Possible development in the Eastern Atlantic (Is Invest 90L)

[cycloneye]

8 AM:

Eastern Tropical Atlantic:
An area of low pressure could form over the eastern tropical
Atlantic by the early to middle part of next week. Environmental
conditions are expected to be conducive for slow development
thereafter while the system moves generally northwestward at 10 to
15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

[Teban54]

We've finally got to the stage where storms are popping up like rabbits.

This is the storm that both global and ensemble models were making a potent west-moving MH a few runs ago. They've trended away from that direction now, partly because it's now expected to recurve much earlier at 40-50W. Right now, GFS, Euro and their ensembles still have a strong hurricane on the recurve. However, this is exactly what they had for Gordon and soon-to-be Joyce.

[cycloneye]

12z GFS develops a monster cane, but it moves it strait to the north and if that happens, it may not produce a good deal of ACE.

[Travorum]

12z GFS develops a monster cane, but it moves it strait to the north and if that happens, it may not produce a good deal of ACE.

https://i.imgur.com/veDtWk8.gif

GFS developed monsters out of both Gordon and Joyce at this equivalent lead time, we shall see if this one sticks.

[cycloneye]

Up to 30%.

Eastern Tropical Atlantic:
An area of low pressure could form over the eastern tropical
Atlantic by the early to middle part of next week. Environmental
conditions are expected to be conducive for slow development
thereafter while the system moves generally northwestward at 10 to
15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

[Teban54]

12z GFS develops a monster cane, but it moves it strait to the north and if that happens, it may not produce a good deal of ACE.

https://i.imgur.com/veDtWk8.gif

GFS developed monsters out of both Gordon and Joyce at this equivalent lead time, we shall see if this one sticks.

One thing in favor of this system is MJO being much more cooperative. It should probably be around phase 1-2 at that time, which are typically associated with significant activity in the open Atlantic.

[galaxy401]

Well it is after the 20th...I told you the switch always flips on the 20th.

Just move everything 30 days later.

[Teban54]

GFS continues to make this a hurricane in the 950s even within MDR proper, while Euro also shows 960s on the recurve past 30N or so. What makes them a bit more believable this time is that the wave has already left Africa.

[cycloneye]

Eastern and Central Tropical Atlantic:
A broad and elongated area of low pressure, associated with a
tropical wave, is producing limited shower activity near and to the
west of the Cabo Verde Islands. Environmental conditions appear
conducive for gradual development of this system, and a tropical
depression could form next week while moving toward the west and
then northwest at about 10 mph across the eastern and central
tropical Atlantic.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...40 percent.

[Hurricane2022]

Nobody wants these type of brief-cane that recurves this early. Something like Hurricane Sam or atleast Hurricane Lorenzo would be much cooler to track.

[Teban54]

Yet another 950s run from GFS. It shows strong TS in 3 days and Cat 1 in 4 days, which I don't recall it showing for Gordon and Joyce at these short lead times.

Edit: 0z ICON bombs out to 937 mb. It also has another MDR low-rider at 968 mb at the end of the run. You usually don't get pressures like this from ICON.

[CrazyC83]

Is there anything that could, in theory, prevent it from going OTS? I know a Cape Verde long-tracker to the coasts is almost unheard-of in October, but Beryl broke rules, so why not Kirk (or Leslie)?

[cycloneye]

Eastern and Central Tropical Atlantic:
A broad and elongated area of low pressure, associated with a
tropical wave, is producing limited shower activity near and to the
west of the Cabo Verde Islands. Environmental conditions appear
conducive for gradual development of this system, and a tropical
depression could form next week while moving toward the west and
then northwest at about 10 mph across the eastern and central
tropical Atlantic.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...50 percent.

[kevin]

06z GFS peaks at 944 mb at +189 hrs. Already a TD at +24 and a TS at +30 hrs. Looks like the season's big ACE-maker. But only if (and that's a big if) GFS is finally correct regarding improved TC conditions in the MDR. I'm especially curious if TC genesis will really be as early as GFS is currently showing, I'll take a closer look at the ensemble once it arrives.

[cycloneye]

06z GFS peaks at 944 mb at +189 hrs. Already a TD at +24 and a TS at +30 hrs. Looks like the season's big ACE-maker. But only if (and that's a big if) GFS is finally correct regarding improved TC conditions in the MDR. I'm especially curious if TC genesis will really be as early as GFS is currently showing, I'll take a closer look at the ensemble once it arrives.

It would be a huge ACE maker if it not recurves so fast as GFS is doing.

[kevin]

I have a suspicion this might get named much sooner than the NHC is thinking right now. 06z GEFS has 31! out of 32 members developing a TD at +42, 36 hours from now. So according to GEFS a 90% - 100% chance of development over the next 48 hours. Similarly 00z Euro develops 33 out of 51 members over the next 36 hours -> 65%. Combining both with equal weight gives an 80% chance of development over the next 36 hours.

The reason why I'm putting faith in the models is because of their performance with Helene. NHC had Helene at only 10% development chances over the next 48 hours during the 12z runs on September 22. Back then 90% of GEFS members showed development at +42. Soon afterwards, the disturbance indeed started to consolidate and we had a PTC at +27 hrs compared to the 12z run. We then officially got Helene at +51 hrs (15z, September 24) with a TD perhaps being added a few hours earlier in the post-season. If the 12z model cycles of the Euro and GEFS show similar development as the 00z/06z runs I expect the development chances to be raised significantly.

[cycloneye]

Already has a good vorticity signature. They will raise the percents at 8 AM.

[Teban54]

[cycloneye]

8 AM:

Eastern and Central Tropical Atlantic:
A broad and elongated area of low pressure, associated with a
tropical wave, is producing disorganized showers and thunderstorms
near and to the west of the Cabo Verde Islands. Environmental
conditions appear conducive for gradual development of this system,
and a tropical depression could form during the early or middle
part of next week while the system moves toward the west and then
northwest across the eastern and central tropical Atlantic.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...medium...60 percent.

[cycloneye]

This could be invest 90L anytime today as it looking better as time goes by.