1. 3-5 January 2008 West Coast Extratropical Cyclone Cameron G. Loughlin San Francisco State University

2. Outline Impact of Storm on Northern California Synoptic History Methodology Assessment of Terms Discussion Cameron Loughlin Quasigeostrophic Effects of 3-5 January Cyclone

3. Impact of Storm on West Coast Record-setting wind speeds Rapid Decline in Pressure Heavy Precipitation Cameron Loughlin Quasigeostrophic Effects of 3-5 January Cyclone

6. Outline Impact of Storm on Northern California Synoptic History Methodology Assessment of Terms Discussion Cameron Loughlin Quasigeostrophic Effects of 3-5 January Cyclone

7. Outline Impact of Storm on Northern California Synoptic History Methodology Assessment of Terms Discussion Cameron Loughlin Quasigeostrophic Effects of 3-5 January Cyclone

8. Synoptic Overview Cyclone formed south of Aleutian Islands on 3 January Low Developed over North Pacific Ocean on 3 January Minimum Central Pressure of 956 mb Low advanced into Northern California on 4 January bring heavy rain and strong winds Cameron Loughlin Quasigeostrophic Effects of 3-5 January Cyclone

9. Outline Impact of Storm on Northern California Synoptic History Methodology Assessment of Terms Discussion

10. Methodology - Quasigeostrophic (QG) Omega Equation LHS: Omega RHS: Vorticity advection, temperature advection -Sutcliffe Petterssen Equation (SPDE) LHS: Relative vorticity tendency RHS: 500 mb vorticity advection, 1000 mb horizontal temperature advection

11. Outline Impact of Storm on Northern California Synoptic History Methodology Assessment of Terms Discussion

12. Assessment of Terms Cyclone will be examined at 3 different times at 4 January 0Z, 4 January 12Z and 5 January 0Z Analyze maps using QG Omega Equation Terms and SPDE

13. SPDE 4 Jan 00Z Terms: Weak absolute vorticity advection Positive Relative vorticity tendency Warm advection Pressure Change: 976 mb. 12 UTC 3 Jan 2008 964 mb. 00 UTC 4 Jan 2008

14. 0000 UTC 4 J an 2008

16. QG Omega 4 January 00Z San Francisco Negative omega Strong negative vorticity advection Weak warm advection Dominating Term: Temp Advection

17. Outline Impact of Storm on West Coast Synoptic History Methodology Assessment of Terms Discussion

18. Quasigeostrophic Assessment Quasigeostrophic Assessment at 00Z 4 January, 12Z 4 January and 0Z 5 January for the following: Temperature Advection Differential Vorticity Advection