A predictability study using geostationary satellite wind observations during NORPEX

(1999a) reported that assimilation of geostationary satellite wind data during NORPEX reduced forecast errors in upper-tropospheric height over western North America by 10%-25% overall at 48 h, with reductions of up to 50% in individual cases. [...]these authors found that the overall impact of NORPEX targeted dropsonde data decreased to near zero when assimilated using a background (first guess) forecast that included all available satellite wind observations in each analysis cycle. [...]we wish to thank Craig Bishop and the anonymous reviewers for their excellent critiques and helpful suggestions for improving the paper.