2015 AIR Hurricane Season Preview

Transcription

1 2015 AIR Hurricane Season Preview Tim Doggett, Ph.D. 1

2 Agenda Seasonal hurricane forecasts for 2015 Historical perspective on seasonal forecasting Accounting for uncertainty Forecasts for the 2015 Atlantic and East Pacific hurricane seasons Best practices for managing hurricane risk using ALERT TM How seasonal forecasts relate to catastrophe models AIR real-time risk management tools 2

3 A Brief History of Seasonal Hurricane Forecasting Dr. William Gray, a member of the Colorado State University (CSU) faculty at the time, issued the first seasonal hurricane forecast in 1984 Several other operational forecast organizations, including NOAA, have issued forecasts for the Atlantic and other basins in subsequent years Most forecast basin counts of storms and hurricanes, not landfalls or losses Seasonal forecasts come in various forms, and are released by academic, government, and private organizations 3

4 Progression of Storm Counts in the Typical Atlantic Hurricane Season Average Counts From Atlantic Basin Storm Count TROPICAL STORMS HURRICANES MAJOR HURRICANES (56%) 3.0 (26%) May Jun Jul Aug Sep Oct Nov Dec Jan Atlantic Hurricane Season 4

5 Seasonal Forecasts Anticipate Environmental Conditions Critical to Storm Development Sea Surface Temperatures (SSTs) Predictive models are somewhat limited in ability to skillfully forecast SSTs, typically no more than 6 to 9 months in advance Ocean anomalies persist due to thermal inertia The depth of ocean warmth is as important as the surface temperature, but useful historical data are limited Atmospheric Wind Shear El Niño (La Niña) tends to increase (decrease) wind shear and suppress (enhance) Atlantic storm activity Other sources of wind shear are associated with tropical and midlatitude jet stream features Other Important Factors Ultimately, landfall risk is dependent on steering currents at the time storms are active, which is highly uncertain in advance of the season Storm development can be suppressed or enhanced by factors such as upper-level moisture availability, Saharan Air Layer, Loop Current interactions, NAO, and MJO that are not skillfully forecasted 5

6 The 2015 AMO Signal in the Atlantic Remains Warm AMO (from Enfield et al.): 1948 to 2015 Source: NOAA Earth System Research Laboratory; 6

7 ENSO Conditions Have Been Steadily Warming for the Past Four Months El Niño 7

8 Observed and Forecasted Atlantic and Pacific Sea Surface Temperature Anomalies Observed May 2015 SST Anomalies Forecast Issued in June for July, August, September 2015 Source: International Research Institute for Climate and Society (IRI) 8

9 Models Currently Predict a Higher Probability that El Niño Conditions Will Persist Through the Hurricane Season El Niño Neutral La Niña Source: International Research Institute (IRI) for Climate and Society (May 2015). 9

10 CPC/IRI Probabilistic ENSO Outlook The chances of El Niño increase during the remainder of 2015, exceeding 65% by summer (JJA) and peaking near 80% during the late fall / early winter Updated: 14 May

11 Progression of ENSO Indicators Is Not Always a Predictor of Things to Come Last year at this time Last hurricane season El Niño 11

12 So Just How Influential Are ENSO Conditions on Storm Activity? Hurricane Counts Hurricane Counts as a function of ENSO R² = MEI La Niña El Niño Named Storms Hurricanes Major Hurricanes Mean Std. Dev. Mean Std. Dev. Mean Std. Dev. El Niño La Niña ENSO Neutral

13 Hurricane Counts What About the AMO? 16 Hurricane Counts as a function of AMO R² = AMO Cool Warm Named Storms Hurricanes Major Hurricanes Mean Std. Dev. Mean Std. Dev. Mean Std. Dev. AMO Warm AMO Cool AMO Neutral

14 The 2015 Outlook From NOAA Indicates a High Probability For Below Normal Activity This Year 14

15 Industry Forecasts of 2015 Atlantic Seasonal Basin Activity (Count of Tropical Storms and Hurricanes) Agency Tropical Storm Risk Colorado State University Forecast Date Named Storms Hurricanes Major Hurricanes May June North Carolina State University April 13 5 (Range of 4-6) 2 (Range of 1-3) 1 UK Met Office May 21 WSI/ Weather Channel NOAA May 27 8 (Range of 6-10) 5 (Range of 3-7) April (Range of 6-11) 4.5 (Range of 3-6) NA 1 (Range of 0-2) Accuweather May Consensus Average

16 2015 Atlantic Seasonal Forecasts of Basin Activity (Count of Tropical Storms and Hurricanes) TROPICAL STORM COUNT HURRICANE COUNT long-term average = 11.3 long-term average = TSR WSI CSU ACCU WRC NOAA NC State Met Office <Dec Jan Feb Mar Apr May Jun Month of Forecast Release <Dec Jan Feb Mar Apr May Jun 16

17 Forecast Level of Activity Rarely Matches Actual Level of Activity Actual - Forecast Actual - Forecast Source: 17

18 Forecasts for the Eastern and Central Pacific Vary from Those for the Atlantic The Eastern Pacific Basin Season runs from May 15 through Nov. 30 First events of the 2015 season have formed Tropical Storm Andres and Major Hurricane Blanca Agency Forecast Date Named Storms Hurricanes Major Hurricanes NOAA 5/27/ SMN 4/10/ Average ( ) Central Pacific NOAA is calling for an above normal season with a 70% chance of an abovenormal season, a 25% chance of a near-normal season, and a 5% chance of a below-normal season for 2015 NOAA expects 5 to 8 tropical cyclones to affect the Central Pacific this season Average season has 4 to 5 tropical cyclones 18

19 Some Takeaways on the Value of Seasonal Hurricane Forecasts Meant to provide an indication of activity in the upcoming season relative to average Seasonal forecasts are unable to capture the year-to-year volatility in landfalling hurricane counts and, more importantly, in the resulting losses Robust risk management requires the probabilistic assessment of potential losses provided by catastrophe models AIR s U.S. Hurricane Model estimates climatological, i.e., longterm, risk The standard catalog assumes neutral climate conditions The AIR Warm SST Conditioned Catalog probabilistically estimates landfall risk for the typical warm Atlantic season 19

20 It s Been Almost 10 Years Since Wilma, the Last Major Hurricane Landfall in the U.S. Number of landfalling events Consecutive years Major US landfalling hurricanes Seasons with major US landfalls Year Seasons with no major US landfalls Shouldn t we be prepared for the inverse? Year 20

21 AIR Does Not Forecast Seasonal or Near-Term (Multi-Season) Activity AIR Standard Catalog Long-term view of risk conditioned on the characteristics of all Atlantic hurricane seasons since 1900 AIR WSST Catalog Consistent, long-term view of risk, conditioned only to seasons since 1900 in which the Atlantic Ocean has been warmer than average Neither of the catalogs was designed to forecast losses for the upcoming season While both view of risk are credible and scientifically valid, the WSST view is about 10% higher risk. Since the WSST catalog is based on less data, it is subject to a higher level of uncertainty 21

22 Count Long-Term Mean and WSST Mean Are Reasonable Views of Risk 45 Cumulative Actual (>$25m insured loss) Climatology (Long-Term Mean) Warm Climate Conditioned (WSST Mean) Charley Frances Gaston Ivan Jeanne Cindy Dennis Katrina Ophelia Rita Wilma Humberto Dolly Gustav Ike Isaac Sandy Irene Total = Erin Opal Bertha Fran Danny Bonnie Earl Georges Bret Dennis Floyd Irene Gordon Lili Claudette Isabel 22

23 Tropical Storm Ana Gave the 2015 Season an Early Start But Caused Minimal Losses Ana attained peak maximum sustained winds of 60 mph Dry air and northwesterly wind shear plagued the system Ana made landfall along the coast of South Carolina, just north of Myrtle Beach at ~6:00 am EDT on May 10 th 23

24 1992 Was an El Niño Year, Showing that Even in a Low Frequency Year, All It Takes Is One Storm Atlantic Basin Very inactive year in the Atlantic 7 storms, 4 hurricanes, 1 major hurricane Hurricane Andrew Very little early and late season activity East Pacific Basin Record high storm activity in the East Pacific basin 28 storms, 16 hurricanes, 10 major hurricanes Iniki formed in the East Pacific and traversed into Central Pacific, causing extensive damage to the Hawaiian island of Kauaʻi 24

25 Preparing for the Upcoming Season 25

26 New This Season The AIR Storm Surge Module for the U.S. Hurricane Model High-resolution elevation data enhances storm surge depth estimates Most up-to-date levee information available for New Orleans Leverages primary risk characteristics and a host of secondary characteristics New catalog based on HURDAT2 and the latest reanlaysis data Newly published land use/land cover information Explicit treatment of square footage for high-value homes Enhancements to the mobile home vulnerability 26

27 Overview of the AIR Loss Estimation in Real-Time (ALERT) Process for U.S. Hurricanes System forms System intensifies System gets closer to land Landfall System dissipates 48h 24h Monitoring ALERT TM Event Information and Loss Postings Post-disas ter surveys Detailed claims analyses 27

28 ALERT Event Sets Work Seamlessly in Touchstone 28

29 NewsALERT Subscribers Receive Notification of Significant Events NewsALERT s begin several days prior to landfall Provide summary information about event Updates are sent when new information becomes available Sign up today at by clicking Register at the top of the page 29

30 In the Aftermath of an Event, AIR Communicates the Results of Further Analyses in a Variety of Formats - AIRCurrent - CATWeek - By-line articles - Whitepapers - Webinars Pre-season Post-season 30

31 This Season AIR Is Also Partnering with WRIN to Provide Interviews and Insights Throughout the Hurricane Season 31

32 Additional Supplemental Information is Available From the National Hurricane Center

33 Thank You! 33