New hurricane forecast products with more lead time for disaster preparation by electric utilities Iris Grossmann, PhD. With Phil Klotzbach, Ph.D. (Colorado State) and Mitch Small, Ph.D. (CMU) Center for Climate and Energy Decision Making (CEDM) Image source: Pepco

2 Motivation: Tropical cyclones (TC) may become more intense in a warmer world…. 2 Center for Climate and Energy Decision Making

Hurricane season: 7 TC landfalls in US, 40 million customers experienced outages TS Fay Cat 1 Dolly Cat 2 Gustav TS Edouard Cat 2 Ike TS Hanna Cat 1 Kyle Image source: NOAA/NHC

4 Utility preparation prior to expected TC landfall  Assess needs for line & tree crews and equipment  Request crews through mutual assistance groups  Ready crews; plan transportation, lodging etc  Deploy crews  Revise... Problems: 1.Preparation is expensive 2.Need to prepare well in advance, e.g., at least 3 days, but forecasts at that time are not very good. Center for Climate and Energy Decision Making

55 How good are hurricane track forecasts? Center for Climate and Energy Decision Making m error Image source: NOAA/NHC

66 Very intense storms may change intensity too quickly for accurate forecasting Center for Climate and Energy Decision Making Cat 5 Cat 4 Cat 3 Cat 2 Cat 1 Cat 5 Cat 4 Cat 3 Cat 2 Cat 1 Hurricane Felix 2007 Hurricane Opal 1995 Image source: NOAA/NHC

7 2-phase approach to TC forecasting & power restoration (project in review with NSF Infrastructure Management & Extreme Events) I.New statistical TC forecasting scheme II.Dynamic programming model for power line restoration planning Center for Climate and Energy Decision Making

8 2-phase approach to TC forecasting & power restoration (project in review with NSF Infrastructure Management & Extreme Events) I.New statistical 5-14 day TC forecasting scheme i.Assess probability that TC will undergo rapid intensification (RI) and probability that it will become long-lasting major TC ii.Assess likelihood ranges for landfall locations, using historic tracks in proximity to given TC, analog years, and prevailing tracking patterns during given season Short-term (conventional) forecast and individual utility planning New long-range forecast scheme and individual utility planning Short-term (conventional) forecast and utility consortium planning New long-range forecast scheme and utility consortium planning II.Dynamic programming model for restoration planning i.Successive evaluation of optimal allocation / deployment ii.In each step: should crews stay or move? iii.Compare cost across 4 options below:

9 1.Thermal energy from difference between warm ocean and colder atmosphere 2.Unstable atmosphere 3.Mid-tropospheric moisture 4.Low vertical wind shear 5.Vorticity (spin) 6.Coriolis force Forecast scheme makes use of conditions that determine TC formation and intensity Center for Climate and Energy Decision Making Image source: Wikipedia

10 Early stage storms: “invests” Center for Climate and Energy Decision Making Bottom: fully formed hurricane Image sources: NOAA/NHC, NASA

11 Preliminary studies till date (in collaboration with forecaster Phil Klotzbach) Center for Climate and Energy Decision Making I.Pilot-study: scheme to evaluate potential for TC formation II.Assess probability that an invest will spend „long“ time period in major TC stage III.Assess probability of rapid intensification (RI) IV.Tracking patterns and analog years

12 I. Pilot study on TC formation forecasting scheme Center for Climate and Energy Decision Making MDR Genesis Parameter (10-20°N, 20-60°W)

13 I. Pre-cursor signals for TC formation (from Phil Klotzbach) 9 – 11 Day Lead6 – 8 Day Lead Day Lead0 - 2 Day Lead

14 Conditions at time of initial TC formation for soon-to-be major hurricanes vs weaker storms Center for Climate and Energy Decision Making 56% less wind shear than non-developing invests, 44% less than all hurricanes. 16.5% more humidity than non-developing invests, 3% more than all hurricanes. 1.6K warmer sea surface temperature than for non- developing invests, 0.8K warmer than for all hurricanes. II. Assess probability that invest will spend “long” time period in major TC status

15 Relationship between duration in major TC status and damages Center for Climate and Energy Decision Making Hours as major hurricane (mean) Hours as major hurricane (median) All major hurricanes Major hurricanes that made landfall Major hurricanes causing US damages ≥ $1 billion % of hurricanes that spend at least 36 hours in major hurricane status cause ≥ $1 billion in (normalized) US damages.

16 Center for Climate and Energy Decision Making III. Assess probability of rapid intensification by MJO phase during TC formation RI 25ktRI 30ktRI 35ktRI 40kt + Phase 1& 276%67%47%38% Phase 6 & 733%22% 6%  The MJO (Madden Julian Oscillation) is a large-scale pattern of variability on the day scale.  It is not free-standing but travels eastward as an atmospheric wave.  It progresses through 8 phases. Probability of RI by MJO phase during which TC formed

17 IV. Steering patterns: pattern persistence Image source: NOAA/NHC

IV. Steering patterns: pattern persistence (2) Image source: NOAA/NHC

19 Other climate work that I am engaged in Center for Climate and Energy Decision Making  Decision-analysis of hurricane modification (completed)  Assessing and communicating non-stationary hurricane return periods given multidecadal variability and global warming (project in review at NSF Earth System Models)  Assessment of hurricane risks to off-shore wind turbines (published in PNAS)  Assessment of changes in US Southwest drought risks  “Force majeure“ – due to climate change, climate hazards may no longer be classifiable as act of God  Evaluation of solar insolation data for large-scale solar networks (in review at Renewable & Sustainable Energy Reviews)

20 Thank you for your attention Center for Climate and Energy Decision Making