Effects of Synoptic Surveillance on model forecasts for
29 August 2005 0600 UTC
Katrina.

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 73 85 80162
AVNO 48 57 58135
%IMP34%33%27%17%
GFNO 91128 74237
GFDL 59100 42186
%IMP35%12%43%22%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-17-11-11 -3
AVNO -3-12-10 -3
%IMP82%-9% 9% 0%
GFNO 35 -3 0 22
GFDL 25 -9 -2 19
%IMP29%-200%und%14%

Landfall forecasts
29/1110 UTC 29.3N 89.6W Near Buras, LA 5.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.3090.07 6.0 45.5Grand Isle, LA
AVNO29.3689.77 6.0 17.8Grand Isle, LA
%IMP 0% 61%
GFNO29.3290.06 6.0 44.6Grand Isle, LA
GFDL29.4489.98 5.5 39.9Grand Isle, LA
%IMP 50% 11%
29/1445 UTC 30.2N 89.6W Near LA/MS border 8.75 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.3090.07 6.0109.8Grand Isle, LA
AVNO29.3689.77 6.0 94.8Grand Isle, LA
%IMP 0% 14%
GFNO29.3290.06 6.0107.4Grand Isle, LA
GFDL29.4489.98 5.5 92.0Grand Isle, LA
%IMP 50% 14%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 29 August 2005 0600 UTC (Hurricane Katrina).

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 29 August 2005 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 29 August 2005 0600 UTC.

Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 29 August 2005 0600 UTC.