Effects of Synoptic Surveillance on model forecasts for
25 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 61186284299372442608640695795
AVNO 41179232262355419564601655802
%IMP33% 4%18%12% 5% 5% 7% 6% 6%-1%
GFNO 59180226290307288339333300314
GFDL 83201242308322304339314289281
%IMP-41%-12%-7%-6%-5%-6% 0% 6% 4%11%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-34-33-55-67-71-97-124-105-51-10
AVNO-35-34-55-67-69-99-124-101-50 -7
%IMP-3%-3% 0% 0% 3%-2% 0% 4% 2%30%
GFNO 7 22 1 -1 0-20-44-22 20 12
GFDL 21 27 7 9 17 -9-35-17 24 8
%IMP-200%-23%-600%-800%und%55%20%23%-20%33%

Landfall forecasts

25/2230 UTC 26.0N 80.1W at Broward/Miami-Dade County line, FL 16.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 26.1080.10 36.0 11.1Fort Lauderdale, FL
AVNO26.0680.09 30.0 6.7Hollywood, FL
%IMP 31% 40%
GFNO25.3180.28 34.5 78.8Homestead, FL
GFDL24.8880.56 41.5132.7Islamorada, FL
%IMP -17% -68%
29/1110 UTC 29.3N 89.6W Near Buras, LA 101.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.4583.27 92.0613.1Suwannee, FL
AVNO29.7583.56 98.0586.0Steinhatchee, FL
%IMP 67% 4%
GFNO30.3986.60108.5313.4Fort Walton Beach, FL
GFDL30.4086.62106.5312.1Fort Walton Beach, FL
%IMP 27% 0%
29/1445 UTC 30.2N 89.6W Near LA/MS border 104.75 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.4583.27 92.0615.8Suwannee, FL
AVNO29.7583.56 98.0583.4Steinhatchee, FL
%IMP 47% 5%
GFNO30.3986.60108.5288.6Fort Walton Beach, FL
GFDL30.4086.62106.5286.7Fort Walton Beach, FL
%IMP 62% 1%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 25 August 2005 0600 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 0600 UTC.

Figure 3. Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 25 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 25 August 2005 0600 UTC.