1. Radar and Orographic Precipitation Paul Joe EUMETCAL Weather Radar and Nowcasting 20080114

2. Radars in the Mountains Germann, MCH

3. Freezing Level and Mountain Sited Radars Time-Height Temperature Freezing Level from Radiosondes March 2008 Payerne July 2008 Payerne Most of the time, the radar sees snow!

4. Orographic Precipitation Rain shadow

5. Two Conceptual Models of Orographic Precipitation Medina and Houze, 2003 Stable Unstable

6. Stable Case: Blocked Flow from South North South ALPS Precipitation on plains, Italy Flow is blocked, flow is towards the south MAP IOP-8 Medina and Houze, 2003

7. Radial Velocity - Blocked Flow Medina and Houze, 2003

8. Unstable Case: Up and Over Precipitation is on the first range No blocked flow. Flow is from the south Medina and Houze, 2003

9. Radial Velocity – Up and Over Medina and Houze, 2003

10. FOEHN, no rain H3km The Alps Lee Side Suppression

11. Erzgebirge Ore mountains, grey Doppler No rain 1h accumulation No rain Accumulations

12. Wind Drives Precipitation Germann, MCH

13. Summary Precipitation in orographic situations is complex both from a measurement and a forecast perspective Simplified conceptual models presented for understanding purposes Some operational examples