Effects of Synoptic Surveillance on model forecasts for
22 August 1999 0000 UTC
BRET.
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 | 11. | 30. | 15. | 116. | 192. | 304.
| AVAL | 24. | 54. | 59. | 195. | 273. | 336.
| %IMP | -118% | -80% | -293% | -68% | -42% | -11%
|
| GFNO | 45. | 15. | 69. | 135. | 270.
| GFAL | 63. | 45. | 59. | 115. | 155.
| %IMP | -40% | -200% | 14% | 15% | 43%
| INTENSITY (kt)
| MODEL | 12 h | 24 h | 36 h | 48 h | 60 h | 72 h | 84 h | 96 h | 108 h | 120 h
|
| AVNN | -90. | -68. | -33. | -11. | -7. | -4.
| AVAL | -92. | -68. | -32. | -8. | -4. | -1.
| %IMP | -2% | 0% | 3% | 27% | 43% | 75%
|
| GFNO | -26. | -9. | -8. | 12. | 14.
| GFAL | -30. | -5. | -3. | 13. | 24.
| %IMP | -15% | 44% | 63% | -8% | -71%
|
| SHNO | -5. | 23. | 64. | 93. | 92. | 93.
| SHAL | -5. | 23. | 64. | 93. | 92. | 93.
| %IMP | 0% | 0% | 0% | 0% | 0% | 0%
|
| DSNO | -5. | 23. | 2. | 8. | 5. | 8.
| DSAL | -5. | 23. | 3. | 8. | 5. | 8.
| %IMP | 0% | 0% | -50% | 0% | 0% | 0%
| | ||||||||||
| Landfall forecasts | |||||
| 23/0000UTC 26.9N 97.4W Central Padre Island, TX 24 h into forecast | |||||
| LAT | LON | FTIME | ERROR | LOCATION | |
| AVNN | 27.05 | 97.49 | 28.0 | 18.9 | Central Padre Island, TX |
| AVAL | 26.85 | 97.36 | 29.0 | 6.8 | Central Padre Island, TX |
| %IMP | -20% | 64% | |||
| LAT | LON | FTIME | ERROR | LOCATION | |
| GFNO | 26.88 | 97.51 | 25.5 | 11.1 | Central Padre Island, TX |
| GFAL | 26.69 | 97.47 | 27.0 | 24.3 | Central Padre Island, TX |
| %IMP | -100% | -117% | |||
Figure 1. NCEP 850 - 200 hPa mean wind analysis for 22 August 1999 0000 UTC (Hurricane Bret).
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 22 August 1999 0000 UTC. The best track is shown in black.
Figure 3. Ensemble perturbation variance at the nominal sampling time 22 August 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 22 August 1999 0000 UTC. The green circles represent the dropwindsonde locations.
