SWIO: INVEST 99S

[Chacor]

Off-season INVEST 99S has just popped up in the Southwest Indian Ocean:



By JTWC's definition, this should be 90S (the JTWC season starts on July 1).

The SW Indian Ocean cyclone season officially begins November 15.

[HurricaneBill]

By JTWC's definition, this should be 90S (the JTWC season starts on July 1).

The SW Indian Ocean cyclone season officially begins November 15.

So if it developed into a named storm, would it be given the "D" name from the 2010-11 list? Or would it be given the "A" name from the 2011-12 list?

[supercane]

Advisory from earlier today from RSMC La Reunion:

AWIO20 FMEE 041101
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER IN
THE SOUTHWEST
INDIAN OCEAN
DATE: 2011/07/04 AT 1200 UTC
PART 1 :
WARNING SUMMARY : Nil.
PART 2 :
TROPICAL WEATHER DISCUSSION
:
The basin shows a near-equatorial trough (NET) pattern.
Associated convective activity is fluctuating and disorganized
north of 05S from The Seychelles to The Chagos.
It's consistent and well organized in relationship with a deepening
low
from 70E to 80E between 5S and 12S.
At 1000Z, Meteosat7 satellite animation reveal a LLCC near
8.9S/81.5S moving west-southwestwards at 06/08kt.
0414Z ascat swath allows shows winds remaining however dissymetric
with 10/20kt in the northern semi-circle and 25kt locally 30kt in
the southern one due to the gradient effect with the subtropical
high pressures.
Buoy 53005 at 0900Z permit to estimate MSLP near 1005hPa.
This low exists within a neutral to slightly favourable environment
undergoing a good high level divergence but a weakening low level
poleward inflow and limited SST (26.5 C).
There is no other suspect area on the basin.
For the next 72 hours,
development of a tropical depression is not expected.


No mention of this area in JTWC's Indian Ocean outlook.

Latest SAB Dvorak:
TXXS26 KNES 050100
TCSSIO
A. TROPICAL DISTURBANCE (99S)
B. 05/0000Z
C. 9.3S
D. 81.3E
E. FIVE/MET-7
F. T1.0/1.5/W0.5/12HRS
G. IR/EIR
H. REMARKS... GREATER THAN 2/10 BANDING FOR DT=1.0. MET AND PT AGREE.
FT IS BASED ON DT.
I. ADDL POSITIONS
NIL
...SALEMI

HurricaneBill, RSMC La Reunion's Tropical Cyclone Operation Plan for the South-west Indian Ocean is unclear on this question, but given it is past June 30, I would assume we are in the 2011-2012 season and that this would be Alenga and not Dalilou.