Marblehead, Massachusetts Weather Forecast Discussion

281
FXUS61 KBOX 301913
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
313 PM EDT Tue Sep 30 2025
.SYNOPSIS...
Turning cooler over the next 12-24 hours. Northeast winds increase
tonight and especially into Wednesday, and gusts could reach as high
as 40 mph across the Cape and Islands as Hurricane Humberto makes
its closest approach. While neither Wednesday nor Thursday are ideal
beach days due to the breezes and cooler temps, high surf and rip
currents will affect the beaches. Above to well above normal
temperatures are expected by the weekend which continues into early
next week. Dry weather is expected to prevail today through the
early part of next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Key Messages...
* Clearing skies this evening with some mid clouds returning over
  southeast MA overnight.
* Increasing NE winds and high surf peaking Wednesday.
The synoptic pattern during this period features an expansive high
pressure system over southeast Canada to our north with TC Humberto
passing well to our south. This places SNE in between, beneath a
tightening pressure gradient which will produce gusty winds over the
next 24-36 hours. These northeasterly winds will ramp up this
evening and overnight, peaking on Wednesday. At the peak we expect
wind gusts as high as 35-40 mph over the Cape and Island, more like
15-25 mph further inland. Cool advection on this northeast flow
will also serve to drop high temperatures by about 10 degrees from
Tuesday, in the low to  mid 60s. The coolest spots (low 60s) will be
along the coast and in the higher elevations with the warmest
location being the CT Valley.
We also expect increasingly rough seas with wave heights as high as
10-12 ft on the outer waters, 6-8 closer to shore. Not a great beach
day with temps in the low 60s but even so, be aware that rip current
risk will be high, especially on south facing beaches.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
Key Messages...
* Cool, dry weather continues with decreasing winds.
Overnight Wednesday remains dry with Humberto moving further east
and high pressure expanding south. This means a slackening pressure
gradient and decreasing winds as we go through the night. It will be
the coldest night of the week so far as lows drop into the upper 30s
(high elevations) and low 40s.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Messages:
* Prolonged dry weather continues - next chance for rain is
  maybe late Tuesday.
* Temperatures through late week are seasonable, but above to well
  above normal temperatures are anticipated for this weekend into
  early next week.
Details:
Strong surface high pressure will remain close to southern New
England during this portion of the forecast. The main impact will be
where we are in relation to the center of this high pressure. When
this high center is just to our north Thursday, temperatures should
be below normal. Once this high center moves to our south on Friday,
we being a trend of near to above normal temperatures that continues
into next week.
The prolonged dry conditions will only exacerbate fire weather
concerns, especially as leaves start to fall. It would not take much
wind to increase this risk further.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18Z TAF Update:
Tonight: Overall high confidence but moderate on low clouds over
the Cape and Islands.
VFR with some potential for FEW/BKN mid level clouds off the
water bringing VFR/MVFR bases after 09z. NE to N winds increase
to around 20-25 kt with gusts 30-35 kt Cape and Islands, around
10-15 kt/ 20-25 kt gusts BOS-PVD, and around 10 kt inland.
Wednesday: High confidence.
VFR. NE gusts 30-35 kt Cape and Islands, around 20-25 kt for
BOS/PVD. Lighter northerly winds inland.
Wednesday Night: High confidence.
VFR. Winds will steadily be decreasing through the night,
generally blowing 15-20 kts over southeast MA terminals, gusting
to 20-25 kts by 12z. Inland terminals will see sustained winds
5-10 kts.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Thursday through Sunday/...
Thursday: VFR. Breezy.
Thursday Night through Sunday: VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Wednesday night: High confidence.
A tightening pressure gradient and cooler air over the milder waters
will allow for increased northeast winds peaking on Wednesday.
Gale warnings remain in effect adjacent to the Cape and Islands for
Tue night through Wed night. NE gusts increase tonight to around 25-
35 kt in the Gale Warning area, with 30-35 kt gusts more likely into
Wed. Elsewhere, SCAs are in effect for most of the remaining waters,
with gusts around 25-30 kt. NE winds over eastern portions of ANZ256
may approach gale force Wed. Seas will be building to 7-12 ft over
the outer waters, and around 4-6 ft nearshore. Both seas and wind
gusts diminish through the overnight hours.
Outlook /Thursday through Sunday/...
Thursday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Areas of rough seas.
Thursday Night through Friday Night: Winds less than 25 kt.
Areas of seas approaching 5 ft.
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Saturday Night: Winds less than 25 kt.
Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 11 PM this evening to 2 AM EDT
     Thursday for ANZ230.
     Gale Warning from 8 PM this evening to 2 AM EDT Thursday for
     ANZ231>234.
     Small Craft Advisory until 2 PM EDT Thursday for ANZ235-237.
     Small Craft Advisory until 2 AM EDT Friday for ANZ250-256.
     Small Craft Advisory from 11 PM this evening to 2 PM EDT
     Thursday for ANZ251.
     Small Craft Advisory until 8 PM EDT this evening for ANZ254-
     255.
     Gale Warning from 8 PM this evening to 5 AM EDT Thursday for
     ANZ254-255.
&&
$$
SYNOPSIS...Belk/BW
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...Belk
AVIATION...Belk/BW
MARINE...Belk/BW

NWS BOX Office Area Forecast Discussion