SATL: RAONI - Post-Tropical

[Felipe Freitas]

TXST21 KNES 290105
TCSSTL

A. TROPICAL DISTURBANCE

B. 28/2330Z

C. 37.0S

D. 52.0W

E. THREE/GOES-E

F. T3.5/3.5

G. IR/EIR/SWIR

H. REMARKS...0.85 CURVED BANDING RESULTS IN A DT OF 3.5. THE MET AND
THE PT ARE NOT AVAILABLE AS THIS SYSTEM HAS TRANSITIONED FROM SUBTROPICAL
TO TROPICAL. THE FT IS BASED ON THE DT. OF NOTE IS THE APPEARANCE OF AN
EYE AFTER THE 2330Z IMAGE WITH CONTINUALLY COOLING CLOUD TOPS IN THE CDO.

I. ADDL POSITIONS

NIL


...HOSLEY

[HurricaneFrances04]

Jeesh in the middle of winter too?

The entire Atlantic basin is really spinning up everything this month.

[Felipe Freitas]

 https://twitter.com/i/status/1409550283206795264




 https://twitter.com/RyanMaue/status/1409683149106257922

[aspen]

https://twitter.com/i/status/1409550283206795264

https://twitter.com/RyanMaue/status/1409683149106257922

That looks like an excellent subtropical cyclone. What a surprise for the South Atlantic at this time of year.

[TheAustinMan]

What a phenomenal sight for winter. Certainly of the most organized systems we've seen in the South Atlantic. I mean, look at that!

1MB. Source: Marshall Space Flight Center

[EquusStorm]

This thing is REALLY cool

[Sciencerocks]

I wonder how long it will take Brazil to finally upgrade this system? You know the people that upgrade every extratropical system that looks nothing like cyclones every years. lol

[AJC3]

Can the OP (or anyone else, for that matter) reference the "Invest N1" designation?

If it's not an official Invest, then this thread will need to be moved into TT (in spite of how good it looks) and the title changed. Maybe Navy Brazil or METSUL will call it an STS here soon.

[Felipe Freitas]

System has not been named as it is in Uruguay's area of responsibility.

AVISO NR 676/2021

AVISO ESPECIAL
EMITIDO ÀS 0300Z – TER – 29/JUN/2021

TEMPESTADE SUBTROPICAL COM PRESSÃO CENTRAL ESTIMADA DE 988 HPA EM 37S051.6W, MOVENDO-SE PARA NORDESTE COM VENTOS MÁXIMOS ESTIMADOS EM 50 NÓS NO SETOR SUL DO CICLONE.
PREVISÃO: VENTOS CICLÔNICOS FORÇA 9/10 (41 A 55 NÓS) COM RAJADAS NO RAIO DE 400MN AO REDOR DO CENTRO DO SISTEMA E VENTOS W/SW FORÇA 8/9 (34 A 47 NÓS) JUNTO À COSTA NA ÁREA ALFA. MAR GROSSO/ALTO ASSOCIADO.
POSIÇÃO ESTIMADA:
291200 HMG: 35.1S048.9W – 990 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 40-45 NÓS – TEMPESTADE SUBTROPICAL
300000 HMG: 33.6S045.9W – 996 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 45-50 NÓS – TEMPESTADE SUBTROPICAL
301200 HMG: 30.8S043.5W – 1006 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 35-40 NÓS – TEMPESTADE SUBTROPICAL
010000 HMG: 27.9S041.6W – 1013 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 30-35 NÓS – DEPRESSÃO SUBTROPICAL
VÁLIDO ATÉ 010000 HMG.
ESTE AVISO SUBSTITUI O AVISO NR 675/2021.

[Felipe Freitas]

Can the OP (or anyone else, for that matter) reference the "Invest N1" designation?

If it's not an official Invest, then this thread will need to be moved into TT (in spite of how good it looks) and the title changed. Maybe Navy Brazil or METSUL will call it an STS here soon.

NOAA: https://www.ssd.noaa.gov/PS/TROP/storms/Invest1.html

[AJC3]

System has not been named as it is in Uruguay's area of responsibility.

https://imgur.com/a/n6Y9xuJ

AVISO NR 676/2021

AVISO ESPECIAL
EMITIDO ÀS 0300Z – TER – 29/JUN/2021

TEMPESTADE SUBTROPICAL COM PRESSÃO CENTRAL ESTIMADA DE 988 HPA EM 37S051.6W, MOVENDO-SE PARA NORDESTE COM VENTOS MÁXIMOS ESTIMADOS EM 50 NÓS NO SETOR SUL DO CICLONE.
PREVISÃO: VENTOS CICLÔNICOS FORÇA 9/10 (41 A 55 NÓS) COM RAJADAS NO RAIO DE 400MN AO REDOR DO CENTRO DO SISTEMA E VENTOS W/SW FORÇA 8/9 (34 A 47 NÓS) JUNTO À COSTA NA ÁREA ALFA. MAR GROSSO/ALTO ASSOCIADO.
POSIÇÃO ESTIMADA:
291200 HMG: 35.1S048.9W – 990 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 40-45 NÓS – TEMPESTADE SUBTROPICAL
300000 HMG: 33.6S045.9W – 996 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 45-50 NÓS – TEMPESTADE SUBTROPICAL
301200 HMG: 30.8S043.5W – 1006 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 35-40 NÓS – TEMPESTADE SUBTROPICAL
010000 HMG: 27.9S041.6W – 1013 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 30-35 NÓS – DEPRESSÃO SUBTROPICAL
VÁLIDO ATÉ 010000 HMG.
ESTE AVISO SUBSTITUI O AVISO NR 675/2021.

Thank you for posting this. I will leave the thread here and retitle it as a STC. Can you post or PM me the link to that advisory? Thanks

[Nancy Smar]

System has not been named as it is in Uruguay's area of responsibility.

https://imgur.com/a/n6Y9xuJ

AVISO NR 676/2021

AVISO ESPECIAL
EMITIDO ÀS 0300Z – TER – 29/JUN/2021

TEMPESTADE SUBTROPICAL COM PRESSÃO CENTRAL ESTIMADA DE 988 HPA EM 37S051.6W, MOVENDO-SE PARA NORDESTE COM VENTOS MÁXIMOS ESTIMADOS EM 50 NÓS NO SETOR SUL DO CICLONE.
PREVISÃO: VENTOS CICLÔNICOS FORÇA 9/10 (41 A 55 NÓS) COM RAJADAS NO RAIO DE 400MN AO REDOR DO CENTRO DO SISTEMA E VENTOS W/SW FORÇA 8/9 (34 A 47 NÓS) JUNTO À COSTA NA ÁREA ALFA. MAR GROSSO/ALTO ASSOCIADO.
POSIÇÃO ESTIMADA:
291200 HMG: 35.1S048.9W – 990 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 40-45 NÓS – TEMPESTADE SUBTROPICAL
300000 HMG: 33.6S045.9W – 996 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 45-50 NÓS – TEMPESTADE SUBTROPICAL
301200 HMG: 30.8S043.5W – 1006 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 35-40 NÓS – TEMPESTADE SUBTROPICAL
010000 HMG: 27.9S041.6W – 1013 HPA – VENTO MÁXIMO MANTIDO ESTIMADO EM 30-35 NÓS – DEPRESSÃO SUBTROPICAL
VÁLIDO ATÉ 010000 HMG.
ESTE AVISO SUBSTITUI O AVISO NR 675/2021.

Thank you for posting this. I will leave the thread here and retitle it as a STC. Can you post or PM me the link to that advisory? Thanks

https://www.marinha.mil.br/chm/dados-do ... -mau-tempo

[galaxy401]

When I first saw this thread, I thought it was another North Atlantic invest. Looks quite decent for a middle of the winter storm in the South Atlantic.

Not surprised there isn't a name since this is something that Uruguay never would have expected to monitor anyways.

[Vince_and_Grace_fan]

It looks more tropical now, the convection almost fully wrapping around the center. An ASCAT pass at 02:00 UTC supported highest winds around 50-55 kt.

[Hypercane_Kyle]

Reminds me of Hurricane Alex in 2016, just in the southern Atlantic.

[Argcane]

Breath-taking storm.





Humph, careful..
 https://twitter.com/RyanMaue/status/1409897694244581376

[EquusStorm]

We are certainly witnessing the most intense and organized system in the South Atlantic since 2004, it's been absolutely fascinating to watch. The fact it's developed and existed below like 30°S in Southern Hemisphere winter is astounding. It's quite like Alex indeed.

[Vince_and_Grace_fan]

The convection temporarily weakened in the afternoon, but near sunset new bursts of deep convection fired up around the center which have been trying to wrap around it since then. The eye was the most well-defined between 13:30-14:00 UTC when two deep convective band persisted on the north and south part of the eyewall.





Full daytime visible satellite animation:

[rodolfo alves]

WPC/NOAA in the South America section defines Raoni as "Subtropical Storm".

[Hypercane_Kyle]

Yeah, this is not a subtropical storm.