Effects of Synoptic Surveillance on model forecasts for
27 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 56 83 61 97176255226301
AVNO 84 45113116 95 83145177
%IMP-50%46%-85%-20%46%67%36%41%
GFNO 63 69 60 59155287346624
GFDL 49 33107110 57 96 45259
%IMP22%52%-78%-86%63%67%87%58%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-49-69-92-55 -5 0 -8-10
AVNO-24-43-67-32-14-10-12 -3
%IMP51%38%27%42%-180%und%-50%70%
GFNO 1 -6-23 -9 28 19 -2 -6
GFDL 3-10-35 -5 13 -9 -4 3
%IMP-200%-67%-52%44%54%53%-100%50%

Landfall forecasts

29/1110 UTC 29.3N 89.6W Near Buras, LA 53.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.1390.23 57.5 63.9Grand Isle, LA
AVNO30.4088.65 57.0152.7Pascagoula, MS
%IMP 11%-139%
GFNO29.2890.49 56.0 86.3Cocodrie, LA
GFDL30.3789.03 56.0131.0Gulfport, MS
%IMP 0% -52%
29/1445 UTC 30.2N 89.6W Near LA/MS border 56.75 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 29.1390.23 57.5133.5Grand Isle, LA
AVNO30.4088.65 57.0 93.8Pascagoula, MS
%IMP-200% 30%
GFNO29.2890.49 56.0133.5Cocodrie, LA
GFDL30.3789.03 56.0 57.9Gulfport, MS
%IMP 0% 57%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 27 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 27 August 2005 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 27 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 27 August 2005 0600 UTC.