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

[StretchCT]

12z EFI again showing unusual atmospheric conditions

[StretchCT]

BOX disco “absurd 105k jet at 925mb.” 

Spoiler

Latest suite of deterministic and ensemble model guidance are in
good agreement for a robust low-pressure system to impact The
Northeast Tuesday night into Wednesday. Unlike the system we will
experience this weekend, this system is forecast to take an inland
track which is likely to support an event that will be entirely
rainfall. Though temperatures may be cold enough ahead of the storm
to allow a brief front end thump of snowfall prior to a change to
rain. Model guidance is hinting at exceptionally strong QG forcing
for ascent with rapid height falls over the region. This combined
with anomalously high moisture will set the stage for a significant
rainfall event. 100 member LREF ensemble is already indicating a 30
to 60 percent chance of 2+ inches of rain in 24 hours over portions
of RI and the CT River Valley. With a fresh snow pack in place, this
may introduce some flood concerns along areas and river in streams.
The multi-model hydrologic ensemble (MMEFS), is already indicating a
30 percent chance of several river gauges reaching flood stage next
week. In addition to the rain/flood threat, this storm will be
packing a dynamic punch with a very impressive wind field. The 12Z
deterministic GFS is resolving an absurd 105 knot jet at 925 hPa
over The Gulf of Maine at 12Z on Wednesday. Even if we take the more
practical long term probabilistic approach, ensemble probabilities
of 850 hPa winds exceeding 80 knots are 20 to 50 percent over the
east coast and east coastal waters. Thus, we may be looking at a
significant wind thread in addition to the rain/flooding threat.
Furthermore, the strong southerly flow is likely to produce a storm
surge that could introduce some coastal flood concerns to the south
coast. We`re well outside of the time range of our surge models, so
really know early predictions as of yet as coastal flood forecasts
are heavily dependent on surge/high tide timing. We`ll be ironing
out all the details as confidence in this forecast grows late
this/weekend early next week.

 

[SnowloverSid]

Wednesday’s max in Binghamton has been raised from 40 to 46, only three degrees shy of the daily record high for January 10. It is the only sub-50 record max fin January, the other two being in early February. A 46-degree rain would leave the area with bare ground and mud— yuck.

[StretchCT]

Max gusts from 12z gfs today -keep in mind it's in kts.  60 kts is 69mph.

[Undertakerson2.0]

So, where does this go? 

[StretchCT]

We have an outlook for excessive rainfall/flash flooding from WPC

 

Edited January 6 by StretchCT

[StretchCT]

Some qpf maps - up to and over 4.5" on some

Edited January 6 by StretchCT

[StretchCT]

5 minutes ago, Undertakerson2.0 said:

So, where does this go? 

Passaic river

[MaineJay]

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.

 

[MaineJay]

Oops, I clicked back a frame, this is the same time stamp at the 850 winds. Mid 40s are more concerning.

[MaineJay]

These pink dots near the outer Banks and DelMarVa suggest we are at the extreme of climatology when it comes to wind gusts.

[MainelySnow]

3 hours ago, MaineJay said:

These pink dots near the outer Banks and DelMarVa suggest we are at the extreme of climatology when it comes to wind gusts.

We do not need a repeat of 12/17.  Without power for 4 days, was so glad to finally shut off the generator and have silence.  We lost 3 80 ft pines and there are going to be a lot of trees that survived that storm, but barely, that won't withstand another, especially with saturated ground.  Gonna be an interesting week...

 

[Jon Snow]

Reading through the NWS forecast discussion from Blacksburg, Va, for this time peroid.  I hope they know their attempts at a little humor here and there is appreciated. 

 

But wait; there`s more. Model forecast soundings from around the
region are saturated (understatement) and the overall thermodynamic
profile isn`t great. At all. However, strong wind fields will allow
plenty of wind shear to be present. This could pose a risk of strong
wind gusts with any convection. Right now, the location of the
convective risk will be dependent on where a northward-moving warm
front ultimately ends up. Right now, this risk appears to be much
greater farther south of our area. But we will continue to monitor.

[ionizer]

Can we start getting some wind model forecasts?  Worried about the winds for central NJ coast.

[MaineJay]

6 hours ago, ionizer said:

Can we start getting some wind model forecasts?  Worried about the winds for central NJ coast.

I used Toms River.

Looks like 25-35mph winds. Gusts are 50-60mph.  I would note the operational is by far the weakest winds of the bunch.  Hopefully the core of the winds are on the move, with little residence time over any one area.  With such a strong low level jet, it certainly needs to be watched.

[MaineJay]

GYX

Quote

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
The focus on the long term remains fixed on the passage of a multi-
hazard storm system crossing mid-week. While seasonable high
pressure will start the week... conditions are expected to
deteriorate Tuesday night through Wed with heavy rain, heavy
snow, strong to damaging winds, and coastal inundation/erosion
(see dedicated section below) all possible for the area.

The broad model suite continues to show stronger than normal
agreement on the general timeline and evolution of a low
pressure system presently over the PacNW. The system is progged
to drop through the Rockies on its way to the central and
southern Plains, where it will begin to ingest significant
moisture before shifting NE through the Ohio Valley... maturing
in the process. The primary low pressure circulation is progged
to cross well west of New England as it occludes, however a
peripheral lobe of vorticity has consistently shown itself in
model guidance and supports secondary triple point low
development closer to the coast which throws a wrench in the
otherwise ordinary inland-runner.

The inland low promotes the development of a strong
southeasterly LLJ around 80-90 kts which is the main driver of
impacts centered on late Tuesday night into Wednesday. This is
forecast to be a progressive system, with the jet crossing the
area in relatively quick order... providing around a 6-9 hour
period of impacts. Generally speaking, inland lows typically
lead to greater inroads of warm and moist air through the low
levels, which in turn supports a quicker changeover from snow to
rain, strong to damaging wind potential, and a greater moisture
influx leading to heavy rain. On the other hand the eastern
component of the low pressure circulation will help to steady
the CAD over portions of the interior for longer... leading to
more snow and staving off the worst of the winds in those
locations. The balance between these is the primary source of
uncertainty WRT to the geographical distribution of impacts.

For winds... model guidance has been steady and consistent in
bringing 45-60 mph maximum wind gusts on average to coastal
areas up to about the I-95 corridor. Similar gusts are projected
to occur in the northwest-facing downslopes and adjacent
valleys north of the mountains, from the upper Connecticut River
Valley across through the Rangeley Lakes region and to
Moosehead. Ultimately the strength of the jet will determine the
high-end potential for winds, with some of the higher outlier
solutions suggesting a few gusts near 70 mph... however for now
confidence is greater in 45-60 mph winds. Areas most likely to
remain sheltered from these stronger winds are the lakes and
foothills regions south of the mountains, and down through the
interior of southern New Hampshire owing to unfavorable boundary
layer lapse rates. Though, when the system`s cold front crosses
and mixing improves later in the day, southwesterly gusts to
25-35 mph or so will be possible anywhere.

For QPF... models are fairly well clustered in the 1.5-2.5 inch
range, with highest totals over the foothills and into the
mountains as the jet ascends over the CAD and up the higher
terrain. Higher QPF solutions are generally tied to warmer
scenarios... since the overall model suite has generally trended
a little cooler, I wouldn`t necessarily hang my hat on those
higher solutions. Other than the terrain-enhancement, there is
also a signal for an axis of higher precipitation totals over
portions of the southern interior where moisture convergence is
at its maximum. Given this is expected to be mostly rain here,
and there will be around 0.75-1.0 inches of liquid equivalent on
the ground from today`s snowfall, this could offer a pretty
messy start to Wed with potential for flooding. This general
threat of flooding due to rain over frozen grounds combined with
snow melt is present for much of the interior, reflected in a
marginal risk for excessive rainfall across all of Maine and
most of New Hampshire... though we`ll likely be able to hone in
on more specific locations as the forecast process progresses.

Perhaps a bigger question is what ends up falling as rain vs
what falls as snow. Most locations, besides the NH Seacoast and
nearby areas, are forecast to start the event Tuesday evening as
snow. As southeasterly flow ramps up upon the approach of the
LLJ, the rain/snow line will make its way inland and
northward... with most folks, at least in the urban corridor,
experiencing rain when they wake up Wed morning. Further north
in the CAD area, mostly confined to the higher elevations of
northwestern Maine, snow is more likely to hold through the
morning... with some mixed precipitation before an ultimate
transition to rain. Though, some of these places especially
toward the upper Kennebec basin may only see a brief period of
rain before steady precipitation ends altogether. Snowfall
totals thus run the gamut from hardly-anything (that melts by
the time the sun rises)... to a sloppy couple-to-few inches over
the interior, capped with a bout of rainfall... and up to a
foot or more in the mountains, ending as lighter mixed or liquid
precipitation. Similar to winds, the strength of forcing will
determine the high end potential of snowfall totals, but for
most people the timing of the transition to rain will determine
snowfall totals with plenty of uncertainty left there.

For all its potential hazards, this system is at least fairly
fast- moving with the dry slot quickly cutting in behind the
system during the afternoon and through the evening hours...
bringing a quick end to steady precipitation and a westerly wind
shift. The upper level low swings through the area afterward
with mountain snow showers into Thursday before high pressure
briefly builds in. Another storm approaches for the weekend but
with widely varying solutions.

 

[Wtkidz]

1 hour ago, MaineJay said:

GYX

 

Nice write up. 

[Wtkidz]

Not to be out done. LWX (Sterling) write up

this way we cover the north and the south. 😜

Quote

A powerful storm system is likely to impact the entire region
Tuesday into Tuesday night. A highly amplified mid/upper trough over
the Central Plains pushes eastward toward the MS Valley. A
tremendous amount of upper diffluence will cause a surface low to
develop and rapidly deepen as it tracks from the lee of the Rockies,
across the Central Plains and central Great Lakes. A secondary wave
of low pressure develops near the northern Gulf Coast, and is
scooped up by the larger low to the north. As the entire complex
pushes east, very strong WAA advection and an associated strong cold
front are likely to bring significant impacts to our area.
Temperatures ahead of this system shoot up to the 50s to low 60s.

Wintry Mix: A residual cold air mass ahead of this system will
likely result in a wintry mix of snow and freezing rain for areas
west of US-15 Tuesday morning. Some snow accumulation and ice
accretion are possible in the higher elevations west of the Blue
Ridge. The strong synoptic forcing is going to help produce a quick
burst of wintry precip, then strong WAA quickly transitions all p-
type to rain by late morning.

Heavy Rain: A period of moderate to heavy rain is likely to
overspread the area Tuesday afternoon and evening, with the heaviest
rain east of the Blue Ridge. Widespread rain amounts of 1.5-2.5" are
currently forecast, though given the strong moisture flux, deep
moist airmass, and strong diffluence, those totals could certainly
end up higher. This heavy rainfall could lead to urban and river
flooding.

Strong Winds: The kinematic profile with this system is very
concerning as all models indicate a strong LLJ overspreading the
area east of the Blue Ridge. Current soundings from the GFS, ECMWF,
and NAM12 all have 50-70KT at 925mb, and 70-90KT at 850mb.
Generally, southerly wind events have a hard time mixing down fully
in this area, but even if just half of that wind reaches the
surface, it could result in numerous instances of wind damage. Over
the waters, this means Gale conditions are likely, and could
possibly approach storm force (gusts of 50KT or greater).

Continue to monitor the progress of this system in the coming
days.

 

[MaineJay]

Stout LLJ

[MaineJay]

Never seen anything like this. First frame is hr 240, yeah, there's a little wiggle early, but this is one week of runs. Incredible consistency.

[StretchCT]

25 minutes ago, MaineJay said:

Never seen anything like this. First frame is hr 240, yeah, there's a little wiggle early, but this is one week of runs. Incredible consistency.

 

Consistency between models too. Here's the latest qpf. The placement and amounts are generally all in line.  Of course todays storm had that too at one point but didn't work out for me.  

[StretchCT]

Max gusts from latest runs.

[StretchCT]

Even the NBM has gusts 40-60mph

[JDClapper]

Looking through some early Tues AM 2m temps, dews, 700mb fronto .. does seem to be a legit chance at a quick 1-3" in the interior of PA and especially north on the front end of this one.  I know it's not the main impact from this one (Rain/flooding/winds), but hey... could be dicey for an hour or two on the wintry side for some.

[NotInKansasAnymore]

Watching this one carefully in Hunterdon County, NJ. I have 2-3 inches of very heavy, wet slush on the ground and 3+ inches of rain will make for a big mess here. The heavy rain right before Christmas led to school cancellations because our country roads all flood out. We also have a lot of sideways trees left over from Sandy - wet ground and high wind will cause a lot of outages.