ATL: Ex INVEST 99L - Discussion

[Subtrop]

AL, 99, 2025081906, , BEST, 0, 125N, 201W, 30, 1010, DB, 34, NEQ, 0, 0, 0, 0, 1013, 120, 30, 0, 0, L, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 019, SPAWNINVEST, al792025 to al992025,

https://ftp.nhc.noaa.gov/atcf/btk/bal992025.dat

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Aug 18 2025

Eastern Tropical Atlantic:
A tropical wave located just off the coast of Africa is producing a
persistent cluster of disorganized showers and thunderstorms. Some
slight development of this system is possible over the next day or
two as it moves westward at around 15 mph. On Thursday, this system
should reach a less favorable environment, which should reduce its
chances for development.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...10 percent.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Tue Aug 19 2025

Eastern Tropical Atlantic:
A tropical wave located a few hundred miles to the southeast of the
Cabo Verde Islands continues to produce a concentrated area of
showers and thunderstorms. Environmental conditions appear generally
favorable for additional development over the next couple of days as
the system moves westward at around 15 mph. Towards the end of this
week, this system could encounter a less favorable environment,
limiting its development chances after that time.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...low...30 percent.

[Cachondo23]

We have an invest but is not the one of 60% chance…

[ouragans]

Everyone was focused on the central Atlantic wave and this one just popped out.

But what are the unfavorable conditions on its way from Thursday? SAL is ok, windshear seems to be ok, and SST too

[eastcoastFL]

This wave is much more impressive than the one out front but I didn't expect it to get tagged first. C'est la vie.

[Nimbus]

This is a new wave about 13.5N.
Might overtake and absorb the area we were looking at further south or get pushed north OTS by competing circulations?

[GCANE]

SAL is back with a vengeance.
I don't there is much to see until this gets to 50W.
Watching if a protected pouch develops with this as it comes off Africa.

[BobHarlem]

99L looks much better organized than the central Atlantic wave. The other one is just an elongated mess, 99L is pretty coherant. Sop far the models take it pretty far south, and then wreck it, but if it gets more organized sooner than expected it could change. Of the globals, the canadian's 850 vorticity model is the easiest to follow on this one. I'd follow this one to see how it goes over the next few days. Right now it seems sickly on the models, but its something that could change given the appearance on satellite. It's getting tugged south.



Also note the wave east of 99L. And the 60% wave on the west side.

[abajan]

Eastern Tropical Atlantic (AL99):
A tropical wave located a couple of hundred miles to the southeast
of the Cabo Verde Islands continues to produce a concentrated area
of showers and thunderstorms. Environmental conditions appear
generally favorable for additional development over the next couple
of days as the system moves westward at around 15 mph. Towards the
end of this week, this system could encounter a less favorable
environment, limiting its development chances after that time.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...low...30 percent.

[Teban54]

[AnnularCane]

This is a new wave about 13.5N.
Might overtake and absorb the area we were looking at further south or get pushed north OTS by competing circulations?

That's what I'm wondering, because I'm not sure why this got a sudden invest tag and the other one didn't, and the TWO isn't telling me anything. Are they thinking the two disturbances might merge? Is that the "unfavorable condition" the TWO is talking about? Except I'm not sure they're close enough together for that. Everything seemed much more straightforward yesterday, but now everything seems so confusing. What exactly is going on here?

[Buck]

Maybe its just my aging eyes, but this looks to have a pretty solid mid-level circulation already.

[Kingarabian]

Unless its due to poof soon this looks like a developing TC

[MGC]

Pretty decent mid level spin. Something to keep an eye on. Decent chance of another long track TC.......MGC

[Sciencerocks]

looking good

[AnnularCane]

Looks nice...trying not to get too attached though.

[abajan]

18Z Best Track:

AL, 99, 2025081918, , BEST, 0, 136N, 232W, 30, 1010, DB...

[Sciencerocks]

looks like a depression to me

[abajan]

Eastern Tropical Atlantic (AL99):
A tropical wave located just southwest of the Cabo Verde Islands
continues to produce shower and thunderstorm activity while it
moves westward at about 15 mph. A short-lived tropical depression
could form during the next day or two before environmental
conditions before unfavorable for further development late this
week.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...low...30 percent.

[BobHarlem]

99L continues to look good on the satellites and vort charts:

[zhukm29]

ASCAT pass that just hit 99L: