ATL: LEE - Post-Tropical - Discussion

[cycloneye]

There has never been at North Atlantic storm sub 900 outside of GOM and the Caribbean Sea.

Not saying it won't happen, but it would be without precedent.

Is there a particular reason for this, or could it just as likely be coincidence?

Historically waters have not been warm enough to support such a storm. Due to the warming, that is no longer the case. The basin is over a degree Celsius above average. That's a lot of fuel.https://uploads.tapatalk-cdn.com/20230907/dab2e521a9079d92d42549ec76de867c.jpg

The only area that may hamper more intensification is the cold wake that Franklin and Idalia left.

[JediChick]

Lees IR presentation looks like what the HAFS-B model has simulated for it to look like late tomorrow night. This thing is way ahead of schedule as far as intensity goes.

What effect (if any) would that have on the steering, if it's that far ahead of schedule intensity-wise? Sorry, newbie to the technicalities here.

[eastcoastFL]

Already a stadium effect going on. I think Lee completely skipped category 3.

How do you already know this? Through satellite or NOAA?

You can see what looks like a stadium effect on high res visible.

[mitchell]

Lol at this point people should lower their expectations. The reason why? Since 2007, EVERY single storm the NHC has forecasted to intensify into a C5 has underperformed/failed to achieve it because of various reasons, including Gustav 2008, Igor 2010, Blanca 2015, and Eta 2020. Some people might call me crazy but the last time they predicted a Cat 5 to occur from a RI’ing storm that ended up verifying was Dean 2007. Every other C5 that’s occurred since had achieved it without NHC expecting it too. So just warning you all that you’re setting yourself up for disappointment when Lee peaks at 130-135 kt and recon finds it on the threshold causing another endless debate.

A bit superstitious but still an interesting observation.

It drives home the point just how hard intensity is to predict. It's still the trickiest part of forecasting a hurricane. We have storm tracks nailed down extremely well now but intensity can be a mixed bag for whichever reason.

There was a "How strong will Lee get?" poll in Talking Tropics and the most popular response was/is "175 MPH or greater"
Had to shake my head at the popularity of that option for an Atlantic system that wasnt a hurricane yet at the time most responders chose it.

[eastcoastFL]

Lees IR presentation looks like what the HAFS-B model has simulated for it to look like late tomorrow night. This thing is way ahead of schedule as far as intensity goes.

What effect (if any) would that have on the steering, if it's that far ahead of schedule intensity-wise? Sorry, newbie to the technicalities here.

I’m not sure if it would have any effect long term. The NHC has it forecast to be a cat 4 tonight so they probably factored any effects into their forecast already.

[TheDreamTraveler]

Oh my, What Andy said as he embarks to St Croix. " Thinking we might see one of the stronger storms the Atlantic has ever produced by this weekend"

Think this storm will go sub 900

There has never been at North Atlantic storm sub 900 outside of GOM and the Caribbean Sea.

Not saying it won't happen, but it would be without precedent.

The Atlantic is many times warmer than it was decades ago so I'd say it's a matter of when at this point.

[Weather Watcher]

Already a stadium effect going on. I think Lee completely skipped category 3.

How do you already know this? Through satellite or NOAA?

You can see what looks like a stadium effect on high res visible.

Link to hi res

[aspen]

Think there are only a handful off storms that have ever made it to an 8, think the last 2 was super typhoon haiyan and Hurricane Patricia

Think it will get to 7 maybe 7.5

Technically Haiyan and Patricia both went over 8, as the ADT makes no allowance for an eye feature embedded in such a thick ring of CDG. Haiyan was an 8.2 or 8.3 while he peaked, and operationally had a central pressure estimated around 858mb.

That would not just beat, but obliterate Tip's "record." What is the reason the official pressure is considered 37mb higher (895mb)?

895 mbar is the JMA’s pressure, while 858 mbar was from the JTWC. JMA is the official organization for the WPac so its (often pretty bad) pressure estimates count as the official ones. I don’t know why their estimates are always at intervals of 5 and are often significantly off from ADT/Dvorak.

[zzzh]

Why would NHC give it 983mb? This is clearly unreasonable.

[Iceresistance]

How do you already know this? Through satellite or NOAA?

You can see what looks like a stadium effect on high res visible.

Link to hi res

http://tropic.ssec.wisc.edu/real-time/storm.php?&basin=atlantic&sname=13L&invest=NO&zoom=4&img=1&vars=11111000000000000000000&loop=0&llval=OFF

[Michele B]

I’m thinking we’re gonna need a special advisory soon. Lee is likely a major and will probably be 115-120 kt, if not higher, by 5pm.

Why would we need a special advisory if it's out in the middle of the ocean away from any land masses?

[tomatkins]

Is there a particular reason for this, or could it just as likely be coincidence?

Historically waters have not been warm enough to support such a storm. Due to the warming, that is no longer the case. The basin is over a degree Celsius above average. That's a lot of fuel.https://uploads.tapatalk-cdn.com/20230907/dab2e521a9079d92d42549ec76de867c.jpg

The only area that may hamper more intensification is the cold wake that Franklin and Idalia left.

Lee is 3-4 days from entering the area where Franklin became a significant storm.

[sicktght311]

Taken on a very symmetrical look in the last 30-60 minutes. Lee is definitely undergoing explosive RI and is primed to make its run for Cat5

[REDHurricane]

There has never been at North Atlantic storm sub 900 outside of GOM and the Caribbean Sea.

Not saying it won't happen, but it would be without precedent.

Is there a particular reason for this, or could it just as likely be coincidence?

Historically waters have not been warm enough to support such a storm. Due to the warming, that is no longer the case. The basin is over a degree Celsius above average. That's a lot of fuel.https://uploads.tapatalk-cdn.com/20230907/dab2e521a9079d92d42549ec76de867c.jpg

Well that shouldn't be a problem for Lee...



I was more so wondering if other factors besides SST (wind shear environment, steering patterns, moisture, land interaction w/atmosphere, etc.) would theoretically put any sort of limit on hurricanes in the open Atlantic. Because if historical SSTs are the only reason why we haven't seen any sub-900mb hurricanes anywhere besides the Gulf/Caribbean, then we should reasonably expect to see more of these in the future.

[Iceresistance]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 07 SEP 2023 Time : 165020 UTC
Lat : 16:26:24 N Lon : 50:20:59 W


CI# /Pressure/ Vmax
4.8 / 975.3mb/ 84.8kt


Final T# Adj T# Raw T#
4.8 5.7 6.4

Estimated radius of max. wind based on IR :N/A km

Center Temp : -1.7C Cloud Region Temp : -69.4C

Scene Type : EYE

Subtropical Adjustment : OFF

Extratropical Adjustment : OFF

Positioning Method : ARCHER POSITIONING

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : 1.3T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 75nmi
- Environmental MSLP : 1013mb

[Teban54]

https://i.imgur.com/xqY3lfQ.png

Taken on a very symmetrical look in the last 30-60 minutes. Lee is definitely undergoing explosive RI and is primed to make its run for Cat5

I know visible can be deceiving, but Ian looked somewhat just like this before, if not during, its Cat 5 peak.

[HurricaneEnzo]

Why would NHC give it 983mb? This is clearly unreasonable.

The system could be embedded in an area of higher ambient pressure than usual. That's just a guess. Pressures can run abnormally high in comparison to the storms strength if that is whats happening. If that is actually the case and it stays in that type of environment gonna be really hard to get sub 900mb. Or it's probably because this thing bombed out so quick the advisories haven't caught up yet.

[sicktght311]

https://i.imgur.com/xqY3lfQ.png

Taken on a very symmetrical look in the last 30-60 minutes. Lee is definitely undergoing explosive RI and is primed to make its run for Cat5

I know visible can be deceiving, but Ian looked somewhat just like this before, if not during, its Cat 5 peak.

Yeah Vis is often not an indicator, but even IR shows it getting a bit more symmetrical. Definitely starting to run away with itself

[tolakram]

COD floater view: https://weather.cod.edu/satrad/?parms=m ... =undefined

[hiflyer]

I’m thinking we’re gonna need a special advisory soon. Lee is likely a major and will probably be 115-120 kt, if not higher, by 5pm.

Why would we need a special advisory if it's out in the middle of the ocean away from any land masses?

Maritime interests…commercial shipping and transatlantic crossings by smaller vessels. Additionally, Lee is about to cross a couple of major air routes to/from Europe from the Caribbean.