ATL: IRMA - Post-Tropical - Discussion

[KWT]

Wow Aric that internal shot is VERY impressive. Inner core already has formed as you say.

I think you maybe right, a major hurricane before 40W. They can't be all that common I wouldn't have thought but I haven't researched that, not really had the need in recent years!

[Kingarabian]

Excluding the WPac, Cat.5 canes without recon are hard to come by.

[1900hurricane]

The southwestward dip before reaching 20ºN should help keep Irma over sufficiently warm waters for a long time, and it actually reminds me somewhat of the all-time ACE champion, Ioke '06. It's probably a safe assumption that we aren't going to challenge Ioke's ~85 units of ACE, but the system's overall longevity at high intensity ceiling is pretty up there. It's just a question of how much is realized.

[caneseddy]

Anything under 920 seems like fairytale stuff to me. There are just some extremes even a hurricane can't achieve at that size...

Ivan, Katrina, Wilma, Labor Day, Allen, Camille, Mitch, Gilbert, Rita, Dean, the 1924 Cuba Hurricane all were sub 920s

[SouthDadeFish]

A possible candidate for unexpected RI? Thin cyan ring on 37-GHz color-composite imagery.

[img]http://i.imgur.com/9HkAQWm.jpg[img]

SouthDadeFish, would a pink ring be a better indicator? Or do we simply look for a cyan ring?

Great question. Kieper and Jiang (2012) suggest a cyan ring is sufficient for RI. A cyan ring is indicative of mostly liquid hydrometeors, whereas a pink ring is composed of very deep convection. A pink ring could be an indicator of RI, but from my experience, is only seen in very intense TCs.

Kieper and Jiang paper here: http://tcpf.fiu.edu/Jiang/research/Kieper_and_Jiang_2012_GRL.pdf

[meriland29]

Anything under 920 seems like fairytale stuff to me. There are just some extremes even a hurricane can't achieve at that size...

Cat 5 is <920. Hardly the stuff of fairytales.

"At that size". But if it does, I am guessing sooner rather than later given it is already organized and ramping up quickly, if it does reach the us, itll be dying off, especially if it hits those cuban mountains...

[KWT]

The southwestward dip before reaching 20ºN should help keep Irma over sufficiently warm waters for a long time, and it actually reminds me somewhat of the all-time ACE champion, Ioke '06. It's probably a safe assumption that we aren't going to challenge Ioke's ~85 units of ACE, but the system's overall longevity at high intensity ceiling is pretty up there. It's just a question of how much is realized.

I think its fair to assume we are going to get more from Irma than every other storm this season combined!

I'd say 50-60 units is looking quite probable at this point.

Also worth noting that the GFS 12z had this to the NORTH of the northern most islands of CV, above 17N by 06z, lets see how that pans out...

[Aric Dunn]

A possible candidate for unexpected RI? Thin cyan ring on 37-GHz color-composite imagery.

[img]http://i.imgur.com/9HkAQWm.jpg[img]

SouthDadeFish, would a pink ring be a better indicator? Or do we simply look for a cyan ring?

Great question. Kieper and Jiang (2012) suggest a cyan ring is sufficient for RI. A cyan ring is indicative of mostly liquid hydrometeors, whereas a pink ring is composed of very deep convection. A pink ring could be an indicator of RI, but from my experience, is only seen in very intense TCs.

Kieper and Jiang paper here: http://tcpf.fiu.edu/Jiang/research/Kieper_and_Jiang_2012_GRL.pdf

I saw that paper a while back.. just wish it had more image comparison. good read though

[Nimbus]

The early strengthening should get factored into the models tonight.
Nothing like a classic Cape Verde major to put a kink in the Jet stream or pull down a trough.
Maybe Irma will climb a couple degrees latitude early and miss the islands through the corner of the Hebert box?

[Kingarabian]

A possible candidate for unexpected RI? Thin cyan ring on 37-GHz color-composite imagery.

[img]http://i.imgur.com/9HkAQWm.jpg[img]

SouthDadeFish, would a pink ring be a better indicator? Or do we simply look for a cyan ring?

Great question. Kieper and Jiang (2012) suggest a cyan ring is sufficient for RI. A cyan ring is indicative of mostly liquid hydrometeors, whereas a pink ring is composed of very deep convection. A pink ring could be an indicator of RI, but from my experience, is only seen in very intense TCs.

Kieper and Jiang paper here: http://tcpf.fiu.edu/Jiang/research/Kieper_and_Jiang_2012_GRL.pdf

Thanks for the link. Will read into it!

[msbee]

[img]http://i.imgur.com/kXXOb1M.png[img]

Beginning to look uneasy for you, Luis.

I am not happy with this forecast
Luis, what do you think?

[Kingarabian]

Anything under 920 seems like fairytale stuff to me. There are just some extremes even a hurricane can't achieve at that size...

Cat 5 is <920. Hardly the stuff of fairytales.

"At that size". But if it does, I am guessing sooner rather than later given it is already organized and ramping up quickly, if it does reach the us, itll be dying off, especially if it hits those cuban mountains...

Cat. 5's come in all kinds of shapes and sizes.

[KWT]

The early strengthening should get factored into the models tonight.
Nothing like a classic Cape Verde major to put a kink in the Jet stream or pull down a trough.
Maybe Irma will climb a couple degrees latitude early and miss the islands through the corner of the Hebert box?

Usually that would be the case but according to experts the opposite will happen this time as it will help to amplify the upper ridge and send it more WSW earlier, meaning its more likely to miss the trough connection as its deeper into the tropics when the weakness starts to close up.

Going to be a very close call I feel, plenty of changes to come and uncertainty.

[ScottNAtlanta]

The last cat 5 that far out that I can recall was Isabel 2003

[Kingarabian]

The southwestward dip before reaching 20ºN should help keep Irma over sufficiently warm waters for a long time, and it actually reminds me somewhat of the all-time ACE champion, Ioke '06. It's probably a safe assumption that we aren't going to challenge Ioke's ~85 units of ACE, but the system's overall longevity at high intensity ceiling is pretty up there. It's just a question of how much is realized.

I think its fair to assume we are going to get more from Irma than every other storm this season combined!

I'd say 50-60 units is looking quite probable at this point.

Also worth noting that the GFS 12z had this to the NORTH of the northern most islands of CV, above 17N by 06z, lets see how that pans out...

18z runs soon, let's see how these latest developments influence the model.

[Exalt]

Anything under 920 seems like fairytale stuff to me. There are just some extremes even a hurricane can't achieve at that size...

Cat 5 is <920. Hardly the stuff of fairytales.

"At that size". But if it does, I am guessing sooner rather than later given it is already organized and ramping up quickly, if it does reach the us, itll be dying off, especially if it hits those cuban mountains...

This isn't a personal attack, but I just wanted to say that these are fairly ignorant statements. Hurricanes have, and with rising sea temps due to climate change, can now more easily reach sub-920mb pressures regardless of size. Also, Cuba isn't really in the crosshairs of this storm, south FL/Bahamas/San Juan or the East Coast are currently in the crosshairs. I wouldn't disregard this storm, disregarding storms, especially one of this magnitude, and even moreso especially after what happened with Harvey, is a dangerous road.

[Exalt]

The last cat 5 that far out that I can recall was Isabel 2003

And guess where she went?

[stormreader]

A possible candidate for unexpected RI? Thin cyan ring on 37-GHz color-composite imagery.

Normally this would be good, with more latitude expected. But here? IDK...

Gaining latitude looks unlikely in the short term with that ridge to the north. Wonder is strengthening might give it more forward impetus as it scoots under that ridge. Making it even more susceptible to the overall upper level west push under that ridge. That would take it further west a little quicker, won't speculate how that might impact longer range forecast. Just a thought, could see an increase in forward speed.

[ScottNAtlanta]

Isabel was also considerably weaker at landfall, however.

[Aric Dunn]

I would go with 60kts right now.. ... hurricane by 11pm ? I mentioned it this morning as a possibly after seeing the trend.