Effects of Synoptic Surveillance on model forecasts for
20 October 1999 1800 UTC
JOSE.


QuickTime movie of DLM wind model forecasts
QuickTime movie of DLM wind data increments


TRACK AND INTENSITY PERFORMANCE

TRACK (km)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN85.80.10.137.249.412.644.
AVAL48.25.0.123.203.305.485.
%IMP44%69%100%10%18%26%25%
GFNO11.94.222.375.603.933.1589.2206.
GFAL15.81.105.244.491.803.1336.1900.
%IMP36%14%53%35%19%14%16%14%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-32.-24.-18.-17.-17.-21.-20.
AVAL-33.-22.-18.-16.-18.-21.-22.
%IMP-3%8%0%6%-6%0%-10%
GFNO29.36.55.58.57.47.30.0.
GFAL12.35.45.56.64.50.38.3.
%IMP59%3%18%3%-12%-6%-27%und%
SHNO19.28.30.28.24.11.4.-2.8.
SHAL19.27.29.26.22.9.1.-4.6.
%IMP0%4%3%7%8%18%75%-100%25%
DSNO19.28.30.28.24.11.4.-2.8.
DSAL19.27.29.26.22.9.1.-4.6.
%IMP0%4%3%7%8%18%75%-100%25%

Landfall forecasts

21/1105 UTC 18.4N 64.6W Tortola 17.08 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN18.3065.1024.053.9 Charlotte Amalie, St. John, USVI
AVAL18.3264.7017.513.8 Road Town, Tortola, British Virgin Islands
%IMP94%74%
GFNO18.3264.8418.526.8 Charlotte Amalie, St. John, USVI
GFAL18.4164.6318.03.4 Road Town, Tortola, British Virgin Islands
%IMP35%87%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 20 October 1999 1800 UTC (Hurricane Jose).

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 20 October 1999 1800 UTC. The best track is shown in black.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 20 October 1999 1800 UTC.

Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 20 October 1999 1800 UTC.