the influence of observations on 3-7 day forecasts
Since 1999, the Ensemble Transform Kalman Filter (ETKF) adaptive
observing strategy has been used in Winter Storm Reconnaissance (WSR)
programs to identify locations for dropwindsonde deployment, in order
to improve 1-3 day forecasts. The ETKF has shown promise in being able
to predict the error reducing effect of observations over this period.
The primary goal of this NOAA THORPEX project is to extend the ETKF to
3-7 days, and assess whether it is capable of predicting the reduction
of forecast error variance in the winter storm track due to rawinsonde
and/or dropwindsonde observations. In parallel, the propagation of the
effects of observations on NCEP GFS forecasts beyond 3 days is being
assessed. Preliminary results and ideas will be presented.