in the Atlantic basin from the ensemble transform Kalman Filter based on

ensembles from the National Centers for Environmental Prediction (NCEP),

total energy singular vectors produced by the Naval Research Laboratory,

and the variance of the 850-200 hPa wind from the NCEP ensemble.

Differences between the different targeting techniques have been

reported for the Atlantic and the Western Pacific basins (Reynolds et

al. 2007, Majumdar et al. 2006). Aberson (2003) performed observing

system experiments during the 1997 and 1998 seasons and showed that the

ensemble variance guidance provides targets that provide forecasts

significantly better than the larger oversampled datasets. The current

study expands this work to include the other available objective

techniques. Results from the large sample of cases during 2004-2006

will be presented.

Aberson, S.D., 2003: Targeted observations to improve operational

tropical cyclone track forecast guidance. Mon. Wea. Rev., 131,

1613-1628.

Majumdar, S. J., Aberson, S.D., Bishop, C. H., Buizza, R., Peng, M. S.,

and Reynolds, C. A. 2006: A Comparison of Adaptive Observing Guidance

for Atlantic Tropical Cyclones, Mon. Wea. Rev., 134, 2354-2372.

Reynolds, C.A., M.S. Peng, S.J. Majumdar, S.D. Aberson, C.H. Bishop, and

R. Buizza, 2007: Interpretation of adaptive observing guidance for

Atlantic tropical cyclones. Accepted by Mon. Wea. Rev.