Effects of Synoptic Surveillance on model forecasts for
04 September 2004 1200 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
AVNN3232828479101 155267291346
AVNO11 232439101146222385389547
%IMP65%21% 78%54%-28%-45%-43%-44%-34%-58%
GFNO102431901712663655466541003
GFDL 015411182423504026488031176
%IMP100% 37% -32%-31%-42%-32%-10%-19%-23%-17%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-34-27 1-9 2 7 3-1 4 8
AVNO-14-20-2-15 5 9 9-4 3 5
%IMP59%26%-100%-67%-150%-29%-200%-300%25%32%
GFNO21122922332516 72340
GFDL12 82721282512121625
%IMP43%33%7%5%15% 0%25%71%30%37%

Landfall forecasts

05/0430 UTC 27.2N 80.2W South end of Hutchinson Island, FL 16.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 27.2280.1921.0 2.4Port St. Lucie, FL
AVNO27.0580.1117.018.9Port St. Lucie, FL
%IMP 89%-688%
GFNO27.1180.1617.510.8Port St. Lucie, FL
GFDL27.1980.2719.0 7.0Port St. Lucie, FL
%IMP-150% 35%
06/1800 UTC 30.1N 84.0WMouth of Aucilla River, FL 54.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNNNo landfall forecast
AVNO29.8084.6955.074.3Carrabelle, FL
%IMP
GFNO29.7785.2952.5129.5Port St. Joe, FL
GFDL30.4586.9358.5283.8Pensacola, FL
%IMP-200%-119%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 04 September 2004 1200 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 04 September 2004 1200 UTC.

Figure 3. NCEP Global Ensemble Predction System track forecasts for all cyclones in the Atlantic basin initialized from 02 september 2004 1800 UTC to 03 September 2004 1200 UTC, showing the tracks of Hurricane Frances.

Figure 4. Ensemble perturbation variance at the nominal sampling time 04 September 2004 1200 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 04 September 2004 1200 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 04 September 2004 1200 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 04 September 2004 1200 UTC.