ATL: MARCO - Remnants - Discussion

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SoupBone
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#601 Postby SoupBone » Thu Aug 20, 2020 4:27 pm

wxman57 wrote:Remember, the models that accelerate it northwestward are relying on a stronger tropical storm (that's farther north to start with). I expect big changes with this forecast over the next day or two.


Could you possibly be any more cryptic? :lol:

If I recall in previous discussion on this system, slower, less consolidated, etc., models were showing it crashing into Tex/Mex.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#602 Postby eastcoastFL » Thu Aug 20, 2020 4:27 pm

Very nice shot of both systems


Image
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#603 Postby wxman57 » Thu Aug 20, 2020 4:28 pm

xironman wrote:I could definitely see the coc migrating northward to the best convection.


Maybe, but it would require persistent strong convection near that mid-level rotation.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#604 Postby storm_in_a_teacup » Thu Aug 20, 2020 4:32 pm

Feel free to delete if too off topic but...

How do you know so much without being an actual meteorologist? Like, I looked up potential vorticity, and that's some real physics stuff. The only subject I can talk about at such a high level is astrophysics, but I actually am in that field.


GCANE wrote:
Kingarabian wrote:
lrak wrote:

So the potential vorticity streamers break up the Rossby wave and helps the storm to strengthen? Or if a Rossby wave is not occurring then they weaken the storm? Thanks....

Would love to answer your question but it's out of my pay grade. Maybe GCANE can answer.


PVS's are basically small elongated upper level vorts in about the 300mb to 200 mb level. That is the about the top of the troposphere. Because they are so high, they don't have updraft. Its actually the opposite, they create downdraft, sinking air, subsidence. So if there is a LL vort and a PVS gets over it, the PVS pushes down on the vort column and the vort spins less. Its the opposite of an anticyclone which allows the vort column to stretch vertically and spin faster.

PVS's come from many features such as TUTTs, Rossby Waves, UL Eddy's, etc. Sometimes its hard to figure out where they come from and how they evolve. The air is very thin up there, so they are very volatile. Many things can quickly effect them, especially strong convection. For a strong PVS and weak convection, the PVS wins. For a weak PVS and strong hot tower, the hot tower wins.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#605 Postby GCANE » Thu Aug 20, 2020 4:37 pm

Seeing the highest unflagged rain rate so far was measured at 47 mm/hr.
This is definitely not falling apart.
Likely tonight or just before sunrise, the upper troposphere should be at its coolest which will fire off strong towers.
That would be the best chance to get vorts back in shape.
Saw earlier today that there was a large population of towers with high helicity.
So, there still should be a lot of angular momentum built up in the atmosphere.
One or two big towers could grab that and get the vort down to the surface.
This is the W Carb, I have seen Cat 1's go to Cat 5's in the matter of a couple days.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#606 Postby GCANE » Thu Aug 20, 2020 4:39 pm

storm_in_a_teacup wrote:Feel free to delete if too off topic but...

How do you know so much without being an actual meteorologist? Like, I looked up potential vorticity, and that's some real physics stuff. The only subject I can talk about at such a high level is astrophysics, but I actually am in that field.


GCANE wrote:
Kingarabian wrote:Would love to answer your question but it's out of my pay grade. Maybe GCANE can answer.


PVS's are basically small elongated upper level vorts in about the 300mb to 200 mb level. That is the about the top of the troposphere. Because they are so high, they don't have updraft. Its actually the opposite, they create downdraft, sinking air, subsidence. So if there is a LL vort and a PVS gets over it, the PVS pushes down on the vort column and the vort spins less. Its the opposite of an anticyclone which allows the vort column to stretch vertically and spin faster.

PVS's come from many features such as TUTTs, Rossby Waves, UL Eddy's, etc. Sometimes its hard to figure out where they come from and how they evolve. The air is very thin up there, so they are very volatile. Many things can quickly effect them, especially strong convection. For a strong PVS and weak convection, the PVS wins. For a weak PVS and strong hot tower, the hot tower wins.


I do have an undergrad degree in physics. Post grad in engineering. Every now and then I pick up a few met papers and try and decipher them. Some of the best ones are from Dr Montgomery, Naval Grad School.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#607 Postby aspen » Thu Aug 20, 2020 4:46 pm

The tropics are messing with us. There are not one, but two newly formed and struggling TDs during a favorable MJO, with TD14 in the most favorable environment of the two. They’re really testing our patience.

It still seems like TD14 will be the first to fully get its act together, and I expect a named storm out of this no later than tomorrow night.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#608 Postby storm_in_a_teacup » Thu Aug 20, 2020 4:46 pm

GCANE wrote:
storm_in_a_teacup wrote:Feel free to delete if too off topic but...

How do you know so much without being an actual meteorologist? Like, I looked up potential vorticity, and that's some real physics stuff. The only subject I can talk about at such a high level is astrophysics, but I actually am in that field.


GCANE wrote:
PVS's are basically small elongated upper level vorts in about the 300mb to 200 mb level. That is the about the top of the troposphere. Because they are so high, they don't have updraft. Its actually the opposite, they create downdraft, sinking air, subsidence. So if there is a LL vort and a PVS gets over it, the PVS pushes down on the vort column and the vort spins less. Its the opposite of an anticyclone which allows the vort column to stretch vertically and spin faster.

PVS's come from many features such as TUTTs, Rossby Waves, UL Eddy's, etc. Sometimes its hard to figure out where they come from and how they evolve. The air is very thin up there, so they are very volatile. Many things can quickly effect them, especially strong convection. For a strong PVS and weak convection, the PVS wins. For a weak PVS and strong hot tower, the hot tower wins.


I do have an undergrad degree in physics. Post grad in engineering. Every now and then I pick up a few met papers and try and decipher them. Some of the best ones are from Dr Montgomery, Naval Grad School.


I guess I could do that...once research stops making my brain too tired to read papers in other fields :lol:
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#609 Postby Steve » Thu Aug 20, 2020 4:55 pm

hurricanehunter69 wrote:What a gorgeous storm. This thing is coming together beautifully! 2 days over the NW Caribbean...…..Good Luck! https://www.star.nesdis.noaa.gov/GOES/s ... &length=24


it does look like a bad*** little system.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#610 Postby St0rmTh0r » Thu Aug 20, 2020 5:00 pm

wxman57 wrote:If it is lacking a low-level circulation center, then it may not be as strong as predicted over the next 48-72 hours, and it may not be picked up by the trof as easily. May still track into Mexico. It does appear to have a vigorous mid=level circulation. Perhaps a LLC will eventually develop beneath it.

It looks like it has a LLC. Why would they say it's a depression?
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#611 Postby GCANE » Thu Aug 20, 2020 5:09 pm

Big popups firing over land indicating very unstable air.
Being compressed by the Rossby Wave and TD14 outflow.
TD14 will track into this.

Image
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#612 Postby catskillfire51 » Thu Aug 20, 2020 5:12 pm

GCANE wrote:Big popups firing over land indicating very unstable air.
Being compressed by the Rossby Wave and TD14 outflow.
TD14 will track into this.

https://i.imgur.com/iFfWwAd.png


That should help right?
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#613 Postby GCANE » Thu Aug 20, 2020 5:16 pm

That convection inside the Rossby Wave seems to be weakening it.
Its getting less red.

Image
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#614 Postby GCANE » Thu Aug 20, 2020 5:17 pm

catskillfire51 wrote:
GCANE wrote:Big popups firing over land indicating very unstable air.
Being compressed by the Rossby Wave and TD14 outflow.
TD14 will track into this.

https://i.imgur.com/iFfWwAd.png


That should help right?


To strengthen TD14, yes.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#615 Postby xironman » Thu Aug 20, 2020 5:30 pm

St0rmTh0r wrote:
wxman57 wrote:If it is lacking a low-level circulation center, then it may not be as strong as predicted over the next 48-72 hours, and it may not be picked up by the trof as easily. May still track into Mexico. It does appear to have a vigorous mid=level circulation. Perhaps a LLC will eventually develop beneath it.

It looks like it has a LLC. Why would they say it's a depression?


Because recon did not find TS winds.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#616 Postby GCANE » Thu Aug 20, 2020 5:41 pm

Donut filled back in.
Good example how volatile PVS's are.
Top of the troposphere cooling off now.
Keep an eye out for some big towers that might fire.

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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#617 Postby Frank P » Thu Aug 20, 2020 5:41 pm

Well the last few vis sat loops hints of building convection near what I perceive as a possible center, and perhaps a hint of a more northerly component as well.. banding In the SE quad also appear to be improving.. all in all not too shabby for a TD in the grand scheme of things...
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#618 Postby aspen » Thu Aug 20, 2020 5:44 pm

GCANE wrote:Donut filled back in.
Good example how volatile PVS's are.
Top of the troposphere cooling off now.
Keep an eye out for some big towers that might fire.

https://imgur.com/DqsMxYl

Good timing too. Dmax is not far off, so this might be an excellent opportunity for TD14 to try and fully close off its circulation and become Laura.
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#619 Postby sphelps8681 » Thu Aug 20, 2020 6:09 pm

So in another group I am in (not a weather group) someone posted these two storms could combine and make one. I am like no in my mind. Maybe one will be dominant and make the other weaker but combining is not likely. What do ya'll say?
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Re: ATL: FOURTEEN - Tropical Depression - Discussion

#620 Postby tarheelprogrammer » Thu Aug 20, 2020 6:12 pm

sphelps8681 wrote:So in another group I am in (not a weather group) someone posted these two storms could combine and make one. I am like no in my mind. Maybe one will be dominant and make the other weaker but combining is not likely. What do ya'll say?


I say cocaine is a hell of a drug :lol:

Jokes aside, that is highly unlikely and probably impossible. METS please clarify.
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