Effects of Synoptic Surveillance on model forecasts for
01 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 49 67100 83 60 59 78 78 59118
AVNO100 111129152150134185226254346
%IMP-104%-66% -29%-83%-150%-127%-137%-190%-331%-193%
GFNO 30 68105137181201284360448 480
GFDL 45 53 78 92128126180249325 356
%IMP-50% 22% 26%33%29%37%37%31%27%26%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-74-79-70-51-43-32-29-16 -2 -1
AVNO-56-73-61-36-26-10 -8 0 15 13
%IMP24% 8%13%29%40%69%74%100%-650%-1200%
GFNO 3-11 -7 -1 0 8 0 2 31 22
GFDL 1-15-13 -6 -4 4 6 3 31 26
%IMP67%-36%-86%-500%und% 50%und%-50% 0%-18%

Landfall forecasts

02/1930 UTC 24.0N 74.5W San Salvador Island, Bahamas 37.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN24.5574.03 34.5 77.5Near San Salvador Island, Bahamas
AVNO24.7073.72 34.0110.8Offshore San Salvador Island, Bahamas
%IMP -17% -43%
GFNO24.7173.84 38.0103.4Offshore San Salvador Island, Bahamas
GFDL24.5174.16 41.0 66.3Near San Salvador Island, Bahamas
%IMP-600% 36%
03/0530 UTC 24.6N 75.6W Northern end of Cat Island, Bahamas 47.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN25.7376.08 54.0134.5Near northern tip of Eleuthera Island, Bahamas
AVNO25.7074.65 46.0155.1Offshore Cat Island, Bahamas
%IMP 73% -15%
GFNO25.5074.70 46.0134.9Offshore Cat Island, Bahamas
GFDL25.1975.00 49.0 89.2Near northern tip of Cat Island, Bahamas
%IMP 0% 34%
03/1000 UTC 25.1N 76.1W Eleuthera Island, Bahamas 52.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN25.7376.08 54.0 70.0Near northern tip of Eleuthera Island, Bahamas
AVNO26.1875.76 59.5124.7Offshore Eleuthera Island, Bahamas
%IMP-275% -78%
GFNO25.9175.10 50.0134.7Offshore Eleuthera Island, Bahamas
GFDL25.6475.45 53.5 88.6Near Eleuthera Island, Bahamas
%IMP 25% 34%
04/1000 UTC 26.6N 78.2W Grand Bahama Island, Bahamas 76.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN26.7677.91 70.0 33.8Grand Bahama Island, Bahamas
AVNO26.8976.60 69.5162.0Near Abaco Island, Bahamas
%IMP -8%-379%
GFNO27.1576.25 61.5202.7Near Abaco Island, Bahamas
GFDL27.2277.10 70.0128.9Near Abaco Island, Bahamas
%IMP 59% 36%
05/0430 UTC 27.2N 80.2W South end of Hutchinson Island, FL 94.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN27.9780.52 99.0 91.2Palm Bay, FL
AVNO28.9179.68114.5196.7Near Cape Canaveral, FL
%IMP-345%-116%
GFNO32.3280.67118.5570.6Hilton Head Island, SC
GFDL31.3381.43116.5474.1St. Simons Island, GA
%IMP 8% 17%
06/1800 UTC 30.1N 84.0W Mouth of Aucilla River, FL 132.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNNNo landfall forecast
AVNONo landfall forecast
%IMP
GFNONo landfall forecast
GFDLNo landfall forecast
%IMP

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 01 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 01 September 2004 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 01 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 01 September 2004 0600 UTC.