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
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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 that 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: NANGKA Identifier: 06W
Basin: NORTH-WEST PACIFIC
Start date: 31.05.2003 End date: 04.06.2003
1-minute MSW: 50 knots 10-minute MSW: 45 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.
Forecasts did not predict the rapid north-eastward movement of this storm early in its lifetime and hence track forecast errors were very high. However, skill scores against CLIPER were positive.
Name: GINA Identifier: 29P
Basin: AUSTRALIAN (SW Pacific)
Start date: 04.06.2003 End date: 09.06.2003
1-minute MSW: 90 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.
The first forecast for TC Gina was uninitialised in the model, which explains its large initial position error. Although track forecast errors were above last season's average, the model showed very high skill against CLIPER.
Name: EPI Identifier: -
Basin: AUSTRALIAN (Coral Sea)
Start date: 05.06.2003 End date: 06.06.2003
1-minute MSW: 25 knots 10-minute MSW: 35 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.
Epi was uninitialised in the model and was briefly given tropical storm status by the Papua New Guinea Met. Service. JTWC did not recognise this as a tropical storm.
Name: - Identifier: 02L
Basin: NORTH ATLANTIC
Start date: 11.06.2003 End date: 12.06.2003
1-minute MSW: 30 knots 10-minute MSW: -
There are no verification statistics or forecast plot for this tropical cyclone since its 1-minute averaged winds did not reach tropical storm strength.
A plot of the storm's observed track.
Name: SOUDELOR Identifier: 07W
Basin: NORTH-WEST PACIFIC
Start date: 11.06.2003 End date: 19.06.2003
1-minute MSW: 115 knots 10-minute MSW: 80 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 errors for short range forecasts were above last season's average for this storm, but at longer ranges the errors were smaller. The model showed skill over CLIPER whilst having a slight slow bias.
Name: BLANCA Identifier: 02E
Basin: NORTH-EAST PACIFIC
Start date: 17.06.2003 End date: 22.06.2003
1-minute MSW: 55 knots 10-minute MSW: -
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* DPE for all storms in the 2002 season in the NEP basin
A plot of the storm's observed track and forecasts.
Only a few forecasts were verified for this storm, but track errors were very small and skill scores against CLIPER high.
Name: CARLOS Identifier: 03E
Basin: NORTH-EAST PACIFIC
Start date: 26.06.2003 End date: 27.06.2003
1-minute MSW: 50 knots 10-minute MSW: -
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* DPE for all storms in the 2002 season in the NEP basin
A plot of the storm's observed track and forecasts.
Carlos only briefly reached tropical storm status before landfall, so no forecasts were verified.
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:- 7
Number of storms used in statistics below:- 6
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* DPE for all Northern Hemisphere storms in 2002 season
A plot of the observed tracks of this month's storms in the North-West
Pacific basin.
A plot of the observed tracks of this month's storms in the North-East
Pacific basin.
A plot of the observed tracks of this month's storms in the North
Atlantic basin.
A plot of the observed tracks of this month's storms in the Eastern
Australian basin.
Track forecast errors for this month's storms were slightly above last season's average, except at T+120. However, skill scores against CLIPER were very high indicating that this month's storms had a much lower level of predictability than average. There was a slow bias at early forecast ranges. The overall intensity tendency skill score was 13%, which is lower than recent months.
3. TROPICAL CYCLONE ACTIVITY in the SOUTHERN HEMISPHERE DURING 2002-3 SEASON
| SWI | AUS | TOTAL | |
| Tropical Depressions | 3(2) | 0(3) | 3(5) |
| Tropical Storms | 4(2) | 8(6) | 12(8) |
| Hurricanes/Typhoons | 8(9) | 9(4) | 17(13) |
| Total | 15(13) | 17(13) | 32(26) |
( ) The number in brackets indicates the figure for the 2001-2 season. Definitions based on RSMC 10-minute average wind speeds are used.
3.1 Summary of all Southern Hemisphere Storms in 2001-2
Mean error statistics for all Southern Hemisphere storms that occurred in the 2002-3 season are shown below. Only storms that reached tropical storm intensity at the time of a forecast are used in the statistics below.
Total number of tropical cyclones which occurred:- 32
Number of storms used in statistics below:- 29
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* Best track figures for all Southern Hemisphere storms in 2001-2.
Comments:
Southern Hemisphere warning centres recorded 32 TCs in the 2002-3 season. This was three more than JTWC, Hawaii. The additional storms were an unnamed TC recorded after the event by TCWC Darwin, Luma recorded by RSMC La Reunion and Epi recorded by TCWC Port Moresby.
The 2002-3 season was much more active than the previous three Southern Hemisphere seasons due to increased activity in both the South-West Indian and Australian basins. Of particular note is the total of 17 TCs that reached hurricane/typhoon strength. Of these, according to JTWC, five reached 'super typhoon' strength (maximum sustained winds 130 knots or greater).
SWI 
Western AUS
Eastern
AUS
The charts below show forecast positional errors for the last few seasons. In the South-West Indian basin forecast errors are lower than last season, particularly so at T+48 and T+72. Forecast errors are also below last season's values up to T+72 in the Australian basin. Overall, there was a significant drop in errors compared to the last two seasons and at T+48, T+72 and T+96 the errors were the lowest ever recorded for the Southern Hemisphere.
Skill scores against CLIPER were above 30% at all forecast times and were better than the previous two seasons. Cross track errors were significantly smaller than last season and slightly smaller than two seasons ago at all forecast times except T+120. Along track errors were virtually eliminated at all forecast times except T+120 when there was a slight slow bias.
Intensity tendency skill score averaged for all forecasts was 41% in the 2002-3 Southern Hemisphere season. This compares to the figure of 18% for the 2001-2 season.
A revised Southern Hemisphere summary will be issued once best track data has been collected later in the year.
Forecast positional errors
SWI 
AUS 
Combined Southern Hemisphere.
Southern Hemisphere skill.
Southern Hemisphere Cross Track errors.
Southern Hemisphere Along Track errors.
