1 / 27

January 3-5 2008 West Coast Extratropical Cyclone

January 3-5 2008 West Coast Extratropical Cyclone. Henry D. Bartholomew San Francisco State University. The purpose of my study . I want to answer questions like… Why did the low rapidly intensify? Why did it produce strong negative omega?. Outline. Synoptic Overview Strong Winds

rhonda-graham
Télécharger la présentation

January 3-5 2008 West Coast Extratropical Cyclone

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. January 3-5 2008 West Coast Extratropical Cyclone Henry D. Bartholomew San Francisco State University

  2. The purpose of my study • I want to answer questions like… • Why did the low rapidly intensify? • Why did it produce strong negative omega?

  3. Outline • Synoptic Overview • Strong Winds • Heavy Precipitation • Quasigeostrophic Equations Discussion • Quasigeostrophic Diagnosis • Summary and Conclusions

  4. Synoptic Overview • Formed on 3 Jan 2008 • First located south of the Aleutian Islands • Moved east and strengthened • Reached minimum pressure of 956 mb • Impacted California on 4 Jan 2008 • Brought heavy rain and strong winds to CA

  5. Outline • Synoptic Overview • Strong Winds • Heavy Precipitation • Quasigeostrophic Equations Discussion • Quasigeostrophic Diagnosis • Summary and Conclusions

  6. Strong Winds in California • Concord: 45 mph • Chico: 58 mph • SFO: 68 mph • North Oakland: 71 mph • Mt. Diablo: 117 mph Generally, sustained winds of 20-50 mph

  7. Note the increase in wind speeds with a corresponding pressure drop Max Gusts: 65 to 70 mph Minimum Pressure: 997 mb

  8. January 3-5 2008 West Coast Extratropical Cyclone • Synoptic Overview • Strong Winds • Heavy Precipitation • Quasigeostrophic Equations Discussion • Quasigeostrophic Diagnosis • Summary and Conclusions

  9. 24-hour Precipitation Amounts12Z 4 Jan 08 to 12Z 5 Jan 08 • San Francisco: 1.72” • Napa: 1.98” • Oakland: 2.07” • Mt. Diablo: 3.69” • Ben Lomond: 5.74”

  10. January 3-5 2008 West Coast Extratropical Cyclone • Synoptic Overview • Strong Winds • Heavy Precipitation • Quasigeostrophic Equations Discussion • Quasigeostrophic Diagnosis • Summary and Conclusions

  11. Quasigeostrophic Analysis of Storm:QG-Omega Equation and SPDE • QG-Omega Equation • LHS: Omega Term • RHS: Differential vorticity advection, temperature advection, sensible heating, friction terms • SPDE • LHS: 1000 mb relative vorticity tendency • RHS: 500 mb absolute vorticity advection, • 1000 mb horizontal temperature advection terms

  12. QG equations, continued • QG-Omega Equation • SPDE

  13. January 3-5 2008 West Coast Extratropical Cyclone • Synoptic Overview • Strong Winds • Heavy Precipitation • Quasigeostrophic Equations Discussion • Quasigeostrophic Diagnosis • Summary and Conclusions

  14. Quasigestrophic Diagnosis • Will be conducted at three times • 0000 and 1200 UTC 4 Jan • 0000 UTC 5 Jan • Terms in each equation analyzed • Find out general nature of omega, and contributing factors • Find out general nature of development, and contributing factors

  15. 0000 UTC 4 Jan 2008SPDE • Center of low • Positive relative vorticity tendency • Weak absolute vorticity advection • Warm advection • Development of system: • 976 mb. 12 UTC 3 Jan 2008 • 964 mb. 00 UTC 4 Jan 2008

  16. 0000 UTC 4 J an 2008

  17. 0000 UTC 4 Jan 2008 QG-Omega Equation • San Francisco • Negative omega • Strong negative vorticity advection • Weak warm advection • Dominating Term: Temp Advection

  18. 1200 UTC 4 Jan 2008\SPDE • Center of low • Slight negative relative vorticity tendency • Weak absolute vorticity advection • Weak temperature advection • No change in intensity: • Low remains at 964 mb.

  19. 1200 UTC 4 Jan 2008QG-Omega Equation • San Francisco • Negative omega • Weak negative vorticity advection • Strong warm advection • Clear dominating term

  20. 0000 UTC 5 Jan 2008SPDE • Center of low • Slight negative relative vorticity tendency • Weak absolute vorticity advection • Warm advection • Low remains at 964 mb.

  21. 0000 UTC 5 Jan 2008 QG-Omega Equation • San Francisco • Weak omega • Negative along coast, positive inland • Mostly warm advection • Weak vorticity advection

  22. January 3-5 2008 West Coast Extratropical Cyclone • Synoptic Overview • Strong Winds • Heavy Precipitation • Quasigeostrophic Equations Discussion • Quasigeostrophic Diagnosis • Summary and Conclusions

  23. Summary and Conclusions • QG-Omega Equation • SF: Dominating factor: Warm advection • Contributed to strong negative omega

More Related