1. Tropical cyclone activity
1.1 Tropical cyclones ending during the month
|
|
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
|
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 62 km x 42 km at the equator.
2.1 Individual tropical cyclone summaries
Name: - Identifier: 02E
Basin: NORTH-EAST PACIFIC
Start date: 03.06.2006 End date: 05.06.2006
1-minute MSW: 30 knots 10-minute MSW:
 |
Plot of the storm'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: ALBERTO Identifier: 01L
Basin: NORTH ATLANTIC
Start date: 10.06.2006 End date: 14.06.2006
1-minute MSW: 60 knots 10-minute MSW: -
|
* DPE for all storms in the 2005 season in the NAT basin.
 |
Plot of the storm's observed track and forecasts |
Just a few forecasts were verified for this first storm of the Atlantic season. At T+24 errors were lower than last season's average, but higher than average for the one T+48 forecast. There was a slow bias in the forecast tracks.
Name: JELAWAT Identifier: 03W
Basin: NORTH-WEST PACIFIC
Start date: 26.06.2006 End date: 29.06.2006
1-minute MSW: 45 knots 10-minute MSW: 40 knots
|
* DPE for all storms in the 2005 season in the NWP basin.
 |
Plot of the storm's observed track and forecasts |
Only two forecasts were verified for this storm. There was a right 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: 3
Number of storms used in statistics below:2
|
* DPE for all northern hemisphere storms in 2005 season
This month's storms were few and short-lived, so not many forecasts were verified. T+24 forecast errors were near to last season's average. There was a slow bias in forecasts. The overall intensity tendency skill score was 0%.
3. Tropical cyclone activity in the southern hemisphere during 2005/6 season
|
The number in brackets () indicates the figure for the 2004/5 season. Definitions based on RSMC 10-minute average wind speeds are used.
3.1 Summary of all southern hemisphere storms in 2005/6
Mean error statistics for all southern hemisphere storms that occurred in the 2005/6 season are shown below. Only storms that reached tropical storm intensity at the time of a forecast are used in the statistics.
Total number of tropical cyclones which occurred: 23
|
* Real time figures for all southern hemisphere storms in 2004/5.
Southern hemisphere warning centres recorded 23 tropical cyclones in the 2005/6 season. This was the quietest season in terms of storm numbers since 2000/1. The south-west Indian region was exceptionally quiet. 12 of the 23 tropical cyclones reached hurricane/typhoon strength.
Observed tracks of this season's TCs
 |
 |
 |
| SWI | Western AUS | Eastern AUS |
The charts show forecast positional errors for the last few seasons. In the south-west Indian basin, forecast errors were lower than last season's at all forecast lead times except T+72, but were still higher than the longer term mean. In the Australian basin forecast errors were a little higher than last season at all lead times except T+120.
Skill scores against CLIPER remained high this season, although at T+48 and T+72 was a little lower than last season. Cross track errors showed a right-of-track bias in forecasts as in previous seasons. Along track errors maintained fairly low values at short lead times.
Intensity tendency skill score averaged for all forecasts was 31% in the 2005/6 southern hemisphere season. This compares to 30% and 22% for the previous two seasons.
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 |
