  touch breezy to start, but winds ease as the day progresses.

Somewhat cyclonic flow in place to start with a trough near Nova
Scotia and a ridge building over the central/eastern Great
Lakes. The ridge builds into western New England by late today.
High pressure builds from New York early today into and through
southern New England by late today.

Dry and quiet weather expected with high pressure in control.
May be a bit breezy to start, especially over eastern areas due
to a tightened pressure gradient. This will relax by mid/late
AM, which will bring an end to the gusts. Early to mid afternoon
seabreezes are possible. Temps running just a bit cooler than
normal with highs generally in the 70s.

&&

.SHORT TERM /SATURDAY/...
Highlights

* Dry and quiet weather tonight with seasonable temperatures.
  Increasing mid to high clouds late.

* Dry for much of the day, but anticipate more clouds than
  sunshine. Showers with perhaps a few isolated thunderstorms
  spreading into the interior late.

Shortwave ridge flattens out and flow becomes quasi-zonal
tonight. A shortwave lifts from the OH Valley/central Great
Lakes this evening into the eastern Great Lake/southern Quebec.
Another shortwave lifts from the OH Valley/central Great Lakes
early on Sat into western New England by late Sat PM. High
pressure builds further offshore toward Nova Scotia tonight. A
warm front lifts into southern New England on Sat.

Overall another fairly quiet period weather wise. Though will
see isolated to perhaps scattered showers/storms pushing into
portions of interior southern New England late Sat. Will also
have increasing southerly winds/gusts on Sat with humidity
levels on the rise. Guidance in fairly good agreement at this
point, so used a consensus. There are some slight nuances with
the precip arrive late afternoon/early evening, but the next
shot for more impactful weather comes in the Sat Night/Sun
timeframe. Though will need to monitor the activity as it is
moving. Should see quite a moisture laden airmass pushing in
with PWATs of 1.5-2+ inches moving in. The NAEFS indicating
values roughly 2-3 STD above model climo. Warm cloud layer
depths increasing to 3.5-4.5 km, but given our cloudiness
appears we will lack the instability (perhaps only a 100-200
J/kg of MUCAPE). Some of these showers/storms could produce some
heavier downpours late Sat.

Will have another day of near seasonable temperatures on Sat.
Will feel noticeably more humid, especially during the
afternoon/evening as southerly flow picks up. Low temps heading
into Sat will be in the 50s. High temps on Sat will generally be
in the 70s.

&&

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

* Periods of showers and thunderstorms associated with a slow-moving
  frontal system into Sunday. Heavy downpours capable of producing
  street flooding are possible, although the risk for severe storms
  appears low.

* Gradually improving conditions Mon.

* Dry and seasonable weather for Tue and Wed with high pressure in
  control.

Expecting another round of showers and thunderstorm ahead of a cold
front. Severe weather potential is complicated at this time. Timing-
wise, it appears that showers start to arrive from the west Saturday
evening. Latest model guidance suite tends to agree on rather potent
0-6 km shear of 30-40 kt, but disagree on the amount of instability
which should be present. Despite the spread, there is enough of a
signal where this potential should be monitored into this weekend.
Current thinking is Sunday will be the day of greatest concern for
stronger thunderstorms.

Besides the risk for strong to damaging gusty winds, we will also
need to monitor the threat of localized flooding. Comfortable
humidity through much of Saturday gets replaced with another
tropical airmass into Sunday. Precipitable water values projected to
be near 2 inches. Thus, there is potential for locally heavy
rainfall, especially if there is training over a given location.

By Monday, the cold front triggering these showers and thunderstorms
should be offshore, with high pressure following close behind. This
high pressure should dominate our weather into Wednesday, before it
too moves offshore from the Mid Atlantic coast. Another cold front
may approach next Thursday.

Brief period of above normal temperatures expected Saturday night
into Sunday, before trending near normal for Monday into Tuesday.
Turning warmer towards the middle of next week. Humidity should be
more comfortable Monday and Tuesday, then gradually increasing
once again into mid week.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:

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

Today...High confidence.

VFR through the day with SKC as high pressure gradually builds
in. Think this slackens the pressure gradient enough that we see
localized seabreezes developing roughly 17-19Z. Elsewhere will
have light N winds gradually shifting to the S by the
afternoon/evening.

Tonight...High confidence.

VFR with increasing mid to high clouds pushing in from west to
east. Winds out of the S/SW at 5-10 kts.

Saturday...High confidence.

VFR for much of the day. Could see some MVFR to perhaps IFR
conditions spreading into western areas late as a warm front
lifts in. This may also bring isolated to scattered
showers and perhaps a few thunderstorms. Winds increasing out of
the S. Will see speeds of 10-15 kts during the afternoon with
gusts of 20-25 kts.

KBOS TAF...High confidence in TAF.

VFR through the forecast. Starting off breezy out of the NW/NNW,
but winds ease as high pressure builds in. Think the pressure
gradient slackens enough that seabreeze develops roughly 17-19Z.
Winds turning S by the evening with increasing mid to high
clouds.

KBDL TAF...High confidence in TAF.

VFR through the forecast. Winds out of the NNW/N at 5-10 kts
this AM. Will become light and variable by early afternoon as
high pressure builds overhead. Then winds shift to the south
this evening with increasing mid to high clouds.

Outlook /Saturday Night through Tuesday/...

Saturday Night: MVFR/IFR conditions possible. Breezy. SHRA,
chance TSRA.

Sunday: Mainly MVFR, with local IFR possible. Breezy. SHRA,
slight chance TSRA.

Sunday Night: VFR. Breezy. Slight chance SHRA.

Monday: VFR. Breezy.

Monday Night through Tuesday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today through Tonight...High confidence.

Tranquil boating conditions as high pressure builds in. Any
gusty winds early in the day ease as the high moves overhead.
Light NNW to N winds during the AM shifting to the S this
afternoon. Expect S winds to increase late tonight to 10-15 kts
toward daybreak. Seas 1-3 ft.

Saturday..High confidence.

Increasing southerly winds to 15-20 kts by the afternoon. Will
have some 20-30 kt gusts, especially late. Small Craft
Advisories may be needed in future updates. Seas building 2-4
ft.

Outlook /Saturday Night through Tuesday/...

Saturday Night through Sunday: Moderate risk for Small Craft
Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Rain
showers, slight chance of thunderstorms.

Sunday Night: Winds less than 25 kt. Local rough seas. Chance
of rain showers, isolated thunderstorms.

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

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

Tuesday: Winds less than 25 kt.

&&

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

&&

$$

SYNOPSIS...Belk/BL
NEAR TERM...Belk/BL/Dooley
SHORT TERM...BL
LONG TERM...Belk
AVIATION...Belk/BL
MARINE...Belk/BL