Rockland, Massachusetts Weather Forecast Discussion

781
FXUS61 KBOX 211038
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
638 AM EDT Sun Sep 21 2025
.SYNOPSIS...
Cooler air this weekend will be followed by a warming trend
early next week. Dry weather continues until the chance for some
unsettled weather returns Tuesday into Wednesday. Temperatures
will also average above normal next week, with Tuesday expected
to be the warmest day; temperatures may reach 80+ degrees at
some locations.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Messages:
* Dry weather continues with some clouds building in today
This period remains relatively unchanged from the previous forecast.
Surface high pressure is expected to continue moving offshore as
upper level ridging moves east. This will allow some clouds to build
in through the day today, but no precipitation is expected with
them. East to southeast winds remain light and high temperatures
remain just slightly below normal in the upper 60s and low 70s as
the cool airmass remains aloft.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Key Messages:
* Cool again tonight
* Warming trend kicks off tomorrow
Another cool night is in store for southern New England as winds
become light/calm once again and 925 mb temperatures remain around
10C. Model soundings are indicating a chance for some patchy fog
late tonight for some spots in the interior along with some clouds
returning after brief clearing earlier on. Lows in the 40s for most
locations while the Cape and Islands can expect the mid 50s.
A warming trend kicks off Monday with southerly flow helping advect
in some more moisture and increased temperatures. High pressure
moves well offshore and 925 mb temperatures increase to around 15C.
Highs Monday increase to the 70s across southern New England.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Key Messages:
* Warmup expected to start the week, peaking Tuesday
* Chance for some beneficial rainfall Tuesday into Wednesday
* Brief quiet period Wednesday before the pattern may become
  unsettled once again through the end of the week
With high pressure offshore, winds shift more SW going into Tuesday,
advecting in more moisture and heat. Ensemble probabilities continue
to hit the CT and Merrimack River Valleys with high chances for high
temperatures Tuesday meeting and exceeding 80F. Deterministic
guidance is in agreement showing 925 mb temperatures over the region
around 20C. Dew points increase into the 60s after a dry weekend,
and ensemble mean PWAT values range between 1.5-1.7" for the
afternoon. Combine this with a front moving east Tuesday with
multiple waves of low pressure along it, we may see some rain
Tuesday evening into Wednesday. Guidance is also indicating some
increased instability with probabilities above 30 percent for MLCAPE
values above 500 J/kg and around 50 percent for SBCAPE above 500
J/kg (slightly lower for values above 1000 J/kg). Showers that
develop may end up being more convective in nature, so localized
heavy downpours and some rumbles of thunder are a possibility. At
this time, severe probabilities remain low and this system is still
a few days out, so stay tuned for more updates.
Once this system moves through, upper level ridging with surface
high pressure build back into the region for Wednesday and
temperatures fall back into the 70s and upper 60s. This quiet period
may not last long though; a longwave trough digs deeper into the
central and midwest US while associated low pressure circulates and
may move east. There is still disagreement across model suites
regarding how this will impact our region going into the end of the
week, but generally, it may keep the overall pattern unsettled.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Sunday...High Confidence.
VFR. Winds becoming E to SE through the day at 10 knots or
lower (slightly higher than 10 knots over the Islands).
localized sea breezes developing after 14z
Sunday Night...High Confidence.
VFR with some patchy MVFR/IFR over parts of the interior from
patchy fog/lower ceilings. Light and variable to S winds away
from the coasts. Light E winds towards the coastal waters.
Monday...High Confidence.
VFR. Primarily S winds less than 10 kts.
KBOS Terminal...High confidence in TAF.
VFR. Sea breeze moves in around 16z and kicks out around 00z.
KBDL Terminal...High confidence in TAF.
VFR. Light northerly winds flip southerly this afternoon.
Outlook /Monday Night through Thursday/...
Monday Night: VFR.
Tuesday: VFR. Breezy. Chance SHRA, slight chance TSRA.
Tuesday Night: Mainly VFR, with local IFR possible. Chance
SHRA, slight chance TSRA.
Wednesday: Mainly VFR, with local IFR possible. Chance SHRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Thursday: VFR. Slight chance SHRA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Through Monday...High Confidence.
E to SE winds mostly below 15 kts through this period. Winds
across all waters shift more S heading into Monday night. Good
visibility. Seas remain at or below 4 ft until Monday when 5 ft
seas begin to build over the outer waters.
Outlook /Monday Night through Thursday/...
Monday Night: Winds less than 25 kt. Seas up to 5 ft.
Tuesday: Winds less than 25 kt. Seas up to 5 ft. Slight chance
of rain showers.
Tuesday Night: Winds less than 25 kt. Seas up to 5 ft. Chance
of rain showers, slight chance of thunderstorms.
Wednesday through Thursday: Winds less than 25 kt. Areas of
seas approaching 5 ft. Chance of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
SYNOPSIS...Belk/Hrencecin/FT
NEAR TERM...Hrencecin
SHORT TERM...Hrencecin
LONG TERM...Hrencecin
AVIATION...Hrencecin/KP
MARINE...Hrencecin

NWS BOX Office Area Forecast Discussion