1. Tropical cyclone activity
1.1 Tropical cyclones ending during the month
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Basin name abbreviations:-
NWP : North-West Pacific (west of 180°E)
NEP : North-East Pacific (east of 180°E)
NAT : North Atlantic
NI : North Indian (west of Malay Peninsula)
SWI : South-West Indian (west of 90°E)
AUS : Australian (east of 90°E)
1-minute MSW: Maximum sustained wind (knots) averaged over
1 minute (JTWC Hawaii, NHC Miami, CPHC Hawaii)
10-minute MSW: Maximum sustained wind (knots) averaged over 10
minutes (JMA Japan, 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.
1.2 Tropical cyclones still active at the end of the month
None
2. FORECAST ERROR STATISTICS
The Met Office global Numerical Weather Prediction model produces a 6-day forecast every 12 hours. The performance of the model in forecasting this month's tropical cyclones is assessed below. Mean error statistics for each storm which ended during the month are presented together with a final table of statistics for all storms ending this month. Verification is performed at 24 hour intervals up to forecast time T+120. Some mean error statistics for last year's storms are included for the purposes of a comparison. The present global model has a resolution of 0.83°x 0.55°x 39 levels. This is equivalent to a horizontal resolution of 93km x 62km at the equator.
2.1 Individual Tropical Cyclone Summaries
Name: EBULA Identifier: 09S
Basin: SOUTH-WEST INDIAN
Start date: 08.01.2003 End date: 12.01.2003
1-minute MSW: 65 knots 10-minute MSW: 60 knots
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* DPE for all storms in the 2001-2 season in the SWI basin
A plot of the storm's observed track and forecasts.
Forecast errors were near to or below last season's average for this storm. Skill scores against CLIPER were high.
Name: AMI Identifier: 10P
Basin: AUSTRALIAN (SW Pacific)
Start date: 12.01.2003 End date: 15.01.2003
1-minute MSW: 110 knots 10-minute MSW: 80 knots
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* DPE for all storms in the 2001-2 season in the AUS basin
A plot of the storm's observed track and forecasts.
T+24 forecasts were good for this storm, but longer range forecasts were poor due to failure to predict the rapid rate of south and south-eastwards acceleration.
Name: YANYAN Identifier: 01W
Basin: NORTH-WEST PACIFIC
Start date: 15.01.2003 End date: 21.01.2003
1-minute MSW: 50 knots 10-minute MSW: 35 knots
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* DPE for all storms in the 2002 season in the NWP basin
A plot of the storm's observed track and forecasts.
Track forecasts were slow for this storm and errors large at T+24 and T+48. However, the model showed skill over CLIPER.
Name: FARI Identifier: 11S
Basin: SOUTH-WEST INDIAN
Start date: 23.01.2003 End date: 31.01.2003
1-minute MSW: 55 knots 10-minute MSW: 50 knots
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* DPE for all storms in the 2001-2 season in the SWI basin
A plot of the storm's observed track and forecasts.
Fari persisted for a long time as a tropical depression, but only briefly reached tropical storm status, so no forecasts were verified.
Name: BENI Identifier: 12P
Basin: AUSTRALIAN (SW Pacific)
Start date: 25.01.2003 End date: 31.01.2003
1-minute MSW: 125 knots 10-minute MSW: 110 knots
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* DPE for all storms in the 2001-2 season in the AUS basin
A plot of the storm's observed track and forecasts.
Forecasts failed to predict the extent of the south-eastwards turn of this storm and hence errors were generally high.
Name: CILLA Identifier: 13P
Basin: AUSTRALIAN (S Pacific)
Start date: 27.01.2003 End date: 29.01.2003
1-minute MSW: 35 knots 10-minute MSW: 40 knots
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* DPE for all storms in the 2001-2 season in the AUS basin
A plot of the storm's observed track and forecasts.
Track forecasts for Cilla had a slow bias and hence errors were high.
2.2 Summary of all Tropical Cyclones
Mean error statistics for all tropical cyclones (of at least tropical storm strength) which have ended this month are shown below.
Total number of depressions ending this month:- 6
Number of storms used in statistics below:- 6
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* DPE for all southern hemisphere storms in 2001-2 season
A plot of the observed tracks of this month's storms in the South-West
Indian Ocean.
A plot of the observed tracks of this month's storms in the Eastern
Australian basin.
A plot of the observed tracks of this month's storms in the North-West
Pacific Ocean.
Track forecast errors were above last season's average at short forecast ranges, but were below average at longer ranges. There was a slow bias and tendency to underpredict recurvature. Intensity tendency forecasts were very good this month with a skill score of 42% averaged over all forecasts.
