424
FXUS61 KBOX 121116
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
716 AM EDT Wed Mar 12 2025

.SYNOPSIS...
Chillier conditions today and Thursday with a period of light
rain/snow showers possible tonight into early Thursday. Milder
air begins to return across the interior Friday and elsewhere
this weekend when 60s are expected by Sunday along with windy
conditions. A period of heavy rain along with the potential for
strong to damaging southerly wind gusts are possible Sunday
night into Monday. Drier weather returns by Tuesday with
relatively mild temperatures.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Messages...

* Colder today, but near normal along the coast and slightly
  above normal farther inland
* Mainly dry today, with a low risk for light snow showers late
  towards the Berkshires

High pressure over Ontario and Quebec will follow a cold front
into southern New England today. However, since the center of
this high pressure will remain across eastern Canada and far
northern New England, we will be dealing with north winds this
morning and east winds this afternoon. With water temperatures
around 40F degrees, this will mean lower temperatures today
despite having plenty of sunshine this morning. Increasing
clouds this afternoon will also assist in keeping high
temperatures closer to normal for mid March.

Mainly dry today. A sheared mid level shortwave starts to arrive
late today from the west. It may be enough to trigger some light
rain or snow showers towards early evening.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Key Messages...

* Light rain and snow possible overnight.

A sheared mid level shortwave passes by tonight. Thinking it
will be a rather narrow window for light precipitation. For one,
the lift and humidity within the dendritic growth zone is
limited and largely off to our east by midnight or so. Thus, not
looking for much snowfall accumulation, with most of that being
along an north of Route 2 in northern MA.

Latest NationalBlend data suggest only about a 15-25% chance for
an inch of snow across central and western MA in the 24 hours
ending 2 PM EDT Thursday. HREF is way more aggressive and
farther south, having a 30-60% chance along and just south of
the MA border into CT and RI during that same time. Not sold on
these higher probabilities given the progressive nature of the
lift and lack of humidity. However, it is something to keep in
mind with later forecast updates today.

All precipitation should move out of southern New England by mid
morning Thursday. High pressure over the Maritimes maintaining
the easterly onshore flow. Should be slightly cooler than today,
but still near normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Key Messages:

* Mild day Friday for the interior, cooler on the eastern MA
  coastline

* Unseasonably mild weekend with winds picking up Sunday

* Heavy rain with strong to damaging winds possible Sunday night
  into Monday

Details...

Cloudy conditions Thursday are expected into the nighttime hours
with continued onshore flow due to high pressure circulating over
the Maritimes. Lows expected to be in the 30s for much of
southern New England, with parts of northern MA in the upper
20s.

Mid-level ridging builds into the region Friday, allowing for
the return of milder weather. Onshore flow will continue to keep
the eastern coastline cooler than the interior. Highs in the
interior will likely sit in 50s, with temperatures closer to 60F
possible in the CT Valley. Highs along the immediate eastern MA
coast will sit more so in the 40s by contrast. Overnight, lows
are expected to be in the 40s and upper 30s due to continued
cloud cover and onshore winds.

A strong upper level trough digs through the plains this
weekend, amplifying the upper level flow across the eastern US.
Meridional low will help usher in unseasonably mild temperatures
and more moisture. Ensembles continue to indicate high
probabilities of temperatures over 60F by Sunday, especially
over the urban centers. Highs Saturday and for the rest of the
region Sunday will likely sit in the mid to upper 50s, with dew
points in the 40s Saturday and getting into the 50s Sunday.
Something to monitor during the day Sunday will be the chance
for strong to damaging winds. Ensembles indicate a 60-63 kt
southerly jet at 850 mb (reaching that same mark Sunday evening
over the Cape and Islands at 925 mb), which when combined with
diurnal heating will likely increase this risk.

The shortwave energy that has been tracking east finally reaches
southern New England Sunday night, increasing forcing for
ascent. With the continued meridional flow, PWAT values are
still forecast to reach 1" to 1.25" or higher, which is 3-4
standard deviations above normal. Combining these ingredients
with the robust LLJ over the region will result in the chance of
heavy rain. Guidance currently has the highest probabilities for
this heavy rain across SE CT into RI and SE MA. Locations for
this heavy rain will most likely still change, and overall, the
entire region still has a good chance of seeing a good soaking
rain Sunday night into Monday morning.

We dry out behind this system for Tuesday morning and winds
shift more to the WNW before mid to upper level ridging builds
back in during the day behind the shortwave. Highs will likely
be in the 50s across southern New England.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Forecast Confidence Levels:

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

Today...High confidence.

VFR. N winds 5-15 kt with gusts up to 25 kt this morning,
becoming E 5-15 kt this afternoon. Gusts expected to end by the
early afternoon hours.

Tonight...High confidence.

VFR for all terminals to start. -SN/-RA moves in overnight which
may drop cigs to MVFR for some terminals, especially north of
the MA pike. Light E winds.

Thursday...High confidence.

Mainly VFR, with areas MVFR in lingering -SN early. E winds
5-15 kt.

KBOS TAF...High Confidence in TAF.

KBDL TAF...High Confidence in TAF.

Outlook /Thursday Night through Sunday/...

Thursday Night: Mainly VFR, with local MVFR possible.

Friday: VFR.

Friday Night: Mainly VFR, with local IFR possible.

Saturday: Mainly VFR, with areas IFR possible. Breezy. Slight
chance RA.

Saturday Night: Mainly VFR, with areas IFR possible. Windy with
local gusts up to 30 kt. Chance RA.

Sunday: MVFR/IFR conditions possible. Windy with gusts up to
35 kt. Chance RA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Thursday...High confidence.

A cold front moves past the waters early this morning. SW
winds shift to the NNE later this morning, then to the E for
this afternoon. Gusts of 20 to 30 knots across the eastern
waters develop behind the front into mid afternoon. E winds
continue tonight into Thursday.

Outlook /Thursday Night through Sunday/...

Thursday Night through Friday: Winds less than 25 kt. Seas up
to 5 ft.

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

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

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

Sunday: Strong winds with gusts up to 35 kt. Rough seas up to
11 ft. Chance of rain.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for
     ANZ231>235.
     Small Craft Advisory from 7 AM to 8 PM EDT Thursday for ANZ250.
     Small Craft Advisory until 8 PM EDT Thursday for ANZ254>256.

&&

$$

SYNOPSIS...Belk/Hrencecin
NEAR TERM...Belk
SHORT TERM...Belk
LONG TERM...Hrencecin
AVIATION...Belk/Hrencecin
MARINE...Belk/Hrencecin