Effects of Synoptic Surveillance on model forecasts for
15 August 2003 0000 UTC
Erika.


Quicktime movie of GFS 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
GFSN 52 50110252
GFSO 55 91121273
%IMP-6%-82%-10%-8%
GFNO137134104245
GFDL114144 96213
%IMP17% 7%-8%13
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
GFSN-17-27-44-10
GFSO-16-27-44-10
%IMP 6% 0% 0% 0%
GFNO -1 4-22 5
GFDL 10 -2-14 8
%IMP-900%50%36%-60%
SHNO -1 -2 -4 45
SHIP 6 6 4 43
%IMP-500%-200% 0% 4%
DSNO -1 -2 -4 12
DSHP -2 6 -5 17
%IMP-50%-200%-20%-42%

Landfall forecasts

16/1030 UTC 25.3N 97.4W Boca San Rafael, Mexico 34.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
GFSN25.3597.3641.5 6.9Guajardo, Tamaulipas, Mexico
GFSO24.4497.8550.5105.8Isla las Vaquitas, Tamaulipas, Mexico
%IMP-129%-1433%
GFNO25.4097.3239.013.7Guajardo, Tamaulipas, Mexico
GFDL24.9397.6541.048.2Isla la Tuna, Tamaulipas, Mexico
%IMP-44%-252%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 15 August 2003 0000 UTC (Tropical Storm Erika).

Figure 2. Track forecasts for the no dropwindsonde (NO or NN) and the all dropwindsonde (AL) runs for the GFS and GFDL models initialized on 15 August 2003 0000 UTC.

Figure 3. Ensemble perturbation variance at the nominal sampling time 15 August 2003 0000 UTC from the previous day NCEP ensemble forecast. The circles represent the dropwindsonde locations.

Figure 4. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 15 August 2003 0000 UTC. The circles represent the dropwindsonde locations.

Figure 5. 15-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 15 August 2003 0000 UTC.