Tropical cyclone activity and forecasts - October 2008
Tropical cyclone activity
| NWP | NEP | NAT | NI | SWI | AUS | TOTAL | |
|---|---|---|---|---|---|---|---|
| Total number ending during the month | 3 | 4 | 5 | 2 | 1 | 0 | 15 |
| Name | Identifier | Basin | Start date | End date | 1-minute MSW | 10-minute MSW |
|---|---|---|---|---|---|---|
| Higos | 21W | NWP | 29 September | 04 October | 45 | 40 |
| Laura | 12L | NAT | 29 September | 01 October | 50 | - |
| Marie | 14E | NEP | 01 October | 06 October | 70 | - |
| Norbert | 15E | NEP | 04 October | 12 October | 115 | - |
| Marco | 13L | NAT | 06 October | 08 October | 55 | - |
| Odile | 16E | NEP | 08 October | 12 October | 55 | - |
| Nana | 14L | NAT | 12 October | 14 October | 35 | - |
| Omar | 15L | NAT | 13 October | 18 October | 115 | - |
| - | 22W | NWP | 14 October | 15 October | 35 | - |
| - | 16L | NAT | 14 October | 16 October | 30 | - |
| Asma | 01S | SWI | 16 October | 21 October | 55 | 45 |
| Bavi | 23W | NWP | 18 October | 20 October | 45 | 45 |
| - | 03B | NI | 20 October | 23 October | 35 | 30 |
| - | 17E | NEP | 23 October | 24 October | 30 | - |
| Rashmi | 04B | NI | 26 October | 27 October | 45 | 35 |
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
None.
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: HIGOS Identifier: 21W
Basin:NORTH-WEST PACIFIC
Start date: 29.09.2008 End date: 04.10.2008
1-minute MSW: 45 knots 10-minute MSW: 40 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 8 | 6 | 4 | 2 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | 100 | **** | **** | **** |
| Mean DX | 26 | 104 | 93 | 366 | **** | **** | **** |
| Mean DY | -16 | -7 | 9 | -122 | **** | **** | **** |
| Mean AT | -40 | -117 | -50 | -416 | **** | **** | **** |
| Mean CT | 4 | 55 | 18 | -78 | **** | **** | **** |
| Track skill (%) | **** | 2 | 61 | **** | **** | **** | **** |
| Mean DPE | 63 | 299 | 290 | 506 | **** | **** | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | **** |
| Intensity skill (%) | **** | 33 | 100 | 100 | **** | **** | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of Higos's observed track and forecasts
Track forecast errors were above last season’s average for this storm. There was a slow bias in forecasts.
Name: LAURA Identifier: 12L
Basin: NORTH ATLANTIC
Start date: 29.09.2008 End date: 01.10.2008
1-minute MSW: 50 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 5 | 2 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | **** | **** | **** | **** | **** |
| Mean DX | 22 | 50 | **** | **** | **** | **** | **** |
| Mean DY | 9 | 89 | **** | **** | **** | **** | **** |
| Mean AT | -8 | 80 | **** | **** | **** | **** | **** |
| Mean CT | 19 | 47 | **** | **** | **** | **** | **** |
| Mean DPE | 59 | 101 | **** | **** | **** | **** | **** |
| 2007 DPE * | 63 | 102 | 151 | 179 | 228 | 265 | **** |
| Intensity skill (%) | **** | 100 | **** | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NAT basin
A plot of Laura's observed track and forecasts
Just two forecasts were verified and track forecast errors were near to average.
Name: MARIE Identifier: 14E
Basin: NORTH-EAST PACIFIC
Start date: 01.10.2008 End date: 06.10.2008
1-minute MSW: 70 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 10 | 8 | 6 | 4 | 2 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | 100 | 100 | **** | **** |
| Mean DX | 11 | -85 | -208 | -412 | -645 | **** | **** |
| Mean DY | -17 | 10 | -26 | -111 | -112 | **** | **** |
| Mean AT | -6 | 70 | 117 | 60 | 619 | **** | **** |
| Mean CT | -4 | -14 | -106 | -299 | -114 | **** | **** |
| Track skill (%) | **** | 24 | -6 | -17 | **** | **** | **** |
| Mean DPE | 37 | 124 | 238 | 434 | 655 | **** | **** |
| 2007 DPE * | 56 | 112 | 192 | 246 | 453 | 397 | **** |
| Intensity skill (%) | **** | 50 | 67 | 100 | 0 | **** | **** |
* DPE for all storms in the 2007 season in the NEP basin
A plot of Marie's observed track and forecasts
Track forecast errors were above last season’s average and skill scores were negative at 48 and 72 hours lead times. This was primarily due to poor forecasts of the storms slow northwards drift part way through its life.
Name: NORBERT Identifier: 15E
Basin:NORTH-EAST PACIFIC
Start date: 04.10.2008 End date: 12.10.2008
1-minute MSW: 115 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 15 | 13 | 11 | 9 | 7 | 5 | 3 |
| Detection rate (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Mean DX | -13 | -26 | -6 | 18 | 23 | -16 | -128 |
| Mean DY | -6 | 19 | 49 | 66 | 137 | 185 | 333 |
| Mean AT | 5 | 15 | -2 | -34 | 49 | 153 | 265 |
| Mean CT | -15 | -14 | 5 | 84 | 145 | 112 | -191 |
| Track skill (%) | **** | 50 | 65 | 54 | **** | **** | **** |
| Mean DPE | 33 | 59 | 94 | 165 | 250 | 356 | 370 |
| 2007 DPE * | 56 | 112 | 192 | 246 | 453 | 397 | **** |
| Intensity skill (%) | **** | 8 | 27 | -33 | -14 | 60 | 33 |
* DPE for all storms in the 2007 season in the NEP basin
A plot of Norbert's observed track and forecasts
Early forecasts predicted a straight north-westward track, but later forecasts successfully predicted the gently curving track towards the Baja peninsula. Hence, track forecast errors were well below last season’s average and skill scores against CLIPER were high.
Name: MARCO Identifier: 13L
Basin: NORTH ATLANTIC
Start date: 06.10.2008 End date: 08.10.2008
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 | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | **** | **** | **** | **** | **** | **** |
| Mean DX | 25 | **** | **** | **** | **** | **** | **** |
| Mean DY | 28 | **** | **** | **** | **** | **** | **** |
| Mean AT | -16 | **** | **** | **** | **** | **** | **** |
| Mean CT | 37 | **** | **** | **** | **** | **** | **** |
| Mean DPE | 47 | **** | **** | **** | **** | **** | **** |
| 2007 DPE * | 63 | 102 | 151 | 179 | 228 | 265 | **** |
* DPE for all storms in the 2007 season in the NAT basin
A plot of Marco's observed track and forecasts
Early forecasts predicted a straight north-westward track, but later forecasts successfully predicted the gently curving track towards the Baja peninsula. Hence, track forecast errors were well below last season’s average and skill scores against CLIPER were high.
Name: ODILE Identifier: 16E
Basin: NORTH-EAST PACIFIC
Start date: 08.10.2008 End date: 12.10.2008
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 | 6 | 4 | 2 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | **** | **** | **** | **** |
| Mean DX | 7 | 90 | 171 | **** | **** | **** | **** |
| Mean DY | -31 | -50 | -156 | **** | **** | **** | **** |
| Mean AT | -21 | -102 | -227 | **** | **** | **** | **** |
| Mean CT | -22 | -1 | -51 | **** | **** | **** | **** |
| Track skill (%) | **** | 9 | **** | **** | **** | **** | **** |
| Mean DPE | 56 | 140 | 233 | **** | **** | **** | **** |
| 2007 DPE * | 56 | 112 | 192 | 246 | 453 | 397 | **** |
| Intensity skill (%) | **** | 50 | -100 | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NEP basin
A plot of Odile's observed track and forecasts
Track forecast errors were slightly above last season’s average due to a slow bias
Name: NANA Identifier: 14L
Basin: NORTH ATLANTIC
Start date: 12.10.2008 End date: 14.10.2008
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 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | **** | **** | **** | **** | **** | **** |
| Mean DX | -32 | **** | **** | **** | **** | **** | **** |
| Mean DY | 22 | **** | **** | **** | **** | **** | **** |
| Mean AT | 13 | -43 | -130 | -182 | -175 | -220 | -22 |
| Mean DPE | 34 | **** | **** | **** | **** | **** | **** |
| 2007 DPE * | 63 | 102 | 151 | 179 | 228 | 265 | **** |
* DPE for all storms in the 2007 season in the NAT basin
A plot of Nana's observed track and forecasts
Nana was only briefly a tropical storm and no forecasts were verified.
Name: OMAR Identifier: 15L
Basin: NORTH ATLANTIC
Start date: 13.10.2008 End date: 18.10.2008
1-minute MSW: 115 knots 10-minute MSW: - knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 8 | 6 | 4 | 2 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | 100 | 100 | **** | **** | **** |
| Mean DX | -6 | -56 | -156 | -432 | **** | **** | **** |
| Mean DY | -11 | -110 | -223 | -384 | **** | **** | **** |
| Mean AT | -13 | -115 | -274 | -572 | **** | **** | **** |
| Mean CT | 13 | 17 | -16 | -80 | **** | **** | **** |
| Track skill (%) | **** | 62 | 72 | 75 | **** | **** | **** |
| Mean DPE | 54 | 154 | 293 | 579 | **** | **** | **** |
| 2007 DPE * | 63 | 102 | 151 | 179 | 228 | 265 | **** |
| Intensity skill (%) | **** | 33 | 100 | 100 | **** | **** | **** |
* DPE for all storms in the 2007 season in the NAT basin
A plot of Omar's observed track and forecasts
The acceleration north-eastwards of Omar was correctly predicted by the model although the forward speed was too slow resulting in some large errors. However, the skill scores against CLIPER were very high.
Name: - Identifier: 22W
Basin:NORTH-WEST PACIFIC
Start date: 14.10.2008 End date: 15.10.2008
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 | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | **** | **** | **** | **** | **** | **** |
| Mean DX | 32 | **** | **** | **** | **** | **** | **** |
| Mean DY | -6 | **** | **** | **** | **** | **** | **** |
| Mean AT | -31 | **** | **** | **** | **** | **** | **** |
| Mean CT | 33 | **** | **** | **** | **** | **** | **** |
| Mean DPE | 50 | **** | **** | **** | **** | **** | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of 22W's observed track and forecasts
22W was only briefly a tropical storm and no 24-hour forecasts were verified.
Name: - Identifier: 16L
Basin: NORTH ATLANTIC
Start date: 14.10.2008 End date: 16.10.2008
1-minute MSW: 30 knots 10-minute MSW: - knots
A plot of 16L'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: ASMA Identifier: 01S
Basin:SOUTH-WEST INDIAN
Start date: 16.10.2008 End date: 21.10.2008
1-minute MSW: 55 knots 10-minute MSW: 45 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 3 | 1 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | **** | **** | **** | **** | **** |
| Mean DX | -16 | -98 | **** | **** | **** | **** | **** |
| Mean DY | 67 | 200 | **** | **** | **** | **** | **** |
| Mean AT | 16 | 116 | **** | **** | **** | **** | **** |
| Mean CT | 52 | 186 | **** | **** | **** | **** | **** |
| Track skill (%) | **** | 18 | **** | **** | **** | **** | **** |
| Mean DPE | 77 | 220 | **** | **** | **** | **** | **** |
| 2007 DPE * | 54 | 130 | 283 | 458 | 665 | 802 | **** |
| Intensity skill (%) | **** | 100 | **** | **** | **** | **** | **** |
* DPE for all storms in the 2007-8 season in the SWI basin
A plot of Asma's observed track and forecasts
Asma only briefly attained tropical storm status and just one forecast was verified.
Name: BAVI Identifier: 23W
Basin:NORTH-WEST PACIFIC
Start date: 18.10.2008 End date: 20.10.2008
1-minute MSW: 45 knots 10-minute MSW: 45 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 3 | 1 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | **** | **** | **** | **** | **** |
| Mean DX | 32 | -140 | **** | **** | **** | **** | **** |
| Mean DY | -7 | 22 | **** | **** | **** | **** | **** |
| Mean AT | 26 | -50 | **** | **** | **** | **** | **** |
| Mean CT | 37 | -135 | **** | **** | **** | **** | ***** |
| Mean DPE | 64 | 145 | **** | **** | **** | **** | **** |
| 2007 DPE * | 70 | 136 | 201 | 276 | 404 | 517 | **** |
| Intensity skill (%) | **** | 1000 | **** | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NWP basin
A plot of Bavi's observed track and forecasts
Bavi only briefly attained tropical storm status and just one forecast was verified.
Name: - Identifier: 03B
Basin: NORTH INDIAN (Arabian Sea)
Start date: 20.10.2008 End date: 23.10.2008
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 | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | **** | **** | **** | **** | **** | **** |
| Mean DX | -164 | **** | **** | **** | **** | **** | **** |
| Mean DY | -22 | **** | **** | **** | **** | **** | **** |
| Mean AT | 88 | **** | **** | **** | **** | **** | **** |
| Mean CT | -139 | **** | **** | **** | **** | **** | ***** |
| Mean DPE | 166 | **** | **** | **** | **** | **** | **** |
| 2007 DPE * | 77 | 147 | 203 | 319 | 509 | 387 | **** |
* DPE for all storms in the 2007 season in the NI basin
A plot of 03B's observed track and forecasts
03B only briefly attained tropical storm status (according to JTWC) and no 24-hour forecasts were verified.
Name: - Identifier: 17E
Basin: NORTH-EAST PACIFIC
Start date: 23.10.2008 End date: 24.10.2008
1-minute MSW: 30 knots 10-minute MSW: -
A plot of the 17E's observed track.
There are no verification statistics for this tropical cyclone since its 1-minute averaged winds did not reach tropical storm strength.
Name: RASHMI Identifier: 04B
Basin: NORTH INDIAN (Bay of Bengal)
Start date: 26.10.2008 End date: 27.10.2008
1-minute MSW: 45 knots 10-minute MSW: 35 knots
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 3 | 1 | 0 | 0 | 0 | 0 | 0 |
| Detection rate (%) | 100 | 100 | **** | **** | **** | **** | **** |
| Mean DX | 18 | 10 | **** | **** | **** | **** | **** |
| Mean DY | -75 | -67 | **** | **** | **** | **** | **** |
| Mean AT | -72 | -62 | **** | **** | **** | **** | **** |
| Mean CT | 58 | 37 | **** | **** | **** | **** | ***** |
| Mean DPE | 79 | 73 | **** | **** | **** | **** | **** |
| 2007 DPE * | 77 | 147 | 203 | 319 | 509 | 387 | **** |
| Intensity skill (%) | **** | 100 | **** | **** | **** | **** | **** |
* DPE for all storms in the 2007 season in the NI basin
A plot of Rashmi's observed track and forecasts
Rashmi only briefly attained tropical storm status and just one forecast was verified. This forecast predicted landfall well.
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: 15
Number of storms used in statistics below: 13
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | T+144 | |
|---|---|---|---|---|---|---|---|
| Possibly verified | 68 | 42 | 27 | 17 | 9 | 5 | 3 |
| Detection rate (%) | 100 | 100 | 96 | 100 | 100 | 100 | 100 |
| Mean DX | 15 | -1 | -54 | -95 | -125 | -16 | -128 |
| Mean DY | -6 | -4 | -24 | -51 | 81 | 185 | 333 |
| Mean AT | -7 | -20 | -32 | -120 | 176 | 153 | 265 |
| Mean CT | 0 | 7 | -24 | -45 | 88 | 112 | -191 |
| Track skill (%) | **** | 38 | 61 | 59 | **** | **** | **** |
| Mean DPE | 54 | 135 | 194 | 317 | 340 | 356 | 370 |
| 2007 DPE * | 66 | 127 | 193 | 262 | 401 | 472 | **** |
| Intensity skill (%) | **** | 37 | 54 | 29 | -11 | 60 | 33 |
* Best track DPE for all Northern Hemisphere storms in 2007 season
Despite there being 15 tropical cyclones during the month, many of these were short-lived and only five of them produced 48-hour forecasts to verify. On the whole track forecast errors were close to or slightly below last season’s average. Skill scores against CLIPER were high. The overall intensity tendency skill score was 42%.
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