Effects of Synoptic Surveillance on model forecasts for
03 September 2004 0000 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 37 22 15 41 86 99 95131 56 84
AVNO 11 60 60104161184168141 75 37
%IMP70%-173% -300%-154%-87%-86%-77%-8%-34%-44%
GFNO 20 78 35 63104169124116134 237
GFDL 15 49 15 32 80131118153 91 58
%IMP25% 37% 51%49%23%22% 5%-32%32%76%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-50-34-35-27-15 -2-10 7 7 3
AVNO-25 -8 -9 -2 -1 10 -2 7 0 0
%IMP50%76%74%93%93%-400%80% 0%100%100%
GFNO 22 25 25 12 15 34 20 22 18 27
GFDL 7 19 15 13 15 29 18 32 27 22
%IMP68%24%40%-8% 0% 15%10%-45%-50%19%

Landfall forecasts

03/0530 UTC 24.6N 75.6W Northern end of Cat Island, Bahamas 5.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN24.7175.62 4.0 12.4Cat Island, Bahamas
AVNO24.6775.61 4.5 7.8Cat Island, Bahamas
%IMP 33% 37%
GFNO24.7575.57 7.5 16.9Cat Island, Bahamas
GFDL24.7575.55 5.5 17.4Cat Island, Bahamas
%IMP 100% -3%
03/1000 UTC 25.1N 76.1W Eleuthera Island, Bahamas 10.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN25.2176.24 8.5 18.6Eleuthera Island, Bahamas
AVNO25.1876.12 9.5 9.1Eleuthera Island, Bahamas
%IMP 67% 51%
GFNO25.2376.04 11.5 15.7Eleuthera Island, Bahamas
GFDL25.2076.01 10.0 14.3Eleuthera Island, Bahamas
%IMP 100% 9%
04/1000 UTC 26.6N 78.2W Grand Bahama Island, Bahamas 34.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN26.7078.11 32.0 14.3Grand Bahama Island, Bahamas
AVNO26.8677.64 31.5 62.6Abaco Island, Bahamas
%IMP -25%-338%
GFNO26.9177.85 28.0 48.9Grand Bahama Island, Bahamas
GFDL26.7377.92 30.5 31.3Grand Bahama Island, Bahamas
%IMP 42% 36%
05/0430 UTC 27.2N 80.2W South end of Hutchinson Island, FL 52.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN27.3180.24 62.5 12.8Port St. Lucie, FL
AVNO28.7080.75 74.0175.2Titusville, FL
%IMP-169%-1269%
GFNO28.9580.84 71.5204.3Edgewater, FL
GFDL27.9580.51 67.0 88.7Palm Bay, FL
%IMP 24% 57%
06/1800 UTC 30.1N 84.0W Mouth of Aucilla River, FL 90.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN30.0684.33 97.5 32.0St. Marks, FL
AVNONo landfall forecast
%IMP
GFNONo landfall forecast
GFDLNo landfall forecast
%IMP

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 03 September 2004 0000 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 03 September 2004 0000 UTC.

Figure 3. NCEP Global Ensemble Predction System track forecasts for all cyclones in the Atlantic basin initialized from 01 september 2004 0600 UTC to 02 September 2004 0000 UTC, showing the tracks of Hurricane Frances.

Figure 4. Ensemble perturbation variance at the nominal sampling time 03 September 2004 0000 UTC from the previous day NCEP ensemble forecast. The green circles represent the dropwindsonde locations.

Figure 5. Variance explained within the verification region (large red circle) for observations taken at the sampling time 03 September 2004 0000 UTC from the Ensemble Transform Kalman Filter run from the previous day NCEP ensemble forecast. The green circles represent the dropwindsonde locations.

Figure 6. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 03 September 2004 0000 UTC. The circles represent the dropwindsonde locations.

Figure 7. 24-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 03 September 2004 0000 UTC.