Effects of Synoptic Surveillance on model forecasts for
12 September 2004 1200 UTC
Ivan.
Quicktime movie of AVN 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 | 24 | 0 | 46 | 44 | 38 | 60 | 156 | 202 | 203 | 212
| AVNO | 44 | 56 | 133 | 100 | 112 | 143 | 197 | 232 | 252 | 52
| %IMP | -83% | und% | -189% | -127% | -195% | -138% | -27% | -15% | -24% | 75%
|
| GFNO | 0 | 35 | 83 | 84 | 80 | 78 | 67 | 24 | 116 | 275
| GFDL | 33 | 78 | 118 | 113 | 126 | 140 | 154 | 85 | 67 | 204
| %IMP | und% | -123% | -42% | -35% | -58% | -79% | -130% | -254% | 42% | 26%
|
| INTENSITY (kt)
| MODEL | 12 h | 24 h | 36 h | 48 h | 60 h | 72 h | 84 h | 96 h | 108 h | 120 h
|
| AVNN | -71 | -64 | -58 | -46 | -39 | -39 | -30 | 2 | 8 | 3
| AVNO | -50 | -69 | -67 | -49 | -37 | -37 | -36 | -9 | -2 | 3
| %IMP | 30% | -8% | -16% | -7% | 5% | 5% | -20% | -350% | 75% | 0%
|
| GFNO | -19 | -16 | -15 | -5 | -8 | -8 | -15 | 19 | 20 | 17
| GFDL | -12 | -11 | -12 | -7 | -11 | -9 | -15 | 6 | 11 | 18
| %IMP | 37% | 31% | 20% | -40% | -38% | -13% | 0% | 68% | 45% | 6%
|
| | ||||||||||
| 12/1415 UTC 18.9N 81.5W 22 n mi SSW of Georgetown, Grand Cayman Island 2.25 h into the forecast | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | 18.82 | 81.57 | 2.0 | 11.5 | Near Georgetown, Grand Cayman Island
| AVNO | 19.14 | 81.48 | 2.0 | 26.7 | Near Georgetown, Grand Cayman Island
| %IMP | 0% | -132%
|
| GFNO | 18.85 | 81.60 | 3.0 | 11.9 | Near Georgetown, Grand Cayman island
| GFDL | 18.96 | 81.61 | 3.0 | 13.3 | Near Georgetown, Grand Cayman Island
| %IMP | 0% | -12%
|
|
14/0100 UTC 21.7N 85.2W 15 n mi SW of Cabo San Antonio, Cuba 37.0 h into the forecast
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | 21.87 | 84.92 | 35.0 | 34.5 | Near La Fe, Pinar del Rio, Cuba
| AVNO | 21.94 | 84.66 | 30.5 | 51.7 | Near La Fe, Pinar del Rio, Cuba
| %IMP | -225% | -50%
|
| GFNO | 21.62 | 85.25 | 32.0 | 10.3 | Near La Fe, Pinar del Rio, Cuba
| GFDL | 21.92 | 84.90 | 30.5 | 39.4 | Near La Fe, Pinar del Rio, Cuba
| %IMP | -30% | -283%
|
16/0650 UTC 30.2N 87.9W Near Pine Beach, AL 91.0 h into the forecast
| MODEL | LAT | LON | TIME | ERROR | LOCATION
|
| AVNN | 30.44 | 86.53 | 99.5 | 134.1 | Destin, FL
| AVNO | 30.25 | 85.63 | 94.5 | 218.0 | Panama City, FL
| %IMP | 59% | -63%
|
| GFNO | 30.27 | 87.58 | 90.5 | 31.7 | Orange Beach, AL
| GFDL | 30.41 | 86.83 | 89.0 | 105.3 | Fort Walton Beach, FL
| %IMP | -300% | -222%
| | ||||||||||||||||||||||
Figure 1. NCEP 850 - 200 hPa mean wind analysis for 12 September 2004 1200 UTC (Hurricane Ivan).
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 2004 1200 UTC.
Figure 3. NCEP Global Ensemble Predction System track forecasts for all cyclones in the Atlantic basin initialized from 10 September 2004 1800 UTC to 11 September 2004 1200 UTC, showing the tracks of Hurricane Ivan.
Figure 4. Ensemble perturbation variance at the nominal sampling time 12 September 2004 1200 UTC from the previous day NCEP ensemble forecast. The green circles represent the dropwindsonde locations.
Figure 5. Variance explained within the verification region (large red circle) for observations taken at the sampling time 12 September 2004 1200 UTC from the Ensemble Transform Kalman Filter run from the previous day NCEP ensemble forecast. The green circles represent the dropwindsonde locations.
Figure 6. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 12 September 2004 1200 UTC. The circles represent the dropwindsonde locations.
