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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.

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A Multi-Scale Analysis of the Perfect Storms of 1991

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  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 

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