SATL - IBA - Post-Tropical

[Nancy Smar]

Invest 90Q
TXST21 KNES 240002
TCSSTL
A.  TROPICAL DISTURBANCE (90Q)
B.  23/2330Z
C.  17.6S
D.  36.0W
E.  THREE/GOES-E
F.  T1.0/1.0/D1.0/24HRS
G.  IR/EIR/SWIR
H.  REMARKS...WANING VISIBLE IMAGERY SHOWED A WELL-DEFINED LOW
LEVEL CIRCULATION WITH DEVELOPING CONVECTION OVER AND EAST OF THE
CENTER. CONVECTION HAS FLUCTUATED SOME SINCE THEN BUT MEASURES SLIGHTLY
MORE THAN 2/10 FOR A DT OF 1.0. MET AND PT ARE ALSO 1.0. FT IS BASED
ON DT.
I.  ADDL POSITIONS
    NIL
...TURK

[Sciencerocks]

Looks like a depression
1. Well defined LLC
2. convection

I'd expect it to strengthen into a tropical storm tonight and peak around 50-55 knots.

[Sciencerocks]

[TheAustinMan]

A ScatSat pass at 22:30Z showed quality-controlled winds of 30 knots, with the strongest winds in the southeastern semicircle. Within the more uncertain convection there are higher sampled winds of 35 to 40 knots, though these have been automatically flagged as being more uncertain data points.

254 kB. Source: KNMI

[CyclonicFury]

Wow. The latest GFS is very aggressive with 90Q, bringing it to near hurricane strength.

The sounding shows a deep warm core, with a minimum pressure of 988 mb and maximum sustained winds of at least 55 kt. This is not your ordinary borderline SATL system.

[Vince_and_Grace_fan]

Strong convective burst over(?) the center:

[StruThiO]

This thing has great outflow. A hurricane is definitely possible, in my opinion.

[Sciencerocks]

This is probably close to tropical storm strength within my opinion.

[TheAustinMan]

The system has developed into a classical curved band structure with good outflow both equatorward and poleward supported by a well-positioned anticyclone aloft. At this point, I think it's clear we're looking at a bona fide tropical cyclone in the South Atlantic. The local environment remains favorable for intensification and we may see continued improvement throughout the day under modest wind shear (5-15 kt) and warm sea surface temperatures above 28C.

812 KB. Source: SSEC RealEarth

[Vince_and_Grace_fan]

ASCAT found 35 kt wind vectors under the southeastern convective blob so it is a weak TS now, but the circulation is still a bit elongated as visible satellite images also suggest.

[Hypercane_Kyle]

Looks 100% tropical. GFS takes it down to 993mb. Probably one of the most well-organized tropical cyclones in the Southern Atlantic. If it keeps up we could be looking at the 2nd ever recorded hurricane in the SATL.

[TheAustinMan]

At 16 UTC, the Brazilian Navy (the de facto agency for the South Atlantic) declared the system to be a tropical storm with winds of 35 kt and central pressure of 1008 mb, designating it with the name Iba. The system remains a disturbance in NHC/JTWC ATCF.

WARNING NR 208/2019
SPECIAL WARNING
ISSUED AT 1600 UTC - SUN - 24/MAR/2019
TROPICAL STORM "IBA" WITH ESTIMATED CENTRAL PRESSURE OF 1008 HPA AT 18.5S036W AND ESTIMATED MAXIMUM WINDS 35 KT. FORECAST: WIND SE/NE FORCE 7/9 (28-47 KNOTS) WITH GUSTS IN THE EAST SECTOR OF THE SYSTEM AND WIND SW/S FORCE 7 (28-33 KNOTS) NEAR THE COAST OVER AREA ECHO SOUTH OF 16S AND OVER AREA DELTA NORTH OF 23S.
ESTIMATED POSITION:
241800 UTC: 18.5S036.5W - 1008 HPA – ESTIMATED MAXIMUM SUSTAINED WIND 30-35 KNOTS - TROPICAL STORM
250000 UTC: 19S036.5W - 1008 HPA – ESTIMATED MAXIMUM SUSTAINED WIND 35-40 KNOTS - TROPICAL STORM
250600 UTC: 19S037W - 1008 HPA – ESTIMATED MAXIMUM SUSTAINED WIND 40-45 KNOTS - TROPICAL STORM
251200 UTC: 19.5S037W - 1008 HPA – ESTIMATED MAXIMUM SUSTAINED WIND 40-45 KNOTS - TROPICAL STORM
THIS WARNING REPLACES THE WARNING NR 205/2019.

[CyclonicFury]

JTWC/NHC still have it as 90Q, but this is the first SATL Tropical Storm since 2010!

[TorSkk]

A disturbance to the NW of Iba also has a nice spin, better visible on a loop

[jaguarjace]

[AJC3]

It's odd to see them use a frontal cyclone model for Iba in the surface analysis. They're must be used to placing fronts on any type of low.

[Dave C]

It's odd to see them use a frontal cyclone model for Iba in the surface analysis. They're must be used to placing fronts on any type of low.

Actually the system with the fronts is to the south, it confused me too.Iba is north of there at 20 latitude

[AJC3]

It's odd to see them use a frontal cyclone model for Iba in the surface analysis. They're must be used to placing fronts on any type of low.

Actually the system with the fronts is to the south, it confused me too.Iba is north of there at 20 latitude

I only missed it by 22 degrees and two lows!

[Dave C]

It's odd to see them use a frontal cyclone model for Iba in the surface analysis. They're must be used to placing fronts on any type of low.

Actually the system with the fronts is to the south, it confused me too.Iba is north of there at 20 latitude

I only missed it by 22 degrees and two lows!

South America is a long continent, easy to get lost.

[tolakram]

SLIDER shortwave

http://rammb-slider.cira.colostate.edu/?sat=goes-16&z=4&im=24&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=full_disk&p%5B0%5D=band_07&x=18074&y=14902