Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/30/24
Area Forecast Discussion
National Weather Service Boston/Norton MA
929 PM EST Mon Jan 29 2024
.SYNOPSIS...
Ocean low exits seaward with high pressure building into New England
from west to east tonight. This yields diminishing winds along with
decreasing clouds overnight, except over coastal Plymouth
county, Cape Cod and the Islands, snow showers continue with a
coating possible. High pressure delivers dry but cold weather
Tuesday, along with partial sunshine, except remaining mostly
cloudy over southeast MA. Temperatures begin to moderate
Wednesday and especially by Thursday and Friday. A few brief
rain/snow showers are possible sometime Thursday and/or Friday
with a cold front, but significant/organized precipitation is
not expected at this time. Colder weather returns for the
weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
9:30 PM Update...
Temperatures at this hour are uniform across the region, ranging
from a low of 30 in Orange and Worcester and a high of 36 in
Norwood and Taunton. Given temps are running a bit more mild
than forecast, likely due to the higher than forecast dewpoints,
especially across SE MA where precip is still falling, blended
in HRRR guidance to bring the forecast more in line with
observations. While cold air is still expected to filter in from
the northeast overnight and Tuesday, it appears to be ever so
slightly delayed. Looking upstream, temperatures across NH and
southern ME remain in the upper 20s and low 30s, so it may be
several hours before we start to see the real impact of the
coldpool backing southwest from Nova Scotia.
Otherwise, a few light snow showers continue to plague SE MA and
the Cape, with vsbys reduced to between 1-3SM in New Bedford.
Given surface temps remain above freezing in places it is
snowing, shouldn`t see much by way of accumulation over the
next few hours as snow band intensity is not great enough to
compensate for surface temps.
Previous update...
325 PM Update...
This evening & tonight...
* Windy/blustery this evening, then slowly diminishing overnight
* Snow showers coastal Plymouth & Cape Cod, but only a coating or so
expected
* Colder, lows in the 20s but colder wind chills
Interesting narrow snow band from southern NH into the Worcester
Hills southward into RI. This band appears tied to a strong trailing
short wave moving across eastern NY state. This short wave is
inducing a wind shift/convergence line across the area mentioned
above, resulting in a narrow snow band of 20-25 dbz.
This band is drifting westward as short wave traverse from eastern
NY state to south of New England. Surface temps above freezing
(except high terrain) will confine any minor snow accums to non
paved surfaces. Vsbys could briefly lower to 2 miles given 20-25 dbz.
Elsewhere this evening, overcast and blustery with temps in the 30s
but wind chills in the 20s. Over coastal Plymouth and Cape Cod, OES
continues with CAA on north winds streaming across SSTs in the low
40s. Surface temps will remain above freezing, therefore any accums
will be confined to non paved surfaces. Snow showers begin to erode
after 03z or so, as short wave moves offshore and column begins to
dry from top down. Ocean effect clouds and flurries will continue
given the cold air streaming across the relatively warm ocean.
Although, accums will be limited as temps don`t fall below freezing
until snow showers move offshore after 03z.
Colder tonight with low level CAA commencing behind departing wave.
925 mb temps cool from -5C at 00z to -10C by 12z Tue. Lows from the
upper teens across northern MA (except around 25 in Boston), to 20-
25 elsewhere. It will feel colder given the blustery north winds,
especially Cape Cod and Islands, but slowly easing overnight.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
325 PM update...
Tuesday...
* Sunshine returns, albeit partial sunshine.
* Clouds likely persist over southeast MA
* Coldest day of the week, highs only U20s-L30s
Short wave ridging and accompanying surface ridge provide dry
weather along with much lighter winds Tue. Sufficient subsidence for
at least partial sunshine! Haven`t had widespread sunshine across
MA/RI/CT since last Monday. Clouds may be stubborn across southeast
MA, as low level moisture gets trapped beneath subsidence inversion.
Shallow cold air (-8C to -12C eastern MA) combined with limited
boundary layer mixing from subsidence inversion, will only yield
highs in the lower 30s, upper 20s for the high terrain, colder than
normal. However not much a wind chill given light winds along with
some sunshine away from southeast MA to help take the edge off the
cold temps.
Tuesday night...
Cold but dry with short wave ridging holding on. Surface ridge
provides light winds and combined with a dry airmass, will result in
cold temps, lows in the teens, low 20s for the urban areas including
the coastline. Some mid level clouds may impact temps late at night,
perhaps temps leveling off. Could also be closer to 10 degs across
northern Worcester county and the Berkshires given fresh snowpack
exists
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
325 PM update...
* Temperatures on the uptick through the end of the week
* Weak clipper system may produce some rain/snow showers Thursday
into Friday morning
* Cold front pushes through the region Friday afternoon bringing
temperatures down to near/slightly below normal temperatures for
the weekend.
Wednesday through Friday
Dry and seasonable conditions forecast for Wednesday as an upper-
level ridge axis slowly builds off the east coast with high pressure
at the surface supporting quiet weather in southern New England. 925
hPa temps around -5 Celsius should support afternoon high
temperatures in the mid to upper 30s which is close to normal for
late January. As high pressure shifts east Wednesday night into
Thursday, west/southwest flow begins to take control at the low-
levels. This will allow for a warming trend that will have
temperatures in the mid 40s both Thursday and Friday afternoon which
is above normal for this time of year. The only notable feature that
may produce precipitation during the extended forecast is a pulse of
northern stream energy that will be digging through the Northeast
Thursday into Thursday evening. This disturbance will be associated
with an Alberta Clipper type low-pressure system at the surface that
may produce some light rain/snow showers Thursday night into Friday.
The atmosphere will be rather dry however with PWATs only amounting
to 0.3 to 0.5 inches. Thus, not expecting any substantial
accumulations with whatever precipitation we may receive. Given the
limited moisture and forcing associated with this system, we have
placed slight chance PoPs over the region Thursday night and Friday.
As the surface low ejects southeast of the region Friday afternoon,
a strong cold front will follow. North/northwest winds behind the
front will advect a much cooler airmass over the northeast that will
begin a cooling trend for the weekend.
Saturday through Monday
Cool/dry air behind an exiting cold front should support a quiet/dry
weekend across southern New England. Temperatures will come back
down to values closer to normal for late January or even slightly
below normal. Highs/lows Saturday through Monday are forecast to be
in the mid to upper 30s and upper teens/low 20s respectively.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00Z TAF Update...high Confidence on trends, lower on exact
details.
Tonight...
MVFR persists with the best chance for VFR across western
terminals. Ocean effect snow showers will continue at times
tonight across the southeast New England coast. Winds out of the
N/NNE at 10-15 kts with 20-30 kt gusts.
Tuesday...
Any remaining MVFR cloud decks lift to VFR by afternoon. Dry
with decreasing NNE winds at 5-15 knots. Only caveat is how
quickly MVFR cigs slide southeast. Looks like MVFR cigs will
persist over SE Massachusetts much of the day. VFR all other
terminals.
KBOS TAF...Moderate confidence. MVFR conditions tonight. MVFR
cigs Tue morning will exit southeast and give way to VFR in the
afternoon, but exact timing somewhat uncertain.
KBDL TAF...Moderate confidence.
Outlook /Wednesday Night through Friday/...
Thursday: Mainly VFR, with areas MVFR possible. Breezy.
Thursday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance RA.
Friday: Mainly VFR, with areas MVFR possible. Slight chance RA.
Friday Night through Saturday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
325 PM update...
* Gales continue this evening near shore, overnight offshore
* Light freezing spray likely eastern MA waters tonight
Tonight...high Confidence
Northerly gales 25-35 kt, becoming subgale this evening but
lingering overnight offshore. Snow showers reduces vsby 1-3 miles at
times. Rough seas especially eastern MA waters, with heights 7-14
ft.
Tuesday...High Confidence
Offshore low exits seaward, promoting high pressure to advect into
New England. Thus, much lighter north winds Tue. Although, rough seas
will slowly subside. Light freezing spray possible in the morning
across eastern MA waters.
Tuesday night...
High pressure crest over the MA/RI waters, yielding dry weather and
good vsby. This will continue to allow seas to subside.
Outlook /Wednesday Night through Friday/...
Thursday: Winds less than 25 kt. Areas of seas approaching
5 ft.
Thursday Night through Friday: Winds less than 25 kt. Seas
locally approaching 5 ft. Slight chance of rain.
Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain,
slight chance of snow.
Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. Slight chance of snow.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 4 AM EST Tuesday for ANZ230-256.
Gale Warning until 1 AM EST Tuesday for ANZ231-232-251.
Small Craft Advisory until 10 PM EST this evening for
ANZ233>237.
Gale Warning until 4 AM EST Tuesday for ANZ250-254-255.
&&
$$
SYNOPSIS...Nocera/RM
NEAR TERM...Nocera/KS
SHORT TERM...Nocera
LONG TERM...RM
AVIATION...Nocera/RM
MARINE...Nocera/RM