Atlantic Hurricane Season 2024

[WYorksWeather]

Fairly low probabilities of development at the moment (20%, 40% and 20% over the next 7 days) but some possibility that the Atlantic may be about to wake from its slumber. Will probably become clearer in a day or two.

[Don]

 WYorksWeather Given that a very active hurricane season has been forecast, we are seeing a slow start.

[WYorksWeather]

 Don Actually quite an interesting point to dig into - it's not quite as straightforward as that. In terms of named storms, most predictions were around the low to mid 20s. Number of hurricanes was predicted to be around 12, and number of majors (Cat 3 or higher) was around five or six. Those do look pretty hard to catch from here, particularly named storms and total hurricanes. Majors is probably the wildcard - with the way the SSTs are, there's a much higher chance that any storms that do form will intensify into majors.

But in terms of the accumulated cyclone energy (ACE), we're very much still on track for a significantly above average season - what few storms there have been contributed a lot, particularly Beryl. It doesn't take many very strong hurricanes to count for a lot.

Of course regardless of the statistics, the key measure in terms of how memorable a season is will be whether any major hurricanes strike land in a heavily populated area. Hopefully that won't happen.

[Don]

11 minutes ago, WYorksWeather said:

But in terms of the accumulated cyclone energy (ACE), we're very much still on track for a significantly above average season - what few storms there have been contributed a lot, particularly Beryl. It doesn't take many very strong hurricanes to count for a lot.

That's very interesting actually, ref to ACE.  Gavin Partridge (GWV) always keeps an eye on ACE during autumn, so look forward to how this progresses moving forward!

Edited August 30 by Don

[WYorksWeather]

 Don Here's a bit more on the ACE formula if you're interested, including how it is calculated.

Start with the hurricane or tropical storm's surface wind speed in knots every six hours. For each reading, square it, and then calculate the sum of squares. Then add up all the hurricanes. Because this is an energy measure, it makes sense to square the wind speeds. A sustained wind of 100kt has twice as much energy as 70kt, and 140kt has about twice as much energy as 100kt. Then repeat for all hurricanes and tropical storms. The final step is to divide by 10,000 - this is just to make the scale more manageable.

To give a few examples, a minimum-strength tropical storm at 35kt would generate 0.5 ACE units in 24 hours. A Cat 1 at 65kt would generate 1.7 units in 24 hours. A major hurricane Cat 3 at 100kt would generate 4.0, and finally a Cat 5 at 140kt would generate 7.8.

As an example of how much impact a Cat 5 can have, especially if it spends a fair amount of time at major hurricane status, Beryl managed to run up 35.1 ACE units. The total for the 2024 season so far is only 55.1, so Beryl is responsible for more ACE than the other four storms combined.

[matty40s]

Still we wait, record quiet period in the modern age. Last time it was this quiet I had just entered the world...1968!!

 

[*Stormforce~beka*]

 matty40s Any reasons why?

[Derecho]

I think those forecasting a record breaking year may be in for a bust thankfully.

I think one of the key factors is that SSTs have cooled off a bit in the east of the tropical Atlantic which is where a lot of systems are born at this point in the season. 

Others issues that can scupper a favourable season are Saharan dust and a lack of thunderstorms over the western Sahel pushing west.

2013 was the last season that looked favourable on paper but ended up being a major bust.

Still the ACE for this season will be bumped up the Hurricane Beryl.

Activity may pick up later in the season when we see more systems form in the Gulf of Mexico.

[matty40s]

 *Stormforce~beka*

Bit of an discussion here..

Its a pdf

https://t.co/Bz6j7BgufN

[WYorksWeather]

Five areas of interest, all low probabilities. Will any develop?

[matty40s]

Even more strange...

 

[matty40s]

 

[WYorksWeather]

Most of the earlier interest areas didn't amount to much. NHC now calling for 70% chance of formation in the next 7 days in the western Gulf of Mexico. Two other low / moderate chances in the central / eastern tropical Atlantic.

[Don]

Strange things are definitely occurring, but it's very likely the underlying cause is climate change!

[WYorksWeather]

Are things about to pick up I wonder?

The spot in the western Gulf is now 70/80 (2/7 day formation chance), the central Atlantic spot is 30/50, and the eastern Atlantic spot is 0/50.

[matty40s]

 

[matty40s]

 

[WYorksWeather]

We now have Potential Tropical Cyclone Six in the western Gulf of Mexico. The central Atlantic spot is upgraded to 60/70, the eastern Atlantic spot is held at 0/50.

[Kirkcaldy Weather]

 

[WYorksWeather]

Tropical Depression Seven has now formed. Expected to become a tropical storm according to NHC.

The 12z intensity models, from before this system formed, mostly call for a tropical storm, but some going for a hurricane. Probably need a few more runs to see what might happen with this one.

It's a long way from land though at the moment.

[Kirkcaldy Weather]

 

[WYorksWeather]

All very slow at the moment. Again far too early to rule out a big flurry of activity (or maybe a slow burn with the season continuing longer due to high SSTs). But certainly if this continues for much longer, it will be an interesting post-mortem for the seasonal forecasters.

Certainly the number of named storms is very unlikely to reach 20+ from here you would think, and hurricanes unlikely to reach the ~12 that most had predicted. Majors is harder to call because the storms that have formed this season have found conditions ripe for intensification, so we could still have a 'quality over quantity' season I suppose.

[WYorksWeather]

Perhaps I shouldn't have said that. We shall see I guess...

[karyo]

 WYorksWeather

Some gfs runs produce a major hurricane in the GOM, but there is not enough consistency and the ECM has a much shallower low.

[WYorksWeather]

 karyo Yep, long way to go with this one.