Jump to content
  • Member Statistics

    17,604
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

1/28 - 1/30 Storm Thread II


burgertime

Recommended Posts

Phil, I'm taking it this is that tail showing up in the west on the NAM. When that get's absorbed I know you say that is allowing a deeper trough. Is that because it's juicing up that northern energy sitting over TX?

 

I'm not really making a thermodynamic argument here (in regards to added moisture), but rather dynamical. When you get a shortwave interacting with another piece of energy, the two areas of cyclonic vorticity naturally impact motion of each other due to their flow at the respective level.

 

Think of it as a poor man's example of interaction of two tropical cyclones close to each other, which rotate around each other at a common center point if they are of equal intensity. In this case, the tiny piece of vorticity imparts a weak but not negligible motion of the vorticity associated with the stronger shortwave trough, causing it to dig further south. In the meantime that little piece of vorticity gets advected northward and absorbed by the strong mid-latitude shortwave. However, by this point, the damage has been done, and it has altered the initial course that stronger shortwave would have taken had that piece of vorticity not existed. 

Link to comment
Share on other sites

  • Replies 2.4k
  • Created
  • Last Reply

Just wanted to say thanks for all the people that have put so much time and insight into this storm. I am still learning and don't half understand 80% of what you folks are saying but it sure is fun to learn.

 

I would like to echo Gray's appreciation of the comments about this storm.  The temps are dropping quite well here in SEVA and look forward to seeing the outcome Wednesday.

 

Stay safe out there all of you looking at ice!

Link to comment
Share on other sites

So can someone explain what the effect of the baja piece of energy moving east at a faster rate could be?

 

If it moves far enough east, its circulation associated with the vorticity will have the ability to interact with the circulation imparted by the vorticity of the stronger shortwave, causing a mutual interaction. This impact could cause the stronger shortwave to sink further southward, while absorbing the weaker baja shortwave. A deeper shortwave would likely lead to a downstream strengthening of the ridge, which will advect more moisture into the southeast, but also cause mid level thicknesses to rise. In this case the 850 hPa isotherm will also shift north leading to more people in the midlands getting sleet / freezing rain rather than snow. 

Link to comment
Share on other sites

I'm not really making a thermodynamic argument here (in regards to added moisture), but rather dynamical. When you get a shortwave interacting with another piece of energy, the two areas of cyclonic vorticity naturally impact motion of each other due to their flow at the respective level.

 

Think of it as a rudimentary example of binary interaction of two tropical cyclones, which rotate around each other at a common center point if they are of equal intensity. In this case, the tiny piece of vorticity imparts a weak but not negligible motion of the vorticity associated with the stronger shortwave trough, causing it to dig further south. In the meantime that little piece of vorticity gets advected northward and absorbed by the strong mid-latitude shortwave. However, by this point, the damage has been done, and it has altered the initial course that stronger shortwave would have taken had that piece of vorticity not existed. 

 

You lost me at rudimentary

 

XIMQ1Qj.gif

 

In all seriousness though, you're saying that this is helping with a more south trend by affecting it's rotation? If that's wrong don't bother I'll just take your word for it. 

Link to comment
Share on other sites

You lost me at rudimentary

 

XIMQ1Qj.gif

 

In all seriousness though, you're saying that this is helping with a more south trend by affecting it's rotation? If that's wrong don't bother I'll just take your word for it. 

 

Haha sorry... just saying this is a poor man's example of +vort maxes interacting with one another. Only difference is that one vort max (the northern stream shortwave) is much stronger than this feeble piece of energy (the much weaker local +vort max), so it quickly absorbs the weaker feature, but not before shifting slightly further south due to the minor influence of the flow by the weaker feature.

Link to comment
Share on other sites

I think I'm one of the only ones on this board hoping for a partial phase at most.

 

Even the 18z GFS has 850 temps close and has a ton of sleet through the midlands.

NAM starts as sleet, but goes back over to snow pretty quickly.

Euro EPS looks great for KCAE.  Almost every member is honed in with 4-6 inches with some being much higher.

Link to comment
Share on other sites

Haha sorry... just saying this is a poor man's example of +vort maxes interacting with one another. Only difference is that one vort max (the northern stream shortwave) is much stronger than this feeble piece of energy (the much weaker local +vort max), so it quickly absorbs the weaker feature, but not before shifting slightly further south due to the minor influence of the flow by the weaker feature.

 

No worries! Again this is why you get paid to do this. I always love reading your post when you stop in because even if I have to use google I've learned something. I'm liking my odds in south Charlotte...but I feel like I'm going to be on that sharp line of a good snow and a great snow. 

Link to comment
Share on other sites

Haha sorry... just saying this is a poor man's example of +vort maxes interacting with one another. Only difference is that one vort max (the northern stream shortwave) is much stronger than this feeble piece of energy (the much weaker local +vort max), so it quickly absorbs the weaker feature, but not before shifting slightly further south due to the minor influence of the flow by the weaker feature.

 

Thanks for putting this in English for me Phil.  I've been on these boards for 10 years and man did I feel dumb reading that first reply.  Good seeing you on the SE forum again and thanks for the insight!

 

Btw, burger your reply cracked me up because I was thinking the same thing.

Link to comment
Share on other sites

So, for us in the foothills, do WE want the northern energy to pick up that baja low? Would that produce more precip to the west at all or only cause it to move further south?

 

More expansive precip North (huge amounts of snow for whoever has supportive 850mb temps).  KCAE would be ruined with an ice storm most likely.  Phil touched on this noting how the mid levels would involve more warm air for further Northern areas than the coast at that point.

Link to comment
Share on other sites

Instead of two equal cyclones, imagine one is stronger than the other. The momentum of the stronger piece rotating counterclockwise around pulls them both further south. As the stronger piece rotates around, it gets released and tossed out ahead of the slower piece, but by then we're a notch further south. Close Phil?

Link to comment
Share on other sites

So, for us in the foothills, do WE want the northern energy to pick up that baja low? Would that produce more precip to the west at all or only cause it to move further south?

 

its nice to have Phil back, but i am with burger i think i was lost at rudimentary lol.  my understanding was that the interaction will move it farther south, and am guessing near the gulf could bring in some more moisture if it gives pushed far enough, but the draw back is along with the increased moisture and strength warmer air may work in to part of the system above the colder arctic air and give sleet over snow to some of those areas

 

ps. if so, is this what the models have been having such a hard time with getting the interaction, if any, and the result of that interaction

Link to comment
Share on other sites

So, for us in the foothills, do WE want the northern energy to pick up that baja low? Would that produce more precip to the west at all or only cause it to move further south?

 

The northern stream is not going to pick up the southern wave in its entirety, at-least not in enough time to matter.  It would appear based on guidance some energy gets ejected out, current WV supports this, question is how much.  More energy would likely lead to to more moisture slung back west, this has been addressed countless times over the past several days.  

 

I am here to do some cross thread trolling ;).

 

This post is approved!

Link to comment
Share on other sites

Instead of two equal cyclones, imagine one is stronger than the other. The momentum of the stronger piece rotating counterclockwise around pulls them both further south. As the stronger piece rotates around, it gets released and tossed out ahead of the slower piece, but by then we're a notch further south. Close Phil?

 

I think you are on the right track! You can definitely think of it from a momentum perspective, where the stronger vort max imparts more motion on the weaker vort max. This was a concept we had to illustrate in one of my synoptic labs last year. Think of it in terms of the animation below:

 

http://www.atmos.albany.edu/student/ppapin/output/atm511/vortsame_output.html

 

You have two pieces of +vorticity of equal intensity. In the absence of any other features or flow (like coriolis force) these features will rotate symmetrically around each other at a common point because of the counterclockwise flow associated with each vorticity maximum (see images below).

 

piecewisesame_inversion_0.png

 

piecewisesame_inversion_1.png

 

However, when one becomes stronger than the other, it will likely absorb the smaller feature, but not before adjusting its initial position to account for the flow from the smaller feature. This is an example of what we saw today, except in the real world (which is far more complicated, but on a basic level is the same process). 

Link to comment
Share on other sites

It seems Robert has ventured out a bit on his own.  Precip arriving in the western carolinas in the morning and then spreading through VA, s MD, and DE.  I don't know anyone else saying this.  I think he also said he'd be shocked if Hickory only ended up with 1" - I think most everyone else has Hickory at dusting to 1" if that.  So, I'm hoping he posts a snowfall map for us so "stake his claim."   If he ends up right, I think he has separated himself from the pack - again!

TW

Link to comment
Share on other sites

Hay man we need you down here to take some good video. You always seemed to find the best part of the storm.

 

Yeah I will be this weekend on a visit, just a few days too late. I always make it my goal to find worst conditions and document them.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...