Tropical cyclone activity
| Tropical cyclones ending during the month | |||||||
|---|---|---|---|---|---|---|---|
| NWP | NEP | NAT | NI | SWI | AUS | Total | |
| Total number ending during the month | 5 | 2 | 3 | 0 | 0 | 0 | 10 |
| Tropical cyclones active during the month | ||||||
|---|---|---|---|---|---|---|
| Name | Identifier | Basin | Start date | End date | 1-minute MSW | 10-minute MSW |
| Usagi | 05W | NWP | 28 July | 04 August | 120 | 90 |
| Chantal | 03L | NAT | 31 July | 01 August | 45 | - |
| Erick | 08E | NEP | 31 July | 02 August | 35 | - |
| - | 06W | NWP | 02 August | 07 August | 35 | 30 |
| Pabuk | 07W | NWP | 05 August | 09 August | 65 | 65 |
| Wutip | 08W | NWP | 07 August | 09 August | 40 | 40 |
| Flossie | 09E | NEP | 08 August | 16 August | 120 | - |
| Sepat | 09W | NWP | 12 August | 19 August | 140 | 110 |
| Dean | 04L | NAT | 13 August | 23 August | 145 | - |
| Erin | 05L | NAT | 15 August | 16 August | 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
| Tropical cyclones still active at the end of the month | |||
|---|---|---|---|
| Name | Identifier | Basin | Start date |
| Fitow | 10W | NWP | 29 August |
| Gil | 10E | NEP | 29 August |
| Henriette | 11E | NEP | 30 August |
| Felix | 06L | NAT | 31 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 62km x 42km at the equator.
Individual tropical cyclone summaries
Name: USAGI Identifier: 05W
Basin: NORTH-WEST PACIFIC
Start date: 28.07.2007 End
date: 04.08.2007
1-minute MSW: 120 knots
10-minute MSW: 90 knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 13 | 11 | 9 | 7 | 5 | 3 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | 100 | 100 |
| Mean DX | -3 | -8 | -45 | -118 | -273 | -221 |
| Mean DY | -37 | -11 | -68 | -175 | -331 | -389 |
| Mean AT | -29 | -22 | -25 | -156 | -405 | -492 |
| Mean CT | -31 | -17 | -83 | -132 | -64 | 128 |
| Track skill (%) | **** | 58 | 59 | 57 | **** | **** |
| Mean DPE | 81 | 81 | 144 | 269 | 498 | 558 |
| 2006 DPE * | 60 | 114 | 204 | 304 | 422 | 551 |
| Intensity skill (%) | **** | 27 | 33 | 43 | 20 | 33 |
* DPE for all storms in the 2006 season in the NWP basin
 |
Plot of the storm's observed track and forecasts |
Track forecast errors for this typhoon were lower than last season’s average up to T+72. Skill scores against CLIPER were high. There was a slight slow and left-of-track bias in forecasts.
Name: CHANTAL Identifier: 03L
Basin: NORTH ATLANTIC
Start date: 31.07.2007 End date: 01.08.2007
1-minute MSW: 45 knots 10-minute MSW: - knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 2 | 0 | 0 | 0 | 0 | 0 |
| Detection Rate (%) | 100 | **** | **** | **** | **** | **** |
| Mean DX | -72 | **** | **** | **** | **** | **** |
| Mean DY | 33 | **** | **** | **** | **** | **** |
| Mean AT | -14 | **** | **** | **** | **** | **** |
| Mean CT | -76 | **** | **** | **** | **** | **** |
| Mean DPE | 78 | **** | **** | **** | **** | **** |
| 2006 DPE * | 46 | 109 | 213 | 322 | 425 | 529 |
* DPE for all storms in the 2006 season in the NAT basin
 |
Plot of the storm's observed track |
Chantal was only briefly a tropical storm and no forecasts were verified.
Name: ERICK Identifier: 08E
Basin: NORTH-EAST PACIFIC
Start date: 31.07.2007 End date: 02.08.2007
1-minute MSW: 35 knots 10-minute MSW: -
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 2 | 0 | 0 | 0 | 0 | 0 |
| Detection Rate (%) | 100 | **** | **** | **** | **** | **** |
| Mean DX | 27 | **** | **** | **** | **** | **** |
| Mean DY | 0 | **** | **** | **** | **** | **** |
| Mean AT | -28 | **** | **** | **** | **** | **** |
| Mean CT | -1 | **** | **** | **** | **** | **** |
| Mean DPE | 95 | **** | **** | **** | **** | **** |
| 2006 DPE * | 51 | 103 | 185 | 265 | 366 | 430 |
* DPE for all storms in the 2006 season in the NEP basin
 |
Plot of the storm's observed track |
Erick was only briefly a tropical storm and no forecasts were verified.
Name: - Identifier: 06W
Basin: NORTH-WEST PACIFIC
Start date: 02.08.2007 End date: 07.08.2007
1-minute MSW: 35 knots 10-minute MSW: 30 knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 1 | 0 | 0 | 0 | 0 | 0 |
| Detection Rate (%) | 100 | **** | **** | **** | **** | **** |
| Mean DX | -119 | **** | **** | **** | **** | **** |
| Mean DY | -11 | **** | **** | **** | **** | **** |
| Mean AT | 96 | **** | **** | **** | **** | **** |
| Mean CT | 60 | **** | **** | **** | **** | **** |
| Mean DPE | 114 | **** | **** | **** | **** | **** |
| 2006 DPE * | 60 | 114 | 204 | 304 | 422 | 551 |
* DPE for all storms in the 2006 season in the NWP basin
 |
Plot of the storm's observed track |
06W was only briefly a tropical storm (according to its 1-minute sustained winds) and no forecasts were verified.
Name: PABUK Identifier: 07W
Basin: NORTH-WEST PACIFIC
Start date: 05.08.2007 End date: 09.08.2007
1-minute MSW: 65 knots 10-minute MSW: 65 knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 8 | 6 | 4 | 2 | 0 | 0 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | **** | **** |
| Mean DX | 20 | 134 | 266 | 163 | **** | **** |
| Mean DY | -13 | 22 | 228 | 300 | **** | **** |
| Mean AT | -15 | -113 | -278 | -200 | **** | **** |
| Mean CT | -13 | 28 | 223 | 273 | **** | **** |
| Track skill (%) | **** | -9 | -9 | **** | **** | **** |
| Mean DPE | 68 | 189 | 379 | 351 | **** | **** |
| 2006 DPE * | 60 | 114 | 204 | 304 | 422 | 551 |
| Intensity skill (%) | **** | 33 | 0 | 0 | **** | **** |
* DPE for all storms in the 2006 season in the NWP basin
 |
Plot of the storm's observed track and forecasts |
Track forecast errors for this storm were above last season’s average due to a marked slow bias.
Name: WUTIP Identifier: 08W
Basin: NORTH-WEST PACIFIC
Start date: 07.08.2007 End date: 09.08.2007
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 | 2 | 0 | 0 | 0 | 0 | 0 |
| Detection Rate (%) | 100 | **** | **** | **** | **** | **** |
| Mean DX | -11 | **** | **** | **** | **** | **** |
| Mean DY | 0 | **** | **** | **** | **** | **** |
| Mean AT | 10 | **** | **** | **** | **** | **** |
| Mean CT | 1 | **** | **** | **** | **** | **** |
| Mean DPE | 45 | **** | **** | **** | **** | **** |
| 2006 DPE * | 60 | 114 | 204 | 304 | 422 | 551 |
* DPE for all storms in the 2006 season in the NWP basin
 |
Plot of the storm's observed track |
Wutip was only briefly a tropical storm and no forecasts were verified.
Name: FLOSSIE Identifier: 09E
Basin: NORTH-EAST PACIFIC
Start date: 08.08.2007 End date: 16.08.2007
1-minute MSW: 120 knots 10-minute MSW: -
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 15 | 13 | 11 | 9 | 7 | 5 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | 100 | 80 |
| Mean DX | 19 | 2 | -57 | -107 | -196 | -169 |
| Mean DY | 8 | 39 | 46 | 5 | -65 | -114 |
| Mean AT | -14 | 2 | 59 | 99 | 159 | 124 |
| Mean CT | 9 | 34 | 35 | -17 | -119 | -133 |
| Track skill (%) | **** | 36 | 39 | 63 | **** | **** |
| Mean DPE | 45 | 70 | 119 | 163 | **** | **** |
| 2006 DPE * | 51 | 103 | 185 | 265 | 366 | 430 |
| Intensity skill (%) | **** | 69 | 82 | 56 | 100 | 50 |
* DPE for all storms in the 2006 season in the NEP basin
 |
Plot of the storm's observed track and forecasts |
Track forecast errors were low and skill scores high for this hurricane.
Name: SEPAT Identifier: 09W
Basin: NORTH-WEST PACIFIC
Start date: 12.08.2007 End date: 19.08.2007
1-minute MSW: 140 knots 10-minute MSW: 110 knots
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 15 | 13 | 11 | 9 | 7 | 5 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | 100 | 100 |
| Mean DX | 5 | -29 | -64 | -157 | -205 | -60 |
| Mean DY | -28 | 36 | -9 | -82 | -211 | -276 |
| Mean AT | -14 | 20 | -8 | 41 | -1 | -181 |
| Mean CT | -24 | 5 | -75 | -185 | -282 | -249 |
| Track skill (%) | **** | 10 | 30 | 14 | **** | **** |
| Mean DPE | 72 | 111 | 195 | 314 | 389 | 499 |
| 2006 DPE * | 60 | 114 | 204 | 304 | 422 | 551 |
| Intensity skill (%) | **** | 23 | 82 | 11 | 100 | -20 |
* DPE for all storms in the 2006 season in the NWP basin
 |
Plot of the storm's observed track and forecasts |
Track forecast errors were low and skill scores high for this hurricane.
Name: DEAN Identifier: 04L
Basin: NORTH ATLANTIC
Start date: 13.08.2007 End date: 23.08.2007
1-minute MSW: 145 knots 10-minute MSW: -
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 16 | 14 | 12 | 10 | 8 | 6 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | 100 | 100 |
| Mean DX | 11 | 44 | 30 | -36 | -87 | -64 |
| Mean DY | 21 | 21 | 71 | 96 | 134 | 211 |
| Mean AT | -7 | -38 | -18 | 52 | 108 | 106 |
| Mean CT | 23 | 28 | 71 | 90 | 116 | 203 |
| Track skill (%) | **** | 32 | 53 | 69 | **** | **** |
| Mean DPE | 42 | 76 | 133 | 148 | 185 | 264 |
| 2006 DPE * | 46 | 109 | 213 | 322 | 425 | 529 |
| Intensity skill (%) | **** | 14 | -50 | -60 | 25 | -33 |
* DPE for all storms in the 2006 season in the NAT basin
 |
Plot of the storm's observed track and forecasts |
Dean was a fairly straight running hurricane, but was very well forecast by the model with track errors well below last season’s average values. Skill scores against CLIPER were high. All but one forecast correctly predicted landfall on the Yucatan peninsula.
Name: ERIN Identifier: 05L
Basin: NORTH ATLANTIC
Start date: 15.08.2007 End date: 16.08.2007
1-minute MSW: 35 knots 10-minute MSW: -
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 1 | 0 | 0 | 0 | 0 | 0 |
| Detection Rate (%) | 100 | **** | **** | **** | **** | **** |
| Mean DX | 50 | **** | **** | **** | **** | **** |
| Mean DY | -22 | **** | **** | **** | **** | **** |
| Mean AT | -54 | **** | **** | **** | **** | **** |
| Mean CT | 17 | **** | **** | **** | **** | **** |
| Mean DPE | 57 | **** | **** | **** | **** | **** |
| 2006 DPE * | 46 | 109 | 213 | 322 | 425 | 529 |
* DPE for all storms in the 2006 season in the NAT basin
 |
Plot of the storm's observed track |
Erin was only briefly a tropical storm and no forecasts were verified.
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: 10
Number of storms used in statistics below: 10
| MEAN ERROR STATISTICS | ||||||
|---|---|---|---|---|---|---|
| T+0 | T+24 | T+48 | T+72 | T+96 | T+120 | |
| Possibly Verified | 75 | 57 | 47 | 37 | 27 | 19 |
| Detection Rate (%) | 100 | 100 | 100 | 100 | 100 | 95 |
| Mean DX | 6 | 17 | -7 | -87 | -180 | -112 |
| Mean DY | -7 | 22 | 33 | -10 | -93 | -96 |
| Mean AT | -14 | -20 | -21 | 8 | -2 | -69 |
| Mean CT | -6 | 15 | 12 | -35 | -82 | -10 |
| Track skill (%) | **** | 31 | 43 | 54 | **** | **** |
| Mean DPE | 62 | 96 | 167 | 226 | 330 | 402 |
| 2006 DPE * | 57 | 112 | 203 | 303 | 422 | 537 |
| Intensity skill (%) | **** | 33 | 32 | 8 | 63 | 0 |
* DPE for all northern hemisphere storms in 2006 season
This month was characterised by a number of short-lived storms which contributed nothing to the forecast statistics and a few longer running storms. Overall, track forecast errors were below last season’s average and skill scores against CLIPER were good. There were no notable biases when averaged over all cases. The overall intensity tendency skill score was 29%.