Small Craft Advisory 33, NWS Boston/Norton, MA

Area Forecast Discussion
National Weather Service Boston/Norton MA
358 AM EST Thu Mar 6 2025

.SYNOPSIS...
Rain comes to an end early this morning, and while temperatures
today will still be well above normal, expect today to feature
lots of cloudiness around. Atrong but dry cold front brings
more seasonable temperatures, but also a period of strong to
damaging northwesterly wind gusts tonight through Friday.
Strongest of these gusts will be restricted to the higher
terrain of the Berkshires and Worcester County. Drying out for
the weekend with seasonable temperatures, although a warming
trend may develop as we move into early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
330 AM Update:

Key Messages:

* Steady rains and southerly gusts 35-45 mph in eastern MA come to
  an end early this morning. Abundant cloud cover remains
  but temps will still be well above normal today.

* Strong cold front races through SNE this afternoon, with scattered
  showers mixed with graupel. Falling temps and a gusty windshift to
  NW expected mid to late this afternoon.

Details:

Low pressure and deep 500 mb troughing continues to govern our
weather early this morning. Regional radar mosaic shows the areas of
moderate to heavy downpours which moved in last night have shifted
offshore, however there remains steady light to at times moderate
rains across east-central MA, eastern CT on south and east. In fact,
the system's dryslot is clearly seen on early-morning water vapor
imagery across western CT/western MA, leading to more of an
intermittent shower type coverage across most of interior Southern
New England. The earlier exit of steadier rains seems to have
allowed for continued southerly gusts 35-45 mph even into central
MA. On the coastal/tidal flooding front, Fox Point Hurricane Barrier
did see its water level reach minor flood stage for a brief time
after high tide, although the southerly winds are likely keeping
water further up the bay and not evacuating as efficiently in the
face of those winds; we thus felt it best to hold the coastal flood
headlines a little while longer until there is a more apparent
decrease in water levels, and that should happen in short order.
Springlike feel early this morning with current temps in the upper
40s to mid 50s with dewpoints being similar.

So for today, the system's primary cold front and dryslot will
continue to advance eastward through mid-morning. There may still be
some steadier rains across RI and eastern MA through about 6-8 AM or
so, and there could be some brief downpours embedded, but the worst
of the downpours have since ended. That will also bring about a
rapid decrease in southerly winds, and winds are already starting to
lighten up some in far western MA and western CT. The bigger
question mark for today if we can shake free of low cloudiness and
how much if any peeks of sun we could see today. Indication from
NAM/GFS bufkit profiles showing the midlevel dryslot keeping shallow
RH for a good portion of the day. There could be some peeks of sun
by the afternoon, but think the majority of today will feature more
cloud cover than not and that's also the depiction on satellite
imagery further to the west. Wouldn't rule out isolated, hit-or-miss
showers through early this afternoon, but the majority of the time
is dry. Temps could go up another couple degrees to highs in the
50s, but should be fairly close to current values given expectation
of overcast.

Later this afternoon a sharp cold front races eastward, and there
could be more scattered coverage of convective-type showers that
could even have some graupel/"dippin-dots" pellets given presence of
steepening lower level lapse rates. Passage of this front will bring
some cloud clearing, sharply falling temperatures and more
importantly a gusty and marked windshift to the NW. NW winds
increase to around 10-15 mph with gusts 25-30 mph as we near
sundown, but they will start to really howl as we move into tonight.
More on that in the next section.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
330 AM Update:

Key Messages:

* Strong to damaging northwest wind gusts expected tonight into Fri
  in the high terrain (frequent gusts 45-55 mph/peaking 60 mph). NW
  gusts in lower elevations around 35-45 mph tonight, though become
  strong on Friday (up to 50 mph).

* High Wind Warnings in effect tonight into Friday for the
  Berkshires and central MA, with Wind Advisories for the remainder
  of Southern New England. Downed trees and powerlines are possible,
  best chance in Worcester County and the Berkshires.

* Drying out with cooling temperatures.

Details:

The main story for tonight into Friday is a period of very gusty to
strong, locally damaging northwest wind gusts.

We expect an initial surge of gusty to strong northwest winds with
strong cold advection and as the low-level northwest jet increases
to as much as 70 kt at 850 mb! In the lower elevations, a more
shallow mixing depth tonight may keep gusts in the 35-45 mph range,
though could punch up to 50 mph at times. The strongest gusts
tonight should be in and around the eastern slopes of the Berkshires
and into the hills in Worcester County given a lower inversion
height near ridgetop levels. This effect will help channel stronger
winds with gusts in the 55-60 mph range for these terrain areas,
which may also include a small portion of northern Tolland County as
well.

As we move into Friday, clearing skies/full sun and cold advection
aloft will yield an extremely well-mixed atmosphere, with mixing
depths at least to 850 mb or even a bit higher up. While strong to
locally damaging wind gusts 50 to 60 mph will still be confined to
the higher terrain, lower elevations and the cities will start to
experience frequent NW gusts in the 40 to 50 mph range upon
sunrise and continuing through midafternoon. By midafternoon,
the low level jet then begins to diminish more significantly,
with a more rapid decrease in gust speeds thereafter. Putting it
all together, the potential exists for tree and powerline
damage especially with recently wettened soil from today's rain
and some snowmelt, but in particular across the higher terrain.

Other than the very gusty conditions, tonight through Friday will
feature decreased cloudiness and dry weather. Temperatures however
will fall back to more seasonable levels in the mid 30s to lower to
mid 40s on Fri, but it will feel quite chilly with the gusty winds.

&&

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

* Another round of gusty to strong winds possible Sat, but not
  as strong as Fri.

* Mainly dry weather prevails for the weekend into early next
  week. Seasonably cool temps, but possible warmup late.

Mainly zonal flow this weekend into next week, which should keep
southern stream storm tracks south of the region.

An enhanced cyclonic flow and cold pool of air aloft will work
its way through southern New England on Saturday. A continued
tight pressure gradient will again lead to another rather gusty
day with 850 mb winds around 40-45 kt. This isn't quite as
strong as that from Thurs night/Fri, but could still support
gusts in the 35 to 45 mph range.

A couple of northern stream clipper systems move through later
Sat night and possibly again on Monday, which could bring some
light rain/snow showers to the region but this is not set in
stone. High temperatures this weekend don't rebound much with
the reinforcing shot of cold air from Saturdays clipper. High
temps stay in the upper 30s to low 40s, with lows in the high
teens to low 20s. Surface flow turns more westerly late Monday
into Tuesday, allowing temperatures to warm back into the upper
40s to low 50s Monday and Tuesday, with low 60s possible
Wednesday and Thursday.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:

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

Rest of Tonight: Low Confidence.

Moderate to heavy rain continues to move through the region
tonight, but should be offshore by 12z this morning. Mainly IFR
CIGS with the rain tonight, but there has been pockets of LIFR
in heavy downpours, and pockets of MVFR in the dry slot where
rain is briefly letting up.

Thursday: Low Confidence

Despite the rain moving offshore, southerly winds will likely
keep IFR/LIFR CIGS around until the afternoon when winds turn
more westerly. This tends to be a tricky forecast as diurnal
heating may be able to lift the IFR cigs into the MVFR/VFR
range. Once winds turn more westerly in the afternoon to early
evening, CIGS should quickly rise to VFR.

Thursday night: High confidence

VFR with increasing westerly winds gusting 35-45 knots.

Friday: VFR. Strong winds with areas of gusts up to 55 kt.

KBOS TAF...Low confidence in TAF.

KBDL TAF..Low confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night: VFR. Windy with gusts up to 30 kt.

Saturday: VFR. Strong winds with areas of gusts up to 40 kt.

Saturday Night: VFR. Strong winds with local gusts up to 40 kt.

Sunday: VFR. Breezy.

Sunday Night: VFR.

Monday: VFR. Breezy.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today: High confidence.

Gale Warnings still continue through 12z with gusts still around
35 mph on most waters. Those will be downshifted to small craft
advisories with seas still in the 6-10 ft range, however
southerly wind gusts to decreas to around

S to SE wind gusts expected to pick up tonight, reaching Gale
force. Gale Warnings are in effect through 12z Thursday morning.
Seas expected to build up to 13 ft across the outer waters,
particularly in the south. Rain and fog also expected to impact
the waters tonight going into Thursday morning.

Gusts drop off to around 15 to 20 kt during the day Thursday,
shifting more to the WSW. Seas will remain elevated, though, so
Small Craft Advisories will be needed once the Gale-force gusts
end.

Tonight and Friday: High confidence.

Gale Watches remain posted from 00z Friday to 00z Saturday,
however these will be shifted to warnings likely later this
morning once the ongoing Gale Warnings come to an end. W to NW
winds are expected to gust to 40-45 kt starting tonight right
through Friday with good mixing expected. Some spots could
reach storm force gust levels, but widespread Gale conditions
are more likely. Seas expected to be from 7 to 12 ft.

Outlook /Friday Night through Monday/...

Friday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 10 ft.

Saturday: Strong winds with gusts up to 35 kt. Areas of rough
seas.

Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Areas of rough seas.

Sunday: Winds less than 25 kt. Local rough seas.

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

&&

.TIDES/COASTAL FLOODING...
Coastal Flood Advisories and Coastal Flood Statements continue
as water from the overnight high tide has been slow to recede in
the face of continued southerly flow. We expect these headlines
to come down by 7 AM, if not sooner.

However looking into Friday morning's high tide...a period of
strong northwest winds producing a 1 to 1.25 inch storm surge could
allow areas such as Nantucket Harbor and the bay side of Cape
Cod to see minor splashover. Coastal flood statements could be
needed, although significant impacts are not expected.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory from 7 PM this evening to 7 PM EST Friday for
     CTZ002>004.
MA...Wind Advisory from 7 PM this evening to 7 PM EST Friday for
     MAZ003-005>007-010-011-013>024.
     High Wind Warning from 7 PM this evening to 7 PM EST Friday
     for MAZ002-004-008-009-012-026.
     Coastal Flood Advisory until 6 AM EST early this morning for
     MAZ020-021.
RI...Wind Advisory from 7 PM this evening to 7 PM EST Friday for
     RIZ001>008.
     Coastal Flood Advisory until 6 AM EST early this morning for
     RIZ002-004>007.
MARINE...Gale Warning until 7 AM EST this morning for ANZ230>237-250-
     251-254>256.
     Gale Watch from this evening through Friday evening for
     ANZ230>237-250-251-254>256.

&&

SYNOPSIS...Loconto/KP
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...KP
AVIATION...Loconto/KP
MARINE...Belk/Loconto/KP
TIDES/COASTAL FLOODING...Loconto