1. New experiments on WSR 2009- 2011 with modern version high res GFS/GSI Yucheng Song EMC/NCEP/NOAA

2. GDAS: 300mb v (ave:30-60N) OPR run Strong Linkage with downstream wave packet development Sampled 2009 Each winter, we should just focus on several events with clear cut wave packet formed

3. Positive warm color means forecast improvement, negative for degradation Forecast comparison w and without the dropsondes, 12Z, Feb 1, 2009 Surface pressure500m Height

4. RMSE error comparison w and without dropsondes by GFS/GDAS data impact experiments, 12Z Feb 1, 2009 Surface pressure, averaged over 180W to 60W 30N to 70N Surface pressure, averaged over 180W to 60W 30N to 70N

5. Positive warm color means forecast improvement area Forecast comparison w and without the dropsondes, 12Z, Feb 24, 2009

6. RMSE error comparison w and without dropsondes by GFS/GDAS data impact experiments, 12Z Feb 24, 2009 Surface pressure, averaged over 180W to 60W 30N to 70N Surface pressure, averaged over 180W to 60W 30N to 70N

7. 2010 – 2011 experiments Scripts are ready Some test runs are done Data impact on precipitation

8. Issues High resolution T574L64 runs are quite expensive, limited resources We found that the location information were stripped from the TEMP messages (WMO limitation) Drift effect of the dropsondes should be considered in the future ET KF codes need development with more vertical levels and finer scale ETKF codes need to consider error statistics from the operational system Adaptive targeting is quite effective when properly used