Effects of Synoptic Surveillance on model forecasts for
18 September 2002 1800 UTC
Isidore.


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
AVNN71.78.108.147.105.179.102.132.148.156.
AVNO71.103.148.185.178.235.206.274.314.301.
%IMP0%-32%-38%-26%-70%-31%-102%-108%112%-93%
GFNO64.111.157.228.249.404.509.753.1114.1454.
GFAL49.113.148.223.268.406.439.637.922.1250.
%IMP23%-2%6%2%-8%0%14%15%17%14%
AVNN-23.-34.-61.-47.-57.-85.-83.-83.-41.-19.
AVNO-21.-33.-59.-47.-56.-83.-82.-82.-41.-22.
%IMP9%3%3%0%2%2%1%1%0%-16%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
GFNO24.21.0.33.19.9.10.12.39.5.
GFAL32.24.0.31.16.-5.-9.-16.27.23.
%IMP-33%-14%0%6%16%44%10%-33%31%-360%
SHNO-4.-12.-31.-9.-13.-34.-31.-31.7.27.
SHIP-5.-14.-33.-11.-16.-37.-35.-35.4.25.
%IMP-25%-17%-6%-22%-23%-9%-13%-13%43%7%
DSNO-4.-12.-31.-18.-23.-43.-40.-41.-3.17.
DSHP-5.-14.-33.-20.-25.-46.-44.-44.-5.16.
%IMP-25%-17%-6%-11%-9%-7%-10%-7%-67%6%

Landfall forecasts

20/2100 UTC 22.0N 84.1W Cabo Frances, Cuba 51 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN21.4382.8230.0146.5 Near Punta de Guanal, La Isla de la Juventud, Cuba
AVAL21.6582.6028.5159.5 Punta de Guanal, La Isla de la Juventud, Cuba
%IMP-7%-9%
GFNO
GFAL21.6082.5627.5165.0 La Fe, La Isla de la Juventud, Cuba
%IMP
22/2100 UTC 21.3N 89.3W Puerto Telchac, Yucatan, Mexico 99 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN21.1790.63117.0138.5 Celestun, Yucatan, Mexico
AVAL22.9788.92115.5189.6 Well offshore Yucatan, Mexico
%IMP8%-37%
GFNO30.0484.11111.01101.3 Well offshore Yucatan, Mexico
GFAL29.7284.70117.01043.0 Well offshore Yucatan, Mexico
%IMP-50%5%
26/0600 UTC 29.1N 90.3W Just west of Grand Isle, LA 180 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNNNo landfall forecast
AVALNo landfall forecast
%IMP
GFNO30.0484.11111.0607.2 St. Marks, FL
GFAL29.7284.70117.0546.3 Green Point, FL
%IMP9%10%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 18 September 2002 1800 UTC (Tropical Storm Isidore).

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 18 September 2002 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 18 September 2002 1800 UTC.

Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 18 September 2002 1800 UTC.