Effects of Synoptic Surveillance on model forecasts for
14 September 2003 0600 UTC
Isabel.


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
AVNN 72 75 75142191279348390430577
AVNO 56 38 37 46 49102 93129191310
%IMP22%49%51%68%74%74%63%73%61%46%
GFNO 84112120111121125179289424553
GFDL 32 42 30 22 49 68125213350442
%IMP62%62%75%80%60%46%30%26%18%20%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-92-79-69-55-47-41-38-39-30 3
AVNO-66-52-40-21-12-17-15-11 -2 17
%IMP28%34%42%62%74%59%61%72%93%-467%
GFNO-41-31-15 -7 -5 1 3 0 -4 7
GFDL-28-24-15 -5 0 2 3 -1 -1 10
%IMP32%23% 0%29%100%-100% 0%und%75%-43%
SHNO-11 -1 4 14 13 4 1 -9-14 14
SHIP -9 1 10 20 19 10 5 -5-10 16
%IMP18% 0%-150%-43%-46%-150%-400%44%29%-14%
DSNO-11 -1 4 14 13 4 1 -9-29-14
DSHP -9 1 10 20 19 10 5 -5-10 16
%IMP18% 0%-150%-43%-46%-150%-400%44%66%-14%

Landfall forecasts

18/1700 UTC 34.9N 76.2W Drum Inlet, NC 107.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNNNo landfall forecast
AVNO35.8674.62111.0178.5Well offshore Cape Hatteras, NC
%IMP
GFNO35.9973.36100.0284.1Well offshore Cape Hatteras, NC
GFDL36.0274.54101.5195.1Well offshore Cape Hatteras, NC
%IMP 21% 31%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 14 September 2003 0600 UTC (Hurricane Isabel).

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 September 2003 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 14 September 2003 0600 UTC.

Figure 4. 12-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 14 September 2003 0600 UTC.