Effects of Synoptic Surveillance on model forecasts for
12 September 1999 0600 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. | 94. | 122. | 111. | 55. | 126. | 147. | 278. | 467. | 502.
| AVAL | 137. | 125. | 229. | 249. | 201. | 281. | 307. | 491. | 837. | 1123.
| %IMP | -198% | -33% | -88% | -124% | -265% | -123% | -109% | -77% | -79% | -124%
|
| GFNO | 15. | 88. | 156. | 208. | 242. | 260. | 365. | 508. | 690. | 809.
| GFAL | 24. | 54. | 84. | 105. | 91. | 157. | 160. | 267. | 444. | 434.
| %IMP | -60% | 39% | 46% | 50% | 62% | 40% | 56% | 47% | 36% | 46%
| INTENSITY (kt)
| MODEL | 12 h | 24 h | 36 h | 48 h | 60 h | 72 h | 84 h | 96 h | 108 h | 120 h
|
| AVNN | -80. | -98. | -87. | -62. | -65. | -58. | -44. | -37. | -8. | 0.
| AVAL | -62. | -75. | -71. | -48. | -51. | -43. | -18. | -21. | 14. | 3.
| %IMP | 23% | 23% | 18% | 23% | 22% | 26% | 59% | 43% | -75% | und%
|
| GFNO | -4. | -21. | -7. | 14. | 1. | -1. | 12. | -3. | 11. | 3.
| GFAL | 2. | -21. | -7. | 11. | 5. | 8. | 19. | 21. | 36. | 32.
| %IMP | 50% | 0% | 0% | 21% | -400% | -700% | -58% | -600% | -227% | -967%
|
| SHNO | -19. | -36. | -24. | -2. | -4. | -7. | 10. | 19. | 53. | 64.
| SHAL | -20. | -39. | -27. | -6. | -9. | -10. | 6. | 14. | 47. | 58.
| %IMP | -5% | -8% | -13% | -200% | -125% | -43% | 40% | 26% | 11% | 9%
|
| DSNO | -19. | -36. | -24. | -2. | -4. | -7. | 10. | 19. | 53. | 64.
| DSAL | -20. | -39. | -27. | -6. | -9. | -10. | 6. | 14. | 47. | 58.
| %IMP | -5% | -8% | -13% | -200% | -125% | -43% | 40% | 26% | 11% | 9%
| | ||||||||||
| 14/1200 UTC 25.4N 76.3W Near Alice Town, Eleuthera 54 h into the forecast | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | 26.27 | 77.92 | 69.5 | 188.6 | Abaco Island, Bahamas
| AVAL | 25.32 | 76.32 | 65.5 | 9.1 | Eleuthera Island, Bahamas
| %IMP | 26% | 95%
|
| GFNO | 27.75 | 75.56 | 58.5 | 271.2 | Near Abaco Island, Bahamas
| GFAL | 24.17 | 74.50 | 47.5 | 227.2 | San Salvador, Bahamas
| %IMP | -44% | 16%
|
|
14/1900 UTC 26.3N 77.1W Near Cherokee Sound, Abaco 61 h into the forecast
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | 26.77 | 77.92 | 69.5 | 96.8 | Grand Bahama Island, Bahamas
| AVAL | 26.92 | 77.78 | 78.0 | 96.5 | Grand Bahama Island, Bahamas
| %IMP | -100% | 0%
|
| GFNO | 27.75 | 75.56 | 58.5 | 221.8 | Near Abaco Island, Bahamas
| GFAL | 26.72 | 78.24 | 71.5 | 122.6 | Grand Bahama Island, Bahamas
| %IMP | -320% | 45% |
|
|
16/0630 UTC 33.8N 78.0W Near Cape Fear, NC 96.5 h into the forecast
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
|
| AVNN | 34.76 | 76.56 | 118.0 | 169.9 | Morehead City, NC
| AVAL | No landfall forecast
| %IMP |
|
| GFNO | 34.68 | 77.10 | 87.5 | 128.0 | Emerald Isle, NC
| GFAL | 34.08 | 78.00 | 106.5 | 31.1 | Carolina Beach, SC
| %IMP | -11% | 76%
| | ||||||||||||||||||||||||||
Figure 1. NCEP 850 - 200 hPa mean wind analysis for 12 September 1999 0600 UTC (Hurricane 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 12 September 1999 0600 UTC. The best track is shown in black.
Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 12 September 1999 0600 UTC.
Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 12 September 1999 0600 UTC.