Tropical cyclone activity
| Tropical cyclones ending during the month | |||||||
|---|---|---|---|---|---|---|---|
| NWP | NEP | NAT | NI | SWI | AUS | Total | |
| Total number ending during the month | 1 | 0 | 0 | 0 | 0 | 3 | 4 |
| Tropical cyclones active during the month | ||||||
|---|---|---|---|---|---|---|
| Name | Identifier | Basin | Start date | End date | 1-minute MSW | 10-minute MSW |
| Neoguri | 02W | NWP | 14 April | 19 April | 95 | 80 |
| - | 27P | AUS | 18 April | 19 April | 35 | 30 |
| Rosie | 28S | AUS | 21 April | 24 April | 45 | 50 |
| Durga | 29S | AUS | 22 April | 25 April | 40 | 40 |
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 |
| Nargis | 01B | NI | 27 April |
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: NEOGURI Identifier: 02W
Basin: NORTH-WEST PACIFIC
Start date: 14.04.2008 End
date: 19.04.2008
1-minute MSW: 95 knots 10-minute MSW: 80 knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 11 | 9 | 7 | 5 | 3 | 1 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | 100 | 100 |
| Mean DX | 22 | 18 | -70 | -276 | -616 | -1030 |
| Mean DY | 36 | -61 | -176 | -289 | -578 | -767 |
| Mean AT | 18 | -48 | -152 | -246 | -665 | -1259 |
| Mean CT | 25 | -12 | -107 | -276 | -421 | -276 |
| Track skill (%) | **** | 41 | 50 | 30 | **** | **** |
| Mean DPE | 61 | 102 | 208 | 412 | 846 | 1289 |
| 2007 DPE * | 63 | 133 | 199 | 279 | 407 | 513 |
| Intensity skill (%) | **** | 56 | -14 | 100 | 100 | -100 |
* DPE for all storms in the 2007 season in the NWP basin
Plot of Neoguri's observed track and forecasts
There was a left of track bias in early forecasts which resulted in track forecast errors above last season’s average from T+48 onwards. However, skill scores against CLIPER were good.
Name: - Identifier: 27P
Basin: AUSTRALIAN (South Pacific)
Start date: 18.04.2008 End
date: 19.04.2008
1-minute MSW: 35 knots 10-minute MSW: 30 knots
Plot of 27P's observed track and forecasts
There are no verification statistics or forecast plot for this tropical cyclone since its 10-minute averaged winds did not reach tropical storm strength.
Name: ROSIE Identifier: 2S
Basin:AUSTRALIAN (SE Indian)
Start date: 21.04.2008 End
date: 24.04.2008
1-minute MSW: 45 knots 10-minute MSW: 50 knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 3 | 1 | 0 | 0 | 0 | 0 |
| Detection Rate (%) | 100 | 100 | **** | **** | **** | **** |
| Mean DX | -4 | -33 | **** | **** | **** | **** |
| Mean DY | 67 | 167 | **** | **** | **** | **** |
| Mean AT | 2 | 12 | **** | **** | **** | **** |
| Mean CT | -77 | -168 | **** | **** | **** | **** |
| Mean DPE | 77 | 169 | **** | **** | **** | **** |
| 2006-07 DPE * | 72 | 153 | 355 | 665 | 1075 | 1537 |
| Intensity skill (%) | **** | 100 | **** | **** | **** | **** |
* DPE for all storms in the 2006-7 season in the AUS basin
Plot of Rosie's observed track and forecasts
Rosie was short-lived and just one forecast was verified.
Name: DURGA Identifier: 29S
Basin: AUSTRALIAN (SE Indian)
Start date: 22.04.2008 End
date: 25.04.2008
1-minute MSW: 40 knots 10-minute MSW: 40 knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 4 | 2 | 0 | 0 | 0 | 0 |
| Detection Rate (%) | 100 | 100 | **** | **** | **** | **** |
| Mean DX | -8 | -88 | **** | **** | **** | **** |
| Mean DY | -11 | -128 | **** | **** | **** | **** |
| Mean AT | -21 | -162 | **** | **** | **** | **** |
| Mean CT | 9 | 44 | **** | **** | **** | **** |
| Mean DPE | 49 | 194 | **** | **** | **** | **** |
| 2006-07 DPE * | 72 | 153 | 355 | 665 | 1075 | 1537 |
| Intensity skill (%) | **** | 0 | **** | **** | **** | **** |
* DPE for all storms in the 2006-7 season in the AUS basin
Plot of Durga's observed track and forecasts
Durga was short-lived and just two forecasts were verified. Track forecast errors were slightly above last season’s average.
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: 5
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 18 | 12 | 7 | 5 | 3 | 1 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | 100 | 100 |
| Mean DX | 11 | -4 | -70 | -276 | -616 | -1030 |
| Mean DY | 31 | -53 | -176 | -289 | -578 | -767 |
| Mean AT | 9 | -62 | -152 | -246 | -665 | -1259 |
| Mean CT | 9 | -15 | -107 | -276 | -421 | -276 |
| Track skill (%) | **** | 41 | 50 | 30 | **** | **** |
| Mean DPE | 61 | 123 | 208 | 412 | 846 | 1289 |
| 2007 DPE * | 62 | 125 | 193 | 266 | 404 | 469 |
| Intensity skill (%) | **** | 46 | 59 | 24 | 29 | 33 |
* DPE for all northern hemisphere storms in 2007 season
This month’s figures were dominated by Typhoon Neoguri, which was the longest lived TC of the month. Track errors were above last season’s average at most lead times, but skill scores against CLIPER were high. The overall intensity tendency skill score was 42%.