Effects of Synoptic Surveillance on model forecasts for
16 September 2004 0600 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 29 65145308491651690875
AVNO 11 35 91151294360393586
%IMP62%46%37%51%40%45%43%33%
GFNO 191322593906418971039118814191505
GFDL 11 85201313551870946116514411447
%IMP43%36%22%20%14% 4% 9% 2%-2% 4%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-10 -1 -1 3 -9-21-24-25
AVNO-10 0 0 6 -6-16-21-22
%IMP 0%100%100%-100%33%24%12%12%
GFNO 1 11 16 21 18 5 -1-19 0-10
GFDL 4 10 18 26 14 5 -3-19 -2-10
%IMP-300%-9%-13%-24%22% 0%-200% 0%und% 0%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 16 September 2004 0600 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 16 September 2004 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 16 September 2004 0600 UTC.

Figure 4. 16-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 16 September 2004 0600 UTC.