Effects of Synoptic Surveillance on model forecasts for
31 October 2001 1800 UTC
Tropical Depression #15.


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
AVNN82.142.181.169.110.85.94.167.211.297.
AVAL87.127.159.159.105.47.73.141.181.241.
%IMP -6%11%12% 6% 5%45%22%16%14%19%
GFNO156.212.213.177.124.69.177.231.393.485.
GFAL185.254.247.238.184.169.240.253.270.480.
%IMP-19%-20%-16%-34%-48%-145%-36%-10%31% 1%
VBNO31.84.177.253.233.246.264.310.350.449.
VBAL31.78.178.255.242.274.295.338.373.458.
%IMP 0% 7%-1%-1%-4%-11%-12%-9%-7%-2%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-22.-26.-39.-57.-82.-85.-95.-88.-52.-41.
AVAL-21.-26.-38.-55.-80.-84.-95.-87.-50.-40.
%IMP 5% 0% 3% 4% 2% 1% 0% 1% 4% 2%
GFNO-12.-3.-22.-38.-42.-27.-26.-18.28.28.
GFAL-11.-12.-24.-41.-60.-49.-18.-5.34.28.
%IMP 8%-300%-9%-8%-43%-81%31%72%-21%0%
SHNO-11.-10.-10.-19.-35.-35.-46.-43.-11.-5.
SHAL-11.-10.-11.-20.-36.-36.-47.-44.-12.-7.
%IMP 0% 0%-10%-5%-3%-3%-2%-2%-9%-40%
DSNO-11.-10.-10.-19.-35.-35.-50.-69.-37.-31.
DSAL-12.-11.-12.-20.-36.-37.-67.-70.-38.-32.
%IMP-9%-10%-20%=5%-3%-6%-34%-1%-3%-3%

Landfall forecasts

04/1800UTC
21.5N 81.8W Cayo Largo, Cuba
96 h into forecast
MODELLATLONTIMEERRORLOCATION
AVNN21.7781.55107.039.6Cayo Largo, Cuba
AVAL21.4681.45104.536.5Cayo Largo, Cuba
%IMP23%8%
GFNO21.9484.1390.0245.4Las Martinas, Pinar del Rio, Cuba
GFAL20.5886.7483.5522.3Approach to Isla Cozumel, Qintana Roo, Mexico
%IMP-108%-113%
VBNO21.4683.07106.0131.4Punta del Guanal, La Isla de la Juventud, Cuba
VBAL21.6283.19107.0144.2Punta Frances, La Isla de la Juventud, Cuba
%IMP-1%-2%
04/2300UTC
22.1N 81.2W at Bahia de Cochinos, Cuba
101 h into forecast
MODELLATLONTIMEERRORLOCATION
AVNN21.9580.33111.591.1Near Cienfuegos, Cienfuegos, Cuba
AVAL21.8280.21109.5106.6 Near Cienfuegos, Cienfuegos, Cuba
%IMP19%-17%
GFNO21.9484.1390.0245.4Las Martinas, Pinar del Rio, Cuba
GFAL22.0184.2995.5318.3La Fe, Pinar del Rio, Cuba
%IMP55%-30%
VBNO22.1281.36114.016.6Near Bahia de Cochinos, Matanzas, Cuba
VBAL22.2181.64114.046.9Near Bahia de Cochinos, Matanzas, Cuba
%IMP0%-183%
05/1200UTC
24.3N 78.0W at Andros Island, Bahamas
114 h into forecast
MODELLATLONTIMEERRORLOCATION
AVNN23.1077.90120.0133.7
AVAL23.3077.00120.0150.6
%IMP0%-13%
GFNO24.5481.81101.0386.3Key West, FL
GFAL24.5681.81107.5386.5Key West, FL
%IMP50%0%
VBNO22.8079.60120.0372.7
VBAL22.9080.00120.0353.1
%IMP0%5%
05/1800UTC
25.4N 76.4W at Eleuthera Island, Bahamas
120 h into forecast
MODELLATLONTIMEERRORLOCATION
AVNN23.1077.90120.0297.3
AVAL23.3077.00120.0241.1
%IMP0%19%
GFNO25.5681.19104.5480.7Big Lostmans Bay, FL
GFAL25.4081.15110.5476.7Graveyard Creek, FL
%IMP-73%1%
VBNO22.8079.60120.0434.5
VBAL22.9080.00120.0458.6
%IMP0%-6%


Figure 1. NCEP 850 - 200 hPa mean wind analysis for 31 October 2001 1800 UTC
Tropical Depression #15.


Figure 2. Track forecasts for the no dropwindsonde (NO or NN) and the all dropwindsonde (AL) runs for the AVN, GFDL, and VBAR models initialized on 31 October 2001 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 31 October 2001 1800 UTC.


Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases
for 31 October 2001 1800 UTC.