March 12-15, 2023 | NE / Mid-Atlantic Winter Storm

[Poco]

It’s the time of year where we see trowal and inv trof type features, feels like it’s partly in the rise of closed lows barelling down from the north.  

3 minutes ago, MaineJay said:

It's funny how all these storms seem to have an inverted trof focus. All the best storms over here this winter have been like 24 hour affairs.  I hate relying on what I remember, because memory can be so selective.

It’s that time of year, was just opining the same thoughts the other day.    When you see the backward J in the nothern stream someone is gonna feel it 

[MaineJay]

Looks like there are blizzard warning in the upper plains associated with this system.  I know that's largely due to the winds, but hopefully it brings that kind of energy further east.

[Poco]

Let me post all 3 it’s pretty impressive look from Rausch 

[MaineJay]

4 minutes ago, Poco said:

Let me post all 3 it’s pretty impressive look from Rausch 

 

[Poco]

18z Nam at 84 has a band set up straight into nepa unlike gfs 

[telejunkie]

11 minutes ago, MaineJay said:

  I wonder if that ukie run had a bit of a double barrel low structure, but the cyclone tracking only picked up on the dominant low.

 Anywho, gotta be honest, was hoping to see more 970s solutions today.  Feeling like the weak solutions might have some real localized lollipops, whereas those stuck in the lighter stuff might get screwed. 

that's why I put track in parenthesis...cause there is definitely a lot more dynamics that the cyclone tracker can show. Double barrel seems about right.

I mean, it seems like trough is going negative, then pinching off...where and when is still to be determined, but think it'll have some strong forcing even it it's not 960s like models were showing in the past. I'm fine with 979 with a good track that brings subtropical moisture.

[Poco]

Nam much more compact with energy in sharper trof 

[telejunkie]

6 minutes ago, Poco said:

Nam much more compact with energy in sharper trof 

Still like the RGEM depiction more...southern stream energy much closer to our trough...need UT's praying portal for this one....

[Poco]

 

[Chinook]

I'm kind of fascinated by this coastal. It looks like Boston will reel in this low like an expert fisherman reels in a fish.

Edited March 11, 2023 by Chinook

[NEPAsnow]

18z control 

[StretchCT]

NBM being a Debbie Downer.  2.2 of that 3.7 imby is from tonight. 

NWS often uses this model.  Upton is being pretty low key about it so far. Another reason to be spooked. 

Spoiler

Precip could begin late Sunday night/early Monday AM, as a
rain/snow mix in the NYC metro area and along the coast and as
snow north/west, then transition to rain throughout by
afternoon, with some minor accumulations mainly NW of NYC. Precip
looks to be heaviest from late day Mon into Tue morning as the
low passes to the SE, and as an inverted trough extending NW
from the low interacts with the approaching closed low to the
west. How much snow falls and how far south going into this time
frame will ultimately depend on how much cold air the storm
itself can manufacture via dynamic cooling, and with the ECMWF
showing a low track farther west into New England than previous
cycles this is more in question for most of the metro area,
coastal sections, and SE CT. North and west of those areas the
potential remains for a heavy wet snow, especially across
interior NE NJ, the Hudson Valley north of I-287, and interior S
CT north of the Merritt Pkwy.

Boston is a little more bullish mentioning the possibility of a foot of heavy wet snow, most likely in the Berks and Worcester hills.  Also mentions the winds.

Spoiler

Monday night through Wednesday...

Deterministic and ensemble guidance indicating a potential
significant winter storm for this period, although as is expected in
a Day 3-5 forecast specific details remain uncertain. Coastal low
off the Mid Atlc coast is expected to deepen as it lifts northward
toward New Eng. While there is still considerable spread in storm
track, the GEFS/EPS/CMC ensembles are all clustered on a track to
vicinity of eastern New Eng Tue then slowing considerably as storm
gets captured by upper low with downstream blocking preventing a
quick exit. This will result in a long duration event.

Given that antecedent cold air will be lacking and cooling will come
from top down as heights fall, the highest prob of significant
snowfall will likely be confined to high elevations of Berkshires
and Worcester Hills. It`s too early to be talking specific accum at
this time range but ensemble guidance indicate high probs of more
than an inch QPF so potential for a foot or more of snow is on the
table for the high elevations. Given that this is likely to be a
heavy wet snow, there is concern for snow load issues and power
outages if these amounts come to fruition. More rain than snow is
likely near the coast and valleys and expect mainly rain Mon night
here. But as heights fall rapidly on Tue there could be a flip to
snow all the way to the coast but could also be dealing with
potential dry slot issues which will be dependent on exact track of
surface and mid level low so it will take some time to iron out
these details.

It does appear Mon night into Tue will be the brunt of the storm,
but snow will likely linger into Tue night with any rain near the
coast changing to snow as colder air deepens behind slowly departing
storm. Some improvement is expected Wed, but could see some
lingering light precip across eastern New Eng.

A period of strong wind is possible in eastern New Eng, especially
near the coast as fairly potent low level jet lifts north across the
region Mon night. Strong winds also likely on back side of storm Tue
night into Wed as storm pulls away.

Regarding coastal flood threat, astronomical tides are low but
potential for a 2-3 ft surge could bring areas of minor coastal
flooding to east coastal MA if the surge coincides with high tide.

 

[StretchCT]

Mt Holly for the record. May need winter storm warnings for the Poconos.

Spoiler

Sunday night, ridge axis passes east of New England while closed
low moves into the Great Lakes. Surface low accompanying the
upper low begins to weaken over the eastern Great Lakes while
new surface low pressure begins to take shape along the
Carolina coast. Warm advection precip will break out across
western areas, with precip likely across most of the area by the
time the sun starts to rise. Enough cold air looks present to
result in snow across the Poconos with some mixing into the
Lehigh Valley and north-central NJ, while further south, mainly
rain is expected along the I-95 corridor. Temps will drop into
the 30s for most, with 20s in the Poconos. Winter Weather
Advisories, at minimum, may be needed for the Poconos by this
time, but further south, uncertainty remains high regarding
snowfall.

Monday, upper low continues moving eastward across the lower
Great Lakes. The primary low drifts into southern Ontario as it
continues to weaken while the secondary low strengthens and
moves northward off the Virginia capes. Widespread rain is
expected for the majority of the forecast area, but the Lehigh
Valley may still have mixing issues at least in the morning
while the Poconos will struggle to mix over. Depending on the
exact low track, we may need winter storm warnings for the
Poconos, but this track is still uncertain given a fair amount
of model spread. Temperatures likely end up in the 40s from
I-95 south and east, possibly all the way to the Lehigh Valley,
but staying in the 30s in the Poconos.

Monday night, closed upper low pushes into far western New York
and northwestern Pennsylvania. Primary surface low will have
completely dissipated by this point as the secondary low off the
coast strengthens and moves northward towards eastern Long
Island. Rainfall will begin to taper off in the Delmarva,
possibly even into the Philly metro area, while further north
and east, cold air may start wrapping back south and allow rain
to change back to snow. Again, storm track will make all the
difference here, as if it stays a bit further east, precip may
end too soon for much changeover, while if it stays tucked in
too much, changeover will be difficult with warmer air nearer to
the low center. Temps may fall back toward freezing for many
areas, where as mentioned it may become a race between drying
and chilling.

BGM going right to the NBM - "Right now, the NBM 50th percentile shows the potential for 6-12 inches along and east of I-81 (locally 18" in the Catskills) with 3-7 inches west of I-81."

Spoiler

This period starts off with some light to moderate snow (or some
valley rain/snow mix) Sunday evening into Sunday night as an upper
level trough approaches from the west. Right now, QPF amounts look
to be around 0.10 to 0.20" Sunday night, and with snow to liquid
ratios (SLRs) 8-12:1, and surface temperatures in the upper 20s to
lower 30s snow amounts look to be only a coating to 2 inches.

On Monday, a closed 700 and 500mb low moves across lower Michigan,
becoming negatively tilted late in the day as it phases with some
southern stream energy. This looks to initiate surface cyclogenesis
near Cape Hatteras, with the low moving NNE along the coast and
deepening through the day. There remain model differences in just
how close this low will track to the coast; but guidance is starting
to hone in on a track east of the Delmarva by early Monday evening.
There is good ensemble support for a band of precipitation to
redevelop across eastern PA, and move north across most of CNY late
Monday into Monday night. As the surface low strengthens and drifts
north along the coast Monday night, the 700mb and 500mb low
strengthen and move right across our CWA. The low looks to become
nearly vertically stacked somewhere near Long Island or over CT
Monday night into Tuesday. With this low track, plenty of Atlantic
moisture would be wrapped around the well defined circulation back
into our area. Stuck close to the NBM guidance for PoPs, and WPC for
QPF...this gave categorical PoPs late Monday through Tuesday over
the eastern/northern half of the area. Thermal profiles, along with
added lift look cold enough to support mainly snow over our region
Monday evening through the end of the event; Tuesday night or
Wednesday. Currently the GFS remains further east with the low track
compared to the ECMWF and CMC...again there remains uncertainty in
the exact track this far out. Ensemble mean 48 hour QPF totals 7 AM
Monday through 7 AM Wednesday range from: 0.75 to 1.50 inches on the
12z ECS...highest over the Catskills...with 0.50 to 1.00 inches on
the GEFS and 0.70 to 1.4 on the CMC ens mean. So with these high QPF
amounts and snow ratios likely averaging out around 10:1 for the
whole system, snow amounts do have the potential to be quite high in
parts of the area. Right now, the NBM 50th percentile shows the
potential for 6-12 inches along and east of I-81 (locally 18" in the
Catskills) with 3-7 inches west of I-81. These amounts were surely
fluctuate, shift and change as we hone in on the details of the
system`s track and intensity. There is a significant range in
potential snowfall totals between the plausible 10th and and 90th
percentile scenarios. Current guidance has the snow finally tapering
off to lake enhanced snow showers on Wednesday, in a moderately cold
northwest flow, with 850mb temperatures around -7C. Northwest winds
will also become breezy to windy Tuesday night and Wednesday on the
back side of the low. Stay tuned for updates over the weekend on
this potentially impactful winter storm.

 

Edited March 11, 2023 by StretchCT

[StretchCT]

12z v 18z euro runs

[NEPAsnow]

nam is tucked in nice!!

[MDBlueridge]

5 minutes ago, NEPAsnow said:

nam is tucked in nice!!

Wow!

 

[MaineJay]

9 minutes ago, NEPAsnow said:

nam is tucked in nice!!

NAM seems to consolidate everything better than in previous runs.  Trof is trying to swing negative a bit earlier as well.

Last 3 runs.

[StretchCT]

8 minutes ago, NEPAsnow said:

nam is tucked in nice!!

Big jump 

[MDBlueridge]

2 minutes ago, MaineJay said:

NAM seems to consolidate everything better than in previous runs.  Trof is trying to swing negative a bit earlier as well.

Last 3 runs.

 Man that's the look

Paste job

[Lazman]

I'll be sitting this one out. Driving to Charleston, SC on Sunday, for my 31st Anniversary until the following weekend. My first Anniversary it took us about 14 hours to get home from OCMD, because it was the SOTC. Hoping NOT to repeat that scenario again, but WHO knows what evil lurks in that NAMBINO? 

Here's to hoping you have something worthwhile to track, and raise your totals for this PATHETIC Winter. 🥂❄️☯️🦖

Edited March 13, 2023 by Lazman

[Sentinel]

00z Euro 

[NEPAsnow]

with the better ridging out west I would suspect this comes west a bit, but who knows

[MaineJay]

12 minutes ago, NEPAsnow said:

with the better ridging out west I would suspect this comes west a bit, but who knows

I think there's additional considerations.  The more southern part of the storm is a very, and I do mean very, subtle ripple in the flow, especially at H5.

This piece southern piece shows up better at H7, and it out runs the more impressive, more northern energy.  Exactly where, but more importantly when, it exits the eastern seaboard determine the early track.  It gets to far out ahead, and it'll need to be reeled in as @Chinooknoted.

  In some nice past storms, we see energy lingering near OBX, waiting for the more energetic northern energy to strengthen it, and bring it up, along the coast. 

  Second part of the track will be determined by the incoming trof, and as you noted, the western ridge will play a role there.

   This storm isn't currently progged to deepen rapidly after it's initial east coast exit, instead it likely occludes and spins itself out somewhat.  So I think we can expect that initial front end thump, associated with a TROWAL and some good frontogenesis.

  After that initial development, I'd expect a dry slot to begin spiraling in, and the precip shield to take on some swiss cheesiness. Pockets of heavy stuff, but highly variable intensity.

Additional semi pertinent info as I ramble on.

There's occasionally lee side cyclogenesis coming off the Rockies.  The highest peaks reach to almost 600mb, I imagine these aspects are related. Plenty of Colorado reaches 700mb, so the actual low level (even mid level) circulation barely even exists yet.

 

[NEPAsnow]

[Poco]

12z nam