January 9-10, 2024 | NE / Mid-Atlantic Winter Storm

[LUCC]

This is not looking good for all of NJ, I see flood warmings in our future. 🙄🙄

[StretchCT]

Gust EFI

Rain EFI

[Phillyfan]

Flood watches are already going up

[TheRex]

BTV's forecast discussion for the midweek storm.  Looks like we will have heavy wet snow, heavy rain, and lots of wind.  They mention some places (higher terrain) could see 8-12 inches of snow.  I'm surprised by those totals.  They downplay flooding but they also downplayed the last flooding event we had.  I hope there isn't a flooding issue, because the same places as last time will probably be the areas that get the flooding again.  This would be three flooding events in about 6 months.

Quote

SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 423 PM EST Sunday...**High Wind Watch now effect from 7 PM
Tuesday through 1 PM Wednesday. All zones in effect except northern
and western St. Lawrence County, NY, as well as eastern Windsor
County, VT.**

We continue to monitor a potentially significant storm system early-
mid week. Vertically-stacked low pressure is expected to rapidly
deepen as it moves from the South Central to the Great Lakes and
into Ontario/Quebec. High pressure in eastern Quebec will help
create the optimal conditions for a strong pressure gradient across
the forecast area. A plume of moisture and warmth will advect into
the area from the Gulf of Mexico. Warm air advection over colder air
in place will produce an inversion evidenced in model soundings for
this period. Best frontogenesis and positive vorticity advection
from this system is expected Tuesday night/Wednesday morning.

Winds: Winds continue to be the primary threat from this storm
system. Synoptically, the pattern features a deepening system
traveling up the St. Lawrence Valley and strong high pressure to the
northeast of the forecast area. This pattern continues to match
previous high wind events. Wind direction could be out of the
southeast, favorable for both advecting moisture and warmth as well
as for downsloping on northern and western slopes of our mountains.
However, there`s a chance that as more detailed model guidance comes
in there could be a wind shift to southerly. For our forecast peak
wind gusts Tues night/Wed AM, we have 40-60 mph. Wind speeds of 45-
55 mph could cause several small and larger limbs and small shallow
rooted trees to be knocked down, and scattered power outages are
possible. If wind speeds reach 55-65 mph, numerous branches, several
small trees, and a few large trees may be knocked down, and
scattered shingle and minor structural damage is possible. In areas
with 55-65 mph wind speeds, scattered to numerous power outages are
likely. We have expanded our High Wind Watch to cover almost the
entire forecast area excluding northern and western St. Lawrence
County, NY, as well as eastern Windsor County, VT. We also pushed
the start time of the High Wind Watch earlier to 7 PM instead of 10
PM Tuesday.

Snow: A warm front will provide isentropic lift for some snow on the
front end of the storm, likely of the heavy and wet variety due to
the warmth and moisture. Snow ratios will drop throughout the event,
landing relatively low during the heaviest snow, around 6-8:1.
Snowfall totals of 2-6 inches are expected, with some higher end 6-8
inch amounts possible on terrain. The wider valleys could have less,
more like Trace-2 inches, due to shadowing. At this time, snow looks
to be heaviest between 7 PM Tuesday and 1 AM Wednesday. With
relatively low snow ratios, areas that get 4-8 inches could see
numerous weighted tree limbs and some power lines, with isolated to
scattered power outages possible. If areas see 8-12 inches of snow,
weighted/snapped tree limbs are possible, and scattered to numerous
power outages are likely. This is without factoring in winds,
though. The heavy, wet snow, combined with the gusty winds in the
forecast, increases the potential coverage of power outages.

Rainfall and Ice: Rainfall amounts could be somewhat tricky as the
changeover from snow to rain will not happen all at once across the
forecast area. Higher elevations as well as eastern slopes/eastern
Vermont will hold onto snow a bit longer than other areas. Rain and
snowmelt are expected to cause river rises Wednesday into Thursday
night. At this time, the model trend is backing off river flooding,
but solutions continue to show actions and even minor flood stage as
a possibility. There remains the potential for some brief, isolated
freezing rain causing slick roads and slippery travel during the
changeover from snow to freezing rain, between 7 PM Tuesday and 1 AM
Wednesday as warm air moves in aloft and cold air (lows Tues night
in 20s and lower 30s) stays stubbornly in spots.

 

[Miller A]

The wind. The wind will be worst enemy along the coast

no snow pack and not as much rain reduces the threat her that NNJ will be facing there 

 

[ionizer]

what's the expected timing for peak winds on the NJ coast at the moment?

[SnowloverSid]

On 1/6/2024 at 1:28 PM, MaineJay said:

Incredible consistency on this.

Surface temps around 40 indicate CAD likely holding enough to keep the worst winds at bay, but this is a bit closer for comfort.

 

Of course there is consistency: it is an umbrella event. The difference is the amount of rain near the coast and in New England. Rainfall amounts are trending toward ordinary in Binghamton (probably just enough to melt snow). I fear that many trees could be uprooted in New England because of the winds and the inordinate amount of rain there in the last month.

[StretchCT]

850 Jet over SNJ.

I don't remember ever seeing 80+mph gusts this far from a storm center/non tropical.

 

[StretchCT]

NAM is nuts.

 

[Greenjacket]

NNJ forecast seems apocalyptic.  Saturated grounds, melting snow and a potential of another 2”+ of rain PLUS wind.   Is this really happening?

[clm]

52 minutes ago, StretchCT said:

NAM is nuts.

 

Is that the common core math?

What the heck is NAM drinking?

[MaineJay]

6 hours ago, StretchCT said:

850 Jet over SNJ.

I don't remember ever seeing 80+mph gusts this far from a storm center/non tropical.

 

And one might think that with a southerly wind that the south facing slopes get the worst winds, but it's actually on the backside (north slopes) that actually help translate winds to the surface *generally* getting the highest winds.

 

EPS says 3-6" thump, but thatI retain much of the snowcover, at least till the weekend.

[Wtkidz]

Long write up about the upcoming storm. From Sterling.

Quote

SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
A multi-hazard, high-impact weather event is all but expected across
the Mid-Atlantic Tuesday into Wednesday.

A powerful and highly amplified upper level trough over the Central
Plains pushes east toward the Eastern Seaboard Tuesday into
Wednesday. A rapidly deepening surface low over the Southern Plains
rapidly moves northeast toward the Great Lakes Tuesday, as a
secondary wave of low pressure develops over the northern Gulf Coast
and is swept up by a strong cold front rapidly pushing east. Ahead
of this complex, winds begin to increase Tuesday morning as the
pressure gradient across the region tightens. A wintry mix of
freezing rain and sleet is likely west of the Blue Ridge, with snow
focused west of the Shenandoah Valley from US-48 up toward the
Cumberland area. Heavy rainfall overspread the area Tuesday
afternoon into Tuesday night, likely leading to widespread flooding
issues. River flooding is also likely to occur given the heavy rain,
and addition of some snowmelt into the rivers upstream. Windy
conditions expected, with the strongest winds Tuesday evening.
Dangerous marine conditions expected Tuesday into Wednesday.

In terms of temperatures, very strong WAA in southerly flow is going
to rapidly bring temps to the 40s by early afternoon, then to the
50s and low 60s in the evening. Now for the impacts:

Wintry Mix: Winter Weather Advisories have been issued for the
Allegheny Front where confidence is highest in wintry precip. For
Highland and Pendleton the main threat will be a mix of freezing
rain and sleet, with ice accumulation of a few hundredths of an
inch, with possibly 1-2" of snow. To the north, there is good model
agreement in high snow rates resulting in heavy snow across portions
of eastern Garrett, western Allegany, western Mineral, and western
Grant Counties. Snow accumulations of 3-5" are likely, and some of
the spots could approach 6" of snow.

Freezing rain is possible in elevations above 1500 feet along and
west of the Blue Ridge, though confidence is low at this time. P-
type could end up as sleet or only very short duration freezing rain
with little to no impacts. Decision to let the upcoming day shift
decide if Winter Weather Advisories need to be expanded.

Heavy Rain: Very efficient warm-cloud processes are expected to
produce significant rainfall totals east of the Blue Ridge. This
system has all the ingredients - strong diffluence aloft, a deep
moist airmass originating from the Gulf of Mexico, record high
integrated water vapor transport (based on climatology) - to produce
widespread flooding, especially in urban areas. Widespread rainfall
amounts of 2-3" are expected, with higher amounts of 4" possible
along/east of the Blue Ridge. The foothills of the Blue Ridge could
see totals up to 5" given the strong convergent flow into the ridge.
To the west of the Blue Ridge, rain totals between 1.5-2.5".

Flood Watches have been issued for most of the area from Tuesday
morning through early Wednesday morning. The upcoming heavy
rainfall is likely to produce widespread flooding, with
significant urban and river flooding possible.

Strong Winds: An unprecedented LLJ is likely to develop over the
eastern half of the CWA Tuesday afternoon into Tuesday night as the
main surface low moves through. Current soundings from the GFS,
ECMWF, and NAM12 all have 50-70KT at 925mb, and 70-90KT at 850mb.
The evening sounding on Tuesday at IAD could break observed wind
records at 925mb, 850mb, and 700mb.

The main issue is going to be whether all of this wind mixes down to
the surface. Southerly wind events struggle to do this as warm air
aloft moving over a cooler surface airmass results in a stable
environment. However, given the strength and speed of this system,
strong pressure falls, and high precip rates, some of this wind
should mix down. The current thinking is winds gust to 40-50mph
along and east of I-95, with higher gusts possible along the
immediate Western Shore. A High Wind Watch has been issued for St.
Mary`s County, and this could be expanded north to other Western
Shore counties. Peak wind gusts occur between 4PM to 10PM Tuesday.

A Wind Advisory has been issued for the Allegheny Front on Tuesday
morning as winds ahead of the surface low gusts to 50mph.

Severe: While the environment is expected to remain stable, there
could be a narrow line of convection from Fredericksburg area into
southern MD that could mix down those wind gusts in excess of 60mph.

The cold front sweeps through the area Tuesday night, though some
showers and light rain linger into Wednesday morning. On the
backside mountain snow showers are expected to pick up Wednesday
morning and continue through Wednesday night. Snow accumulations
could reach Advisory level for parts of the Allegheny Front. Dry
conditions return to all except the Alleghenies by late Wednesday
morning. While strong winds decrease Tuesday night, then are
expected to pick back up late Wednesday morning and afternoon. Gusts
of 35-45 mph are possible, with up to 50mph in the higher
elevations. The upper trough finally moves east of the area
Wednesday night, bringing the return of calmer weather
conditions.

 

[JDClapper]

CTP first thoughts on the inland thump. Latest NAMs went a bit warmer, but its a gametime decision honestly. Earlier arrival would help for snow, 6z delayed til noonish here, rather than 10ish, when it was a degree warmer.

[MaineJay]

Very thump-y from GYX.  Guaranteed it's not the same consistency as the stuff on the ground now. 

 

[TheRex]

BTV's forecast discussion for this event.  They are expecting quite the wind event for the region.

 

Quote

Now, let`s go ahead and break down what we expected Tuesday and
Wednesday. To begin, let`s take a look at the synoptic pattern
before going into individual components and hazards. A deepening mid-
latitude cyclone is slated to track up the Mississippi River Valley
into the southern Great Lakes on Tuesday. Attached to this mid-
latitude cyclone will be an impressive cold front draping southward
with a warm front expected to lift across the Mid-Atlantic up into
New England. One minor change to the forecast this morning was to
warm temperatures slightly on Tuesday as the push of warm air
advection from the south continues to look more and more impressive.
The latest high-res guidance is beginning to see a frontal occlusion
and subsequent triple point low developing across the St. Lawrence
Valley which is the perfect location for a low for high winds events
in the North Country based off of case studies. The development of
this triple point low will only compact the pressure gradient
further and increase the confidence and likelihood of a significant
wind event across the region.

Let`s start off by talking about the winds because they will be by
far the most impactful part of the upcoming storm system. Now that
we are in range of high-resolution models, the signals for strong to
damaging winds gusts only continue to get better. Over the past
several nights, we have been using ensemble probabilities to increase
our confidence in these strong winds. The 00Z ensemble runs of the
GEFS and ECMWF show that much of our area is in a 60-90% chance of
seeing wind gusts above 50 mph with a 50-80% chance of seeing wind
gusts in excess of 65 mph along portions of the slopes of the
western Green Mountains. The gradient alone is expected to be enough
to produce widespread wind gusts in the 35 to 50 mph range but the
potential for a downslope wind event would have the ability to bring
near hurricane force winds to portions of the western Green
Mountains. One feature that has been lacking lately is an inversion
around 3000-4000 ft which would allow for winds to upslope over the
higher terrain and then crash back down to the surface. Well, the
latest NAM and even the end of the extended HRRR now shows this
signal for multiple places near the spine of the Green Mountain. The
overall wind threat hasn`t changed all that much, but our confidence
continues to grow. Loose objects, especially holiday decorations,
could easily be blown away or damaged with these winds so people are
encouraged to secure loose objects and prepare for high winds.
Looking back at historical analogs, events like this have produced
tens of thousands of customers without power due to downed trees and
powerlines.

The next hazard we will talk about will be the potential for heavy
wet snow at the onset of precipitation Tuesday afternoon. Snowfall
is now expected to start earlier in the day on Tuesday as the storm
system is slightly slower than before. This will likely yield
slightly less snow totals than before across the deeper valleys but
should be a prolific snow maker for the higher terrain of the
southern Green Mountains and northern Adirondack Mountains. We could
easily see 6-12" of wet snow above 2000 ft in the aforementioned
locations with 1-4" expected elsewhere across our forecast area.
Snow is expected to be brief for the lower elevations as snow will
quickly change to rain given very impressive warm air advection.
Still, we could briefly see 1-2"/hour snowfall rates as the warm
front/frontal occlusion lifts north across the North Country leading
to some impacts to the evening commute. Plus, any of this snow that
sticks to trees or powerlines would just exasperate the power outage
threat even further.

Last, but certainly not least, we are still monitoring for any flood
threats across the region. The good news is our rivers are at what
we call "base flow". This just means the rivers are low and have a
long ways to go before reaching flood stage. With around 0.75 to
2.0" of rain in the forecast Tuesday night through Wednesday coupled
with significant snow melt from this past event, sharp river rises
are expected. We have several models that output river forecasts and
probability of reaching flood stage but all these models keep our
rivers within bankful at this time. Sharp river rises are still
expected, nonetheless, and ponding of water on area roads due to
blocked drainage from this past snow event is still expected. We
will be monitoring this hydrology threat over the next few days and
provide updates if needed.

 

[MDBlueridge]

URGENT - WINTER WEATHER MESSAGE
National Weather Service Baltimore MD/Washington DC
352 AM EST Mon Jan 8 2024

MDZ001-501-081700-
/O.NEW.KLWX.WW.Y.0003.240109T0900Z-240109T1800Z/
Garrett-Extreme Western Allegany-
352 AM EST Mon Jan 8 2024

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM TO 1 PM EST
TUESDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations of
around an inch west of Keyser`s Ridge, with two to four inches
expected east toward Savage Mountain and Frostburg. Ice
accumulations of a few hundredths to around one tenth of an
inch. Winds gusting as high as 50 mph.

* WHERE...Garrett and Extreme Western Allegany Counties.

* WHEN...From 4 AM to 1 PM EST Tuesday.

* IMPACTS...Plan on slippery road conditions. The hazardous
conditions could impact the morning commute. Gusty winds could
bring down tree branches.

* ADDITIONAL DETAILS...Precipitation will overspread the area in
the predawn Tuesday. A wintry mix is expected through the
morning before a changeover to rain by afternoon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

When venturing outside, watch your first few steps taken on
steps, sidewalks, and driveways, which could be icy and slippery,
increasing your risk of a fall and injury.
 

[LUCC]

That's a lot of liquid for the entire US! This next storm is going to suck, so is the next one and the one after that if models don't change. 🙄

 

[MDBlueridge]

3 hours ago, JDClapper said:

CTP first thoughts on the inland thump. Latest NAMs went a bit warmer, but its a gametime decision honestly. Earlier arrival would help for snow, 6z delayed til noonish here, rather than 10ish, when it was a degree warmer.

These are classic for coming in front end loaded but I agree arrival time means a lot. 

My bet for down here is areas that saw 5"+ of snow will see huge flakes flying tomorrow morning. And the models (even 3K) are horrible with CAD. 

Edited January 8 by MDBlueridge

[clm]

 

Getting the high wind watch here too.  

High Wind Watch

URGENT - WEATHER MESSAGE
National Weather Service New York NY
403 AM EST Mon Jan 8 2024

NYZ075-078>081-176>179-081715-
/O.EXT.KOKX.HW.A.0001.240109T2300Z-240110T1100Z/
Kings (Brooklyn)-Northwest Suffolk-Northeast Suffolk-
Southwest Suffolk-Southeast Suffolk-Northern Queens-
Northern Nassau-Southern Queens-Southern Nassau-
403 AM EST Mon Jan 8 2024

...HIGH WIND WATCH NOW IN EFFECT FROM TUESDAY EVENING THROUGH
LATE TUESDAY NIGHT...

* WHAT...Southeast winds 30 to 40 mph with gusts up to 60 mph
  possible.

* WHERE...Kings (Brooklyn), Northwest Suffolk, Northeast
  Suffolk, Southwest Suffolk, Southeast Suffolk, Northern
  Queens, Northern Nassau, Southern Queens and Southern Nassau
  Counties.

* WHEN...From Tuesday evening through late Tuesday night.

* IMPACTS...Damaging winds could blow down trees and power
  lines. Widespread power outages are possible. Travel could be
  difficult, especially for high profile vehicles.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts and warnings for updates on this
situation. Fasten loose objects or shelter objects in a safe
location prior to the onset of winds.

[clm]

21 minutes ago, LUCC said:

That's a lot of liquid for the entire US! This next storm is going to suck, so is the next one and the one after that if models don't change. 🙄

 

So what you're saying is that the US is a lush?

Imagine if all/most of that was snow.

Edited January 8 by clm

[Wtkidz]

Well and so it goes…. IMBY

 

[telejunkie]

NAM not making too much of the precip field in these parts. I'll gladly take that...

 

Edited January 8 by telejunkie

[BossaNova]

Quote

Tuesday Night through Wednesday...

Placed all emphasis of the extended on this period of the forecast
as a high impact weather event is possible across southern New
England. Signals have continued to point toward this over the past
couple of days. A multi-faceted system is anticipated to bring
strong to damaging winds, heavy rain, coastal flooding and river
flooding. Could also have a quick front end thump, mainly across the
higher terrain, before ptype changes over to all rain.

Synoptic details...

A deep neutrally tilted trough will be located over the Lower/Middle
Mississippi River Valley Tue AM.  Low/Mid Mississippi River Valley
Tue AM. This will lift into the TN/OH Valley beginning to become
slightly negatively tilted Tue evening. The trough continues to lift
northeastward into the eastern Great Lakes/Mid Atlantic Wed
afternoon becoming negatively tilted. The trough lifts through by
Wed Night. A powerful frontal system lifts through southern New
England during this timeframe.

Wind Signals...

Confidence remains high for strong to damaging winds. In our latest
update have issued a High Wind Watch across roughly the I-95
corridor eastward and Storm Watches for the marine areas. The latest
NAEFS/EPS guidance still showing winds 5-6 STD above model climo
over the BOX area! The main timeframe that is highlighted is Tue
Night into early Fri morning period. During this timeframe a 60-90+
kt S/SSE low level jet slides through. At 925 hPa level
deterministic guidance progged to push a 40-80+ kt SSE/S jet
through. The big question that remains is how much of these winds
mix down, especially given the snowpack we just received could
hamper the amount of mixing within the boundary layer. The GFS/NAM
Bufkit soundings show 40-80 kts only 1 kft off the deck. Given the
melting snowpack due to rain will not be immediate have hoisted the
High Wind Watch generally over the areas where this is not an issue
and where am most confident. The EPS guidance continues to indicate
moderate to high probs (40-100%) of gusts AOA 50 kts across the
eastern MA coast. Further inland probs are low to moderate (<10 to
40%) from eastern CT into RI and eastern portions of central MA. The
EPS also still showing low to moderate (10-60%) probs of gusts AOA
64 kts across SE MA, Cape Ann and the waters. Not out of the
question there could be occasional Hurricane Force Wind gusts across
the ocean waters, but given the ocean SST we don`t tend to mix as
well over the waters with S/SSE flow.

Heavy precipitation...

As was the case over the past couple of days confidence also remains
high in heavy precipitation. Due to this have put up a Flood Watch
for much of southern New England as the combination of heavy
rainfall combined with the snowpack has the potential to result in
significant flooding. Interestingly, the risk for heavy downpours
appears to be over a relatively short period as there are signals of
a fine line working its way through Tue Night into early Wed.
Showing PWATs per the ensemble situational awareness table of 3-4+
STD above model climo over the BOX area. Generally looks like we get
into 1-1.5 inch PWATs, which is near or above record values for CHH
(per SPC Sounding Climo). Still seeing efficient warm rain processes
as warm cloud layer depths are roughly 8-10 kft, though do not have
much experience looking at warm cloud layer depths in Jan at this
latitude. The GEFS and EPS M-Climate continue to show much of
central/western southern New England nearing or over the max of
reforecast climo (going back to the early 2000s) with mean of 2" of
QPF. On top of this the ECWMF Extreme forecast index also hammering
a highly atypical event, especially across the CT River Valley where
some upslope component will enhance rainfall totals. At this point
anticipating widespread 1.5-3 inches of rainfall. Very concerned
given the snowpack we`ve got across the region. This will likely not
only impact the immediate flood risk, but also extended into river
flooding. Given these signals collaborated with WPC to include
portions of southern New England in the Moderate risk for excessive
rainfall.

River Flooding...

Given the precip anticipated in combination with rapidly melting
snow (as dew points will climb into the mid 40s to low 50s with the
rain and strong winds) will likely have river flooding as well. At
this point the MMEFS indicating several locations have a 30% chance
of exceeding minor flooding and a few having a 30% chance of
exceeding moderate.

Coastal Flooding...

Could still have an impactful coastal flooding event across the
region with the strong SSE/S flow, but need to really time the surge
of the strongest winds and pressure rise/fall couplet. Given there
is some timing uncertainty with the 2-4+ ft surge and if it
coincides with high tide have held off from any headlines at this
point. If there are impacts it could be for the Wed AM High tide.
This is something we will need to look at closer in future forecast
updates.

Snowfall...

Will have a brief opportunity for some accumulating snowfall across
the higher terrain areas Tue eve before precipitation changes over
to all rain. Given the higher impacts with the winds, rain and
flooding did not place a lot of emphasis in this area. Will see a
thump of accumulating snow across generally the higher terrain from
00-06Z, but should have most spots change over to all rain by 03Z.
There is some discrepancy with how quickly the warmer air gets in
with most guidance a being fairly quick. Given this uncertainty have
generally stuck with the NBM, but it is not out of the question that
Winter Weather headlines may be necessary for portions of the region
in later updates.

Some of the quoted disco from the regional NWS sites posted here this morning are downright ominous. Interestingly BOX hints that the snow here in SNE might help to mitigate the wind? That would be good news. The bad news - flood watches up for nearly all of CT, RI, MA, southern NH.

[LUCC]

36 minutes ago, clm said:

So what you're saying is that the US is a lush?

Imagine if all/most of that was snow.

A lot of it is, out west and up north....