Observed and forecast tracks: southern hemisphere 2011-12

Click on the name of the tropical cyclone to see a chart of the observed track and forecast tracks from the Met Office global model. Verification statistics on each tropical cyclone are available upon request from [email protected]. At the end of the season a verification report on the performance of the Met Office global model will be published.

South-West Indian (west of 90°E)
Name & ID Start & end dates 1-/10-minute MSW Comments on Met Office global model forecasts
Alenga (01S) *1 05-09 December 90/80 knots Track forecast errors were a little above last season's average, but skill scores were very high.
02S 06-07 December 35/30 knots 02S only briefly reached tropical storm status (according to JTWC only) and no forecasts were verified.
Benilde (04S) 28 December-04 January 90/80 knots Track forecast errors were above last season's average. Forecasts had left-of-track, right-of-track and slow biases.
Chanda (05S) 07-11 January 35/35 knots Chanda was only briefly a tropical storm and no forecasts were verified.
Dando 11-16 January 30/45 knots JTWC did not consider Dando a tropical storm and RSMC La Réunion advised on it as a subtropical storm. 24-hour prediction of landfall was very good.
Ethel (07S) 18-22 January 70/55 knots There was a slow and right-of track bias which resulted in track forecast errors above last season's average.
Funso (08S) 19-29 January 120/105 knots At times the model had a right-of-track bias taking Funso too close to Tanzania. However, overall, forecasts were good with track forecast errors either near to or below last season's average.
Giovanna (12S) 09-21 February 125/100 knots

Short period track forecast errors were low and skill scores against CLIPER high. However, longer lead time errors were large due to the failure to predict the leftward turn and eastwards track after Giovanna had crossed Madagascar.

Hilwa (13S) 14-23 February 40/40 knots Hilwa was a depression for a long time before finally becoming a storm. Track forecast errors were near to or below last season's average.
Irina (14S) 26 February-10 March 50/50 knots Track forecast errors were larger than last year's average and the model tended to incorrectly turn the storm towards Mozambique. However, the model still showed considerable skill over CLIPER.

15S

29 February-03 March 35/30 knots This was short-lived as a storm and no forecasts were verified.
Koji-Joni (16S) *2 07-12 March 70/55 knots Track forecast errors were above last season's average due to a slow bias.
Kuena (20S) 06-07 June 50/50 knots Kuena was short-lived and only a few forecasts were verified.

*1: Moved into the Australian region

*2: Moved from the Australian region

Tropical cyclone names

South-West Indian observed tracks in 2011-12

Australian (90-160°E)
Name & ID Start & end dates 1-/10-minute MSW Comments on Met Office global model forecasts
Alenga (01S) *3 05-09 December 90/80 knots Track forecast errors were a little above last season's average, but skill scores were very high.
Fina 20-22 December 30/35 knots Fina was only briefly a tropical storm (according to Australian BoM) and no forecasts were verified.
Grant (03S) 21-27 December 40/55 knots Grant was short-lived as a storm, but track forecast errors were low.
Heidi (06S) 10-12 January 55/60 knots Heidi became a tropical storm barely more than 24 hours before landfall. Predictions of landfall location were good, although the model turned the storm right too quickly after landfall.
Iggy (09S) 25 January-02 February 65/55 knots Forecasts for Iggy were mixed. Some early forecasts incorrectly predicted landfall, but later forecasts predicted its track very well. Track forecast errors were low at short lead times, but at longer lead times near to or above last season's average. Skill scores against CLIPER were high.
Jasmine (10P) *4 04-16 February 115/100 knots Jasmine was well predicted by the model. Track forecast errors were low and skill scores high. The unusual equatorwards turn was well predicted, although the degree to which the storm looped westwards again was over-predicted.
Koji-Joni (16S) *5 07-12 March 70/55 knots Track forecast errors were above last season's average due to a slow bias.
Lua (17S)      
13-18 March 95/95 knots Track forecast errors were low and skill scores high as the model predicted the turn towards land well. There was a slight left-of-track bias in some forecasts.
19S 07-09 May 30/30 knots 19S did not reach tropical storm strength and no forecasts were verified.
21P 29-30 June 35/- knots 21P was only recognised by JTWC and was short-lived. No forecasts were verified.

*3: Moved from the South-West Indian region

*4: Moved into the Fiji region

*5: Moved into the South-West Indian region

Tropical cyclone names

 

Fiji (east of 160°E)
Name & ID Start & end dates 1-/10-minute MSW Comments on Met Office global model forecasts
Jasmine (10P) *6 04-16 February 115/100 knots Jasmine was well predicted by the model. Track forecast errors were low and skill scores high. The unusual equatorwards turn was well predicted, although the degree to which the storm looped westwards again was over-predicted.
Cyril (11P) 06-08 February 45/50 knots Cyril only lasted a couple of days an accelerated into the mid-latitudes. Track forecasts were a little slow, but gave reasonable guidance.
Daphne (18P) 02-03 April 50/50 knots Only a few forecasts were verified and the model tended to move Daphne too slowly to the south-east.

*6: Moved from the Australian region

Tropical cyclone names

Western Australian observed tracks in 2011-12
Eastern Australian and South Pacific observed tracks in 2011-12

Note on estimated wind speeds

1-minute MSW: Maximum sustained wind (knots) averaged over 1 minute (JTWC Hawaii)
10-minute MSW: Maximum sustained wind (knots) averaged over 10 minutes (Southern Hemisphere RSMCs and TCWCs)

Note: Although 1-minute average winds should be stronger than 10-minute average, this may not be the case here since estimates are obtained from different warning centres.