1 / 60

A Multi-Scale Analysis of the Perfect Storms of 1991

A Multi-Scale Analysis of the Perfect Storms of 1991. Jason M. Cordeira and Lance F. Bosart Department of Earth and Atmospheric Sciences, University at Albany, Albany, NY. cordeira@atmos.albany.edu. Supported by: NSF Grant ATM-0304254. NROW VIII 1-2 November, 2006. H. H.

davina
Download Presentation

A Multi-Scale Analysis of the Perfect Storms of 1991

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. A Multi-Scale Analysis of the Perfect Storms of 1991 Jason M. Cordeira and Lance F. Bosart Department of Earth and Atmospheric Sciences, University at Albany, Albany, NY cordeira@atmos.albany.edu Supported by:NSF Grant ATM-0304254 NROW VIII 1-2 November, 2006

  2. H H What were the Perfect Storms? Z 1051 Perfect Storm One (PS1) 1044 Z heavy snow A cold coastal flooding and waves Perfect Storm Two (PS2) Z Hurricane Grace (G) A A

  3. Why Study the Perfect Storms? • Large-scale regime transition associated with extreme weather phenomena. • Perfect Storm One (PS1) • Extratropical transition of Hurricane Grace. • Rapid deepening of PS1. • Tropical Transition. • Perfect Storm Two (PS2) • Track and intensity. • Heavy snow and cold temperatures. • Historical Impact…

  4. Historical Impact: PS1 • Coastal flooding and high winds from Canada to Puerto Rico. • 67 kt at Chatham, MA. • 55 kt at Blue Hill Observatory. • 30 m waves SE of Nova Scotia. • 8 m waves offshore MA.

  5. Historical Impact: PS2 • State record: 93.7 cm of snow in Duluth, MN. • Other records: • Earliest 20.0 cm snowfall. • Daily and monthly snowfall records. • Earliest temperature below 0 °F (-18 °C)in Minneapolis, MN. Duluth Minneapolis

  6. Outline • Large-scale flow regime • Synoptic overview • 250 hPa heights and winds • 500 hPa heights and absolute vorticity • MSLP and 1000-500 hPa Thickness • Backward trajectories (Lagrangian) • Two cross sections of PS1 and PS2 • Theta, Potential Vorticity (PV), Omega, and Winds • Results • Future direction

  7. largest Oct. positive to negative transition in 57 years lowest Oct. PNA index in 57 years Large-scale flow regime PS2 PS1

  8. 01-Oct to 30 Nov 60 Day 500 hPa 01-Oct 01-Oct 30-Oct 30-Oct 30-Nov 30-Nov Images provided by the NOAA/ESRL Physical Sciences Division, Boulder Colorado from their Web site at http://www.cdc.noaa.gov/.

  9. 01-Oct to 30 Nov 850 hPa 01-Oct 01-Oct 30-Oct 30-Oct 30-Nov 30-Nov Images provided by the NOAA/ESRL Physical Sciences Division, Boulder Colorado from their Web site at http://www.cdc.noaa.gov/.

  10. 250 hPa Heights/Winds Synoptic Overview 1 G 29/12Z

  11. 250 hPa Heights/Winds Synoptic Overview 1 30/00Z

  12. 250 hPa Heights/Winds Synoptic Overview 1 2 30/12Z

  13. 250 hPa Heights/Winds Synoptic Overview 1 2 31/00Z

  14. 250 hPa Heights/Winds Synoptic Overview 1 2 31/12Z

  15. 250 hPa Heights/Winds Synoptic Overview 2 1 01/00Z

  16. 250 hPa Heights/Winds Synoptic Overview 2 1 01/12Z

  17. 250 hPa Heights/Winds Synoptic Overview 2 1 02/00Z

  18. 250 hPa Heights/Winds Synoptic Overview 2 1 02/12Z

  19. 250 hPa Heights/Winds Synoptic Overview 2 1 03/00Z

  20. 500 hPa Heights & Absolute Vorticity Synoptic Overview 1 G 29/12Z 12 16 20 24 28 32

  21. 500 hPa Heights & Absolute Vorticity Synoptic Overview 1 30/00Z 12 16 20 24 28 32

  22. 500 hPa Heights & Absolute Vorticity Synoptic Overview 1 2 30/12Z 12 16 20 24 28 32

  23. 500 hPa Heights & Absolute Vorticity Synoptic Overview 1 2 31/00Z 12 16 20 24 28 32

  24. 500 hPa Heights & Absolute Vorticity Synoptic Overview 1 2 31/12Z 12 16 20 24 28 32

  25. 500 hPa Heights & Absolute Vorticity Synoptic Overview 2 1 01/00Z 12 16 20 24 28 32

  26. 500 hPa Heights & Absolute Vorticity Synoptic Overview 2 1 01/12Z 12 16 20 24 28 32

  27. 500 hPa Heights & Absolute Vorticity Synoptic Overview 2 1 02/00Z 12 16 20 24 28 32

  28. 500 hPa Heights & Absolute Vorticity Synoptic Overview 2 1 02/12Z 12 16 20 24 28 32

  29. 500 hPa Heights & Absolute Vorticity Synoptic Overview 2 1 03/00Z 12 16 20 24 28 32

  30. Synoptic Overview MSLP & 1000-500 hPa Thickness 1 G 29/12Z

  31. Synoptic Overview MSLP & 1000-500 hPa Thickness 1 30/00Z

  32. Synoptic Overview MSLP & 1000-500 hPa Thickness 1 30/12Z

  33. Synoptic Overview MSLP & 1000-500 hPa Thickness 1 31/00Z

  34. Synoptic Overview MSLP & 1000-500 hPa Thickness 1 2 31/12Z

  35. Synoptic Overview MSLP & 1000-500 hPa Thickness 1 2 01/00Z

  36. Synoptic Overview MSLP & 1000-500 hPa Thickness 2 1 01/12Z

  37. Synoptic Overview MSLP & 1000-500 hPa Thickness 2 1 02/00Z

  38. Synoptic Overview MSLP & 1000-500 hPa Thickness 2 1 02/12Z

  39. Synoptic Overview MSLP & 1000-500 hPa Thickness 2 1 03/00Z

  40. Minimum Central Pressure (hPa) HG PS2 PS1 988 hPa 980 hPa 980 hPa 972 hPa

  41. Backward trajectories 144 h – Ending 29/12Z at 500 hPa Z500 A300 A900

  42. Backward trajectories 144 h – Ending 30/00Z at 300 hPa Z300 A900

  43. Backward trajectories 144 h – Ending 02/00Z at 500 hPa A300 Z500 A900

  44. Backward trajectories 144 h – Ending 03/00Z at 500 hPa Z500 A600 A900

  45. Cross-Sections: ω(dashed/μ s-1), PV(blue/PVU), θ(red/K), Wind (kts) PS1 θ on the DT (2.0 PVU) 30/1200 UTC 1 W E μs-1 PVU K

  46. Cross-Sections: ω(dashed/μ s-1), PV(blue/PVU), θ(red/K), Wind (kts) PS2 θ on the DT (2.0 PVU) 02/0000 UTC 2 NW SE μs-1 PVU K

  47. Synoptic Review • Downstream development produces trough that interacts with Hurricane Grace and aids in forming PS1. • High pressure (1044 hPa) in SE Canada induces strong pressure gradient and strong winds. • PS1 retrogrades and loops as upstream ridge folds over and reforms downstream in the North Atlantic. • PS2 forms in W. Gulf of Mexico and tracks north with a deepening and negatively tilted trough. • Strong high pressure (1051 hPa) behind PS2 ushers unseasonably cold temperatures.

  48. Synoptic Review (cont’d) • Cross sections reveal relatively low DT (~500 hPa) with coupled regions of ascent/descent about the PV anomaly. • PS2: Maximum ascent located above regions of low-level PV and low-level cold air in MN and WS. • What role did the cyclonic PV anomalies play in cyclogenesis? • Hoskins 1985 suggests a positive feedback mechanism between an upper-level PV anomaly and a surface baroclinic zone that induces surface cyclogenesis.

  49. Future Work • Further detail into the potential vorticity perspective of the two Perfect Storms. • Linking weather and intraseasonal climate with the Perfect Storms • E.g. What role did two extratropical transitioning typhoons in the NW Pacific play in preconditioning the large-scale regime of the NH? • More and not limited to… • Detailed surface and satellite analyses (including marine observations!) • The role of oceanic heat fluxes • Etc. cordeira@atmos.albany.edu

  50. Extras 

More Related