2024 Global Model Runs Discussion (Out thru day 16)

[CyclonicFury]

12z EPS has practically nothing behind 98L

[Stratton23]

Yeah I dont buy that at all, not even remotely, its going to be a problem if the ensembles are this oblivious to a favorable MJO passage,

[aspen]

12z EPS has practically nothing behind 98L

Which is odd because just 2 days ago it had multiple members developing the wave right behind it, plus other models showing additional waves rolling off of Africa. Surely at least one of those should develop as the MJO roll through.

[Teban54]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

[Stratton23]

That will only delay the uptick slightly, the atlantic will explode, that is inevitable, but you know folks are going to “ cancel” the season when they see that tweet lol

[Category5Kaiju]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

Of all possible Atlantic hurricane seasons, the one with an early July Category 5 hurricane and a (soon-to-be) strong pre-August 20 hurricane isn't necessarily a season where I would think this would be an issue.

I guarantee you that there will be a big rampup in activity after future Ernesto leaves the picture. Just watch.

[Hurricane2022]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

[skyline385]

Here comes the buzzword
https://x.com/dmorris9661/status/182232 ... 80615?s=19

https://imageshack.com/i/pn3tLCzqp

So going to try my best to stop the buzzword from spreading by saying that Danny is wrong here and the reason we dont see activity has nothing to do with wavebreaking. Below is a 355k PVU plot (useful for locating PV streamers which result from wavebreaking and impart shear) of the GFS after 98L. This is not what an extensive wavebreaking setup would like, there are pretty much zero strong PVS extending into the deep tropics imparting shear on any wave incoming through the MDR. This is also confirmed through the shear plots, which while not recommended for actually looking at shear, will show PVS easily because they have very high shear values along their boundary (the high shear near Africa is not because of a PVS as noted from the PVU plot). The warm blob in the subtropics also isnt solely going to cause wavebreaking, its a sharp gradient in SSTs setting up near the east coast which can cause enhanced wavebreaking (this is noted by Philip K in the 2022 seasonal outlook) which we are completely missing this year with the entirety of the NATL running warm without any cold pool seen to create the gradient unlike 2022.

TCA also pretty confirmed this few days ago in his tweet where he noted that the current +AMO setup is associated with record low PVS (or wavebreaking) activity.

So, what is the reason for the reduced activity then? I think its partly related to the strong SAL season we are having which is because of the particularly strong AEJ we have seen this year which has been continuously pumping out AEWs since mid May. There were several instances of wave trains even in June where we had 5 TW active in the NATL because of the active AEJ. This is also seen in the GFS plot showing another outbreak following 98L. SAL will of course eventually decrease past mid-August and the NATL will go into peak season mode assisted by the active AEJ again, but for now it is having a strong year.



 https://x.com/WxTca/status/1812584195748696494



 https://x.com/MichaelRLowry/status/1815889034939412724

[LarryWx]

The 12Z UKMET has TCG along the NC coast Tue night. The 18Z GFS has extratropical energy moving offshore then. 10% of 18Z EPS members develop this, too. Anyone know anything about this? Likely bogus but sometimes this kind of thing surprises:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 90 HOURS
FORECAST POSITION AT T+ 90 : 35.1N 75.6W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 14.08.2024 96 35.1N 73.8W 1009 33
0000UTC 15.08.2024 108 34.0N 70.4W 1007 33
1200UTC 15.08.2024 120 35.8N 66.2W 1005 31
0000UTC 16.08.2024 132 38.8N 61.7W 1003 41
1200UTC 16.08.2024 144 43.1N 58.2W 999 39
0000UTC 17.08.2024 156 47.1N 53.8W 996 36
1200UTC 17.08.2024 168 50.4N 48.6W 992 35

[mantis83]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

season cancel?.......

[REDHurricane]

Here comes the buzzword
https://x.com/dmorris9661/status/182232 ... 80615?s=19

https://imageshack.com/i/pn3tLCzqp

So going to try my best to stop the buzzword from spreading by saying that Danny is wrong here and the reason we dont see activity has nothing to do with wavebreaking. Below is a 355k PVU plot (useful for locating PV streamers which result from wavebreaking and impart shear) of the GFS after 98L. This is not what an extensive wavebreaking setup would like, there are pretty much zero strong PVS extending into the deep tropics imparting shear on any wave incoming through the MDR. This is also confirmed through the shear plots, which while not recommended for actually looking at shear, will show PVS easily because they have very high shear values along their boundary (the high shear near Africa is not because of a PVS as noted from the PVU plot). The warm blob in the subtropics also isnt solely going to cause wavebreaking, its a sharp gradient in SSTs setting up near the east coast which can cause enhanced wavebreaking (this is noted by Philip K in the 2022 seasonal outlook) which we are completely missing this year with the entirety of the NATL running warm without any cold pool seen to create the gradient unlike 2022.

TCA also pretty confirmed this few days ago in his tweet where he noted that the current +AMO setup is associated with record low PVS (or wavebreaking) activity.

So, what is the reason for the reduced activity then? I think its partly related to the strong SAL season we are having which is because of the particularly strong AEJ we have seen this year which has been continuously pumping out AEWs since mid May. There were several instances of wave trains even in June where we had 5 TW active in the NATL because of the active AEJ. This is also seen in the GFS plot showing another outbreak following 98L. SAL will of course eventually decrease past mid-August and the NATL will go into peak season mode assisted by the active AEJ again, but for now it is having a strong year.

Great post. There's no reason to expect anything other than an explosion of activity (incoming Ernesto notwithstanding) starting around the magic August 20th, the models always seem to struggle with seeing the start of peak season until it's already happening. The only way the Atlantic doesn't get to at least 200 ACE in my understanding is if weather/climate science as a whole discovers an entirely unforeseen phenomenon that significantly hinders tropical cyclone formation, because essentially every single known ingredient associated with extremely active hurricane activity is in place, sitting in the oven and just waiting for when the start button gets pushed at the end of August/early September like it does every year.

[cheezyWXguy]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

season cancel?.......

Dude…

[IsabelaWeather]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

season cancel?.......

Dude…

This is already an extremely impactful year, even if we were to get no more storms. Some islands just got obliterated, Ernesto looks poised to swamp PR. If thats it (its not) then its already up there....

[Stratton23]

mantis83 just stop, and please just delete this comment, its going to age like expired food

[Hammy]

https://imageshack.com/i/pn3tLCzqp

So going to try my best to stop the buzzword from spreading by saying that Danny is wrong here and the reason we dont see activity has nothing to do with wavebreaking. Below is a 355k PVU plot (useful for locating PV streamers which result from wavebreaking and impart shear) of the GFS after 98L. This is not what an extensive wavebreaking setup would like, there are pretty much zero strong PVS extending into the deep tropics imparting shear on any wave incoming through the MDR. This is also confirmed through the shear plots, which while not recommended for actually looking at shear, will show PVS easily because they have very high shear values along their boundary (the high shear near Africa is not because of a PVS as noted from the PVU plot). The warm blob in the subtropics also isnt solely going to cause wavebreaking, its a sharp gradient in SSTs setting up near the east coast which can cause enhanced wavebreaking (this is noted by Philip K in the 2022 seasonal outlook) which we are completely missing this year with the entirety of the NATL running warm without any cold pool seen to create the gradient unlike 2022.

TCA also pretty confirmed this few days ago in his tweet where he noted that the current +AMO setup is associated with record low PVS (or wavebreaking) activity.

So, what is the reason for the reduced activity then? I think its partly related to the strong SAL season we are having which is because of the particularly strong AEJ we have seen this year which has been continuously pumping out AEWs since mid May. There were several instances of wave trains even in June where we had 5 TW active in the NATL because of the active AEJ. This is also seen in the GFS plot showing another outbreak following 98L. SAL will of course eventually decrease past mid-August and the NATL will go into peak season mode assisted by the active AEJ again, but for now it is having a strong year.

Great post. There's no reason to expect anything other than an explosion of activity (incoming Ernesto notwithstanding) starting around the magic August 20th, the models always seem to struggle with seeing the start of peak season until it's already happening. The only way the Atlantic doesn't get to at least 200 ACE in my understanding is if weather/climate science as a whole discovers an entirely unforeseen phenomenon that significantly hinders tropical cyclone formation, because essentially every single known ingredient associated with extremely active hurricane activity is in place, sitting in the oven and just waiting for when the start button gets pushed at the end of August/early September like it does every year.

The biggest inhibiting factor right now is the moonsoon trough still seems to be too far north, which is causing more stable and dry air to come off with the waves (and why I think the 20+ numbers might not verify, if we continue seeing a dearth of formation in the subtropics. )

The ACE forecasts still have a high chance of verifying, as do the hurricane numbers, since the storms that do develop seem more than able to take advantage of the conditions--especially with Debby reaching 80 mph (and even restrengthening to 60 for it's second landfall) even in marginal conditions--it would not surprise me if most of the storms that form for the duration of the season and have 48 or so hours or more over water reach hurricane intensity.

[SFLcane]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

season cancel?.......

This is ridiculous! We are 2 weeks barely into Aug lol even the most hyper active years go quite but I think you know this. Do you post these comments intentionally? No offense but this is getting rather annoying and provides 0 contribution wise to the thread. There is a reason why 85% percent of major hurricanes occur after 8/20. Patience grasshopper

[Category5Kaiju]

Here comes the buzzword
 https://x.com/dmorris9661/status/1822326665210380615

season cancel?.......

We literally just had an early July Category 5 hurricane….

[Steve]

He used a question mark and the bug eyes, so I don’t think it was serious - just more of a commentary on Morris’s tweet (icbw).

It’s just about go time. Click on or mouse over any of the MJO models. All the good ones show the deep plunge into Phases 1-2-3. It’s particularly amplified in 2 and 3 before coming back up toward the end of the month. Easy bet there will be at least 3 named systems between now and the end of the month - if not more. So we should be close to at least the G storm by September 1. Watch for the models to wake up heading into next weekend.

https://www.cpc.ncep.noaa.gov/products/ ... r_wh.shtml

[wzrgirl1]

Can someone please tell me how ACE is calculated. I know what the acronym stands for but unsure of the
algorithm.

[Steve]

Can someone please tell me how ACE is calculated. I know what the acronym stands for but unsure of the
algorithm.

It wouldn’t copy and paste due to symbols.

https://en.m.wikipedia.org/wiki/Accumul ... alculation