Effects of Synoptic Surveillance on model forecasts for
14 September 2003 0000 UTC
Isabel.
Quicktime movie of GFS DLM wind model
forecast
Quicktime movie of DLM wind data
increment
| TRACK (km) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| MODEL | 12 h | 24 h | 36 h | 48 h | 60 h | 72 h | 84 h | 96 h | 108 h | 120 h
|
| AVNN | 33 | 44 | 33 | 67 | 156 | 233 | 300 | 300 | 325 | 303
| AVNO | 24 | 46 | 32 | 52 | 41 | 54 | 67 | 124 | 184 | 255
| %IMP | 27% | -5% | 3% | 22% | 74% | 77% | 78% | 59% | 43% | 16%
|
| GFNO | 20 | 52 | 107 | 122 | 132 | 114 | 179 | 258 | 391 | 505
| GFDL | 15 | 38 | 94 | 126 | 128 | 135 | 173 | 273 | 385 | 502
| %IMP | 25% | 27% | 12% | -3% | 3% | -18% | 3% | -6% | 2% | 1%
| INTENSITY (kt)
| MODEL | 12 h | 24 h | 36 h | 48 h | 60 h | 72 h | 84 h | 96 h | 108 h | 120 h
|
| AVNN | -95 | -82 | -67 | -51 | -48 | -33 | -28 | -23 | -22 | 8
| AVNO | -72 | -62 | -50 | -32 | -23 | -17 | -14 | -7 | -9 | 4
| %IMP | 24% | 24% | 25% | 37% | 52% | 48% | 50% | 70% | 59% | 50%
|
| GFNO | -27 | -30 | -18 | -7 | -3 | 1 | 0 | 3 | -4 | 6
| GFDL | -16 | -26 | -21 | -12 | -6 | -3 | 6 | 3 | -6 | 8
| %IMP | 41% | 13% | -17% | -71% | -100% | -200% | und% | 100% | -50% | -33%
|
| SHNO | 0 | -2 | 0 | 7 | 10 | -1 | -4 | -11 | -19 | 0
| SHIP | 1 | 0 | 3 | 12 | 15 | 7 | 5 | -4 | -14 | 5
| %IMP | und% | 100% | und% | -71% | -50% | -600% | -25% | 64% | 26% | und%
|
| DSNO | 0 | -2 | 0 | 7 | 10 | -1 | -4 | -11 | -19 | 0
| DSHP | 1 | 0 | 3 | 12 | 15 | 7 | 5 | -4 | -14 | 5
| %IMP | und% | 100% | und% | -71% | -50% | -600% | -25% | 64% | 26% | und%
| | ||||||||||
| 18/1700 UTC 34.9N 76.2W Drum Inlet, NC 113.0 h into the forecast | |||||||||||||||||||||||||||||||||||||||||
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | No landfall forecast
| AVNO | 36.12 | 74.32 | 113.0 | 217.4 | Well offshore Cape Hatteras, NC
| %IMP |
|
| GFNO | 36.12 | 73.42 | 106.0 | 285.6 | Well offshore Cape Hatteras, NC
| GFDL | 36.26 | 73.10 | 106.0 | 318.3 | Well offshore Cape Hatteras, NC
| %IMP | 0% | -11% |
| | ||||||||
Figure 1. NCEP 850 - 200 hPa mean wind analysis for 14 September 2003 0000 UTC (Hurricane Isabel).
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 14 September 2003 0000 UTC.
Figure 3. Ensemble perturbation variance at the nominal sampling time 14 September 2003 0000 UTC from the previous day NCEP ensemble forecast. The 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 14 September 2003 0000 UTC. The circles represent the dropwindsonde locations.
