034
FXUS61 KBOX 241052
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
652 AM EDT Thu Apr 24 2025

.SYNOPSIS...
Pleasant and dry today under high pressure, with the exception of a
slight chance of showers this evening across northern Massachusetts.
Unseasonably warm temperatures arrive Friday. Cooler with widespread
rain showers Saturday ahead of our next system, drying out for
Sunday. Cooler and breezy on Sunday, followed by continued dry
weather through Wednesday and mild temperatures. A front arrives
Wednesday with next chance of showers.

&&

.NEAR TERM /THROUGH TONIGHT/...
* Warmer on Thursday with quiet and dry weather, save for the chance
  of a spot shower in NW MA in the evening.

A quiet and clear night continues with temperatures in the urban
centers in the mid to upper 50s while some typically good radiative
cooling spots in southeast MA are in the upper 30s at this hour.
Even so, temperatures will rebound quickly with sunrise as a warm
front lifts north through the region and brings with it high
temperatures quite a bit warmer than yesterday for the interior of
SNE, in the mid to upper 70s. The location with the best shot at
seeing upper 70s will be in the CT Valley. Dry, under high pressure
and largely zonal flow; the only exception is northwestern/north
central MA, in closest proximity to a weak shortwave crossing
northern New England tonight which may provide enough lift to kick
off a few spot showers this evening. Tonight winds may become a bit
breezy along the south coast with the warm frontal passage; this
with increased cloudcover and warm advection will keep low
temperatures quite mild overnight, in the 40s and 50s.

&&

.SHORT TERM /FRIDAY/...
* Dry, unseasonably warm.

Friday will be much warmer than average as warm advection in the mid
levels pushes 850 mb temps to 11C. BUFKIT soundings show a good
mixing environment; can expect high temperatures in the upper 70s
and even low 80s, warmest in the CT valley. Given onshore southerly
flow, temperatures along the south coast will remain in the low to
mid 60s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Key Messages:

* The next chance for widespread rain comes in Saturday, but there
  are uncertainties with the exact timing.

* Drier conditions Sunday though is cooler with breezy NW winds.

* Dry and warm for the first half of next week.

Big Picture: High pressure shifts offshore late Friday, a northern
stream trough moves in from the eastern Great Lakes. Developing low
pressure system to the northwest with a modest LLJ (40-60 kt) over
southern New England, helping to advect higher PWATs ~1.5", setting
the stage for a soggy and breezy Saturday. Good news, should be able
to salvage the second-half of the weekend, improvements Sunday, but
will be cooler (seasonable) and breezy. High pressure and mid-level
ridging will dry things out and aid in warming our temperatures for
Monday and Tuesday, followed up by a possible cold front passage
and showers for Wednesday.

Friday Night through Sunday: Increasing clouds overnight with rain
holding off, likely not arriving until Friday morning. These clouds
help to keep nighttime lows mild in the lower and middle 50s.
Southwesterly LLJ of 40-60 kt usher in moisture and PWATs increase to
1.5", 2-3 standard deviations above normal. There is a marginal risk,
at least 5% chance of rainfall exceeding flash flood guidance for
all of southern New England. Global ensembles settling towards 0.50"
to 0.75" for rainfall amounts. Prob rainfall greater than 1.0" have
walked back over the past 24 hours, 30 to 40 percent the previous 24
hours. And now is less than 20 percent. There are timing issues for
the rain, as mentioned previously, GFS is biased towards a quicker
arrival and departure, though continued to lean towards the slower
solution, ECMWF/GEM, which would bring in the rain from west to east
sometime between 8am and 12pm. Rain continues throughout the day, a
few rumbles of thunder cannot be ruled out either due to limited
instability. It will be quite windy on Saturday as a southerly LLJ
of 45-55 knots develops over eastern MA and RI. With cold ocean
waters still in the 40s, it will be tough to mix down much of that
wind. Hence, gusts should stay in the 25-35mph range. High temps
range from the low to upper 60s. System moves out late night into
early Sunday morning, clearing from west to east as NW flow advects
cooler and drier air into the region, may hold onto clouds or a spot
shower across parts of eastern/central MA and RI on Sunday with the
departure of the mid-level low. Much cooler Sunday, highs in the 50s
with gusty NW winds 30-40 mph.

Monday through Wednesday: Really nice period of weather, especially
Monday and Tuesday, with high pressure and mid-level ridging. Will
see temperatures rebound to the low and middle 70s on Monday and
Tuesday is warmer in the middle to upper 70s, while at the coast
it`s cooler in the 60s. Frontal boundary arrives for Wednesday and
depending on the

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

12Z TAF Update:

Today: High Confidence.

VFR. Winds light and variable, becoming southerly 5-10 kts in
the afternoon. Expect haze and smoke to begin moving into CT
during the afternoon which could cause some visibility
obstruction. A few spot showers are possible in northern MA in
the evening.

Tonight: High Confidence.

VFR. Primarily SSWly winds 5-10kts. Smoke/haze continues to
spread into the rest of SNE with visibility obstruction
possible.

Friday: High Confidence.

VFR. Winds light and variable in the morning increasing to 5-10
kts out of the S/SW/SE in the afternoon.

KBOS TAF...High confidence...

Sea breeze kicks in early today between 12-13z. Sea breeze
kicks out in the late afternoon/evening, then winds aloft begin
to increase, bringing some light wind shear Thursday evening.
Smoke/haze could cause some visibility obstruction overnight
Thursday into Friday morning.

KBDL TAF...High confidence in TAF.

Light and variable winds tonight turning southerly tomorrow.
Smoke/haze could cause some visibility obstruction as early as
Thursday afternoon, possibly into Friday morning.

Outlook /Friday Night through Monday/...

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

Saturday: Mainly MVFR, with areas IFR possible. Breezy. SHRA,
isolated TSRA.

Saturday Night: Mainly VFR, with areas MVFR possible. Breezy.
Chance SHRA.

Sunday: VFR. Windy with local gusts up to 30 kt.

Sunday Night: VFR. Breezy.

Monday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today...

High pressure to the south of the coastal waters will support
another calm day with light northeast winds in the morning becoming
steady out of the south during the afternoon from 10 to 15 knots.
Seas remain 2 feet or less.

Tonight...

South/southwest winds up to 10 knots with seas building to 2-3 feet.

Friday...

High pressure overhead. Winds 10-15 kts, seas 2-3 ft.

Outlook /Friday Night through Monday/...

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

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Rain showers, isolated
thunderstorms.

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Chance of rain showers,
isolated thunderstorms.

Sunday: Winds less than 25 kt. Seas up to 5 ft.

Sunday Night: Winds less than 25 kt. Areas of seas approaching
5 ft.

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

&&

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

&&

$$

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