2021 Tropical Waves Thread

[Cpv17]

Is this wave the one currently predicted on the 06z GFS run to impact texas near hour 264? I tried to track the 850 vorticity but lose it south of Jamaica on the GFS.

Yes.

[USTropics]

Is this wave the one currently predicted on the 06z GFS run to impact texas near hour 264? I tried to track the 850 vorticity but lose it south of Jamaica on the GFS.

Yes, also AEWs have more of a signature at the mid-levels, so following the 700mb vorticity (especially the wind barbs) is easier (https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=atl&pkg=z700_vort&runtime=2021062112&fh=36).

The current 12z GFS forecasts a wave fracture (likely do to some intermediate development); I've highlighted the northern flank of the AEW in teal and the southern flank of the wave in green. While there is an additional wave behind this one (highlighted in red, centered around 34W/8N in current analysis), it's currently at a lower latitude and easy to follow its propagation over South America (and not the catalyst for what the GFS is attempting to form in the western Caribbean).



12z GFS loop:


06z Analysis:


I also would advise not getting too caught up in the operational model outputs at this current time, in terms of end track especially. They're good for analyzing potential synoptic pattern and development catalyst, but I would instead recommend focusing on ensemble trends at this timeframe:

[cycloneye]

A tropical wave located about 750 miles east-southeast of the
Windward Islands is producing disorganized showers and a few
thunderstorms. Although shower activity has diminished some this
afternoon, recent satellite-derived surface wind data indicate that
the wave has become better defined since yesterday. Some additional
development of this disturbance will be possible during the next
couple of days before upper-level winds become less conducive for
further organization by Thursday. The system is expected to move
westward to west-northwestward at 15 to 20 mph.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...low...30 percent.

[Aric Dunn]

oddly enough im hoping the cloud debris clears a little more.. you can almost see the LLC..

[cycloneye]

Aric, do you have the link to the ASCAT?

[Aric Dunn]

Aric, do you have the link to the ASCAT?

On the right side don't click just hover over all the passes since last night. This mornings passes are on the edges so the ambiguities are rather high. So check those and the HY-2B and -2C are a little less accurate but do well with less deep convection.

just the simple fact that any of the SCATS are showing closed wind field with such a small system is worth noting.. Marcos last year the SCATS were having trouble.

https://scatterometer.knmi.nl/tile_prod ... 0&imgt=fla

[cycloneye]

Aric, do you have the link to the ASCAT?

On the right side don't click just hover over all the passes since last night. This mornings passes are on the edges so the ambiguities are rather high. So check those and the HY-2B and -2C are a little less accurate but do well with less deep convection.

just the simple fact that any of the SCATS are showing closed wind field with such a small system is worth noting.. Marcos last year the SCATS were having trouble.

https://scatterometer.knmi.nl/tile_prod ... 0&imgt=fla

Thank you.

[Aric Dunn]

This is the best I can tell from the low level curved Cloud lines. they are moving pretty quick and are fairly tightly packed... meaning the llc is likely well defined just small like other systems in this area.

that hot tower looks to be firing right on top of the LLC so it does not look like we will get a peek of the LLC.

[Category5Kaiju]

This is the best I can tell from the low level curved Cloud lines. they are moving pretty quick and are fairly tightly packed... meaning the llc is likely well defined just small like other systems in this area.

that hot tower looks to be firing right on top of the LLC so it does not look like we will get a peek of the LLC.

https://i.ibb.co/DLQC4Sj/Capture.png

At first glance when I saw that image I had an adrenaline surge, I literally thought that that was an eye.

[Nimbus]

This is the best I can tell from the low level curved Cloud lines. they are moving pretty quick and are fairly tightly packed... meaning the llc is likely well defined just small like other systems in this area.

that hot tower looks to be firing right on top of the LLC so it does not look like we will get a peek of the LLC.

https://i.ibb.co/DLQC4Sj/Capture.png

So that is the area closer to the SAL on the northeast apex of the wave?

[Blown Away]

The windshield wiper continues. Now the GFS has landfall around Mobile again. At least it's not pushing back the formation time yet. It is still insisting that the wave east of the Caribbean will develop eventually. We will see.

12z GFS

[Category5Kaiju]

https://twitter.com/webberweather/status/1407067489545068545

That wave this gif is showing develop isn't the one marked as 30% now and the one that the GFS want to develop in the WCAR, right? It's a separate one?

[Aric Dunn]

https://twitter.com/webberweather/status/1407067489545068545

That wave this gif is showing develop isn't the one marked as 30% now and the one that the GFS want to develop in the WCAR, right? It's a separate one?

It is the same wave.

[SoupBone]

What is the GFS sniffing out that the Euro isn't at this point? Or is the Euro just a late bloomer?

[Cpv17]

What is the GFS sniffing out that the Euro isn't at this point? Or is the Euro just a late bloomer?

Or the GFS has a phantom problem. But I do think the Euro has a slight problem forecasting genesis. Last year it was really bad with that. But just about every model was last year.

[SoupBone]

What is the GFS sniffing out that the Euro isn't at this point? Or is the Euro just a late bloomer?

Or the GFS has a phantom problem. But I do think the Euro has a slight problem forecasting genesis. Last year it was really bad with that. But just about every model was last year.

If the NHC hadn't highlighted the system with a 30% development chance I'd maybe agree, but it seems at least they think something has a decent chance of forming.

[Kingarabian]

What is the GFS sniffing out that the Euro isn't at this point? Or is the Euro just a late bloomer?

Or the GFS has a phantom problem. But I do think the Euro has a slight problem forecasting genesis. Last year it was really bad with that. But just about every model was last year.

If the NHC hadn't highlighted the system with a 30% development chance I'd maybe agree, but it seems at least they think something has a decent chance of forming.

Yeah this isn't a phantom storm. There's EPS support for this system. IMO, the main difference between the GFS and the Euro solutions is that the latter eventually tracks most of its energy SE then NE of Florida, while the GFS steers it at a lower latitude and into the Caribbean and then the GOM.

12z Euro:


12z GFS:

[cycloneye]

A tropical wave located about 700 miles east-southeast of the
Windward Islands is producing disorganized showers and a few
thunderstorms. Some additional development of this disturbance will
be possible during the next couple of days before upper-level winds
become less conducive for further organization by Thursday. The
system is expected to move westward to west-northwestward at 15 to
20 mph.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...low...30 percent.

[Stormybajan]

Tonight might be the last chance for the wave to accomplish anything east of the islands. Starting to see a bit more in pop up convection again but nothing major right now

[floridasun78]

i think area have very slim chance becoming td area not area you see td this time a year but could sign that we going see busy july to sep in tropic