Effects of Synoptic Surveillance on model forecasts for
28 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 23 51128147154247
AVNO 51 56125179144193
%IMP-122%-10% 2%-22% 6%22%
GFNO 33 53 78107182464
GFDL 23 81102 89 84360
%IMP30%-53%-31%17%54%22%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-95-50 -5 -9-10 -9
AVNO-52-26 6 -6-11 -8
%IMP45%48%-20%33%-10%11%
GFNO-33-12 31 -6 -3 -7
GFDL-26-16 28 -8 -2 0
%IMP21%-25%10%-33%33%100%

Landfall forecasts
29/1110 UTC 29.3N 89.6W Near Buras, LA 29.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.1490.16 31.5 57.1Grand Isle, LA
AVNO29.4989.90 36.5 35.9Grand Isle, LA
%IMP-200% 37%
GFNO28.9189.48 29.5 44.9South Pass, LA
GFDL29.2088.98 31.0 61.1Pilottown, LA
%IMP-300% -36%
29/1445 UTC 30.2N 89.6W Near LA/MS border 32.75 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.1490.16 31.5129.6Grand Isle, LA
AVNO29.4989.90 36.5 84.0Grand Isle, LA
%IMP-200% -35%
GFNO28.9189.48 29.5143.8Grand Isle, LA
GFDL30.4088.90 36.0 70.7Biloxi, MS
%IMP 0% 51%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 28 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 28 August 2005 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 28 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 28 August 2005 0600 UTC.