148
FXUS61 KBOX 111411
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1011 AM EDT Tue Mar 11 2025

.SYNOPSIS...
Breezy and unseasonably mild conditions today ahead of cold
front, then chillier conditions arrive Wednesday and Thursday
with a period of light rain/snow showers possible Wednesday
night into early Thursday. Milder air begin to return across the
interior Friday and elsewhere this weekend when 60+ degrees are
possible. A period of heavy rain along with the potential for
strong to damaging southerly wind gusts are possible later
Sunday into Sunday night.

&&

.NEAR TERM /THROUGH TONIGHT/...

10 am update...

Temperatures have begun to climb quite quickly, into the low 50s
in the last hour for many locations around the region, and more
will see those 50s arriving in the next few hours. Forecast
remains on track.

Previous discussion...

Another rather tranquil day as weak high pressure moves
offshore. Increasing south winds ahead of an approaching cold
front. Model soundings still showed a hint of a subsidence
inversion, despite mixing to about 2 kft. This will be enough to
keep the stronger winds aloft, but still looking at gusts 25-35
mph. Expecting another day of above normal temperatures, even
near the south coast which will be cooler. Still having to
contend with water temperatures around 40F degrees.

&&

.SHORT TERM /WEDNESDAY/...
A cold front passes by overnight, then moves farther offshore
Wednesday. Not quite as warm Wednesday, but still should be near
normal for mid March. Not a lot of moisture to accompany this
front. Expecting mainly clouds, but cannot completely dismiss
the risk for a stray shower or two across northern MA this
evening.

&&

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

* Light snow/rain showers possible Wednesday night into Thursday
  morning

* Unseasonably mild temperatures over the weekend

* Potential for heavy rain and strong to damaging southerly winds
  for late Sunday into Sunday night

Details...

Not much has changed from the previous update in this period.
Onshore flow persists and lows Wednesday night are expected to
settle in the 30s for much of the region following a cold front
passage earlier in the day. Highs Thursday won`t be too much
higher, sitting in the 40s. A front is expected to cross the
region Wednesday night that may bring some light snow/rain
showers, and with that, some light accumulations of a coating to
an inch are possible.

Milder temps return in the interior Friday with upper level
ridging building back in. NAEFS and ECMWF guidance indicate
temperatures in the mid- to low levels to be around a standard
deviation above normal, and ensemble probabilites for surface
temperatures at least above 50F are generally above 50% for much
of the interior. Areas near the coast may still be cooler due to
onshore flow from the high pressure sitting over the Canadian
Maritimes. Highs Friday, as a result, will likely be in the 50s
for much of the interior, with the CT Valley getting close to
60F. Lows Friday night will likely be slightly higher than
Thursday`s, with mid to high 30s and some spots in the 40s.

A potent shortwave digging through the central US will lead to
meridional flow over southern New England in response. Southerly
winds develop for the weekend, bringing in the chance for some
more high temperatures in the 60s. Ensemble probs for
temperatures over 60F, particularly Sunday afternoon, are up to
80% in some spots of eastern MA. For Saturday, probabilities are
not as high, with a 20 percent chance over Boston and around 30
percent over Providence. Urban centers have the higher chances
of reaching 60F this weekend or above on Sunday. Heavy rain
could be in the mix for Sunday night into Monday with the
advancing of this shortwave. PWAT values in the latest NAEFS
guidance were 2 to 3 standard deviations above normal, sitting
at 1.25" (or higher) in some spots of southern New England.
Ensembles indicate a decent chance for accumulations of 1.5" or
higher associated with this system. Strong southerly winds will
also be something to monitor, as a LLJ sits over the region with
winds at 60 to 75 kt at 850 mb Sunday night. Pockets of 75 kt
winds are also possible at 925 mb.

Timing may still change for this event, as it is still a
significant amount of time away from now. This rain, as of now,
should finish moving through by Monday morning, giving way to a
breezy day of westerly winds and highs in the upper 50s.

&&

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

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

Today...High Confidence.

VFR. Increasing S winds with gusts 20-30 kt developing this
afternoon.

Tonight...Moderate confidence.

Mostly VFR, but patchy stratus and fog may develop along the
south coast. S-SW 8-15 kt this evening becoming NW after
midnight.

Wednesday...High confidence.

VFR. N winds 5-15 kt with gusts up to 25 kt.

KBOS TAF...High Confidence in TAF.

KBDL TAF...High Confidence in TAF.

Outlook /Wednesday Night through Saturday/...

Wednesday Night: Mainly VFR, with local MVFR possible. Slight
chance SN.

Thursday: Mainly VFR, with local IFR possible. Slight chance
RA, slight chance SN.

Thursday Night: Mainly VFR, with local IFR possible.

Friday: VFR.

Friday Night: Mainly VFR, with areas IFR possible.

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

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Wednesday...High confidence.

Weak high pressure moves across the waters today, with a cold
front moving past the waters tonight. High pressure arrives from
the west Wednesday. Gusty south winds today across the eastern
MA coastal waters. Seas are marginal for a Small Craft Advisory,
so did not not yet expand the existing advisories to the
southern coastal waters, but that will need to be considered for
Wednesday as a low pressure passes by well south of the waters.
Rough seas may reach the southern coastal waters by then.

Outlook /Wednesday Night through Saturday/...

Wednesday Night through Thursday Night: Winds less than 25 kt.
Seas up to 5 ft. Slight chance of rain.

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

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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ230-
     251.
     Small Craft Advisory until 8 AM EDT Wednesday for ANZ250.

&&

$$

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