The South ATLC peeps are looking in the wrong place

[P.K.]

TPNT KGWC 240353
A. TROPICAL DISTURBANCE IN SOUTH ATLANTIC
B. 24/0231Z (17)
C. 28.9S/9
D. 40.8W/2
E. SIX/GOES12
F. T1.5/1.5/STT: S0.0/07HRS -23/2331Z-
G. IR/EIR

47A/ PBO PTLY XPSD LLCC/AMNTN.

AODT: T2.2 (SHEAR)

LAURENTI

[P.K.]

Found this on a Brazilian website which has picked up on this.

As best as I can tell looking at the imagery, this low probably became a subtropical cyclone - a hybrid cyclone with the characteristics and energetics of both the extratropical frontal low and the tropical cyclone. Subtropical cyclones can have powerful winds near the center similar to tropical cyclones, but they still rely to some degree on baroclinic energy release as well.

This system formed as part of a baroclinic system (possibly behind a cold front?). Additionally, the system does not seem to have developed the upper-level outflow pattern that Catarina had.

So, I'm a bit hesitant to say this system became a fully tropical cyclone like I believe Catarina did. However, the presence of the convection and the short-lived eye shows that it at least started down the evolutionary path that Catarina followed.

I think the biggest difference between this system and Catarina is the evolution of the synoptic pattern. In the case of Catarina, the system cut off from the westerlies which wound up isolating the cyclone from vertical wind shear and a continuous inflow cooler air, which allowed the convection to gradually increase and the system to become a tropical cyclone.

If the global models I've looked at are correct, the current system has little chance to develop further as it won't be able to isolate itself from the westerlies.

Once again, thanks for the images, and please feel free to write again if you need more help with this system.

Yours sincerely,

Jack Beven

Tropical Prediction Center

http://www.estiagem.com.br/website/default.asp?CodArea=53&Secao=86&Subsecao=298

[senorpepr]

Thanks for the find, PK!

[Matt-hurricanewatcher]

If it was not for the shear this would of went far. This thing was really starting to pull its self together this morning. Reminds me of tropical depression 10...o shoot that system really had a sneak attack on us(at least new orleans)

[P.K.]

Not much left of it this morning is there. Sadly I can't find an MetArea forecasts since 1200 GMT yesterday.

[P.K.]

TPNT KGWC 241000
A. TROPICAL DISTURBANCE IN SOUTH ATLANTIC
B. 24/0831Z (17)
C. 29.1S/2
D. 38.7W/8
E. THREE/GOES12
F. T0.5/1.5/STT: W1.0/16HRS -24/0831Z-
G. IR/EIR

17A/ PBO XPSD LLCC/AMNTN. LLCC LOCATED 27NM NW OF DG,
YIELDING A DT OF 3.0. FINAL T BASED ON PT.

AODT: T2.3 (SHEAR)

LAING/LUDOVISSIE

[senorpepr]

T0.5... now that's just pathetic.

[P.K.]

METAREA V ISSUED BY BRAZILIAN NAVY MARINE METEOROLOGICAL SERVICE
NAVY HYDROGRAPHIC CENTER
WEATHER AND SEA BULLETIN REFERENT ANALYSIS TO 0000 - 24/FEB/2006

DATE AND TIME REFERENCE MERIDIAN OF GREENWICH - GMT
PRESSURE HPA
BEAUFORT SCALE WINDS
WAVES HEIGHT METERS

PART TWO - ANALYSIS AT 240000
LOW 1002 32S059W. LOW 1002 30S042W. LOW 998 35S032W. C-FRONT
AT 33S056W, 28S056W AND 22S059W MOVING AT 10 KTS TO E/NE. C-FRONT
AT 36S029W, 32S029W AND 28S032W MOVING AT 10 KTS TO E/NE.
I T C Z 01N020W, 01S030W, 02N040W AND 01N050W WITH 3/4
DEGREES WIDE WITH LIGHT/MOD OCNL HVY SHWRS AND ISOL THUNDERSTORMS IN
THE WHOLE BAND.

NNNN

[Coredesat]

0.5? Never thought I'd see a T-number that low.

[senorpepr]

Slight filling of the low... up 2 hPa.

[P.K.]

It looked much better 11 hours ago though. I guess it has filled further since then.

[cycloneye]

TPNT KGWC 241852
A. TROPICAL DISTURBANCE IN SOUTH ATLANTIC
B. 24/1731Z (17)
C. XX.X
D. XXX.X
E. GOES12
F. TX.X/1.5 -24/1731Z-
G. IR/EIR/VIS/MSI

CNF. THERE IS NO LONGER ANY CNVCTN ASSOCIATED WITH THIS
SYSTEM. THIS WILL BE THE LAST MESSAGE ON THIS SYSTEM FROM
AFWA. THIS SYSTEM WILL CONTINUED TO BE MONITORED FOR SIGNS
OF REGENERATION.

AODT: N/A

WOLLMANN/CAMPBELL



The Air Force folks bring the killing message for the disturbance.Well while it lasted it offered some excitment here.

[P.K.]

The South Atlantic obviously wasn't happy at how active other basins in the Southern Hemisphere are. Just need a SE Pacific system now.

[TheEuropean]

Flare up again?

[JonathanBelles]

i hope

[Matt-hurricanewatcher]

Wow something is going on with the south Atlantic. Is the central south Atlantic high weaker or growing weaker? I would think if there was a warmer climate that there would be lower pressure?

That system looks like something I would look into.

[MiamiensisWx]

There were probably other systems like this in the South Atlantic in the past that were overlooked.

[JamesFromMaine2]

[Matt-hurricanewatcher]

The system appears to have at least some cirulation. But its moving eastward in has to deal with shear.

http://wwwghcc.msfc.nasa.gov/GOES/goeseastfullir.html

[AJC3]

Flare up again?

This area of convection developed a little to the northwest of the dissipating (dissipated?) circulation that we had been tracking for several days. Recent SSMI data doesn't show much, and as someone else pointed out, neither does QS.

MHO is that the convection is simply a jet divergence aided t-storm complex, since upper level winds appear to be quite strong and prohibitive for spinup of another circ.