1. Hurricane Sandy: Challenges Posed by a Transitioning Storm 17 th Severe Weather Symposium March 22, 2013 Jay Hobgood

2. Effects of Hurricane Sandy 147 direct fatalities (72 in the U.S.) 87 indirect fatalities at least 50 billion dollars in damages 650,000 houses damaged or destroyed in the U.S. 8.5 million customers lost power

10. Challenges with Sandy Meteorological Challenges Warning Challenges

11. Meteorological Challenges Track forecast - excellent Intensity forecast – very good (near the long term average) Extratropical Transition - problematic

19. Extratropical Transition Extratropical transition – is the process by which a warm-cored tropical cyclone transforms into a cold-cored extratropical cyclone.

20. Types of Cyclones Tropical cyclone – is a warm-core, non- frontal low pressure system of synoptic scale that develops over the tropical or subtropical oceans.

21. Hurricane Sandy north of Cuba on Thursday morning.

22. Types of Cyclones (continued) Extratropical (midlatitude) cyclone – is a cold-core synoptic scale low pressure system whose primary source of energy is baroclinic. It is often associated with frontal systems.

23. Strong extratropical cyclone over the North Pacific Ocean.

24. Types of Cyclones (continued) Subtropical cyclone – is a low pressure system that develops over subtropical oceans and initially has a non-tropical circulation but exhibits some elements of the cloud patterns associated with tropical cyclones. It is often considered a hybrid system with some characteristics of tropical and extratropical cyclones.

25. Subtropical Storm Nicole in 2004.

26. Hurricane Sandy on Saturday afternoon.

27. What kind of cyclone is this?

28. Extratropical cyclone

29. What kind of cyclone is this?

30. Extratropical cyclone

31. A broader view of the same cyclone.

38. Post-Tropical Cyclone A post-tropical cyclone is an umbrella term that covers any low pressure system that was a tropical cyclone at one time. It includes extratropical cyclones, remnant lows and other systems.

39. Why did the classification of Sandy matter?

40. Uncertainty about the potential future classification of the cyclone that was Hurricane Sandy created challenges about the most appropriate warnings to issue for the storm.

41. Warning Challenges What types of warnings to issue for Sandy?

42. Overarching Consideration “the NWS understanding of the preference of the emergency management (EM) community that the warning type not change once watches and warnings were initiated, …”

43. One Option “follow existing protocol and transfer forecast responsibility to other NWS offices, cancel the hurricane warning, and switch to local WFO warnings.” not chosen because of overarching consideration for continuity in warnings

44. Another Option “continue to call Sandy a hurricane when it really was not one (potentially for a full day or two) in order to maintain NHC advisories and the hurricane warning.” not chosen because of potential loss of future credibility

45. A Third Option “to properly call Sandy post-tropical but continue to issue NHC advisories and leave up the hurricane warning.” not chosen because of concerns that automated vendor software might malfunction and disrupt the flow of information

46. Procedure Followed “the NWS decided to issue non-tropical warnings, communicating this warning strategy clearly to NWS partners, while placing special emphasis on Sandy’s hazards …”

47. Possible Change for the Future “it would give the NHC the option to continue issuing formal advisories on post-tropical cyclones as long as those systems pose a significant threat to life and property, and it would give the NWS the option to keep hurricane and tropical storm watches and warnings in place for those systems.”

48. Did Hurricane Irene (2011) Contribute to Complacency

50. Sandy Irene

51. Sources Blake, E.S., T.B. Kimberlain, R.J. Berg, J.P. Cangialosi, and J.L. Beven III, “Tropical Cyclone Report Hurricane Sandy”. Avila, L.A. and J. Cangialosi, “Tropical Cyclone Report Hurricane Irene’. NRL Monterey Tropical Cyclone Page. NOAA GOES Server.