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: BILL Identifier: 03L
Basin: NORTH ATLANTIC
Start date: 29.06.2003 End date: 01.07.2003
1-minute MSW: 50 knots 10-minute MSW: -
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* Best track DPE for all storms in the 2002 season in the NAT basin
A plot of the storm's observed track and forecasts.
Only one forecast was verified for TS Bill. This forecast was a little slow in predicting the landfall of the storm.
Name: DOLORES Identifier: 04E
Basin: NORTH-EAST PACIFIC
Start date: 06.07.2003 End date: 08.07.2003
1-minute MSW: 35 knots 10-minute MSW: -
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* Best track DPE for all storms in the 2002 season in the NEP basin
A plot of the storm's observed track and forecasts.
Dolores only briefly reached tropical storm status and no forecasts were verified.
Name: CLAUDETTE Identifier: 04L
Basin: NORTH ATLANTIC
Start date: 08.07.2003 End date: 16.07.2003
1-minute MSW: 75 knots 10-minute MSW: -
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* Best track DPE for all storms in the 2002 season in the NAT basin
A plot of the storm's observed track and forecasts.
Track forecast errors were below last season's average and skill scores against CLIPER high for this first landfalling hurricane of the Atlantic season. The only noticeable bias was a left-of-track one at longer forecast ranges. This reflects the model's early forecasts that turned the hurricane leftwards towards Mexico, whereas it actually stalled briefly before continuing north-westwards towards landfall in Texas. Forecasts of landfall up to three days in advance were very good.
Name: ENRIQUE Identifier: 05E
Basin: NORTH-EAST PACIFIC
Start date: 10.07.2003 End date: 13.07.2003
1-minute MSW: 55 knots 10-minute MSW: -
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* Best track DPE for all storms in the 2002 season in the NEP basin
A plot of the storm's observed track and forecasts.
Only two forecasts were verified for this storm and track forecast errors were above last season's average.
Name: KONI Identifier: 08W
Basin: NORTH-WEST PACIFIC
Start date: 15.07.2003 End date: 22.07.2003
1-minute MSW: 65 knots 10-minute MSW: 60 knots
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* Best track DPE for all storms in the 2002 season in the NWP basin
A plot of the storm's observed track and forecasts.
Track forecast errors were above last season's average at short forecast ranges. This was primarily due to the early forecasts predicting too great a northward component to the track. The early forecasts also dissipated the storm too early resulting in low detection rates. Once the storm had passed into the South China Sea forecasts were much better. Overall, there was a slow and right-of-track bias. The model showed skill over CLIPER most notably at T+72 and the intensity tendency skill was excellent.
Name: DANNY Identifier: 05L
Basin: NORTH ATLANTIC
Start date: 16.07.2003 End date: 20.07.2003
1-minute MSW: 65 knots 10-minute MSW: -
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* DPE for all storms in the 2002 season in the NAT basin
A plot of the storm's observed track and forecasts.
Although the direction of motion of this hurricane was well predicted, the forecasts of speed of movement varied. This resulted in track forecast errors above last season's average at T+48 and T+72. However, the model showed skill over CLIPER.
Name: IMBUDO Identifier: 09W
Basin: NORTH-WEST PACIFIC
Start date: 16.07.2003 End date: 24.07.2003
1-minute MSW: 130 knots 10-minute MSW: 85 knots
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* Best track DPE for all storms in the 2002 season in the NWP basin
A plot of the storm's observed track and forecasts.
There was a slow and right-of-track bias to track forecasts for this typhoon. Track forecast errors were near to last season's average up to T+72, but were greater than average at longer ranges. Landfall over the Philippines was well predicted up to two days in advance as was the later landfall over southern China. The model showed modest skill over CLIPER.
Name: FELICIA Identifier: 06E
Basin: NORTH-EAST PACIFIC
Start date: 18.07.2003 End date: 23.07.2003
1-minute MSW: 45 knots 10-minute MSW: -
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* Best track DPE for all storms in the 2002 season in the NEP basin
A plot of the storm's observed track and forecasts.
Felicia was a tropical storm for only a brief time, although persisted as a tropical depression for a lot longer. T+24 forecast errors for the two forecasts verified were low and skill scores high.
Name: - Identifier: 06L
Basin: NORTH ATLANTIC
Start date: 19.07.2003 End date: 21.07.2003
1-minute MSW: 30 knots 10-minute MSW: -
A plot of the depression's observed track.
There are no verification statistics or forecast plot for this tropical cyclone since its 1-minute averaged winds did not reach tropical storm strength.
Name: - Identifier: 07L
Basin: NORTH ATLANTIC
Start date: 25.07.2003 End date: 26.07.2003
1-minute MSW: 30 knots 10-minute MSW: -
A plot of the depression's observed track.
There are no verification statistics or forecast plot for this tropical cyclone since its 1-minute averaged winds did not reach tropical storm strength.
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:- 10
Number of storms used in statistics below:- 8
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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.
Track forecast errors for this month's storms were near to or below last season's average at all forecast times except T+120. There was a slight slow and right-of-track bias overall. Model forecasts showed a good level of skill over CLIPER. The overall intensity tendency skill score was 25%.
