Effects of Synoptic Surveillance on model forecasts for
25 August 2005 1200 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 11 83151180254399564599698840
AVNO 15 90171195268408568601679814
%IMP-36%-8%-13%-8%-6%-2%-1% 0% 3% 3%
GFNO 59 81115120 75 73 77157314372
GFDL 35 78135172134150158153224216
%IMP41% 4%-17%-43%-79%-105%-105% 3%29%42%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-40-46-64-73-75-118-120-91-22 0
AVNO-39-45-62-72-74-115-114-84-23 -1
%IMP 2% 2% 3% 1% 1% 3% 5% 8%-5%und%
GFNO 3 7 14 12 10-30-28 2 53 23
GFDL 1 -7 7 15 15-34-29 -1 56 -2
%IMP67% 0%50%-25%-50%-13%-4%50%-6%91%

Landfall forecasts

25/2230 UTC 26.0N 80.1W at Broward/Miami-Dade County line, FL 10.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 26.0680.09 10.0 6.7Hollywood, FL
AVNO26.1480.09 8.5 15.6Fort Lauderdale, FL
%IMP-300%-133%
GFNO25.3080.28 14.0 79.8Homestead, FL
GFDL25.5880.30 13.0 50.8Miami, FL
%IMP 29% 36%
29/1110 UTC 29.3N 89.6W Near Buras, LA 95.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.6583.43 95.5598.0Steinhatchee, FL
AVNO29.7383.55 92.5586.9Howell Place, FL
%IMP-400% 2%
GFNO29.5490.11106.0 56.1Grand Isle, LA
GFDL30.3988.36106.5170.1Pascagoula, MS
%IMP -5%-203%
29/1445 UTC 30.2N 89.6W Near LA/MS border 98.75 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.6583.43 95.5597.2Steinhatchee, FL
AVNO29.7383.55 92.5584.6Howell Place, FL
%IMP -92% 2%
GFNO30.3890.06110.5 48.4Slidell, LA
GFDL30.3988.36106.5120.8Pascagoula, MS
%IMP 34%-150%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 25 August 2005 1200 UTC (Tropical Storm 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 25 August 2005 1200 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 25 August 2005 1200 UTC.

Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 25 August 2005 1200 UTC.