Effects of Synoptic Surveillance on model forecasts for
14 October 1999 0000 UTC
IRENE.


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
AVNN150.163.185.306.388.423.345.
AVAL108.99.84.219.282.256.168.
%IMP28%39%55%28%27%39%51%
GFNO94.108.122.108.212.267.482.11025.1483.
GFAL100.111.144.167.214.220.283.648.1107.
%IMP-6%-3%-18%-55%-1%18%41%37%25%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-33.-34.-36.-38.-36.-39.-36.
AVAL-34.-32.-36.-34.-33.-38.-33.
%IMP-3%6%0%11%8%3%8%
GFNO22.28.29.10.6.-5.12.-2.-26.
GFAL20.25.15.23.30.31.38.15.-19.
%IMP9%11%48%-130%-400%-620%-217%-650%27%
SHNO3.10.10.12.12.8.7.-10.-22.-15.
SHAL3.10.12.15.16.10.9.-8.-21.-13.
%IMP0%0%-20%-25%-33%-25%-29%20%5%13%
DSNO-7.-10.-10.-8.-8.-12.-13.-30.-43.-35.
DSAL-7.-10.-8.-6.-4.-10.-11.-28.-41.-34.
%IMP0%0%20%25%50%17%15%7%5%3%

Landfall forecasts

14/1200 UTC 21.7N 83.0W Western Isle of Youth, Cuba 12 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN21.9284.2112.5127.2 La Fe, Pinar del Rio, Cuba
AVAL21.8283.7912.582.6 Near Cabo Frances, Pinar del Rio, Cuba
%IMP0%35%
GFNO22.1983.6717.587.9 San Juan y Martines, Pinar del Rio, Cuba
GFAL22.1883.7216.591.4 San Juan y Martines, Pinar del Rio, Cuba
%IMP18%-4%
14/1900 UTC 22.7N 82.5W Batabano, Cuba 19 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN21.9284.2112.5196.0 La Fe, Pinar del Rio, Cuba
AVAL22.2183.3621.5103.7 Near San Juan y Martines, Pinar del Rio, Cuba
%IMP62%47%
GFNO22.1983.6717.5132.8 San Juan y Martines, Pinar del Rio, Cuba
GFAL22.1883.7216.5138.0 San Juan y Martines, Pinar del Rio, Cuba
%IMP-67%-4%
15/1300 UTC 24.6N 81.6W Key West, FL 37 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN24.7382.1459.056.4 Dry Tortugas, FL
AVAL24.7380.9954.563.3 Marathon, FL
%IMP20%-12%
GFNO25.0082.4139.593.0 Dry Tortugas, FL
GFAL24.6680.5248.5109.3 Near Layton, FL
%IMP-360%-18%
15/2000 UTC 25.3N 81.1W Cape Sable, FL 44 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN25.9081.5072.077.8 Fakahatchee, FL
AVAL25.1880.6659.046.2 Everglades National Park, FL
%IMP44%41%
GFNO25.9281.6543.588.2 Goodland, FL
GFAL24.6680.5248.592.0 Near Layton, FL
%IMP-800%-4%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 14 October 1999 0000 UTC (Tropical Storm Irene).

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 14 October 1999 0000 UTC. The best track is shown in black.

Figure 3. Ensemble perturbation variance at the nominal sampling time 14 October 1999 0000 UTC from the previous day NCEP ensemble forecast. The green 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 14 October 1999 0000 UTC. The green circles represent the dropwindsonde locations.

Figure 5. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 14 October 1999 0000 UTC.