Brookline, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

365
FXUS61 KBOX 292021
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
321 PM EST Wed Jan 29 2025

.SYNOPSIS...
Cold conditions and blustery winds last into Thursday.
Monitoring a storm system which could bring the potential for
wintry mixed precipitation and/or rain to Southern New England
Friday into Friday night but the details are still uncertain.
Turning drier with a return to below normal temperatures this
weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
A snow squall that made its way through western and central MA
has switched to rain as it has made its way east into a warmer
area. Rain is expected to affect SE MA and RI until around 5 pm
tonight. Following this snow and rain, a strong cold front will
be moving across southern New England. 850 mb temps may reach
as low as -20C by early Thursday morning, and may settle around
-15C during the day. Lows tonight expected to be in the teens
and single digits.

The cold airmass remains over the region, and the tighter pressure
gradient between the high pressure building in from the SW and
the low pressure moving offshore to the northeast will maintain
gusty winds for much of the day Thursday. Wind chills will
likely be in the teens with highs in the 20s and dry conditions
during the day. Once this gradient slackens a bit, winds will
die down going into the evening hours.

Wind Advisories remain in effect through 7 am Thursday (the
Cape and Islands) and 10 pm (rest of MA, RI, and northern CT)
due to the gusts from the passing cold front and the strong CAA
coming with it. Gusts up to and over 50 mph continue to be
possible for this reason.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
Tonight:

Not as gusty overnight as the cold front moves offshore, and the
loss of diurnal heating will lead to a more shallow mixed layer.
The pressure gradient remains tight overnight, and 20-30 mph
gusts will continue. With the cold airmass in place and
overnight lows in the teens to single digits, the wind chill
factor will be near or below zero and possibly approaching
cold weather advisory criteria in NW MA.

Thursday:

Rising heights and high pressure will keep conditions dry
Thursday, but cold airmass remains in place, keeping
temperatures in the low to mid-20s. Gusty WNW winds of 20-30 mph
continue through the day, which will keep the wind chill factor
in the teens. The pressure gradient relaxes briefly on Thursday
evening, allowing gusts to drop off briefly before the next
system arrives on Friday.

&&

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

* Frontal system Fri into Fri night brings mix of wintry precip
  and rain to Southern New England. Snow/ice accumulations
  possible, especially near/north of the Mass Pike, although
  exact amts are uncertain.

* Turning drier with cooler than normal temps for the weekend.

* Possible Clipper system may bring light snow late Sun night/Mon.

Details:

Thursday Night:

Rather cold airmass on Thurs then modifies starting Thurs night
with increased cloud cover and warm advection processes taking
place. Early lows in the mid teens northern MA to the lower
20s, but then temps gradually warm into the mid 20s north to the
low to mid 30s south coast/Cape and Islands.

Friday and Friday Night:

We continue to monitor potential for active weather Fri into
early Sat associated with a sfc frontal system and parent
deamplifying 500 mb circulation as it moves into the OH
Valley/northern mid- Atlc states. Recent guidance has started to
back off on the potential for drier confluent 500 mb flow to
restrict the northward extent of QPF. Indeed, recent global
ensemble QPF members, even among the previously drier-side of
the QPF envelope the Canadian GEM, have trended toward at least
moderate probs (50-70%) of QPF of at least 0.1 inches. So there
seems to be an increasing chance at seeing some precipitation
during this forecast period, with PoPs in the Likely to
Categorical range.

The bigger question at this point is with regard to what form
that precip might take, and the precip types and changeovers
therein are still uncertain. Rather strong warm advection buoyed
by 925 mb SW winds of 45 kt support intrusion of warmer air
aloft into at least part of Southern New England. A variety of
precip types (snow, sleet/freezing rain and/or plain rain) could
be possible, depending on sfc temps and how far north warmer
air aloft may make it. A later- arrival to precip would allow
sfc temps to warm up enough to lead to more of a liquid p-type
too. Given the above precip-type uncertainties, it`s still too
early to delineate snow and/or ice accumulations at this point
but at the moment the best chance at some sustained wintry
conditions would tend to be near/north of the Mass Pike. While
some wintry impacts could be possible, substantial snow or ice
accretions do not appear likely at this point in time.

The Weekend into Monday:

Strong high pressure from Canada then advects in for Sat into
Sun, with drier conditions then returning along with a shot of
around or slightly colder than normal temperatures.

Moisture associated with another fast-moving Clipper system may
bring another round of light snow late Sun night into Mon.
Varying strength and QPF associated with this wave of low
pressure though, so uncertainty regarding this wave remains
large.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
Forecast Confidence Levels:

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

Today: High confidence in trends, moderate confidence in timing.

VFR for most going into the afternoon. Winds have started to
ramp up at some terminals with daytime mixing, and gusts 30-40
knots are still possible this afternoon. Primarily -RA showers have
started to pass through the region as temperatures have climbed
into the 40s (and even low 50s) at the surface. Brief periods
of MVFR vsbys are possible with -RA, but confidence is not high.
These are expected to move through the region from now until
20z. PROB30s for these showers have been upgraded to TEMPOs. Snow
squalls remain possible towards the Berkshires.

Tonight: High confidence.

VFR. Gusty west winds continue at 20-30 knots.

Thursday: High confidence.

VFR. NW gusts may pick up to around 25-30 kt during the mid
morning to mid afternoon, then begin to ease late-day.

KBOS TAF...Moderate confidence in TAF.

VFR. Chance for rain showers higher than snow showers/squalls
between 19-21z. Could reach MVFR vsbys during -RA, but
confidence is very low (did not include in TAF). Strong winds
expected today with gusts up to 40knots. Gusts subside slightly
tonight to 30 knots.

KBDL TAF...High Confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night: MVFR/IFR conditions possible. Breezy. RA likely,
chance SN, FZRA likely.

Saturday through Saturday Night: VFR. Breezy.

Sunday: VFR. Slight chance SN.

Sunday Night: MVFR/IFR conditions possible. Breezy. Chance SN,
chance RA.

Monday: Mainly VFR, with local IFR possible. Breezy. Chance RA.

&&

.MARINE...
Forecaster Confidence Levels:

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

High Confidence.

Increasing west winds today as another strong cold front
approaches the waters. Expecting gale force winds across all the
coastal waters, with dangerous waves of 6-10 feet in the open
waters. With very cold air behind the cold front, light to
moderate freezing spray will become of concern overnight through
Thursday. A freezing spray advisory has been hoisted for much of
the eastern coastal waters starting tonight, through Thursday
evening. Winds gradually diminish overnight into Thursday, but
remain around 20-30 knots from the West.

Outlook /Friday Night through Monday/...

Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Rain. Local visibility
1 to 3 nm.

Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Rough seas up to 10 ft.

Saturday Night: Winds less than 25 kt. Areas of rough seas.

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of
rain, chance of snow.

Monday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Seas up to 5 ft. Chance of rain.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 10 PM EST this evening for CTZ002>004.
MA...Wind Advisory until 10 PM EST this evening for MAZ002>021-026.
     Winter Weather Advisory until 7 PM EST this evening for MAZ002-
     008.
     Wind Advisory until 1 AM EST Thursday for MAZ022>024.
RI...Wind Advisory until 10 PM EST this evening for RIZ001>007.
     Wind Advisory until 1 AM EST Thursday for RIZ008.
MARINE...Gale Warning until 7 AM EST Thursday for ANZ230>237-250-251-
     254>256.
     Freezing Spray Advisory from 7 PM this evening to 7 PM EST
     Thursday for ANZ230>232-250-251-254-255.

&&

$$

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