Effects of Synoptic Surveillance on model forecasts for
10 September 1999 0000 UTC
FLOYD.
QuickTime movie of DLM wind model
forecasts
QuickTime movie of DLM wind data
increments
| TRACK (km) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| MODEL | 12 h | 24 h | 36 h | 48 h | 60 h | 72 h | 84 h | 96 h | 108 h | 120 h
|
| AVNN | 46. | 156. | 231. | 280. | 238. | 289. | 308. | 351. | 338. | 383.
| AVAL | 100. | 164. | 145. | 137. | 161. | 233. | 324. | 399. | 427. | 447.
| %IMP | -117% | -5% | 37% | 51% | 32% | 19% | -5% | -14% | -26% | -17%
|
| GFNO | 84. | 166. | 191. | 247. | 270. | 249. | 182. | 119. | 82. | 32.
| GFAL | 43. | 126. | 187. | 270. | 268. | 263. | 226. | 188. | 180. | 163.
| %IMP | 49% | 24% | 2% | -9% | 1% | -6% | -24% | -58% | -120% | -409%
| INTENSITY (kt)
| MODEL | 12 h | 24 h | 36 h | 48 h | 60 h | 72 h | 84 h | 96 h | 108 h | 120 h
|
| AVNN | -34. | -45. | -58. | -45. | -63. | -86. | -93. | -72. | -60. | -67.
| AVAL | -30. | -41. | -50. | -40. | -65. | -82. | -87. | -67. | -52. | -57.
| %IMP | 12% | 9% | 14% | 11% | -3% | 5% | 6% | 7% | 13% | 15%
|
| GFNO | 17. | 25. | 14. | 13. | 4. | -7. | -19. | 2. | 11. | 5.
| GFAL | 21. | 17. | 15. | 22. | 2. | -9. | -20. | -5. | 0. | 4.
| %IMP | 24% | 32% | -7% | -69% | 50% | -29% | -5% | -150% | 100% | 20%
|
| SHNO | -3. | -7. | -17. | -1. | -18. | -34. | -42. | -20. | -8. | -17.
| SHAL | -3. | -9. | -21. | -8. | -26. | -43. | -52. | -32. | -20. | -29.
| %IMP | 0% | -29% | -24% | -700% | -44% | -26% | -24% | -60% | -150% | -71%
|
| DSNO | -3. | -7. | -17. | -1. | -18. | -34. | -42. | -20. | -8. | -17.
| DSAL | -3. | -9. | -21. | -8. | -26. | -43. | -52. | -32. | -20. | -29.
| %IMP | 0% | -29% | -24% | -700% | -44% | -26% | -24% | -60% | -150% | -71%
| | ||||||||||
| 14/1200 UTC 25.4N 76.3W Near Alice Town, Eleuthera 108 h into the forecast | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | 23.83 | 74.55 | 112.5 | 248.3 | San Salvador, Bahamas
| AVAL | 22.82 | 72.57 | 105.5 | 474.6 | North Caicos, Turks and Caicos Islands
| %IMP | 44% | -91%
|
| GFNO | 26.84 | 77.47 | 117.0 | 198.0 | Near Abaco Island, Bahamas
| GFAL | 27.56 | 76.99 | 113.0 | 249.6 | Eleuthera Island, Bahamas
| %IMP | 44% | -26%
|
|
14/1900 UTC 26.3N 77.1W Near Cherokee Sound, Abaco 115 h into the forecast
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | 24.05 | 75.52 | 118.0 | 296.2 | Cat Island, Bahamas
| AVAL | 24.02 | 74.46 | 118.5 | 366.9 | Near Ragged Island, Bahamas
| %IMP | -17% | -24%
|
| GFNO | 26.84 | 77.47 | 117.0 | 70.4 | Near Abaco Island, Bahamas
| GFAL | 27.56 | 76.99 | 113.0 | 140.4 | Abaco Island, Bahamas
| %IMP | 0% | -99%
|
|
16/0630 UTC 33.8N 78.0W Near Cape Fear, NC 150.5 h into the forecast
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
|
| AVNN | No landfall forecast
| AVAL | No landfall forecast
| %IMP |
|
| GFNO | No landfall forecast
| GFAL | No landfall forecast
| %IMP |
| | ||||||||||||||||||||||||||||||||||||||||||
Figure 1. NCEP 850 - 200 hPa mean wind analysis for 10 September 1999 0000 UTC (Tropical Storm Floyd).
Figure 2. Track forecasts for the no dropwindsonde (NO or NN) and the all dropwindsonde (AL) runs for the AVN and GFDL models initialized on 10 September 1999 0000 UTC. The best track is shown in black.
Figure 3. Ensemble perturbation variance at the nominal sampling time 10 September 1999 0000 UTC from the previous day NCEP ensemble forecast. The green circles represent the dropwindsonde locations.
Figure 4. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 10 September 1999 0000 UTC. The green circles represent the dropwindsonde locations.
