Major Hurricane Ida

[ncforecaster89]

Mods:  please feel free to move both the post from Normandy and my own (as I wouldn’t have made mine without theirs) to banter…if you feel appropriate, as I don’t think either belong here.  

Thanks,

Tony

[ncforecaster89]

On 9/18/2021 at 9:03 PM, Normandy said:

From what I remember Grand Isle did get into the eyewall....Port Fourchoun was in the middle of the eye and Grand Isle is a few miles east of that location.  Its fairly likely Grande Isle received the worst winds in Ida

You’re absolutely correct.  I’ll add that the strongest winds measured by Recon (located in the innermost portion of the E eyewall) actually moved in between the two aforementioned locations…with Grand Isle likely getting higher winds than Port Fourchon.  See attached radar image, below.  

It’s important to remember that the most intense winds are generally located in the innermost portion of the NE eyewall…as the winds are not uniformly distributed throughout the eyewall, as some incorrectly assume.  

[Jockwilliamschasing]

Hi everyone I wanted to put my thoughts on this matter this is jock williams meteorologist and researcher. Cj at the time he made those posts I and other individual had already progressed way north by 45 min at no point during my intercept was I concerned cj had asked to follow I informed him of the consequences and being this was his first major Cain  what would happen he agreed  fast-forward  surge was not a concern as a matter of fact nothing was concerning given my expertise and 18 years of doing this type of work and going to college for my masters having completed in 4 years. I do everything for the scientific side and to educate and help prepare people for these events.    Thank you all and always keep calm I never yell or panic because why would I need to 

[Rjay]

That's quite a long sentence.  

[ncforecaster89]

To better understand (determine) how that 223 mph instantaneous wind gust corresponds to a one-minute sustained wind speed at standard height…one can use the power law to covert from that 30 meter height to 10 meters elevation. 
 

First, we need to convert the instantaneous gust to a 1-minute sustained wind speed.  Extensive research

https://www.yumpu.com/en/document/view/12031496/estimating-3-second-and-maximum-instantaneous-gusts-from-1-/3

has shown that an instantaneous wind gust can be converted to a 1-minute wind speed by a factor of 1.45.  In this case, it would translate to 154 mph.

Then, we’ll simply use the power law equation to extrapolate the aforementioned 154 mph wind at 30 m to a 10 m equivalent.  To do so accurately, you need to utilize the appropriate surface roughness length.  In this case, I’m using 0.10 for open ocean.  
 

This converts to a 139 mph (120 kt) one minute sustained wind value.  That’s a very impressive in-situ measurement to be captured at landfall in Port Fourchon.  
 

Given its highly unlikely that any anemometer would be positioned perfectly to capture the highest wind speed in the eyewall, and taking into account that the strongest winds were likely found just to the E…this measurement provides excellent additional support for the operational intensity of 130 kt.  

[ncforecaster89]

“Ida” is a prime example of why I wish the NHC would add the descriptive term of “Super” for major hurricanes with a MSW of 130 kt or greater…similar to the WPAC.

Reasoning being there is a significant difference in the ferocity of the wind and its destructive ability at these velocities in comparison with those at the lower-end of the Cat 4 range.   

[the ghost of OT]

22 hours ago, ncforecaster89 said:

“Ida” is a prime example of why I wish the NHC would add the descriptive term of “Super” for major hurricanes with a MSW of 130 kt or greater…similar to the WPAC.

Reasoning being there is a significant difference in the ferocity of the wind and its destructive ability at these velocities in comparison with those at the lower-end of the Cat 4 range.   

If they did that the climate change deniers would pitch a fit and say it’s being done to make global warming seem scarier. 

[NorthHillsWx]

23 hours ago, ncforecaster89 said:

“Ida” is a prime example of why I wish the NHC would add the descriptive term of “Super” for major hurricanes with a MSW of 130 kt or greater…similar to the WPAC.

Reasoning being there is a significant difference in the ferocity of the wind and its destructive ability at these velocities in comparison with those at the lower-end of the Cat 4 range.   

Though I agree somewhat, I think a better solution would be to look at revising the wind speed category system. To me, cat 4 should comprise 130-150 mph, cat 5 should be 150-170 mph and there should be a cat 6, for storms such as Dorian and Irma. I think the difference in wind magnitude between a 160 mph hurricane and a 180 mph hurricane is enough to justify a separate category for only the strongest storms on earth. 

[Windspeed]

Though I agree somewhat, I think a better solution would be to look at revising the wind speed category system. To me, cat 4 should comprise 130-150 mph, cat 5 should be 150-170 mph and there should be a cat 6, for storms such as Dorian and Irma. I think the difference in wind magnitude between a 160 mph hurricane and a 180 mph hurricane is enough to justify a separate category for only the strongest storms on earth. 

The problem with having a "Category 6" based on Dorian is the limitations of categorically confining a value of time and motion. Dorian was horrible regardless, but even worse due to its slow motion. You cannot underestimate how much the long duration of sustained Category 5 winds did to magnify the devastation. In reality, anything above 155 mph sustained that persists for a slow mover is going to be magnified. There is no need for a Category 6. If it's a fast moving intense hurricane, the damage is going to be less than a slow moving intense hurricane due to inevitable structural failure caused by prolonged wind force.

[Scorpion]

On 10/27/2021 at 12:53 PM, NorthHillsWx said:

Though I agree somewhat, I think a better solution would be to look at revising the wind speed category system. To me, cat 4 should comprise 130-150 mph, cat 5 should be 150-170 mph and there should be a cat 6, for storms such as Dorian and Irma. I think the difference in wind magnitude between a 160 mph hurricane and a 180 mph hurricane is enough to justify a separate category for only the strongest storms on earth. 

No location got 155 kt winds in either Irma or Dorian. If they did they would have been completely flattened. They were Cat 5’s just like all the others. I do think the only hurricane that you could debate as Cat 6 would be 1935 Labor Day.