Effects of Synoptic Surveillance on model forecasts for
02 September 2004 0600 UTC
Frances.


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 30 20 60 56 83 77 98135 87108
AVNO 38 15 73 41 80 99154191163195
%IMP-27%25% -22%27% 4%-29%-57%-41%-87%-80%
GFNO 49 64 83 64 79111141182150 174
GFDL 49 60 92 60 60 82120188164 199
%IMP 0% 6% -11% 6%24%26%15%-3%-9%-14%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-73-54-46-32-27-27 -2 2 5 10
AVNO-38-32-16-13 -7-16 6 2 11 5
%IMP38%41%65%59%76%41%-200%100%-120%50%
GFNO-15 -1 -2 11 7 1 21 29 35 34
GFDL-10 -4 5 13 9 3 25 26 29 36
%IMP33%-300%-150%-18%-29% -200%-19%10%17%-6%

Landfall forecasts

02/1930 UTC 24.0N 74.5W San Salvador Island, Bahamas 13.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN24.0974.45 15.5 11.2San Salvador Island, Bahamas
AVNO24.1974.44 15.0 22.0San Salvador Island, Bahamas
%IMP 25% -96%
GFNO23.9374.59 18.0 12.0San Salvador Island, Bahamas
GFDL23.8574.62 17.5 20.6San Salvador Island, Bahamas
%IMP 11% -72%
03/0530 UTC 24.6N 75.6W Northern end of Cat Island, Bahamas 23.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN24.7975.67 25.5 22.3Northern end of Cat Island, Bahamas
AVNO24.7675.55 23.5 18.5Northern end of Cat Island, Bahamas
%IMP 100% 17%
GFNO24.8275.47 27.5 27.7Northern end of Cat Island, Bahamas
GFDL24.7375.59 28.0 14.5Northern end of Cat Island, Bahamas
%IMP -13% 48%
03/1000 UTC 25.1N 76.1W Eleuthera Island, Bahamas 28.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN24.9976.11 29.5 12.3Eleuthera Island, Bahamas
AVNO25.2375.98 28.5 18.8Eleuthera Island, Bahamas
%IMP 67% -53%
GFNO25.4376.30 35.0 41.8Eleuthera Island, Bahamas
GFDL25.2576.30 35.0 26.1Eleuthera Island, Bahamas
%IMP 0% 38%
04/1000 UTC 26.6N 78.2W Grand Bahama Island, Bahamas 52.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN26.3578.77 62.0 63.1Grand Bahama Island, Bahamas
AVNO26.7078.12 57.5 13.7Grand Bahama Island, Bahamas
%IMP 45% 78%
GFNO26.7478.05 57.0 21.5Grand Bahama Island, Bahamas
GFDL26.7178.38 58.5 21.7Grand Bahama Island, Bahamas
%IMP -30% -1%
05/0430 UTC 27.2N 80.2W South end of Hutchinson Island, FL 70.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN26.6380.01 73.0 66.1Lake Worth, FL
AVNO28.5080.55 87.5148.5Cape Canaveral, FL
%IMP-580%-115%
GFNO28.3580.62 87.0134.3Cocoa Beach, FL
GFDL28.0380.54 84.5 98.1Palm Bay, FL
%IMP 15% 27%
06/1800 UTC 30.1N 84.0W Mouth of Aucilla River, FL 108.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN29.7083.40108.0 72.9Steinhatchee, FL
AVNONo landfall forecast
%IMP
GFNONo landfall forecast
GFDLNo landfall forecast
%IMP

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 02 September 2004 0600 UTC (Hurricane Frances).

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 02 September 2004 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 02 September 2004 0600 UTC.

Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 02 September 2004 0600 UTC.