ATL: Tropical Depression Edouard

[coreyl]

Will it continue moving slowly across the gulf?

[Category 5]

TCHP is not on its side.

[RL3AO]

Bertha became a cat 3 in that dark blue stuff.

[Steve]

>>TCHP is not on its side.

I don't think it's a big deal though as far as what the most-likely (IMHO see S2K disclaimer above) end-game potential is. If we're talking a TD/TS, that deep water isn't as important for development. There's plenty enough heat to sustain a tropical entity if not so much a giant, 2005-like Cat 5 like Rita or Wilma.

Steve

[LaBreeze]

That's the latest prediction to my understanding, coreyl. We'll have to keep an eye on it.

[Johnny]

Hey Ed, not updates from JB lately?

[MGC]

The GOM is plenty warm to support a hurricane. Heat content will not be an issue. Dry air will be. I don't see a depression out of this till tomorrow afternoon if then. 91L might just drift along like its twin did last week......MGC

[Ed Mahmoud]

Hey Ed, not updates from JB lately?

None since this morning. He is on a road trip to Houston.

He should be in town in case we do get a TD or TS.

[ROCK]

OHC is much higher in the Caribbean than the Gulf.


I have always been of the opinion, maybe mistaken, that for weak systems, that don't cause a lot of severe wave action, or fast moving systems, that don't linger over the upwelling they have produced, OHC isn't as important as sea surface temperature, which, based on my petroleum engineering knowledge of equilibrium gas/liquid systems, would mean higher partial pressure of water vapor near surface.


Of course, for a lumbering or strong system, depth of the 26º isotherm and OHC are more important. A slow moving Cat 5 like Mitch would quickly starve itself in the Gulf.

Well Ed, not saying your mistaken however I have always looked to this map to determine MHP of a tropical entity regardless of the 26 degree isotherm. Not that I totally discount it however Dr. Emanuel does have some sound data to come up with these maps....

http://wind.mit.edu/~emanuel/pcmin/pclat/pclat.html

[ROCK]

The GOM is plenty warm to support a hurricane. Heat content will not be an issue. Dry air will be. I don't see a depression out of this till tomorrow afternoon if then. 91L might just drift along like its twin did last week......MGC

Looks pretty moist to me given the lastest WV loop...


http://www.ssd.noaa.gov/goes/east/gmex/loop-wv.html

[ROCK]

don't be surprised if convection totally disappears overnight, only to refire tomorrow

as on cue the tops are warming somewhat....good call Derek..

[MGC]

Well Rock we must be looking at different satellite loops. I see a swath of quite dry air pushing off the mouth of the Mississippi headed right towards 91L. I'm quite certain this dry air will get entrained into any fledging circulation that is down in the GOM tonight....MGC

[Ed Mahmoud]

OHC is much higher in the Caribbean than the Gulf.


I have always been of the opinion, maybe mistaken, that for weak systems, that don't cause a lot of severe wave action, or fast moving systems, that don't linger over the upwelling they have produced, OHC isn't as important as sea surface temperature, which, based on my petroleum engineering knowledge of equilibrium gas/liquid systems, would mean higher partial pressure of water vapor near surface.


Of course, for a lumbering or strong system, depth of the 26º isotherm and OHC are more important. A slow moving Cat 5 like Mitch would quickly starve itself in the Gulf.

Well Ed, not saying your mistaken however I have always looked to this map to determine MHP of a tropical entity regardless of the 26 degree isotherm. Not that I totally discount it however Dr. Emanuel does have some sound data to come up with these maps....

http://wind.mit.edu/~emanuel/pcmin/pclat/pclat.html

Don't have a PhD in any subject, or a met degree, however, Emanuel is talking about Maximum Intensity Estimation. Or a potential. You can grow stronger cyclones in the Caribbean, all else being equal. Since we aren't expecting (I hope) a major storm, which would upwell cooler surface waters through wave action (and increase evaporative cooling of the sea surface through wind and reduced atmospheric pressure), we aren't dealing with a maximum possible intensity. With perfect atmospheric conditions and time to strengthen, can get stronger storms over high OHC. But we are talking a system that will never (we hope) approach maximum intensity its OHC would allow.


Note that generally weak systems, through non-major hurricanes, seem able to strengthen up to landfall on the Texas coast. Major hurricanes are usually weakening. The two places in the US that have experienced Cat 5 landfalls, Mississippi coast and South Florida, are close to water in excess of 50 KJ/cm^2

[ROCK]

Well Rock we must be looking at different satellite loops. I see a swath of quite dry air pushing off the mouth of the Mississippi headed right towards 91L. I'm quite certain this dry air will get entrained into any fledging circulation that is down in the GOM tonight....MGC

quite possibly though 91L does have a nice envelope to work with attm.

[Bailey1777]

MGC,

NHC I expect see the now and future pretty well, why would they say conditions seem favorable if they are not?

[Bailey1777]

Also if you watch the w/v you see the environment is fixing to get alot moister alot of moisture coming down from the north.

[HouTXmetro]

Will the storms pushing South off the Northern Gulf Coast mingle with 91L?

[Ed Mahmoud]

Bed time.


While cloud tops have warmed some, at least through now, no poof-ation, much of the clouds are -50ºC, and a new burst with tops colder than -60º seems to be starting on the Northern edge of the blob.


It may poof overnight, but it may not. Pressures not screaming down, no East wind where I'd expect one to be, except Ram Powell offshore platform, and it isn't a NOAA buoy. But it seems to be maintaining convection.

Off to post image of 0Z Canadian (very similar to 12Z Canadian) on model thread, than bed time.

[ROCK]

OHC is much higher in the Caribbean than the Gulf.


I have always been of the opinion, maybe mistaken, that for weak systems, that don't cause a lot of severe wave action, or fast moving systems, that don't linger over the upwelling they have produced, OHC isn't as important as sea surface temperature, which, based on my petroleum engineering knowledge of equilibrium gas/liquid systems, would mean higher partial pressure of water vapor near surface.


Of course, for a lumbering or strong system, depth of the 26º isotherm and OHC are more important. A slow moving Cat 5 like Mitch would quickly starve itself in the Gulf.

Well Ed, not saying your mistaken however I have always looked to this map to determine MHP of a tropical entity regardless of the 26 degree isotherm. Not that I totally discount it however Dr. Emanuel does have some sound data to come up with these maps....

http://wind.mit.edu/~emanuel/pcmin/pclat/pclat.html

Don't have a PhD in any subject, or a met degree, however, Emanuel is talking about Maximum Intensity Estimation. Or a potential. You can grow stronger cyclones in the Caribbean, all else being equal. Since we aren't expecting (I hope) a major storm, which would upwell cooler surface waters through wave action (and increase evaporative cooling of the sea surface through wind and reduced atmospheric pressure), we aren't dealing with a maximum possible intensity. With perfect atmospheric conditions and time to strengthen, can get stronger storms over high OHC. But we are talking a system that will never (we hope) approach maximum intensity its OHC would allow.


Note that generally weak systems, through non-major hurricanes, seem able to strengthen up to landfall on the Texas coast. Major hurricanes are usually weakening. The two places in the US that have experienced Cat 5 landfalls, Mississippi coast and South Florida, are close to water in excess of 50 KJ/cm^2

I am quite aware of the reasoning behind these maps though I suspect Emanuel did include sst's into his equation. As noted in his paper, he did say that TC's hardly never achieve their MHPI b/c of some of the factors you described above.....his maps express the maximum potential that a certain area can support.

to each his own I guess...

[Wx_Warrior]

Dry air eatin' it up