154
FXUS61 KBOX 131905
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
305 PM EDT Mon May 13 2024

.SYNOPSIS...

A warm front brings widely scattered showers tonight followed
by much warm weather tomorrow, a couple of showers and/or an
isolated thundershower are possible in the interior Tuesday
afternoon. Unsettled weather Wednesday through the weekend with
more clouds than sun and periods of rain. Seasonable
temperatures through the upcoming weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Update: 3PM

Overall a stunner of an afternoon with many enjoying a sun-filled
afternoon while others are stuck beneath diurnal cumulus which
developed along the sea-breeze boundary. As these diurnal clouds
wane this afternoon, mid and high clouds increase from the west
ahead of a warm front. Stepping outside this evening should
enjoy temperatures in the low 60s and falling into the upper 50s
shortly after sunset. 850mb jet advects higher PWATs between
1.0 and 1.3 inch tonight and with the warm front passing through
a few showers possible, though the best forcing looks to be
limited to northern Massachusetts and points north into Vermont
& New Hampshire. No washouts are expected, QPF is in the
neighborhood of a few hundredths of an inch. South to southwest
winds overnight are less than 10 mph. Nighttime lows are on
either side of 50 degrees.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Update: 3PM

A warm and summer-like head is on tap! With the passage of the warm
front Monday night, we are placed in the warm sector. Clouds from
overnight do linger across northern Massachusetts, but will give way
to partly sunny skies and fairly mild temperatures. Deep southwest
flow usher in warmer and a more humid air mass. 925mb temperatures
climb to +14C to +18C and BUFKIT shows a well mixed boundary layer
tomorrow, highs will easily climb into the middle 70s away from the
coast. It`s not out of the question a few spots like the Merrimack
and Connecticut River Valley top out around 80 degrees. Back to the
coast, the southwest flow is an onshore wind for coastal Rhode
Island and southeast Massachusetts, here the temperature Tuesday
afternoon only reaches the upper 60s and low 70s. Southwest winds
become gusty as well, 15 to 25 mph. Shower are limited to northwest
Massachusetts during the late afternoon where the best moisture and
instability are located. HREF ensembles have roughly 500-1000 units
of MUCAPE along and west of the Berkshires, so it`s possible there
may be an iso. non severe thunderstorm. Rain chances expand
throughout the overnight hours with a mid-level trough and frontal
boundary approaching from the west. Winds ease overnight becoming
more south less than 10 mph. Night lows fall into the middle and
upper 50s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Update: 3PM

Highlights

* Unsettled weather Wednesday through the weekend with more clouds
  than sun and periods of rain

* Seasonable temperatures through the weekend

Wednesday and Thursday

A coastal low pressure system will pass well south of southern New
England during the day Wednesday. Nonetheless, modest synoptic
forcing and PWATs greater than 1 inch should support periods of rain
during the day Wednesday. Accumulations will be modest with the
strongest forcing to our south, but somewhere between 0.1 and 0.25
inches between Wednesday and Thursday morning should be in the cards
for portions of southern New England. Downstream blocking has
resulted in model guidance trending toward a slower departure of
this system with cloud cover and showers lingering into the first
half of Thursday for much of the forecast area. A mid-level ridge
building in from the west may salvage a partly sunny day for the
western areas on Thursday afternoon. Expect somewhat gusty southwest
winds on Wednesday with northeast gusts along the east coast on
Thursday.

Friday through the weekend

The forecast remains unsettled late week through the weekend. As the
mid-week coastal low departs over the Atlantic Friday afternoon, a
short-wave dropping down from The Great Lakes will support the
development of another surface low-pressure system that is likely to
bring cloudiness and periods of rain to southern New England this
weekend. Confidence in timing, duration, and intensity of potential
rainfall is low at this time so we have leaned on the NBM for
guidance at this time range. Temperatures look to be seasonably
persistent through the weekend with daily lows in the low to mid 50s
and daily highs ranging from the low 60s to low 70s. Coastal
locations continue to run cooler  with highs in the upper 50s/low
60s more common on days with onshore flow.
&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Forecast Confidence Levels:

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

Through 00z...High confidence.

VFR, 4-7k ft CIGs. A rouge shower is possible in far western MA
and NW CT, otherwise dry runways. Sea-breeze along the coast
will continue until 23z/00z, from there wind shifts to the
south. Elsewhere, winds are south to southwest 10 to 15 knots.

Tonight...High confidence.

VFR. Scattered showers are possible across northern MA, with at
times briefly lower VFR CIGs 3-5k ft. Winds are south to
southwest 5 to 10 knots.

Tuesday...High confidence.

VFR. A few convective showers possible across interior MA and
northern CT during the afternoon. Steady southwest winds with
gusts developing in the afternoon 20 to 25 knots.

Tuesday Night...Moderate confidence.

VFR to start, becoming MVFR/IFR heading later into the night
with increasing rain chances from west to east. Southwest winds
8 to 12 knots early, becoming south 5 to 10 knots.

KBOS TAF...High confidence in TAF.

VFR. Sea-breeze continues this afternoon, becoming a southerly
wind after 23z. A brief shower or two is possible overnight, opt
to include a PROB30 for -SHRA between 07z/09z. For Tuesday, most
of the daylight hours are dry, breezy southwest winds with gusts
20 to 25 knots. Rain chances increase Tuesday night.

KBDL TAF...High confidence in TAF.

VFR. Light south-southwest winds today and into tonight.
Increasing wind speeds Tuesday with gusts 20 to 25 knots
possible. Dry for most of Tuesday as well, rain arrives after
00z.

Outlook /Tuesday Night through Saturday/...

Tuesday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SHRA.

Wednesday: Mainly MVFR, with local IFR possible. Chance SHRA.

Wednesday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SHRA.

Thursday: Mainly VFR, with local MVFR possible. Windy with
local gusts up to 30 kt. Chance SHRA.

Thursday Night: VFR. Breezy. Chance SHRA.

Friday: VFR. Breezy. Slight chance SHRA.

Friday Night: VFR. Chance SHRA.

Saturday: Mainly VFR, with local IFR possible. Chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Update: 3PM

Tonight through Tuesday night....

Southwest to south winds this evening with winds speeds between 10
and 15 knots, seas area generally less than 3 feet, near 4 feet on
the outermost waters. A robust southwest jet brings period of more
gusty winds Tuesday afternoon between 20 and 35 knots and seas
building to 4 feet, it is possible later crew could issue a Small
Craft Advisory, especially for the northeast waters where there is a
greater likelihood. Winds diminish Tuesday night with rain chances
during the second-half of the night.

Outlook /Tuesday Night through Saturday/...

Tuesday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers. Local visibility 1 to
3 nm.

Wednesday: Winds less than 25 kt. Chance of rain showers.

Wednesday Night: Winds less than 25 kt. Local rough seas.
Chance of rain showers.

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. Chance of rain showers.

Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. Chance of rain showers.

Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Slight chance of rain showers.

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain showers.

Saturday: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain showers.

&&

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

&&

$$

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