1. Report of the T-PARC Winter Storms Working Group Zoltan Toth, Tim Hewson, Chris Doyle, Roland Stull, Yoshio Asuma, Jeff Musiak, Todd Jacobs, Gary Wick, Craig Bishop, Yi-Leng Chen, Ron Gelaro, Istvan Szunyogh, Charles Spinelli, Yucheng Song

2. Science Interests 1 • Roland Stull • Data impact studies • Hydroelectric Power Production Impact • Yoshio Asuma • Role of interaction between upper level troughs and low-level moisture transport in intense genesis of NE moving cyclones • Istvan Szunyogh • Real time analysis at 30 km resolution • Study of predictability

3. Science Interests 2 • Ron Gelaro • Optimal mix of obsrvations • Regime-dependent targeting • Craig Bishop • Quantitative evaluation of targeting methods • Testing new data assimilation schemes • Integrating new data assimilation schemes with targeting methods (ALEC) • Yi-Leng Chen • Phasing of subtropical and extratripical disturbances • Impact of atmospheric rivers on Hawaii and extratropics

4. Science Interests 3 • Chris Doyle • Socio-economic impact evaluation of forecast improvements due to extra observations • 2010 Winter Olympics • Tim Hewson • Use and evaluation of operational feature-based post-processed ensemble products • Concluding remark on science interests • No strong interest was expressed in specific observations, most research project would benefit from all planned observations

5. PROPOSED OBSERVING PLATFORMS Extensive observational platforms during T-PARC winter phase allow us to track the potential storms and take additional observations as the perturbation propagate downstream into Arctic and US continents Day 4 Radiosondes Russia Alaska VR Day 5-6 Radiosondes Tibet D 1-2 C-130 UAS CONUS VR D 3 G-IV D-1 UAS P-3

6. Observing Platform Issues • Tibetan Network • Produce definitive list of new observations • Real time availability? • Russian network • Distribution of consumables in light of expected request (data density, dynamic sensitivity) • Sequential selection of optimal sites • Global Hawk • Slight preference for LIDAR observations over dropsondes (if a choice has to be made) • ONR P3 • Platform for LIDAR if GH installation is not doable • Data impact evaluation • Both cycled assimilation of THORPEX data and common first guesses • Rapid Scan • There was a strong agreement that rapid scan observations would be highly desirable to achieve the science objectives

7. Infrastructure for Targeting • Adapt ECMWF Preview facility for T-PARC • Modify area for Pacific and NA • Extend lead times for ETKF • Produce series of sensitivity charts spanning observational times • Adaptable verification domain size