ATL: GERT - Post-Tropical - Discussion

[wxman57]

NASA SAL forecast valid Monday is for 99L to be practically embedded in dust. That might inhibit development until it moves farther west.

[weathaguyry]

In general, the overall setup would put a large portion of the US coastline in danger, if something were to develop

[wxman57]

Good ASCAT hit at 1123Z today. LLC near 8.8N / 20.4W

[tolakram]

For what it's worth here is the GOES16 view from SLIDER.

http://rammb-slider.cira.colostate.edu/?sat=goes-16&sec=full_disk&x=21006&y=8915&z=4&im=30&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&p%5B0%5D=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&s=rammb-slider

Looks like banding is setting up pretty quickly, though the angle makes it really difficult to tell.

[JPmia]

With the ECMWF dropping it I have lost some faith in this being more than a TD or a weak TS. Just an opinion of course, and the ECMWF is not always right.

You really are the Debbie Downer of Tropical Cyclone tracking. Kidding with you of course.

[weathaguyry]

Pretty amazing that this already has an LLC, a change from an MLC with a blob of storms on top like we have seen so far this season

[tolakram]

Remember not to use the globals as a guide for intensity. If they were good at it then intensity forecasts would be easy. I don't think we have any real idea, up or down, what this will do yet. It seems early to me, if this was mid August then maybe but this one may turn out to be another weak storm that sets the stage for more later.

or not.

[PTrackerLA]

Just looked at the control run of the 06z GEFS, recurves just west of Bermuda as a significant hurricane. Wouldn't be surprised to see and OTS solution next run but we would probably have a week before this is ironed out.

[RL3AO]

Just looked at the control run of the 06z GEFS, recurves just west of Bermuda as a significant hurricane. Wouldn't be surprised to see and OTS solution next run but we would probably have a week before this is ironed out.

IMO further north and east isn't the likely answer. If anything it should shift further south and west towards the islands.

[gatorcane]

Careful with the upgraded GFS. It has shown an intensity-bias so far this year where it makes systems way too strong (RE: EPAC). If anything I see this getting nowhere near as organized as the GFS has it over the next week or more and staying much further south than the GFS has it. Basically more like the Euro is showing but probably more organized and a bit stronger.

[OuterBanker]

Interesting tweet this am from NC Emergency management. This is why most of NC breathed a sigh of relief and didn't prepare.
Just goes to show even when all the models agree, they can be terribly wrong.

https://twitter.com/hashtag/ReadyNC?src=hash

[wxman57]

Pretty amazing that this already has an LLC, a change from an MLC with a blob of storms on top like we have seen so far this season

It's not uncommon for waves to have a weak LLC as they move off the west coast of Africa. The hard part is keeping that circulation and/or strengthening once the waves move farther west.

[Alyono]

triple facepalm for the 12Z GFS

It develops a phantom at 25W, not the wave coming off of Africa

[RL3AO]

triple facepalm for the 12Z GFS

It develops a phantom at 25W, not the wave coming off of Africa

I guess you can kind of see something at 10N 25W, but I don't see why that area of the wave/trough will become the TC...

[RL3AO]

It's pretty clear that the wave axis is further to the east. Interesting development from the GFS.

[Nimbus]

The Sal was worse back in June but its still a little dry.
The early recurve tracking models must also be assuming early development?

[Siker]

UKMET decently stronger, continues its southern route

Edit: Slightly north of previous runs but still much further south than GFS/CMC:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 42 HOURS
FORECAST POSITION AT T+ 42 : 11.9N 33.2W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 05.08.2017 48 11.9N 34.9W 1008 33
0000UTC 06.08.2017 60 12.5N 37.5W 1006 36
1200UTC 06.08.2017 72 13.3N 40.1W 1003 39
0000UTC 07.08.2017 84 13.9N 43.0W 1001 43
1200UTC 07.08.2017 96 14.1N 46.2W 1001 40
0000UTC 08.08.2017 108 14.4N 49.4W 1000 42
1200UTC 08.08.2017 120 14.8N 52.7W 999 43
0000UTC 09.08.2017 132 15.6N 56.2W 997 49
1200UTC 09.08.2017 144 16.4N 59.9W 993 61

[TheStormExpert]

In exactly a week the 12z GFS is already trending SW of it's 06z 7-day position by a good 100 miles or so.

[WeatherEmperor]

Sent from my iPhone 7 using Tapatalk

[TheStormExpert]

As time goes on I'd expect the GFS to trend further south towards a potential Caribbean cruiser scenario similar to what the Euro/UKMET has.