Feb 22nd/23rd "There's no way..." Storm Thread

[WEATHER53]

2 hours ago, stormtracker said:

Still seems decent.  Seems a bit more progressive.  

Hey what did you decide to do ?

[jayyy]

Euro AI is slowly getting there

[MN Transplant]

1 minute ago, Eskimo Joe said:

That storm gives me PTSD. 

That was the most exaggerated difference between my house and downtown.  Seeing Cantore on the mall with nothing and 4" of absolute paste in my yard was unreal.

[Yeoman]

5 minutes ago, mappy said:

And we’re so glad that after years of lurking you made an account in December 

He was formerly teninchjohnson

[MN Transplant]

Just now, WxMan1 said:

Yeah, it's all about the backside cold conveyor belt (CBB) and deepening Trowal zone, and for us near/within the beltways, I think we're gonna want much of that action after 22Z. Rain or just white rain before that. 

Interesting, I keep seeing IVT tossed around (integrated water vapor transport). Usually a term used with ARs (Atmospheric Rivers), but we certainly to see these plumes here in the East. Analogous to a PW axis, theta -e axis, TROWAL, -- merely another tool to show that there's good moisture pooling/isentropic ascent upstairs. 

Our snow here in the cities will be completely tied to that CCB/Trowal/IVT or backside deformation axis. Any QPF before that is dead to me, but perhaps not to folks well N and W of the fall line.

Setting my bar here in central AA pretty low for now, 2-4" with the wrap around and heavier rates. 

Pretty sure everyone here is using IVT wrong.  I also know it as you stated, but I think people here are using it as shorthand for inverted trough.

[EastCoast NPZ]

7 minutes ago, WxUSAF said:

I think something like 2-6” is a reasonable call for the metro area right now. More for the beaches. Potentially a screw zone somewhere in between?

Or west of the cities 

[WxUSAF]

Just now, MN Transplant said:

Pretty sure everyone here is using IVT wrong.  I also know it as you stated, but I think people here are using it as shorthand for inverted trough.

Yes, not integrated vapor transport 

[NorthArlington101]

2 minutes ago, MN Transplant said:

That was the most exaggerated difference between my house and downtown.  Seeing Cantore on the mall with nothing and 4" of absolute paste in my yard was unreal.

My recall is only 1-2" in my corner of Arlington, so some big gradient differences. Perhaps I'm a little low.

[WEATHER53]

2 hours ago, arlwx12 said:

Slightly updated wording from LWX's AFD at 1029...

 

If the upstream ridge-building event takes place a bit further west
near 120 W longitude on Saturday, downstream trough amplification
would be favorable for phasing over the mid MS Valley into the OH/TN
Valleys Saturday night. A subsequent low track hugging the coast
would become more likely in this scenario, aided by downstream
blocking and a potential source of cold air given the upper lows
over Maritime Canada and surface high pressure attempting to ridge
into northern New England. There is also an appearance of an
inverted trough signature in a subset of model guidance over the
last couple cycles, given interaction between a more amplified
northern stream wave and a bit more distant offshore southern stream
low. This could factor into precipitation amounts and placement.

After reviewing the 00z model guidance suite, some subtle
consistency has been noted although subtle uncertainty remains. Most
of the models has a low tracking up from GA/AL toward the NC
coast and off the Delmarva coast during the late Saturday night
into late Sunday timeframe. The question remains in the proximity
toward the coast along with cold air availability, and the overall
scope of the precip shield pending the placement/intensity of the
system. 25 to 50 miles could make a huge difference between seeing
little to no wintry precip or impactful precip, especially for those
east of the mountains where the confidence remains low due to
thermal issues especially below elevations of 1500 feet. The 00z
GFS/GEFS solutions have come down a tad, but still produce
measurements on the order of 10+" of snow over a large chunk of the
area. Meanwhile, the 12z EPS ensembles came up some, but at much
more conservative levels which align with deterministic runs of the
NAM, RDPS, GDPS, GEM, CMC, EURO/EURO AIFS, and UKMET. The
latest NBM also came up a bit and aligns with the majority
compared to the GFS/GEFS outliers, especially along and east of
I-95. With that said, the 6/12z model suites should put the
remaining puzzle pieces together as we will sit 60 hours from
the event.

Three scenarios remain:

 1) The phase of all of these upper level features occurs too late,
  with low development offshore and too far southeast.

 2) Similar to scenario 1, but an inverted trough on the back side
of the low brings snow to eastern portions of the region.

 3) Low develops closer to shore and strengthens along Delmarva
Peninsula, resulting in the most snow for our areas.

We still remain in the "wait and see" period with this storm, so
just take precautions now, should the worst case scenario play out.
Having a preparedness kit stocked up is never a bad idea.

Lastly, no matter what plays out further east, it seems much more
likely that the mountains will see another round of upslope
snow. The key here will be with how much we manage to get. That
will depend on the storm track as well, but it seems much more
likely for at least advisory to perhaps warning level
accumulations through the Sunday/Monday period along/west of the
Allegheny Front. Of note, the higher sun angle later in the
season becomes a factor especially for lower elevations if
precip occurs during the day. Cold air will also be filtering
into the region as the storm in question approaches, rather than
being locked-in beforehand, which offers another layer of
uncertainty in p-type.

It’s fine to admit you flat out don’t know when you don’t.  They are honest about that.  WhenI said it will all come down to 6 hours before onset I was not kidding

[Grothar of Herndon]

10 minutes ago, LeesburgWx said:

I’m accept. Even at 7-8:1

Basically as long as it is snow let's accept it. I mean several days ago getting even 1" seemed out of reach except for the GFS which we have little of no faith in...most of the time. 

[NorthArlington101]

9 minutes ago, WxUSAF said:

Yeah but it’s still improved over 0z. Other guidance is all very good for the beaches.

Yeah, I take back what I was saying a little bit about the 12z EURO. The inverted trough/CCB/whogivesa improved and that was most of our improvement, BUT the coastal did genuinely improve, though it mostly mattered looking further up the coast. You have to call it a bit of a cave... we need a lot more, though. Feeling like a NJ/LI jackpot at the moment.

[Yeoman]

14 minutes ago, rjvanals said:

IVT. 

2026 weenie term of the year award by a landslide

[DDweatherman]

Just now, NorthArlington101 said:

Yeah, I take back what I was saying a little bit about the 12z EURO. The CCB (if that's what we're calling it now) improved and that was most of our improvement, BUT the coastal did genuinely improve, though it mostly mattered looking further up the coast. You have to call it a bit of a cave... we need a lot more, though. Feeling like a NJ/LI jackpot at the moment.

The euro is making nice incremental h5 shifts every other run. That was the best h5 look yet, but the surface isn’t quite as beefy to correspond. 

[WxMan1]

5 minutes ago, Eskimo Joe said:

That storm gives me PTSD. 

Ah yes, that was the "Snowquester" of March 6, 2013. If you recall, sequester was in the news at that time, because of the lapse of government funding. At NCEP we use the term 'snowquester' because for us near the cities, We got nothing more than a rain snow mix because of the marginal temps. 

But this is important: We never got in on that backside CCB or deformation "death band" either. That's the key. That's what made 3/17 2014 (or 2015) so good for us along and east of I95. That and the fact that it fell at night. Waking up St Patrick's Day morning with 8.5" of snow on the ground was pretty sweet, and a great way to end a solid winter that year. Both 2013-14 and 2014-15 were good for us, well above climo. 

[Nomz]

2 minutes ago, Yeoman said:

2026 weenie term of the year award by a landslide

What about recon

[NorthArlington101]

Just now, DDweatherman said:

The euro is making nice incremental h5 shifts every other run. That was the best h5 look yet, but the surface isn’t quite as beefy to correspond. 

I would've bet we'd been dead 2 days ago so I could be wrong but seeing the GEM/EURO all on a pretty similar wavelength makes me think we gotta almost be done with them trending toward the GFS. They still really aren't close as far as getting hammered on the day Sunday.

[brooklynwx99]

20 hours ago, brooklynwx99 said:

this is either going to be the best or the worst model performance i've ever seen (probably worst but hey it's fun to look at)

well, fuck me

[wxmvpete]

7 minutes ago, WxMan1 said:

Yeah, it's all about the backside cold conveyor belt (CBB) and deepening Trowal zone, and for us near/within the beltways, I think we're gonna want much of that action after 22Z. Rain or just white rain before that. 

Interesting, I keep seeing IVT tossed around (integrated water vapor transport). Usually a term used with ARs (Atmospheric Rivers), but we certainly to see these plumes here in the East. Analogous to a PW axis, theta -e axis, TROWAL, -- merely another tool to show that there's good moisture pooling/isentropic ascent upstairs. 

Our snow here in the cities will be completely tied to that CCB/Trowal/IVT or backside deformation axis. Any QPF before that is dead to me, but perhaps not to folks well N and W of the fall line.

Setting my bar here in central AA pretty low for now, 2-4" with the wrap around and heavier rates. 

Think the IVT here is "inverted trough". To be fair to you though, with all the EROs we write and referring to the IVT in that way so much, I totally get why you took it that way haha.

I share similar thoughts. With the lack of a really cold air-mass, areas along I-95 will rely heavily on rates for anything during the day. Unless you have elevations from like the Catoctins, Bull Run Mountains, Parrs Ridge/far northeast MD, or you are directly beneath the CCB, this is going to be treated like a typical late season storm. 1.) how much snow is falling near/after sunset? 2.) Are you living at a higher elevation? 3.) Is guidance showing you beneath the CCB? 

If you answer all 3 as yes, you are in good shape at the moment. 2 of the 3 at least gives you decent odds of some accumulating snow. 1 of the 3, probably need some help somewhere along the way meteorologically via track or banding. 0 of the 3 speaks for itself.

[bncho]

2 minutes ago, DDweatherman said:

The euro is making nice incremental h5 shifts every other run. That was the best h5 look yet, but the surface isn’t quite as beefy to correspond. 

the surface deception will increase at an exponential rate as the h5 gets better. that's why the last 3-4 Euro runs were quite similar at the surface, but a similar shift in h5 improved it by a decent margin! if we get another one of those I bet it'll be a lot better.

[Lowershoresadness]

5 minutes ago, Yeoman said:

2026 weenie term of the year award by a landslide

"kicker" says no way

[DDweatherman]

3 minutes ago, NorthArlington101 said:

I would've bet we'd been dead 2 days ago so I could be wrong but seeing the GEM/EURO all on a pretty similar wavelength makes me think we gotta almost be done with them trending toward the GFS. They still really aren't close as far as getting hammered on the day Sunday.

To be fair, I’m still expecting 1-2” IMBY. I like the trends but so much fail potential. 
That said, to assume the euro isn’t going to go west more or show more improvement at h5 after the move it just made may not be wise.

[WxMan1]

When temperatures are marginal, it's all about the rates as you all know. Strong ULL and higher rates leads to more diabatic cooling from both melting and evaporation, in the absence of the cold, drier air funneling in isallobarically at low levels like we see in good CAD setups. 

We get the band set up, we get the rates with those clumping aggregates, then we can accumulate at 7, 8, maybe 9-1 SLRs with surface temps of 32.3-33.0. The whole column cooling to the freezing point. 

However, you don't get those rates then you just get a lighter rain snow mix, 33-34F. It will be that drastic of a difference. 

Good luck with that forecast! 

[yoda]

19 minutes ago, Winter Wizard said:

That IVT has a January 2011 or February 2014 flavor. 

I don't remember those... could you give a brief summary?  Or anyone that knows 

[cbmclean]

4 minutes ago, bncho said:

he surface deception

Dang Euro with its surface deceptions...

[Maestrobjwa]

1 minute ago, Nomz said:

What about recon

Recon isn't exactly a weenieism as more sampling as we get closer can give the models more data and give them a slightly better picture of things.

[Cobalt]

AI EPS much wetter than 6z, 0.9" QPF at DC compared to 0.6".  

[Paleocene]

3 minutes ago, yoda said:

I don't remember those... could you give a brief summary?  Or anyone that knows 

I don't remember 2014, but the 2011 was the 'commuteaggedon' puke/paste job which left people stranded on i-66 and elsewhere for many hours.

[baltosquid]

Wall to wall improvements at h5 for 12z. Do we get the extra nudge or two that makes the models more GFS like? Unlikely, but to be fair, even getting to this point was unlikely. 

[wxmvpete]

The EC-AIFS ensembles have been pretty darn good in the days 3-5 range. To see that much of an amplification change inside of 72 hours (model trend over the last 5 runs, starting with yesterday's 12Z run) from the onset of precipitation speaks to how intricate these 500mb disturbances working together can change so much. Any subtle amplification and change in axial tilt can make or break a forecast. Throw in marginal boundary layer temps and this is about as challenging a forecast for not just totals but potential impacts as it gets.

[Eskimo Joe]

8 minutes ago, wxmvpete said:

Think the IVT here is "inverted trough". To be fair to you though, with all the EROs we write and referring to the IVT in that way so much, I totally get why you took it that way haha.

I share similar thoughts. With the lack of a really cold air-mass, areas along I-95 will rely heavily on rates for anything during the day. Unless you have elevations from like the Catoctins, Bull Run Mountains, Parrs Ridge/far northeast MD, or you are directly beneath the CCB, this is going to be treated like a typical late season storm. 1.) how much snow is falling near/after sunset? 2.) Are you living at a higher elevation? 3.) Is guidance showing you beneath the CCB? 

If you answer all 3 as yes, you are in good shape at the moment. 2 of the 3 at least gives you decent odds of some accumulating snow. 1 of the 3, probably need some help somewhere along the way meteorologically via track or banding. 0 of the 3 speaks for itself.

Matches my thoughts well. Coating to 2" for I-95, 2" - 4" immediate suburbs, 4" - 6" in the elevation favored areas, maybe a few 6"+ reports if you get a combo of the three items you listed above. Amazing how we're tripping into this event. First time in awhile I've seen the GFS take the lead on anything.