Major Hurricane Irma

[nwohweather]

This makes sense. I've been skeptical on the intensity aspect of the storm for a while now with NWP lagging behind on the observed trends with Irma and the eventual numerical output. I agree with jpeter on that front for sure, but I feel the biggest reason for a incremental decrease in max winds is the what you mentioned with the expanding core and the increasing size of Irma in general. It's been unanimous on guidance the wind field will be expanding around the system as she heads through the Bahamas and towards the US and in a physics sense, I gotta feel the winds would eventually adjust down just due to sheer size and the decreasing pressure gradient. It's tough to argue the figure skater analogy. If this storm had a small eye, wind speeds would likely be at over 200mph given the lack of shear and dry air intrusion over the last several days with such a robust core. It's been a sight to behold out in the Atlantic. 

However if this thing deepens in pressure as it hits warmer water it may very well keep the pressure gradient to offset for moving away from the Bermuda high

[adiabatic13]

1 minute ago, OUGrad05 said:

Anyone noticing how large the windfield is on the N Side of the storm with current recon?  Pretty impressive winds well out from the center of circulation.

 

Re: 190mph, seems possible but perhaps a long shot. Going over the PR trench, stirring up some cooler water and other environmental influences we may see it slowly weaken a bit in the near term before intensifying again tomorrow.  But getting to 190 is tough, though with this storm?  Anything is possible.

190 mph is absolutely possible, TCHP only increases along projected track, so "cooler water" doesn't seem to be one of the factors we should be holding out hope will lead to a weakening of Irma...rather core fluctuations and land interaction might lead to that outcome, though honestly, taking into consideration the history of Irma to date, divergence from the extraordinarily accurate EURO track is the only real hope for SE FL at this time, we'll see what 12z offers

[Jaguars]

Looks like a little more of a NW component last couple frames.  Probably just a wobble, but maybe something to monitor.

[the ghost of leroy]

3 minutes ago, OUGrad05 said:

Explain, because everything I've read including a conversation I had with a friend at NWS indicate that these storms and Irma in particular with the low pressure will pull up cooler waters that are cooler.  This slightly cooler water may serve to limit intensification until the waters become shallower, which they do fairly quickly once out of the trench.

The trench stuff is not scientific. WPAC cyclones routinely cross the marianas trench without weakening. You are wrong about shallow waters too, they tend to limit TCHP. Warm deep waters are king. 

[OUGrad05]

4 minutes ago, adiabatic13 said:

190 mph is absolutely possible, TCHP only increases along projected track, so "cooler water" doesn't seem to be one of the factors we should be holding out hope will lead to a weakening of Irma...rather core fluctuations and land interaction might lead to that outcome, though honestly, taking into consideration the history of Irma to date, divergence from the extraordinarily accurate EURO track is the only real hope for SE FL at this time, we'll see what 12z offers

Def agree core fluctuation and land interaction will also play a role, I touched on that a few pages back.

[lwg8tr0514]

2 minutes ago, Jaguars said:

Looks like a little more of a NW component last couple frames.  Probably just a wobble, but maybe something to monitor.

Clearly the hoped for going East fish scenario, looked like maybe at the 2pm and 5pm yesterday it was trending that way, but this AM, grim news.  Still hoping the eye stays 30 miles offshore and So Florida is sparred the real nasty stuff. Maybe I am wishcasting. 

[Drz1111]

4 minutes ago, OUGrad05 said:

Explain, because everything I've read including a conversation I had with a friend at NWS indicate that these storms and Irma in particular with the low pressure will pull up cooler waters that are cooler.  This slightly cooler water may serve to limit intensification until the waters become shallower, which they do fairly quickly once out of the trench.

That's not how it works.  And I have a masters  in oceanography.  The physics is too complex to explain on a message board but there's plenty of info on the internet.

Think of it this way: the main development regions in the westpac are some of the deepest basins in the oceans, and the marianas hide behind the deepest trench.  Simply pragmatically your theory doesn't jibe with data.

[pazzo83]

3 minutes ago, cmasty1978 said:

The trench stuff is not scientific. WPAC cyclones routinely cross the marianas trench without weakening. You are wrong about shallow waters too, they tend to limit TCHP. Warm deep waters are king. 

I think the depth of the warm waters closer to the Bahamas is pretty significant.

[gravitylover]

2 minutes ago, lwg8tr0514 said:

Clearly the hoped for going East fish scenario, looked like maybe at the 2pm and 5pm yesterday it was trending that way, but this AM, grim news.  Still hoping the eye stays 30 miles offshore and So Florida is sparred the real nasty stuff. Maybe I am wishcasting. 

Keep in mind that if the center of the eye is 30 miles out the eyewall is raking the coast.

[jojo762]

151kt FL winds in NW quadrant with similar SFMR winds (but a few knots lower, and flagged I believe as well).

[OUGrad05]

1 minute ago, cmasty1978 said:

The trench stuff is not scientific. WPAC cyclones routinely cross the marianas trench without weakening. You are wrong about shallow waters too, they tend to limit TCHP. Warm deep waters are king. 

I agree TCHP is better in deeper waters and it can matter more than SSTs.  But TCHP actually increases as the storm approaches the Bahamas and landfall in FL despite the waters being shallower there then off the coast of PR and Hispanola. Here's the latest map from NOAA - took FOREVER to load, sorry about that.

http://www.aoml.noaa.gov/phod/dataphod1/work/HHP/NEW/2017249ca.jpg

We're not talking about ultra shallow waters where TCHP falls dramatically we're talking about a storm approaching the Turks and Bahamas and ultimately CONUS.  Where despite shallower waters TCHP goes up.  

I do think your have a point though regarding upwelling perhaps not matter for this storm.

[OUGrad05]

10 minutes ago, pazzo83 said:

I think the depth of the warm waters closer to the Bahamas is pretty significant.

It's absolutely significant and TCHP is significantly higher there, then it is where the storm currently sits.

[Rjay]

2 hours ago, Mountain_Patch said:

This will likely be my last post for the day as this forum is decidedly against me communicating. So I figure I'll leave today with this gem. Amazing. Just absolutely amazing.

Quality post for your last post. 

If people don't want to be 5 posted pick up your game or read more and post less.  This doesn't go for people asking questions and trying to learn 

[OUGrad05]

Here's a TCHP loop from NOAA

http://www.aoml.noaa.gov/phod/dataphod1/work/HHP/NEW/cahhp.gif

[ineedsnow]

16 minutes ago, Jaguars said:

Looks like a little more of a NW component last couple frames.  Probably just a wobble, but maybe something to monitor.

Just saw that could be a wobble... Carolinas have to watch this very closely in my opinion...

[wxeyeNH]

I have not been paying attention to the NAM but now that we are getting closer I am watching the 12Z run.  Through hour 48 its well SW of its prior run.  Whether its good or bad with tropical systems would like to see a NE trend not a SW trend..

[eduggs]

1 hour ago, Ralph Wiggum said:

Ugh. This is not good, not that I am expressing anything we already didnt know.

So what is our best hope at this point? A track which makes LF west of Key Largo then stays inland? A track that clips Cuba barely and weakens slightly? A track that remains East of FL?

Im in the camp that there really is no good modeled solution at this point, just want to hear other thoughts. Even if it skirts FL to the East its like robbing Peter to pay Paul as it remains strong over warm water before slamming SC(?).

Sent from my LG-V410 using Tapatalk
 

The eastern end of the ensemble range would possibly spare the US mainland, or at least give Irma time to weaken before landfall.

[jpeters3]

52 minutes ago, MillvilleWx said:

This makes sense. I've been skeptical on the intensity aspect of the storm for a while now with NWP lagging behind on the observed trends with Irma and the eventual numerical output. I agree with jpeter on that front for sure, but I feel the biggest reason for a incremental decrease in max winds is the what you mentioned with the expanding core and the increasing size of Irma in general. It's been unanimous on guidance the wind field will be expanding around the system as she heads through the Bahamas and towards the US and in a physics sense, I gotta feel the winds would eventually adjust down just due to sheer size and the decreasing pressure gradient. It's tough to argue the figure skater analogy. If this storm had a small eye, wind speeds would likely be at over 200mph given the lack of shear and dry air intrusion over the last several days with such a robust core. It's been a sight to behold out in the Atlantic. 

It looks like the storm is at least trying to start an ERC right now, and the outer ring of convection is huge.  I wonder if the wind field expansion that the models have been predicting is going to result from the completion of this ERC.

Most recent MW pass:

[adiabatic13]

1 minute ago, ineedsnow said:

Just saw that could be a wobble... Carolinas have to watch this very closely in my opinion...

analyze no period less than 3 hours in determining track, Irma continues to move along the southern edge of global guidance, or exactly along the EURO 00Z track and 06Z GFS ENS western cluster

[LakeEffectKing]

Beautiful loop....note the restricted outflow in the W and NW sectors...

http://rammb.cira.colostate.edu/ramsdis/online/loop.asp?data_folder=goes-16/mesoscale_01_band_02_sector_05&width=1000&height=1000&number_of_images_to_display=40&loop_speed_ms=80

 

[jojo762]

Southeast quad has weakened remarkably per recon FL of ~130kt and SFMR of ~115kt.

[donsutherland1]

26 minutes ago, OUGrad05 said:

Anyone noticing how large the windfield is on the N Side of the storm with current recon?  Pretty impressive winds well out from the center of circulation.

 

Re: 190mph, seems possible but perhaps a long shot. Going over the PR trench, stirring up some cooler water and other environmental influences we may see it slowly weaken a bit in the near term before intensifying again tomorrow.  But getting to 190 is tough, though with this storm?  Anything is possible.

The Puerto Rico Trench shouldn't have any bearing on Irma's intensity. Here's a link to a basic description of upwelling, which affects the upper ocean.

http://www.rsmas.miami.edu/blog/2012/10/22/what-happens-underwater-during-a-hurricane/

Some research has found mixing down to 750 meters.

http://www.opl.ucsb.edu/tommy/pubs/Black_Dickey_nofigs.pdf

So, whether a water body is 5,000 meters in depth or more than 8,500 meters in depth as is the case with the Puerto Rico Trench is not relevant to hurricane intensity.

 

[OUGrad05]

2 minutes ago, jojo762 said:

Southeast quad has weakened remarkably per recon FL of ~130kt and SFMR of ~115kt.

That's a significant decrease in strength, I wonder how long that will hold up.

[bdgwx]

The OEW appears to be rather large like jpeters said. Here are a couple of more images from different satellites and channels.

 

[OUGrad05]

Just now, donsutherland1 said:

The Puerto Rico Trench shouldn't have any bearing on Irma's intensity. Here's a link to a basic description of upwelling, which affects the upper ocean.

http://www.rsmas.miami.edu/blog/2012/10/22/what-happens-underwater-during-a-hurricane/

Some research has found mixing down to 750 meters.

http://www.opl.ucsb.edu/tommy/pubs/Black_Dickey_nofigs.pdf

So, whether a water body is 5,000 meters in depth or more than 8,500 meters in depth as is the case with the Puerto Rico Trench is not relevant to hurricane intensity.

 

Will read, thank you!

[MichaelJ]

Bastardi put up a video where he says that Irma will likely fall to a 4 tomorrow but increase back to a 5 in the Fla. straits and go sub 900MB before hitting Florida. He also thinks Jose will turn westward and make an impact too, only on a much smaller and weaker scale than Irma.

[jojo762]

2 minutes ago, OUGrad05 said:

That's a significant decrease in strength, I wonder how long that will hold up.

Still Cat 4 intensity, but it is indeed a big decrease from prior SE quad data of 130kt+.

[wxeyeNH]

Big change on 12Z NAM at hour.  Much further SW by 100 miles.  Will be a Florida hit

[donsutherland1]

2 minutes ago, MichaelJ said:

Bastardi put up a video where he says that Irma will likely fall to a 4 tomorrow but increase back to a 5 in the Fla. straits and go sub 900MB before hitting Florida. He also thinks Jose will turn westward and make an impact too, only on a much smaller and weaker scale than Irma.

Irma's interaction with Hispaniola and Cuba, even as it remains offshore, may well contribute to some weakening. A lot of the guidance shows re-intensification as it nears Florida, so we'll see what happens.

[KPITSnow]

5 minutes ago, MichaelJ said:

Bastardi put up a video where he says that Irma will likely fall to a 4 tomorrow but increase back to a 5 in the Fla. straits and go sub 900MB before hitting Florida. He also thinks Jose will turn westward and make an impact too, only on a much smaller and weaker scale than Irma.

I would take bastardi with a grain of salt. 

 

First off, there is very little precedent for a hurricane strengthening to sub 900 in the Atlantic basin. It has only happened once in this position with the Labor Day storm.

 

Two, bastardi is a known overhyper.

 

edit: obviously it could happen, but I tend to "wait and see" on a scenario that extreme.