2017 ACE: NATL - 226.0 | EPAC - 98.2 | WPAC - 154.5 | NIO - 16.1

[RL3AO]

Atlantic Accumulated Cyclone Energy
Name System ACE Max Intensity
------------------ ------------ ---------------
Arlene (01L) [TCR] 0.81 45
Bret (02L) 0.6875 40
Cindy (03L) 1.55 50
Four (04L) 0 25
Don (05L) 0.6875 40
Emily (06L) 0.405 45
Franklin (07L) 3.685 75
Gert (08L) 7.2675 90
Harvey (09L) 11.1225 115
Irma (11L) 26.8825 160
Jose (12L) 0.2825 40
Thirteen (13L) 0 30

Season Total 53.38

[1900hurricane]

At such high intensities, Irma is probably going to drive the season's PDI total to an even larger number than the ACE total, which is a rare occurrence.

[Meteorcane]

Atlantic Accumulated Cyclone Energy
Name System ACE Max Intensity
------------------ ------------ ---------------
Arlene (01L) [TCR] 0.81 45
Bret (02L) 0.6875 40
Cindy (03L) 1.55 50
Four (04L) 0 25
Don (05L) 0.6875 40
Emily (06L) 0.405 45
Franklin (07L) 3.685 75
Gert (08L) 7.2675 90
Harvey (09L) 11.1225 115
Irma (11L) 26.8825 160
Jose (12L) 0.2825 40
Thirteen (13L) 0 30

Season Total 53.38

Irma has now contributed more than half of the season's Atlantic ACE!

[RL3AO]

Atlantic Accumulated Cyclone Energy
Name System ACE Max Intensity
------------------ ------------ ---------------
Arlene (01L) [TCR] 0.81 45
Bret (02L) 0.6875 40
Cindy (03L) 1.55 50
Four (04L) 0 25
Don (05L) 0.6875 40
Emily (06L) 0.405 45
Franklin (07L) 3.685 75
Gert (08L) 7.2675 90
Harvey (09L) 11.1225 115
PTC Ten (10L) 0 0
Irma (11L) 29.4425 160
Jose (12L) 0.485 45
Thirteen (13L) 0 30

Season Total 56.1425

Atlantic could be above the climatological average (about 104) by next week.

[1900hurricane]

Irma dumped 9.345 units in the past 24 hours alone.

[RL3AO]

This has a shot at Ivan's record.

[Hammy]

At such high intensities, Irma is probably going to drive the season's PDI total to an even larger number than the ACE total, which is a rare occurrence.

What does the PDI refer to exactly?

[RL3AO]

After a Klotzbach post, I looked into the best track of Allen.

For most ACE in a 24 hour period, Allen produced 9.63 ACE. If Irma remains at 160 kt for the 6z update, it will be the first hurricane to produce at least 10 ACE in 24 hours.

(Obviously subject to change after reanalysis)

[1900hurricane]

At such high intensities, Irma is probably going to drive the season's PDI total to an even larger number than the ACE total, which is a rare occurrence.

What does the PDI refer to exactly?

PDI is Power Dissipation Index. It's similar to ACE, but rather than squaring the wind values and dividing the sum by 10**4, PDI cubes the wind values and divides the the sum by 10**6. While ACE is more commonly used, some people prefer PDI since the force of the wind increases cubicly. I like to keep track of both and compare them. Because PDI is a cubic function of wind speed vs a quadratic function for ACE, it drops off more quickly and gives lower values than ACE below 100 kt. Above 100 kt, PDI ramps up more quickly and gives higher values of ACE. High ratios of PDI when compared to ACE is indicative of notable major hurricane activity.

[RL3AO]

Atlantic Accumulated Cyclone Energy
Name System ACE Max Intensity
------------------ ------------ ---------------
Arlene (01L) [TCR] 0.81 45
Bret (02L) 0.6875 40
Cindy (03L) 1.55 50
Four (04L) 0 25
Don (05L) 0.6875 40
Emily (06L) 0.405 45
Franklin (07L) 3.685 75
Gert (08L) 7.2675 90
Harvey (09L) 11.1225 115
Irma (11L) 32.0025 160
Jose (12L) 0.6875 45
Katia (13L) 0.1225 35

Season Total 59.0275

[NDG]

Atlantic Accumulated Cyclone Energy
Name System ACE Max Intensity
------------------ ------------ ---------------
Arlene (01L) [TCR] 0.81 45
Bret (02L) 0.6875 40
Cindy (03L) 1.55 50
Four (04L) 0 25
Don (05L) 0.6875 40
Emily (06L) 0.405 45
Franklin (07L) 3.685 75
Gert (08L) 7.2675 90
Harvey (09L) 11.1225 115
Irma (11L) 32.0025 160
Jose (12L) 0.6875 45
Katia (13L) 0.1225 35

Season Total 59.0275

Catching up to the EPAC and WPAC pretty fast.

[RL3AO]

With the models keeping Jose around as a borderline major for two weeks, it's not crazy to think the Atlantic ACE could be above 120 in two weeks.

[RL3AO]

Atlantic Accumulated Cyclone Energy
Name System ACE Max Intensity
------------------ ------------ ---------------
Arlene (01L) [TCR] 0.81 45
Bret (02L) 0.6875 40
Cindy (03L) 1.55 50
Four (04L) 0 25
Don (05L) 0.6875 40
Emily (06L) 0.405 45
Franklin (07L) 3.685 75
Gert (08L) 7.2675 90
Harvey (09L) 11.1225 115
PTC Ten (10L) 0 0
Irma (11L) 34.5625 160
Jose (12L) 0.99 55
Katia (13L) 0.2825 40

Season Total 62.05

The ACE of Irma will surpass the 2013 Atlantic hurricane season this afternoon.

[Ntxw]

The Atlantic also will finally make a run to compete with the Pacific basins, perhaps surpass them for a time even.

[RL3AO]

Atlantic Accumulated Cyclone Energy
Name System ACE Max Intensity
------------------ ------------ ---------------
Arlene (01L) [TCR] 0.81 45
Bret (02L) 0.6875 40
Cindy (03L) 1.55 50
Four (04L) 0 25
Don (05L) 0.6875 40
Emily (06L) 0.405 45
Franklin (07L) 3.685 75
Gert (08L) 7.2675 90
Harvey (09L) 11.1225 115
Irma (11L) 37.1225 160
Jose (12L) 1.4125 65
Katia (13L) 0.705 65

Season Total 65.455

[1900hurricane]

As if Irma wasn't enough, Jose and Katia are now also strengthening hurricanes. The NAtl is pumping out ACE at a meteoric rate right now.

[RL3AO]

Random coding this afternoon. Here are the top 20 ACE producing six hour periods on record in the Atlantic since 1950.

12Z 11 Sep 1961 - Total ACE: 3.865
06Z 11 Sep 1961 - Total ACE: 3.7
18Z 11 Sep 1961 - Total ACE: 3.3875
00Z 11 Sep 1961 - Total ACE: 3.3225
06Z 15 Sep 2010 - Total ACE: 3.075
12Z 15 Sep 2010 - Total ACE: 3.065
18Z 10 Sep 1961 - Total ACE: 2.975
18Z 15 Sep 2010 - Total ACE: 2.8475
12Z 10 Sep 1961 - Total ACE: 2.8125
00Z 15 Sep 2010 - Total ACE: 2.7925
00Z 18 Aug 1969 - Total ACE: 2.77
12Z 17 Aug 1969 - Total ACE: 2.77
06Z 16 Sep 2010 - Total ACE: 2.765
00Z 17 Aug 1969 - Total ACE: 2.74
18Z 07 Aug 1980 - Total ACE: 2.7225
00Z 16 Sep 2010 - Total ACE: 2.7025
12Z 17 Sep 2010 - Total ACE: 2.7
00Z 08 Sep 1951 - Total ACE: 2.69
18Z 31 Aug 1979 - Total ACE: 2.675
06Z 17 Sep 2010 - Total ACE: 2.675

18z made it to #3.

9/6/17 18z - 3.405
9/6/17 12z - 3.0225
9/6/17 6z - 2.885
9/6/17 0z - 2.7525
9/5/17 18z - 2.72

[Alyono]

Atlantic should blow by the WPAC this week with the 3 storms ongoing

[RL3AO]

[Extratropical94]

So if Irma stays at 160, we need Katia and Jose at 80 and 85 knots to get to #1.