Tropical cyclone activity and forecasts - August 2008
Tropical cyclone activity
| NWP | NEP | NAT | NI | SWI | AUS | TOTAL | |
|---|---|---|---|---|---|---|---|
| Total number ending during the month | 6 | 4 | 2 | 0 | 0 | 0 | 12 |
| Name | Identifier | Basin | Start date | End date | 1-minute MSW | 10-minute MSW |
|---|---|---|---|---|---|---|
| Edouard | 05L | NAT | 03 August | 05 August | 55 | - |
| Kammuri | 10W | NWP | 04 August | 07 August | 50 | 50 |
| Hernan | 09E | NEP | 06 August | 13 August | 105 | - |
| Kika | 01C | NEP | 07 August | 13 August | 35 | - |
| Phanfone | - | NWP | 10 August | 11 August | 25 | 40 |
| - | 11W | NWP | 13 August | 14 August | 30 | 30 |
| Iselle | 10E | NEP | 13 August | 17 August | 45 | - |
| Vongfong | 12W | NWP | 14 August | 17 August | 50 | 40 |
| Fay | 06L | NAT | 15 August | 24 August | 55 | - |
| Nuri | 13W | NWP | 17 August | 22 August | 95 | 75 |
| Julio | 11E | NEP | 23 August | 26 August | 45 | - |
| - | 14W | NWP | 26 August | 28 August | 35 | 30 |
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.
Tropical cyclones still active at the end of the month
| Name | Identifier | Basin | Start date |
|---|---|---|---|
| Gustav | 07L | NAT | 25 August |
| Hanna | 08L | NAT | 28 August |
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.
Individual tropical cyclone summaries
Name: EDOUARD Identifier: 05L
Basin: NORTH ATLANTIC
Start date: 03.08.2008 End date: 05.08.2008
1-minute MSW: 55 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 4 | 2 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | **** | **** | **** | **** | **** |
| Mean DX | 29 | 5 | **** | **** | **** | **** | **** |
| Mean DY | -25 | -33 | **** | **** | **** | **** | **** |
| Mean AT | -35 | -25 | **** | **** | **** | **** | **** |
| Mean CT | -10 | -28 | **** | **** | **** | **** | **** |
| Track skill (%) | **** | 62 | **** | **** | **** | **** | **** |
| Mean DPE | 51 | 76 | **** | **** | **** | **** | **** |
| 2007 DPE * | 63 | 102 | 151 | 179 | 228 | 265 | **** |
| Intensity skill (%) | **** | 0 | **** | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NAT basin
A plot of the storm's observed track and forecasts
Track forecast errors were below last season’s average at all lead times except T+72. Skill scores were positive at T+24 and T+48. There was a left-of-track bias and the model showed an unusually low detection percentage indicating that it tended to dissipate the storm too soon.
Name: KAMMURI Identifier: 03E
Basin: NORTH-WEST PACIFIC
Start date: 04.08.2008 End date: 07.08.2008
1-minute MSW: 50 knots 10-minute MSW: 50 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 6 | 4 | 2 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | **** | **** | **** | **** |
| Mean DX | 9 | 26 | -36 | **** | **** | **** | **** |
| Mean DY | -67 | -31 | 57 | **** | **** | **** | **** |
| Mean AT | -21 | -37 | 44 | **** | **** | **** | **** |
| Mean CT | -51 | -24 | 48 | **** | **** | **** | **** |
| Track skill (%) | **** | 62 | **** | **** | **** | **** | **** |
| Mean DPE | 71 | 82 | 73 | **** | **** | **** | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | **** |
| Intensity skill (%) | **** | 0 | 100 | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of the storm's observed track and forecasts
Kammuri was fairly short-lived, but track errors were small and skill scores high.
Name: HERNAN Identifier: 09E
Basin: NORTH-EAST PACIFIC
Start date: 06.08.2008 End date: 13.08.2008
1-minute MSW: 105 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 13 | 11 | 9 | 7 | 5 | 3 | 1 |
| Detection rate (%) | 100 | 100 | 100 | 100 | 100 | 100 | 0 |
| Mean DX | -5 | -62 | -136 | -107 | -86 | -18 | **** |
| Mean DY | -13 | 16 | 14 | -11 | 38 | 41 | **** |
| Mean AT | 1 | 52 | 123 | 125 | 100 | 7 | **** |
| Mean CT | -5 | -1 | -27 | -64 | 9 | 33 | **** |
| Track skill (%) | **** | -18 | -2 | 20 | **** | **** | **** |
| Mean DPE | 36 | 102 | 188 | 205 | 151 | 130 | **** |
| 2007 DPE * | 56 | 112 | 192 | 246 | 453 | 397 | **** |
| Intensity skill (%) | **** | 64 | 56 | 100 | 100 | 100 | **** |
* DPE for all storms in the 2007 season in the NEP basin
A plot of the storm's observed track and forecasts
Track forecast errors were below last season’s average for this storm, although skill scores against CLIPER were only positive at T+72.
Name: KIKA Identifier: 01C
Basin: NORTH-EAST PACIFIC (CENTRAL)
Start date: 07.08.2008 End date: 13.08.2008
1-minute MSW: 35 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 7 | 5 | 3 | 1 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | 100 | **** | **** | **** |
| Mean DX | 22 | -51 | -135 | -22 | **** | **** | **** |
| Mean DY | -31 | 79 | 178 | 311 | **** | **** | **** |
| Mean AT | -21 | 15 | 129 | -46 | **** | **** | **** |
| Mean CT | -23 | 91 | 176 | 312 | **** | **** | **** |
| Track skill (%) | **** | 46 | 39 | **** | **** | **** | **** |
| Mean DPE | 53 | 138 | 265 | 316 | **** | **** | **** |
| 2007 DPE * | 56 | 112 | 192 | 246 | 453 | 397 | **** |
| Intensity skill (%) | **** | 60 | 100 | 100 | **** | **** | **** |
* DPE for all storms in the 2007 season in the NEP basin
Track errors were a little above last season’s average for this storm
A plot of the storm's observed track and forecasts
Name: PHANFONE Identifier: 06E
Basin: NORTH-WEST PACIFIC
Start date: 10.08.2008 End date: 11.08.2008
1-minute MSW: 25 knots 10-minute MSW: 40 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | **** | **** | **** | **** | **** | **** |
| Mean DX | -171 | **** | **** | **** | **** | **** | **** |
| Mean DY | 34 | **** | **** | **** | **** | **** | **** |
| Mean AT | -52 | **** | **** | **** | **** | **** | **** |
| Mean CT | -292 | **** | **** | **** | **** | **** | **** |
| Mean DPE | 188 | **** | **** | **** | **** | **** | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of the storm's observed track and forecasts
Phanfone was short-lived and no forecasts verified.
Name: - Identifier: 11W
Basin: NORTH-WEST PACIFIC
Start date: 13.08.2008 End date: 14.08.2008
1-minute MSW: 30 knots 10-minute MSW: 30 knots
* DPE for all storms in the 2007 season in the NWP basin
A plot of the storm's observed track and forecasts
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: ISELLE Identifier: 10E
Basin: NORTH-EAST PACIFIC
Start date: 13.08.2008 End date: 17.08.2008
1-minute MSW: 45 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 4 | 2 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | **** | **** | **** | **** | **** |
| Mean DX | 8 | -5 | **** | **** | **** | **** | **** |
| Mean DY | -42 | 184 | **** | **** | **** | **** | **** |
| Mean AT | -20 | 12 | **** | **** | **** | **** | **** |
| Mean CT | -40 | 184 | **** | **** | **** | **** | **** |
| Track skill (%) | **** | -44 | **** | **** | **** | **** | **** |
| Mean DPE | 55 | 185 | **** | **** | **** | **** | **** |
| 2007 DPE * | 56 | 112 | 192 | 246 | 453 | 397 | **** |
| Intensity skill (%) | **** | -100 | **** | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NEP basin
A plot of the storm's observed track and forecasts
Just two forecasts were verified for this storm. Track errors were above last season’s average.
Name: VONGFONG Identifier: 12W
Basin: NORTH-WEST PACIFIC
Start date: 14.08.2008 End date: 17.08.2008
1-minute MSW: 50 knots 10-minute MSW: 40 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 5 | 3 | 1 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | **** | **** | **** | **** |
| Mean DX | 22 | -23 | -177 | **** | **** | **** | **** |
| Mean DY | -28 | -26 | -100 | **** | **** | **** | **** |
| Mean AT | -14 | -32 | -202 | **** | **** | **** | **** |
| Mean CT | 38 | 15 | -14 | **** | **** | **** | **** |
| Track skill (%) | **** | 52 | **** | **** | **** | **** | **** |
| Mean DPE | 56 | 97 | 203 | **** | **** | **** | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | **** |
| Intensity skill (%) | **** | 33 | 100 | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of the storm's observed track and forecasts
The track of this short-lived storm was well forecast.
Name: FAY Identifier: 06L
Basin: NORTH ATLANTIC
Start date: 15.08.2008 End date: 24.08.2008
1-minute MSW: 55 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 16 | 14 | 12 | 10 | 8 | 6 | 4 |
| Detection rate (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Mean DX | 22 | 8 | -26 | -112 | -187 | -204 | -53 |
| Mean DY | 34 | 4 | -26 | -39 | 43 | 235 | 468 |
| Mean AT | 14 | -19 | -58 | -58 | 44 | 188 | 138 |
| Mean CT | 28 | 4 | 2 | -74 | -67 | 75 | 441 |
| Track skill (%) | **** | 56 | 74 | 81 | *** | **** | **** |
| Mean DPE | 57 | 75 | 121 | 160 | 238 | 347 | 512 |
| 2007 DPE * | 63 | 102 | 151 | 179 | 228 | 265 | **** |
| Intensity skill (%) | **** | 57 | 83 | 80 | 50 | 67 | 100 |
* DPE for all storms in the 2007 season in the NAT basin
A plot of the storm's observed track and forecasts
Early forecasts failed to predict the double crossing of Florida, but later forecasts predicted the track well. Track errors were generally low. And skill scores high.
Name: NURI Identifier: 13W
Basin:NORTH-WEST PACIFIC
Start date: 17.08.2008 End date: 22.08.2008
1-minute MSW: 95 knots 10-minute MSW: 75 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 11 | 9 | 7 | 5 | 3 | 1 | 0 |
| Detection rate (%) | 100 | 100 | 100 | 100 | 100 | 100 | **** |
| Mean DX | 6 | 10 | 93 | 376 | 691 | 843 | **** |
| Mean DY | -27 | -11 | 71 | 125 | 96 | -11 | **** |
| Mean AT | -15 | -20 | -52 | -268 | -524 | -608 | **** |
| Mean CT | -19 | -14 | 97 | 276 | 444 | 587 | **** |
| Track skill (%) | **** | 47 | 31 | -117 | **** | **** | **** |
| Mean DPE | 60 | 68 | 143 | 412 | 700 | 846 | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | *** |
| Intensity skill (%) | **** | 33 | 71 | 60 | 100 | 100 | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of the storm's observed track and forecasts
Early forecasts stalled the storm and turned it towards Taiwan instead of showing landfall over China. Hence, longer lead time errors were large. Short period forecasts were good.
Name: JULIO Identifier: 11E
Basin: NORTH-EAST PACIFIC
Start date: 23.08.2008 End date: 26.08.2008
1-minute MSW: 45 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 5 | 3 | 1 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | **** | **** | **** | **** |
| Mean DX | 36 | 20 | 69 | **** | **** | **** | **** |
| Mean DY | -4 | -83 | -33 | **** | **** | **** | **** |
| Mean AT | -16 | -79 | -50 | **** | **** | **** | **** |
| Mean CT | 26 | -15 | 59 | **** | **** | **** | **** |
| Track skill (%) | **** | -24 | **** | **** | **** | **** | **** |
| Mean DPE | 100 | 111 | 78 | **** | **** | **** | **** |
| 2007 DPE * | 56 | 112 | 192 | 246 | 453 | 397 | **** |
| Intensity skill (%) | **** | 33 | 100 | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NEP basin
A plot of the storm's observed track and forecasts
Track forecast errors were low for this storm.
Name: - Identifier: 14W
Basin: NORTH-WEST PACIFIC
Start date: 26.08.2008 End date: 28.08.2008
1-minute MSW: 35 knots 10-minute MSW: 30 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | **** | **** | **** | **** | **** | **** |
| Mean DX | -21 | **** | **** | **** | **** | **** | **** |
| Mean DY | -111 | **** | **** | **** | **** | **** | **** |
| Mean DPE | 112 | **** | **** | **** | **** | **** | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of the storm's observed track and forecasts
No forecasts were verified for this storm.
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: 12
Number of storms used in statistics below: 11
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 74 | 53 | 35 | 23 | 16 | 10 | 5 |
| Detection rate (%) | 100 | 100 | 100 | 100 | 100 | 100 | 80 |
| Mean DX | 8 | -12 | -42 | 0 | 9 | -43 | -53 |
| Mean DY | -14 | 7 | 24 | 20 | 51 | 152 | 468 |
| Mean AT | -9 | -6 | 8 | -47 | -45 | 54 | 138 |
| Mean CT | -7 | 11 | 32 | 22 | 53 | 113 | 441 |
| Track skill (%) | **** | 39 | 52 | 55 | **** | **** | **** |
| Mean DPE | 61 | 93 | 153 | 235 | 298 | 332 | 512 |
| 2007 DPE * | 66 | 127 | 193 | 262 | 401 | 472 | **** |
| Intensity skill (%) | **** | 40 | 77 | 83 | 75 | 80 | 100 |
* Best track DPE for all Northern Hemisphere storms in 2007 season
Results for this month were very good. Track forecast errors were below last season’s average and skill scores against CLIPER were high. Biases were small. The overall intensity tendency skill score was 58%.
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