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 0.5625°x 0.375°x 50 levels. This is equivalent to a horizontal resolution of 62km x 42km at the equator.
2.1 Individual tropical cyclone summaries
Name: EWINIAR Identifier: 04W
Basin: NORTH-WEST PACIFIC
Start date: 29.06.2006 End date: 10.07.2006
1-minute MSW: 130 knots 10-minute MSW: 100 knots
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* DPE for all storms in the 2005 season in the NWP basin.
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Plot of the storm's observed track and forecasts |
Early forecasts had a major systematic bias. Ewiniar was forecast to accelerate and turn north-eastwards much sooner than occurred. This resulted in some huge track forecast errors. Despite better forecasts later in the life of the typhoon, the overall track errors and skill reflect this bias during the early stages.
Name: - Identifier: 03B
Basin: NORTH INDIAN (Bay of Bengal)
Start date: 02.07.2006 End date: 03.07.2006
1-minute MSW: 35 knots 10-minute MSW: 30 knots
There are no verification statistics or forecast plot for this tropical cyclone since its 1-minute averaged winds only briefly reached tropical storm strength.
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A plot of the depression's observed track |
Name: BILIS Identifier: 05W
Basin: NORTH-WEST PACIFIC
Start date: 08.07.2006 End date: 15.07.2006
1-minute MSW: 55 knots 10-minute MSW: 60 knots
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* DPE for all storms in the 2005 season in the NWP basin.
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Plot of the storm's observed track and forecasts |
Track forecast errors were near to or slightly above last season's average. There was a left-of-track bias in forecasts and skill scores against CLIPER were modestly positive.
Name: BUD Identifier: 03E
Basin: NORTH-EAST PACIFIC
Start date: 10.07.2006 End date: 15.07.2006
1-minute MSW: 110 knots 10-minute MSW: -
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* DPE for all storms in the 2005 season in the NEP basin.
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Plot of the storm's observed track and forecasts |
Track forecast errors were near to or below last season's average and skill scores were high for this hurricane.
Name: CARLOTTA Identifier: 04E
Basin: NORTH-EAST PACIFIC
Start date: 12.07.2006 End date: 17.07.2006
1-minute MSW: 75 knots 10-minute MSW: -
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* DPE for all storms in the 2005 season in the NEP basin.
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Plot of the storm's observed track and forecasts |
Track forecast errors were near to average at T+24 and T+48. Skill scores were positive.
Name: DANIEL Identifier: 05E
Basin: NORTH-EAST PACIFIC
Start date: 17.07.2006 End date: 26.07.2006
1-minute MSW: 130 knots 10-minute MSW: -
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* DPE for all storms in the 2005 season in the NEP basin.
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Plot of the storm's observed track and forecasts |
Forecasts for Daniel were very good. Track forecast errors were below last season's average and skill scores were high. At longer lead times there was a slow bias.
Name: KAEMI Identifier: 06W
Basin: NORTH-WEST PACIFIC
Start date: 18.07.2006 End date: 26.07.2006
1-minute MSW: 90 knots 10-minute MSW: 80 knots
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* DPE for all storms in the 2005 season in the NWP basin.
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Plot of the storm's observed track and forecasts |
The detection percentage was unusually low at T+72 and beyond indicating that the model dissipated Kaemi too soon in forecasts. Track forecast errors were generally near to average and skill positive at T+24 and T+48. There was a slight right-of-track bias in some forecasts.
Name: BERYL Identifier: 02L
Basin: NORTH ATLANTIC
Start date: 18.07.2006 End date: 21.07.2006
1-minute MSW: 50 knots 10-minute MSW: -
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* DPE for all storms in the 2005 season in the NAT basin.
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Plot of the storm's observed track and forecasts |
Only a few forecasts were verified for Beryl, but these were generally good.
Name: EMILIA Identifier: 06E
Basin: NORTH-EAST PACIFIC
Start date: 21.07.2006 End date: 28.07.2006
1-minute MSW: 60 knots 10-minute MSW: -
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* DPE for all storms in the 2005 season in the NEP basin.
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Plot of the storm's observed track and forecasts |
Track forecast errors were slightly higher than last season's average except at T+96. Skill scores were positive at T+24 and T+48 and there was a left-of-track bias in forecasts.
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: 9
Number of storms used in statistics below: 9
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* DPE for all northern hemisphere storms in 2005 season
Track forecast errors for this month's storms were near to last season's average at short lead times and above average at longer lead times. There was a slight fast bias and skill against CLIPER was modest. The overall intensity tendency skill score was 28%.
