Accumulated Cyclone Energy and Intensification/Deepening

This is the general tropical discussion area. Anyone can take their shot at predicting a storms path.

Moderator: S2k Moderators

Forum rules

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

Help Support Storm2K
Message
Author
Foxfires
Tropical Storm
Tropical Storm
Posts: 146
Joined: Fri Dec 03, 2021 11:50 pm

Accumulated Cyclone Energy and Intensification/Deepening

#1 Postby Foxfires » Sat Dec 03, 2022 10:22 pm

Ok I.. think this is more of a discussion topic so I'm putting it here. This might not really be anything but a product of my own mind but regardless:

Do storms with high ACE tend to not have very high intensification/deepening?
And the opposite
Do storms with high intensification/deepening tend to not have a lot of ACE?
If so, any possible reason why?

Now obviously high ACE storms undergo rapid intensification but I'm more referring to the higher end of the intensification spectrum. I have not defined "high ACE" so try 40s range and go up from there.

This probably requires graph plotting but I don't know how to program so I'd have to insert the values manually. Probably best to do 1966-present for this.
0 likes   

Meteophile
Tropical Depression
Tropical Depression
Posts: 50
Joined: Tue May 12, 2020 3:38 pm

Re: Accumulated Cyclone Energy and Intensification/Deepening

#2 Postby Meteophile » Tue Jan 03, 2023 8:58 am

Small eyes, some oceanic and atmospheric conditions helping a rapid intensification also help the formation of an outer eyewall, so structural changes, so to structure weaknesses at some points.

Would there be anything else having an influence ?
0 likes   

tolakram
Admin
Admin
Posts: 19134
Age: 60
Joined: Sun Aug 27, 2006 8:23 pm
Location: Florence, KY (name is Mark)

Re: Accumulated Cyclone Energy and Intensification/Deepening

#3 Postby tolakram » Tue Jan 03, 2023 12:34 pm

Hurricane Gilbert had a ton of ACE and experienced some of the most rapid deepening observed at the time, but way out in the Atlantic. Jeff Masters, formerly of weatherbell, was on a hurricane hunter flight that got stuck in the eye. Good read: https://www.wunderground.com/blog/JeffM ... ars-l.html

ACE is a function of position rather then deepening speed IMO. You can have monsters rapidly deepen close to shore and have little ACE, and you can have a Gilbert. It's one of the reasons ACE is a questionable metric for determining the 'strength' of a hurricane season. Gilbert was in 1988 and generated a ton of ACE, but the season ended near average.
0 likes   
M a r k
- - - - -
Join us in chat: Storm2K Chatroom Invite. Android and IOS apps also available.

The posts in this forum are NOT official forecasts and should not be used as such. Posts are NOT endorsed by any professional institution or STORM2K.org. For official information and forecasts, please refer to NHC and NWS products.

Category5Kaiju
Category 5
Category 5
Posts: 3344
Age: 22
Joined: Thu Dec 24, 2020 12:45 pm
Location: Seattle

Re: Accumulated Cyclone Energy and Intensification/Deepening

#4 Postby Category5Kaiju » Sun Jan 08, 2023 1:56 am

I definitely feel that there is a trade-off between having high total ACE versus intensifying at an extremely rapid rate. It seems like storms such as Patricia, Wilma, and the 1935 Labor Day hurricane (all of which were storms that went below 900 mbar and are the epitomes of "super-intensifiers") managed to execute this feat in a very short timespan. These storms as a whole did not produce an exceptionally high amount of ACE. Additionally, these kinds of storms are extremely rare, and 1935, 1980, 1988, 2005, and 2015 remain the only recorded years in the EPAC or Atlantic that saw a sub-900 mbar system. This is why I'm kind of on the belief that in order to get a storm that explosively strengthens like that, you GENERALLY need a very localized area (or "pocket") of exceptionally favorable ocean and atmospheric conditions that other regions of the ocean fail to have (very warm ssts, virtually zero knots of mid level and deep layer shear, an extremely moist environment...you get the idea).

Now I said GENERALLY because Allen and Gilbert are a bit different; they were high ACE storms but also managed to reach sub-900 mbar at some points in their lives. As a result, Allen and Gilbert kind of buck the idea that all storms that go sub-900 mbar (in other words, our ideal examples of "super-intensifiers") must have a relatively low total ACE.

There are a plethora of more examples of storms that I can talk about (Ivan, Irma, Isabel, or Sam in the Atlantic, and Hector 2018 or John 1994 in the Pacific) that scored extremely high with total ACE but were not exceptionally powerful at any points in their lives, at least when comparing these storms with our "super-intensifiers." These high ACE major hurricanes seem to love the idea of "cruise-control," where they maintain their strength for long stretches of ocean and undergo multiple eyewall replacement cycles over and over again. It's also interesting to see how "super-intensifiers" are fragile as they tend to weaken greatly after reaching their peaks; they seem unable to maintain such extraordinary strengths compared to our "cruise-control" high ACE major hurricanes that seem somewhat more resistant to sudden, rapid weakening.
0 likes   
Unless explicitly stated, all information covered in my posts is based on my opinions and observations. Please refer to a professional meteorologist or an accredited weather research agency otherwise, especially if serious decisions must be made in the event of a potentially life-threatening tropical storm or hurricane.

Foxfires
Tropical Storm
Tropical Storm
Posts: 146
Joined: Fri Dec 03, 2021 11:50 pm

Re: Accumulated Cyclone Energy and Intensification/Deepening

#5 Postby Foxfires » Fri Jan 13, 2023 12:26 am

I forgot to say I made a graph. This only lists storms with ACE of at least 60 units or storms with 24h intensification of at least 80kt (1-min sustained for consistency reasons) because finding every TC below those criteria is proving more difficult than I had originally anticipated. I did intensification instead of deepening because some storms don't have pressure data. I'm only doing 1966-present for reliability reasons. Now obviously underestimation makes both intensification and ACE go down but I'm not exactly sure June '75 and Nora '73 exactly have high ACE, and that Rita '78 has high intensification (deepening is very low).

https://www.desmos.com/calculator/hbhwg3higb
(image removed because Imgur will be deleting non-account images)

There seems to be a little bit of correlation, at least at the extremes, why? Not exactly sure. For why 80kt+/24h storms don't have 60 ACE, it might be because the point of intensification is to accomplish it in a short time which only requires a small but favourable area, and whatever happens after that is mostly irrelevant (e.i. the storm could collapse immediately afterwards). On the other hand, ACE requires a very large area of favourable conditions, but I'm not sure why the intensifications for Rita '72, John '94, and Paka '97 are so low if there are such favourable conditions as to allow such intensity and high ACE storms. And, yes, they met the criterion for RI but non-majors can do that as well. Maybe it is simply coincidence and I'm crazy and spewing bullcrap. Regardless, it's just a discussion topic.

Also, Tolakram, just mentioning that Gilbert (32.755 units) has less ACE than Wilma (38.9175 units) so unless my source is wrong, Wilma may be a better example for that.

Category5Kaiju talks about very intense storms as high intensifiers, but high intensification can be achieved by sub-C5 storms like Chebi '06 and Yates '96 (both 85kt/24h) since they started at very low intensities (TD), and likewise, a fairly high ACE storm like Rita '78 (which I believe was underestimated for a majority of its lifetime and might've been 60+ ACE) was sub-880mb despite reconnaissance indicating that not once in its life did it fulfill the criterion for rapid deepening unless I can't read.

Edit (14/01/2023): I forgot to mention that if a windspeed increase is spread out over more time it technically racks up more ACE. 50kt to 130kt in 1 day will have less ACE than that same increase in 3 days, but has a higher intensification rate. In this specific way, intensification is inversely proportional to ACE. That doesn't necessarily mean it will stop the former from sustaining 130kt+ for some time after that, but just something to consider.

Edit (01/02/2023): Added Olaf to the graph.

Edit (23/04/2023): Added Freddy to the graph (I added it in March but was too lazy to put it here until now)
1 likes   


Return to “Talkin' Tropics”

Who is online

Users browsing this forum: No registered users and 32 guests