Effects of Synoptic Surveillance on model forecasts for
08 September 2004 0000 UTC
Ivan.


Quicktime movie of AVN DLM wind model forecast
Quicktime movie of DLM wind data increment


TRACK AND INTENSITY PERFORMANCE

TRACK (km)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN 31 33 57 85 98173245301399547
AVNO 55 62124123187273398518647915
%IMP-77%-88%-118%-45%-91%-58%-62%-72%-62%-67%
GFNO1172092562953673995055907631048
GFDL 78151200278374360424504594744
%IMP33% 28% 22% 6%-2%10%16%15%22%29%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-84-81-97-83-79-76-63-91-95-93
AVNO-67-73-90-81-73-74-68-92-87-88
%IMP20%10% 7% 2% 8% 3%-8%-1% 8% 5%
GFNO -1-12-13-12-32-44-44-60-46-43
GFDL 8 5-14 -8-20-45-41-54-44-50
%IMP-700%58%-8%33%37% -2% 7%10% 4%-16%

Landfall forecasts

11/0330 UTC 17.4N 77.2W 20 n mi S of Portland Point, Jamaica 75.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 18.1776.32 87.0126.4Boston Bay, Jamaica
AVNO17.9074.00 72.0343.3Port Salut, Haiti
%IMP 70%-172%
GFNO17.7771.68 51.0586.1Oviedo, Dominican Republic
GFDL18.1973.59 51.0391.8Saint-Louis-De-Sud, Haiti
%IMP 0% 33%
12/1415 UTC 18.9N 81.5W 22 n mi SSW of Georgetown, Grand Cayman Island 110.25 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 19.8877.42101.5441.2Niquero, Granma, Cuba
AVNO19.9075.00 96.0690.1Vateras, Guantanamo, Cuba
%IMP -63% -56%
GFNO18.2172.20 53.5982.5Marigot, Haiti
GFDL19.9576.31 65.0556.2Bellaire, Santiago de Cuba, Cuba
%IMP 20% 43%
14/0100 UTC 21.7N 85.2W 15 n mi SW of Cabo San Antonio, Cuba 145.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 19.8877.42101.5833.0Niquero, Granma, Cuba
AVNO19.9075.00 96.01078.1Vateras, Guantanamo, Cuba
%IMP -15% -29%
GFNO20.0874.41 66.51134.3Cojababo, Guantanamo, Cuba
GFDL19.9576.31 65.0943.4Bellaire, Santiago de Cuba, Cuba
%IMP -2% 17%
16/0650 UTC 30.2N 87.9W Near Pine Beach, AL 204.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNNNo landfall forecast
AVNONo landfall forecast
%IMP
GFNONo landfall forecast
GFDLNo landfall forecast
%IMP

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 08 September 2004 0000 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 08 September 2004 0000 UTC.

Figure 3. NCEP Global Ensemble Predction System track forecasts for all cyclones in the Atlantic basin initialized from 06 september 2004 0600 UTC to 07 September 2004 0000 UTC, showing the tracks of Hurricane Ivan.

Figure 4. Ensemble perturbation variance at the nominal sampling time 08 September 2004 0000 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 08 September 2004 0000 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 08 September 2004 0000 UTC. The circles represent the dropwindsonde locations.

Figure 7. 24-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 08 September 2004 0000 UTC.