Effects of Synoptic Surveillance on model forecasts for
16 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 20 51125187191352705
AVNO 39 22 80 79142318612
%IMP-95%57%36%58%26%10%13%
GFNO 41 50 19 30 43189491
GFDL 11 24 40 47120257523
%IMP74%52%-111%-57%-179%-30%-7%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-46-44-37-36-13 12 5
AVNO -6-21-16 -8 -7 2 2
%IMP87%52%57%78%46%83%68%
GFNO 9 2 12 8 2 6 27
GFDL 16 7 7 7 1 2 7
%IMP-78%-250%42%12%50%67%74%
SHNO 1 0 3 -4 -8 17 27
SHIP 0 -4 -1 -7-10 14 24
%IMP100%und%67%-75%-25%18%11%
DSNO 1 0 3 -4-19-11 1
DSHP 0 -4 -1 -7-24-12 0
%IMP100%und%67%-75%-26% 9%100%

Landfall forecasts

18/1700 UTC 34.9N 76.2W Drum Inlet, NC 59.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN35.1076.09 67.5 24.4Ocracoke, NC
AVNO34.7876.45 65.0 26.4Cape Lookout, NC
%IMP 29% -8%
GFNO34.9876.94 61.0 68.0Emerald Isle, NC
GFDL34.6577.33 58.5106.8Sneads Ferry, NC
%IMP 75% -57%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 16 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 16 September 2003 0600 UTC.

Figure 3. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 16 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 16 September 2003 0600 UTC.