NWS Boston/Norton, MA wrote its last area forecast discussion before the first event at Jan 13, 2:34 AM EST, 26 minutes earlier.
Area forecast discussion, Jan 13, 2:34 AM EST, 26 minutes before
Area Forecast Discussion
National Weather Service Boston/Norton MA
234 AM EST Sat Jan 13 2024
.SYNOPSIS...
A powerful storm impacts southern New England this morning,
bringing a renewed or worsened risk for areal and river
flooding, strong southeast winds and coastal flooding. Windy
and turning colder Sunday with scattered snow showers along with
a few snow squalls possible too. Much colder weather is on tap
for next week with below normal temperatures. We may also have
some snow to deal with sometime Tuesday into early Wednesday and
possibly again next Friday into Saturday... but that is not set
in stone.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Updated: 230AM
* Minor to moderate coastal flooding concerns for the AM/noon high
tide cycle for all of Rhode Island and Massachusetts.
* Southeast gusts 40 to 55 mph along the coast, with localized
higher gusts of 60 mph possible for outer Cape Ann and Cape Cod.
* Areal flooding possible with 1-2+ inches of rain this morning will
aggravate swollen rivers, leading to rising river levels.
Yet another robust winter storm, albeit a rain storm, will impact
our region during the predawn hours through mid-morning. There were
no major updates/changes our forecast this morning. And no changes
made to the headlines. We remain concerned with fresh water/coastal
flooding, strong wind gusts along the immediate coast, and
dangerous marine conditions.
A Coastal Flood Warning remains in effect for the entire
coastline of Rhode Island and Massachusetts through early this
afternoon, once we pass high tide. Full details can be seen in
the Coastal and Tide section of the AFD.
Strong 982mb low-pressure system centered over Lake Michigan tracks
northeast during the predawn hours, with a secondary low developing
over New York State. Do expect wind gust to increase shortly, with
the strongest of the winds between 3AM and 10AM. While there is a
robust 925mb LLJ of 90-ish knots, there is a stubborn inversion at
the surface, this will limit the amount of wind that mixes down to
ground level. This is fairly common due to the southeast wind
direction. Nevertheless, expect there will be gusts along/near the
coast of 40 to 55 mph, with an isolated gust of 60 mph possible for
the extreme outer Cape Ann and Cape Cod. Given the probability is
low, opt to continue with the Wind Advisory, over upgrading to a
High Wind Warning. The wind will become southwest early afternoon
and gusts will continue as there will be better mixing of the
boundary layer. Gusts of 25 to 35 mph, with a isolated higher gust
to 40mph for this afternoon. Given the wind direction, not
surprised that we usher in a warmer air mass. Afternoon
temperatures are generally 55-60 degrees, which try to challenge
a few record highs, but will more than likely this afternoon
will be 2 to 4 degrees too cool.
Feel a bit like a broken record, but the freshwater flooding remains
a valid concern. Still expecting the heaviest/steadiest of the
rain to fall through the predawn hours, before ending from west
to east, at the time of 8AM across western areas and 10AM/11AM
for eastern Massachusetts. As we have been mentioning, this
system is juiced with PWATs ~1.3 inches, but to put that into
context, that is ~400 percent of normal/4 standard deviations
above what is considered normal for early January. When all is
said and done, rainfall totals will have amounted to 1-2 inches,
with locally higher amounts of 2+ inches centered over eastern
Connecticut and much of Rhode Island. This will likely result in
flooding in areas that have experienced poor drainage flooding
earlier this week. Plus, this amount of rain will aggravate
already swollen rivers. Remember, the larger rivers continue to
rise well after the rain ends. Swollen rivers will likely
continue into Sunday and Monday.
Good news, this is a progressive system, with improving conditions
by late morning/early afternoon from west to east. Do expect
sunshine will return along with a few leftover showers. As mentioned
above, do expect wind direction will becomes southwest and will
remain breezy.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Updated: 230AM
* Mainly clear, breezy, and temperatures in the 20s.
* Windy, along with the potential for snow squalls Sunday afternoon.
Tonight:
Clear skies and a breezy southwest gusts 20 to 30 mph. The mixed
boundary layer keeps our temperatures from freefalling. Lows
overnight 25-30 degrees, while the east slope of the Berkshires fall
into the low 20s.
Tomorrow:
A robust shortwave and surface cold front will push across the
region during the afternoon along with a strong 700mb jet of 70 to
90 knots! Why do I bring up the 700mb jet? Bufkit soundings show the
boundary layer is WELL mixed and could extend upwards of 750mb to
650mb. Doesn't mean we will mix ALL of the wind to ground level, but
a fair amount, 35 to 50 mph gusts are not out of the question. Have
held off on issuing any wind headlines as to not draw any confusion
with our current wind headlines. The day shift or the next night
shift may want to consider a Wind Advisory.
In addition, there remains the potential for snow squall during the
early afternoon. The latest 00z high-res guidance signals at
streamers coming off the Great Lakes and racing across southern New
England around noon to 4PM, coinciding with the shortwave passage
and steep lapse rates. The snow squall parameter is also supportive
of this potential along with some of the CAMs. This will bring the
risk for localized/brief hazardous travel with the potential for
roads quickly becoming snow covered and with briefly near zero
visibility and hazardous travel. Greatest risk for this will be
across the interior with colder temperatures. Along the coastal
plain it may be mild enough for an initial mix with rain and result
in most roads initially being wet.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Key Points...
* Cold, with extended period of below normal temperatures most of
next week
* Some snow/mix possible Tue-early Wed, but may miss us to the south
* Another storm system may bring more snow/mix by next Fri-Sat
Mid level synoptic pattern is expected to feature a broad trough
over the CONUS for most of this portion of the forecast. The trough
axis is projected to move towards the East Coast towards Wednesday,
before moving offshore Thursday. There continue to be timing
differences amongst the various models with this feature. Our
position relative to this feature will play a significant role in
determining how close a low pressure passes to our region late
Tuesday into Wednesday.
13/00Z Canadian has the closest track of the deterministic models,
with the 13/00Z GFS the farthest offshore. The 13/00Z ECMWF was
right in the middle. All of these deterministic solutions take a low
pressure southeast of the 40N/70W benchmark Tuesday night into
Wednesday. Thus, it is looking more like a glancing blow from this
particular low pressure. There is still a significant spread in the
ensembled solutions, as both the GEFS and EPS showed some low tracks
closer to our region, along with some even farther offshore.
Thinking it is still too early to commit to a singular solution.
Stayed close to the NBM solution, as that is ensemble-based.
Some potential for snowfall with an offshore track. Still need to
figure out the temperature profiles with more certainty, as there
could also be some mixing towards the coast.
Beyond Wednesday, a large high pressure is projected to move east
along the Gulf Coast for Thursday. This high pressure should reach
into southern New England, at least briefly. Some signals for a low
pressure to pass by towards next Friday, but there is still too much
uncertainty for much details.
Near to below normal temperatures through this portion of the
forecast.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
09z TAF Update
Through 12z...High Confidence in trends, but moderate
confidence in specific timing.
Deterioration continues with moderate to heavy rainfall
overspreading the region with IFR/MVFR cigs and IFR/MVFR vsbys.
Wind gusts begin to exceed 30 knots after 06Z with the strongest
gusts near the coast. Wind gusts peak between 40 and 50 knots
in the hours approaching 12Z along the coast...but significantly
weaker across the interior. LLWS also will be an issue too.
Today...High confidence in trends, but moderate confidence in
timing.
MVFR/IFR conditions persist through about 15Z before gradual
improvements back to VFR from west to east between 15 and 18Z.
Winds shift to the west/southwest by 18Z and remain relatively
strong with sustained winds 15 to 20 knots and continued gusts
from 30 to 35 knots. Strongest gusts over The Cape/Islands
terminals.
Tonight...High Confidence.
VFR. Southwest winds 15 to 20 knots with 25 to 30 knot gusts.
KBOS TAF...High confidence in trends but confidence in timing.
SE 35 to 45 knot gusts expected between roughly 08Z and 15Z
with perhaps a few brief gusts near 50 knots. This time period
is also when IFR/MVFR flight categories will be most likely.
Although return to VFR is expected by 18Z, a prolonged period of
gusty winds (25 to 35 knots) will persist through the weekend.
KBDL TAF...High confidence in trends but confidence in timing.
Outlook /Sunday Night through Wednesday/...
Sunday Night: Mainly VFR, with local IFR possible. Windy with
gusts up to 35 kt.
Martin Luther King Jr Day: VFR. Breezy.
Monday Night: Mainly VFR, with local IFR possible. Breezy.
Slight chance SN.
Tuesday: Mainly IFR, with areas MVFR possible. Breezy. Chance
SN.
Tuesday Night: Mainly IFR, with local MVFR possible. Windy with
gusts up to 30 kt. Chance SN.
Wednesday: Mainly VFR, with areas IFR possible. Windy with
gusts up to 35 kt. Chance SN.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Today and Sunday
* Storm Warnings for eastern waters, Gale Warnings elsewhere.
* Southeast Wind Gusts of 45 to 55 knots this morning.
Marine conditions rapidly deteriorate this morning as strong
winds and high seas develop in response to a strong-low pressure
system moving through. 45 to 55 knot east/southeasterly wind
gusts through this morning with Gale and Storm Warnings in
effect. Winds shift west/southwest by this afternoon, but
continue to produce gale force gusts through the end of the
weekend. Seas remain elevated through this period as well with
15 foot plus seas expected over the outer marine zones and 6 to
10 foot seas over the near-shore zones.
Outlook /Sunday Night through Wednesday/...
Sunday Night: Low risk for gale force winds with areas of gusts
up to 45 kt. Rough seas up to 12 ft. Slight chance of snow
showers. Areas of visibility 1 to 3 nm.
Martin Luther King Jr Day: Low risk for Small Craft Advisory
winds with gusts up to 30 kt. Local rough seas.
Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of snow. Areas of visibility 1 to 3 nm.
Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Rain likely, chance of snow. Visibility 1 to 3 nm.
Tuesday Night: Low risk for gale force winds with gusts up to
30 kt. Seas up to 5 ft. Rain likely, chance of snow. Areas of
visibility 1 to 3 nm.
Wednesday: Moderate risk for gale force winds with gusts up to
35 kt. Areas of rough seas. Chance of snow, slight chance of
snow showers. Visibility 1 to 3 nm.
&&
.HYDROLOGY...
A Flood Watch remains in effect for all of southern New England
through Saturday evening. Many area rivers and streams are still
experiencing flooding that was triggered by heavy rainfall
earlier this week.
An additional 1 to 2+ inches of rain is forecast to fall this
morning across southern New England with the passage of a robust
low pressure system. The area of greatest concern is eastern
Connecticut and Rhode Island, where the heaviest precipitation
is forecast to fall. Any additional rainfall is expected to
prolong or exacerbate the ongoing fresh water flooding across
our region.
&&
.TIDES/COASTAL FLOODING...
Coastal Flood Warnings remain posted for the entire MA/RI coastline.
South Coastal MA/RI:
Peak storm surge of 2-3 ft is expected to occur around 7 AM which is
very close to high tide. This will lead to widespread minor flooding
(less than 1 foot deep) with pockets of moderate flooding (1 to 3
feet deep) especially in areas that have seen significant beach
erosion and damage from recent storms (Misquamicut).
On Narragansett Bay, we think a 3-4 ft surge is reasonable and this
should lead to moderate flooding near the upper part of the bay,
including North Kingstown and Providence.
Eastern MA Including Cape Cod and the Islands:
Lower confidence due to peak surge occurring a few hours before high
tide (10 AM to 1 PM) but surge of 1-2 ft still expected. Winds shift
to south and then southwest by early afternoon which is another
complicating factor. Will this offshore wind help compensate against
greater impacts? We think that could end up being the case, although
wave direction will still be from E/SE so it may not help much.
Model guidance drops surge significantly by 1 PM and may be too
aggressive in doing so.
Similar to the South Coast, there are many areas that have seen
significant beach erosion and damage from recent storms, including
the south shores of Martha's Vineyard and Nantucket and the
Newburyport/Plum Island area in northeast MA. These locations are
more likely to see greater impacts than what would normally be seen
at minor flood levels.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch through this evening for CTZ002>004.
MA...Flood Watch through this evening for MAZ002>021-026.
Wind Advisory until 1 PM EST this afternoon for MAZ007-015-016-
018>024.
Coastal Flood Warning from 10 AM this morning to 4 PM EST this
afternoon for MAZ007-015-016-019-022>024.
Coastal Flood Warning from 7 AM this morning to 1 PM EST this
afternoon for MAZ020-021.
RI...Flood Watch through this evening for RIZ001>007.
Wind Advisory until 1 PM EST this afternoon for RIZ004>008.
Coastal Flood Warning from 7 AM this morning to 1 PM EST this
afternoon for RIZ002-004>008.
MARINE...Gale Warning until 7 PM EST this evening for ANZ230-235>237-
256.
Storm Warning until 11 AM EST this morning for ANZ231>234-250-
251-254-255.
&&
SYNOPSIS...Belk/Dooley
NEAR TERM...Dooley
SHORT TERM...Dooley
LONG TERM...Belk
AVIATION...Belk/Dooley
MARINE...Belk/Dooley/JWD
HYDROLOGY...Belk/Dooley/JWD
TIDES/COASTAL FLOODING...JWD