Low Pressure in the Central Atlantic (Is Invest 91L)

[tolakram]

UKMET with this wave.

[aspen]

I think this is going to end up being a pretty big mess with competing vorts fighting to become dominant, before finally developing closer to the islands. I think the GFS is way too bullish for now but I would be surprised if this doesn't end up developing.

The GFS’s evolution seems pretty reasonable. It shows the currently excellent convection diminishing by tonight or tomorrow morning, and the wave takes another 3-4 days to start firing off like crazy again as the competing vorts and wave axis merge in the process USTropics described. If the GFS was showing that SW vort developing in under 72 hours, then I’d agree it was too aggressive.

[USTropics]

We can watch this evolution in real-time throughout the next several days. Highlighted in blue is the wave axis, with the dashed blue lines being the projected mid-level surge later today. This will begin to impact the convective complex associated with the monsoon trough to the SW, and forcing it to pivot north as the wave axis approaches (red). As the wave axis becomes oriented on the western flank, the associated vorticity will begin to pivot to the SW (orange dashed lines) somewhere along 40-45W. Once this evolution completes (2-3 day process), TCG should occur:

[InfernoFlameCat]

I like how the feature to the west of the wave just decided to like spawn in two days ago. It practically came from nothing.

[AutoPenalti]

Is that ULL really going to stall out that TW for 3 whole days?

[USTropics]

I like how the feature to the west of the wave just decided to like spawn in two days ago. It practically came from nothing.

MJO+ monsoon trough, similar to how the CAG develops in early/late season. Actual mechanics I outlined here - https://www.storm2k.org/phpbb2/viewtopi ... 2#p2982392

[ScottNAtlanta]

https://twitter.com/BigJoeBastardi/status/1563153860428206080?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Etweet

It's pretty simple, NHC is tracking the axis of the trailing wave. The mid-level surge from the trailing wave will pivot this complex north later today. My post from last night outlines this: https://www.storm2k.org/phpbb2/viewtopi ... 9#p2982319

Latest ECMWF (06z) shows this evolution as well:
https://i.ibb.co/8Xd2Gvt/ecmwf-z850-vort-atl-fh0-90.gif

Going to re-quote this excellent post from UStropics. There is a reason the NHC has it at 30% still and all the models are still not 100% decided on which blob will be the dominating one. We have had just one bullish operational run so far so give it some time, it’s very likely not close to 90% or a TD just yet.

Remember just last week how excellent the wave in the BoC looked and when recon got there, it was literally just a wave blowing convection off its axis with 90% off the winds in just one direction.

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In all honesty, that wave never had the surface vorticity this one does. There is also 10 degrees of longitude between the feature "X'd" by NHC and this one

[skyline385]

Some more on this

 https://twitter.com/dcareawx/status/1563171853040230400





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[Iceresistance]

SSTs are only getting higher, also added the coordinates.

https://s4.gifyu.com/images/51593537.gif

That vorticity is strong!
850 MB

https://s4.gifyu.com/images/wg8vor.gif

700 MB

https://s4.gifyu.com/images/wg8vor3.gif

[ChrisH-UK]

I like how the feature to the west of the wave just decided to like spawn in two days ago. It practically came from nothing.

Not yet, once the first one starts moving it starts developing then a third drops of the African coast and then they merge.

[BobHarlem]

Did any of the models show this convective area even a day or two ago being this strong?

[USTropics]

Did any of the models show this convective area even a day or two ago being this strong?

The past 4 runs of the ECMWF and GFS did a good job of forecasting this. Beyond 24 hours? Not the best modeled meso convective complex.

[Iceresistance]

Feeder bands may be developing


https://s4.gifyu.com/images/12615616.gif

[skyline385]

Did any of the models show this convective area even a day or two ago being this strong?

The past 4 runs of the ECMWF and GFS did a good job of forecasting this. Beyond 24 hours? Not the best modeled meso convective complex.

Yea the models have it getting really messy in the next 2-3 days, will be interesting to see if it verifies


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[AutoPenalti]

The GFS run is stuck at hour 18. Not sure if that's a TT thing or it's just really slow.

[skyline385]

The GFS run is stuck at hour 18. Not sure if that's a TT thing or it's just really slow.

Its a TT thing, use pivotal weather for now until Levi fixes the issue he has been having


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[cycloneye]

 https://twitter.com/NHC_TAFB/status/1563199062043529217

[ThomasW]

ICON already backing off. knew it couldn't last haha

[SFLcane]

ICON already backing off. knew it couldn't last haha

?

12z Icon has an intensifying TS nearing the northern islands.

[ThomasW]

ICON already backing off. knew it couldn't last haha

?

12z Icon has an intensifying TS nearing the northern islands.

Talking about the time of TCG respective to the last run