369
FXUS61 KBOX 221530
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1030 AM EST Sat Nov 22 2025

.SYNOPSIS...
A weak wave of low pressure passes well to our south this morning,
which will bring a brief round of showers mainly across parts of
Connecticut, Rhode Island and southeast Massachusetts. Otherwise,
dry and seasonably cool weather is on tap for the weekend into
Monday. Low pressure approaching from the west will likely bring a
period of rain later Tuesday and/or Wednesday with drier and
cooler weather favored by Thanksgiving into Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Messages:

 * Light rain this morning with amounts under 0.25 inches

A weak wave of low pressure passes to the south of SNE this morning.
Guidance has trended this system further north with light rain
possible up to the MA pike, but more measurable amounts (0.1-0.25)
closer to the south coast. With the trend further north, rain will
take a bit longer to move offshore, generally ending between noon
and 2 pm. Cold front moves in behind the rain, helping clear the
clouds from west to east. Unfortunately, with these early sunsets,
eastern MA may not see the clearing before dusk. Winds turn NW with
the cold front, but remain around 5-10mph. Highs on Saturday top out
in the mid- to upper 40s before the cold front, then drop into the
upper 30s in the evening.

&&

.SHORT TERM /SUNDAY/...
Key Messages:

 * Scattered rain/snow showers Sunday afternoon

Tonight

High pressure briefly builds back in overnight, bringing clear skies
and light winds. Good radiational cooling conditions will bring
overnight lows back down into the low to mid 20s, with high teens
possible in far NW MA.

Sunday

Northern stream shortwave and reinforcing cold front drops out of
Canada.  There should be enough mid-level moisture and forcing
available to produce scattered rain showers across the region Sunday
afternoon. Snow may mix in with rain showers across the interior as
wetbulb temps remain around freezing. High temps on Sunday get stuck
in the low 40s with weak CAA. Surface winds remain light out of the
WSW at 5-10mph.

&&

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

* Dry and seasonably cool on Monday, followed by a brief warmup
  Tuesday and Wednesday with periods of rain.

* Cooler conditions return Thursday and Friday, along with a lower
  chance of rain and snow showers.

Overview: Surface high pressure builds across the east coast through
Tuesday. During this time period the mid-levels are quasi-zonal with
uneventful day-to-day weather conditions. A shift in the mid-levels
occurs the second half of Tuesday into Wednesday, with ridging in
the west and troughing in the east. On Tuesday, ensembles show a
developing system, albeit a fair amount of spread in the guidance,
across the northern tier of the Great Lakes with a secondary low
across southern half of New England. LREF cluster analysis of the
500mb pattern have started to come into better agreement for the
26th into the 27th (Thanksgiving). Clusters show a trough over the
midwest with departing ridging over New England. There still is a
bit of uncertainty with the magnitude at this time. By Friday, there
is troughing across much of the northeast with northwest flow. As
this is timeframe is 4 to 6 days out, there are plenty of time to
watch this evolution.

Precipitation: Generally dry weather is expected during the extended,
but a weak low pressure system associated with a mid-level shortwave
does provide some assent Sunday night into early Monday, the issues
is the lack of available moisture with PWATs less than 0.4". A few
upslope flurries across western MA or light rain showers for the
coastal plain are possible, POPs less than 25%. The next threat for
widespread precipitation comes late Tuesday into Wednesday, but
there are questions on whether forcing arrives with the highest
moisture content. So, it is too early for exact details. During this
time PWATs increase to 0.8" to 1.2", which are between 1.5 and 2.0
standard deviations above normal, meaning some heavier rain cannot
be ruled out during this timeframe. Also, there is a good chance the
PType would be plain rain as thermal profiles are above freezing at
the surface and up to ~800mb. Colder air advects in sometime there
after into Thursday/Friday. The flow becomes west-northwest with
signs of lake effect snow showers coming off the eastern Great
Lakes. Do not lock anything in just yet, there is a ton of time
between now and then, but be aware of the potential for unsettled
conditions leading up to the Thanksgiving holiday.

Temperatures: Continued cooler than normal temperatures into Monday
with 850mb temperatures around -5C to -3C. 850mb temperatures warm
Tuesday and Wednesday, reaching +4C on Tuesday to +8C on Wednesday.
A cold front ushers in significantly cooler temperatures aloft on
Thursday into Friday, 850mb temperatures fall to -10C to -8C. So,
after a cool start on Monday in the 40s, temperatures warm into the
low 50s on Tuesday and upper 50s to 60F on Wednesday. Cooling trend
Thursday into Friday, with highs in the upper 40s to 50F for
Thanksgiving (with a breezy westerly wind) and upper 30s to lower
40s on Friday.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...

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

15z TAF Update:

Today: High confidence.

IFR-MVFR visby in rain/mist with mainly VFR-MVFR ceilings,
improving to VFR between 16-22z Sat from west to east. Light
winds but will become WNW/NW under 10 kt.

Tonight: High confidence.

VFR; outside shot (< 30% prob) of sub-VFR patchy mist/fog in
the western river valleys toward sunrise. NW winds under 10 kt
early ease to light west.

Sunday: High confidence thru 18z, then confidence trends
moderate to high.

VFR thru at least 18z, then ceilings turn more of a BKN/OVC
VFR/MVFR range as weak low pressure moves in. Spotty/very light
precip possible after 21z, mainly as -RA but snowflakes could
mix in at ORH. Light W winds become SW and increase to 5-10 kt.

KBOS Terminal...High confidence in TAF. Ceilings are mostly VFR,
reduced visbys (4-6 SM) in light rain/mist thru 16z, then
improving to VFR as rain dissipates. Light S winds become WNW
under 10 kt approx 16-18z Sat thru the period.

KBDL Terminal...High confidence in TAF.

VFR turning MVFR with light rain moving in after 10z.

Outlook /Sunday Night through Wednesday/...

Sunday Night: VFR. Breezy. Isolated SHRA.

Monday: VFR. Breezy.

Monday Night: VFR.

Tuesday: VFR. Chance RA.

Tuesday Night: Mainly MVFR, with local IFR possible. Breezy.
Chance RA.

Wednesday: Mainly VFR, with local MVFR possible. Chance RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Sunday... High confidence.

* Weak system brings showers to southern waters early this morning
  with drying conditions this afternoon.

* Wind and seas remain below advisory criteria through the weekend.

A weak wave of low pressure passes south of the waters and results
in rain showers mainly for the southern waters, high pressure builds
into the region late today into Sunday. Winds and seas remain below
Small Craft Advisory thresholds through the period.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Scattered rain showers.

Monday through Monday Night: Winds less than 25 kt. Seas
locally approaching 5 ft.

Tuesday: Winds less than 25 kt.

Tuesday Night through Wednesday: Winds less than 25 kt. Areas
of seas approaching 5 ft. Rain likely.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...Dooley/KP
NEAR TERM...KP
SHORT TERM...KP
LONG TERM...Dooley
AVIATION...Loconto/Dooley/KP
MARINE...Dooley/KP