Pattern Magnificent March

[Rain Cold]

It's a stale Arctic air mass modified by March sun. But it's a winter storm pattern...

We need us a good 300dm ULL. Do they still make those?

 

[pcbjr]

I agree, I think that's the only way anyone from NC south outside of higher elevations would get more than 1" of snow out of this pattern, and I see no potential for that to happen at this point. It's a non-zero chance, sure, but for most of us I wouldn't give it more than a 10% probability and probably not even that for most outside of the climo favored areas of Upstate SC and western Piedmont of NC (outside of the mountains).

I also think one thing that can sometimes trip people up looking at H5 analogs is they forget or just don't fully consider that you are comparing a snapshot in time, but not considering the path that got you to that point. What happened in the week leading up to that point? Where did your air mass originate from and what kind of snowpack was laid down out ahead of it. This stuff matters significantly for us in January, and all the more so in March.

So damn well said ... Thanks!

 

[Tarheel1]

I hope I’m allowed to post this here in the March thread...

 

[Jon]

I also think one thing that can sometimes trip people up looking at H5 analogs is they forget or just don't fully consider that you are comparing a snapshot in time, but not considering the path that got you to that point. What happened in the week leading up to that point? Where did your air mass originate from and what kind of snowpack was laid down out ahead of it. This stuff matters significantly for us in January, and all the more so in March.

Interesting. I don’t know anyone who does what you’re saying lol. But I agree — usually analogs aren’t just storm specific but pattern-specific, meaning one would consider many things including what happened leading up to the storm, base state, etc.

For example....



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[ForsythSnow]

I agree, I think that's the only way anyone from NC south outside of higher elevations would get more than 1" of snow out of this pattern, and I see no potential for that to happen at this point. It's a non-zero chance, sure, but for most of us I wouldn't give it more than a 10% probability and probably not even that for most outside of the climo favored areas of Upstate SC and western Piedmont of NC (outside of the mountains).

I also think one thing that can sometimes trip people up looking at H5 analogs is they forget or just don't fully consider that you are comparing a snapshot in time, but not considering the path that got you to that point. What happened in the week leading up to that point? Where did your air mass originate from and what kind of snowpack was laid down out ahead of it. This stuff matters significantly for us in January, and all the more so in March.

Definitely agree about the time frame. We're going to be in March, and BL will be a big issue many will overlook and think rates will overcome, but how can rates overcome about 2 to 3 thousand feet? They just can't especially when the surface is in the upper 40s and the 925 layer is in the upper 30s. The only way as mentioned for something widespread is for something uncommon to happen that causes all levels to support snow, which I can't see happening at this time.

 

[Webberweather53]

Definitely agree about the time frame. We're going to be in March, and BL will be a big issue many will overlook and think rates will overcome, but how can rates overcome about 2 to 3 thousand feet? They just can't especially when the surface is in the upper 40s and the 925 layer is in the upper 30s. The only way as mentioned for something widespread is for something uncommon to happen that causes all levels to support snow, which I can't see happening at this time.

This exact "uncommon" scenario played out in early December when many were counting out much snow to begin with because BL, ground, and low-level temps were too warm, etc. and we know how that shook out

 

[ForsythSnow]

This exact "uncommon" scenario played out in early December when many were counting out much snow to begin with because BL, ground, and low-level temps were too warm, etc. and we know how that shook out

However, that was a different setup. We had a good storm from a large +PNA and eastern trough. In addition, the surface was in the 30s and the 925 layer was a few degrees above freezing at most. Here, it's a different scenario with a -NAO bringing the trough down. Is it impossible? No, but it's not likely we see a big system like December, especially after December.

 

[Webberweather53]

However, that was a different setup. We had a good storm from a large +PNA and eastern trough. In addition, the surface was in the 30s and the 925 layer was a few degrees above freezing at most. Here, it's a different scenario with a -NAO bringing the trough down. Is it impossible? No, but it's not likely we see a big system like December, especially after December.

Actually, the temperatures weren't just a few degrees above freezing, they were about +5C (~8-10F above freezing) between the 925 hPa layer and the surface before the precipitation began around 12z on December 7th according to soundings conducted in Atlanta, which is very difficult to overcome. The above freezing layer was fairly deep and extended up to 800mb (~6500 feet above ground level). By 0z on the 8th some precipitation had already began and the layer was already cooling but was still several degrees above freezing. The snowfall climatology of the southeastern US in early December is comparable to mid-March.

 

[ForsythSnow]

Actually, the temperatures weren't just a few degrees above freezing, they were about +5C (~8-10F above freezing) between the 925 hPa layer and the surface before the precipitation began around 12z on December 7th according to soundings conducted in Atlanta, which is very difficult to overcome. The above freezing layer was fairly deep and extended up to 800mb. By 0z on the 8th some precipitation had already began and the layer was already cooling but was still several degrees above freezing. The snowfall climatology of the southeastern US in early December is comparable to mid-March.
View attachment 4163
View attachment 4162

That's until 0Z on the 8th, or late at night on the 7th. It didn't change over until around 12Z, or some time after sunrise here. ATL was some time later I believe.

 

[Webberweather53]

That's until 0Z on the 8th, or late at night on the 7th. It didn't change over until around 12Z, or some time after sunrise here. ATL was some time later I believe.

By 12z, some cooling of the layer had already taken place due to evaporation, melting of hydrometeors & sensible heat transfer. The point is the near-surface warm layer was several times larger in breadth and magnitude than you were willing to admit and the actual sounding data confirms this. There's a big difference between "a few degrees above freezing" and nearly 10F above and a layer that's only "2000-3000 feet deep" and one that's 6000-7000 feet deep which was observed in Atlanta. Also have to remember the balloon trajectory in this case was to the northeast towards the cold side of the storm with southwesterly flow aloft, arguably the near-surface layer is a tad warmer and deeper than the sounding advertises over Atlanta.

 

[GaWx]

As much as I've been trying to divert the discussion from too much excitement about winter storm potential this March so as to avoid potential disappointment & the resulting whining that would inevitably follow, it hasn't worked. All we know just about for sure is that it will cool down substantially from the current torch of torches.

 

[ForsythSnow]

As much as I've been trying to divert the discussion from too much excitement about winter storm potential this March so as to avoid potential disappointment & the resulting whining that would inevitably follow, it hasn't worked. All we know just about for sure is that it will cool down substantially from the current torch of torches.

I've been trying to help as well, but unfortunately it seems to not be working. They'll learn some day that the big March cool down doesn't always mean snow.

 

[Webberweather53]

As much as I've been trying to divert the discussion from too much excitement about winter storm potential this March so as to avoid potential disappointment & the resulting whining that would inevitably follow, it hasn't worked. All we know just about for sure is that it will cool down substantially from the current torch of torches.

I've been trying to help as well, but unfortunately it seems to not be working. They'll learn some day that the big March cool down doesn't always mean snow.

I'm looking back in this thread and trying to find any posts that reference any particular winter storms in early-mid March but apparently I'm missing something. Almost the entire discussion is geared towards the large-scale pattern & climatology

 

[Jon]

I'm looking back in this thread and trying to find any posts that reference any particular winter storms in early-mid March but apparently I'm missing something. Almost the entire discussion is geared towards the large-scale pattern & climatology

The excitement in this thread is out of control apparently. Missed on me as well.

I’ll leave this here, again, because people don’t get it.

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[Webberweather53]

It took longer than expected due to ENSO interference, a sudden stratospheric warming event, wave breaking in the EP, TCs and EQ Rossby Waves in the SW & WP respectively augmented by the EQBO, but the MJO is going to finally enter phase 1 & 2 w/ no problem.

 

[Webberweather53]

These freezing rain and freezing rain/thundersleet climatology graphics (from Chris McCray) are pretty sick. 10 ish annual hours of freezing rain w/ about one long duration event per season sounds about right here in RDU.

 

[GaWx]

I'm looking back in this thread and trying to find any posts that reference any particular winter storms in early-mid March but apparently I'm missing something. Almost the entire discussion is geared towards the large-scale pattern & climatology

I don't disagree. But there's a lot of talk about potential that I think will translate to a winter storm being deemed likely in some people's minds. I'm already predicting that if the first half of March ends up cold dominated without a significant winter storm in much of the area that there will be plenty of whining about it getting cold with little wintry precip. despite no winter storm being predicted.

 

[whatalife]

Nice paste bomb on the Euro control...only a matter of time before models have fantasy storms, then you’ll see about 100 posts in an hour here lol

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The excitement in this thread is out of control apparently. Missed on me as well.

I’ll leave this here, again, because people don’t get it.

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I’m sure this doesn’t help in getting people to excited.


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[Webberweather53]

The excitement in this thread is out of control apparently. Missed on me as well.

I’ll leave this here, again, because people don’t get it.

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Yeah beats me (as well as HM) apparently discussing a favorable long range pattern, how/why it's evolving a particular way, and the actual climatology of RDU & the I-40 corridor automatically means we're expecting a snowstorm to occur in this period, lol.

I don't disagree. But there's a lot of talk about potential that I think will translate to a winter storm being deemed likely in some people's minds. I'm already predicting that if the first half of March ends up cold dominated without a significant winter storm in much of the area that there will be plenty of whining about it getting cold with little wintry precip. despite no winter storm being predicted.

I don't disagree with that at all, we see it every winter at every turn even when the modeled pattern absolutely sucks. It's equivalent to when people perceive most or every atmospheric scientist as an on-air Television broadcaster, or get flustered when there's an opportunity for scattered thunderstorms and they remain high & dry. It's an integral part of the public's perception of atmospheric science to anticipate absolutes when we provide probabilistic distributions, large-scale patterns, and occasional deterministic values particularly in the short range. There's often a major disconnect in communication and inherent intent even between well seasoned enthusiasts and mets.

 

[Jon]

I’m sure this doesn’t help in getting people to excited.


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If that gets folks rocks off it’s not really my problem. I was more or less doing a two things:
1. Justifying the pattern in general supports a storm on the eastern seaboard
2. Poking fun at model run-to-run model watchers who continue to slide into my DM’s telling me the runs have been warm (they’ve since piped down) and the fact that, for some reason, people need a fantasy storm on an Op for “proof” a pattern is capable of producing which I think is coming hence my 100 posts an hour comment.



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