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2013 North Atlantic Hurricane & Typhoon Season Primer
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2013 North Atlantic Hurricane & Typhoon Season Primer

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The webinar addressed anticipated 2013 activity of North Atlantic hurricanes and Pacific typhoons and their effects on the reinsurance industry.

The webinar addressed anticipated 2013 activity of North Atlantic hurricanes and Pacific typhoons and their effects on the reinsurance industry.

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  • I’d like to go over some Long-Term factors which can influence tropical storm activity in the northern Atlantic and Western North Pacific. These are frequently discussed in hurricane pre-season and start-of-season forecasts.(Next Slide)
  • Here is a schematic map that illustrates how the El Nino warm phase can affect tropical cyclone activity….In the central Pacific… Above Average SSTs promote convection, that is, thunderstorm development. … and clusters of thunderstorms can act as the “seeds” from which Tropical Cyclones can develop as they drift westward with the trade winds. So more storms may develop under these conditions. Plus, they may form further out than under normal conditions, and have more time to organize and intensify as they move west toward Asia.The increased thunderstorm activity due to an El Nino can actually cause vertical wind shear conditions in the western north Atlantic. Vertical Shear is a marked change in the wind speed and/or direction with increasing altitude. Shear disrupts tropical cyclone development, which do best under light wind conditions up through the atmosphere.
  • And in the Cool, La Nina phase, we see conditions in the North Pacific that are less favorable for tropical development.(Read Bullets)
  • Can we see the affect of PDO and AMO phases on tropical cyclone activity?This slide shows the count of Named Storms and Typhoons in the WNP on the top chart, and the Named Storms and Hurricanes for the Atlantic on the bottom.The total height of the Blue Bar indicates the number of Named Tropical Cyclones in the basin for that year.The Red portion of the bar shows the Typhoon count in the Western North Pacific, and Hurricane count in the North AtlanticThe Horizontal RED line: long-term average Hurricane or Typhoon Count[And the Horizontal BLUE line: long-term average count for Named Storms.]WNP: Change in activity in 1998 (shift in PDO to cool)NATL: Change in activity in 1995 (shift in AMO to warm) 1 animation click. Queue line:“When the years of the AMO and PDO shifts are displayed, it becomes a bit easier to compare the activity on the left and right of the yellow lines… the phase change years.Decreased Typhoon activity in the Pacific is evident starting in 1998, followed by an increase in the early 2000’s, and then a decrease later in the decade. This follows what we just saw on the PDO index in the previous slide.On the bottom chart, there is a clear increase in Hurricane Activity in the Atlantic after 1995, when the AMO warm phase started.
  • NOAA – National Oceanic & Atmospheric Administration – Govt ForecastCSU – Colorado State University – Dr. William Gray / Phillip KlotzbachTSR – Tropical Storm Risk – London-basedWSI - Weather Services International (now a Weather Channel Company)Internal Note: Warm AMO average is basically correct. Here is what I get 1950-2011: Average Warm Cool (1950-1969 / 1995-2011) (1970-1994)Named 11.11 12.32 9.32Hurr 6.31 7.16 5.04 Maj 2.71 3.49 1.56
  • Can we see the affect of PDO and AMO phases on tropical cyclone activity?This slide shows the count of Named Storms and Typhoons in the WNP on the top chart, and the Named Storms and Hurricanes for the Atlantic on the bottom.The total height of the Blue Bar indicates the number of Named Tropical Cyclones in the basin for that year.The Red portion of the bar shows the Typhoon count in the Western North Pacific, and Hurricane count in the North AtlanticThe Horizontal RED line: long-term average Hurricane or Typhoon Count[And the Horizontal BLUE line: long-term average count for Named Storms.]WNP: Change in activity in 1998 (shift in PDO to cool)NATL: Change in activity in 1995 (shift in AMO to warm) 1 animation click. Queue line:“When the years of the AMO and PDO shifts are displayed, it becomes a bit easier to compare the activity on the left and right of the yellow lines… the phase change years.Decreased Typhoon activity in the Pacific is evident starting in 1998, followed by an increase in the early 2000’s, and then a decrease later in the decade. This follows what we just saw on the PDO index in the previous slide.On the bottom chart, there is a clear increase in Hurricane Activity in the Atlantic after 1995, when the AMO warm phase started.
  • Atlantic- one landfall in US, 2nd in MexicoE. Pacific- One landfall – BarbaraW Pacific – One Ty and Soulik is a super TY

2013 North Atlantic Hurricane & Typhoon Season Primer 2013 North Atlantic Hurricane & Typhoon Season Primer Presentation Transcript

  • The 2013 North Atlantic Hurricane & Typhoon Season Primer July 16, 2013
  • Today’s Presenters • John Mangano – Research Scientist, Model Development Group • Justin Brolley – Research Scientist, Model Development Group • Iain Willis – Product Manager, Product Management Group • Aarti Dinesh – Product Manager, Product Management Group
  • Agenda • Factors affecting Tropical Cyclone Activity • North Atlantic Hurricane • West Pacific Typhoon • CatWatch™
  • Hurricane & Typhoon Activity Long-Term Factors Influencing Atlantic and Pacific Tropical Storm Activity
  • Global Tropical Cyclone Basins • Average annual number of named storms by basin Source: IBTracks 166 1127 11 6 9
  • Major Factors Influencing Atlantic and North Pacific Tropical Cyclone Activity El Niño / La Niña – ENSO AMO - Atlantic Multidecadal Oscillation PDO – Pacific Decadal Oscillation
  • ENSO - El Niño-Southern Oscillation • WARM Phase (El Niño) – Above average sea surface temperatures – Shear Impedes development in Atlantic – Tropical cyclones have more time to develop in W. Pacific Ocean • COOL Phase (La Niña) – Below average sea surface temperatures – Low shear allows for development in Atlantic – Tropical cyclones have less time to develop before landfall or re-curvature in W. Pacific • Cycles last roughly 2-7 years
  • ENSO: WARM PHASE (EL NIÑO) EFFECTS Above average sea surface temperatures in the main development region Storms form farther south and east than normal Tropical cyclones have more time to develop Increased vertical wind shear inhibits development
  • ENSO: COOL PHASE (LA NIÑA) EFFECTS Below average sea surface temperatures in the main development region Storms form farther north and west than normal Tropical cyclones have less time to develop Low vertical wind shear promotes tropical storm development
  • Going into the 2013 season with cool neutral phase ENSO Phases 1950-Present http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory http://www.cdc.noaa.gov/enso/enso.mei_index.html http://www.esrl.noaa.gov/psd/enso/mei/
  • Source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/figure6.gif El Nino (Warm) Neutral La Nina (Cool) Latest ENSO Forecasts (June 2013) Forecasts of sea surface temperature (SST) anomalies for the Nino 3.4 region (5°N – 5°S, 120°W – 170°W). Figure courtesy of the International Research Institute (IRI) for Climate and Society. Figure updated 18 June 2013.
  • AMO – Atlantic Multidecadal Oscillation Source of AMO Data: NOAA Earth System Research Laboratory
  • AMO – Atlantic Multidecadal Oscillation • COOL Phase – Cooler SSTs – less energy for development – Increased shear above tropical surface easterlies – Unfavorable environment for hurricanes • WARM Phase – Warmer SSTs – more energy for development – Reduced shear above tropical surface easterlies – Favorable environment for hurricanes For more information, please refer to the white paper at: http://www.eqecat.com/pdfs/north-atlantic-hurricane-model-near-term-2010-04-29.pdf
  • AMO: Affect on Tropical Cyclones North Atlantic Annual Count AMO shift to warm phase
  • Major factors influencing Atlantic and North pacific tropical cyclone activity • El Niño / La Niña – ENSO – Two-Seven year cycle in sea surface temperature in the central and eastern Equatorial Pacific Ocean – A cool neutral ENSO is expected persist throughout the season. • AMO - Atlantic Multidecadal Oscillation – 70-year cycle in sea surface temperatures in the North Atlantic Ocean – Still in Warm Phase of Cycle (since 1995) • PDO – Pacific Decadal Oscillation – 20-30 year cycle of warmer/cooler than normal sea surface temperatures over the North Pacific – Currently in Cool Phase of Cycle
  • North Atlantic Hurricane – Season forecast and prior years’ seasonal forecast – Factors influencing this season’s activity
  • 2012 HURRICANE SEASONAL FORECASTS Date & Forecaster Named Storm Hurricanes Major Hurricanes 5/23 NOAA 13-20 7-11 3-6 6/3 CSU 18 9 4 6/4 TSR 15.6 7.7 3.5 4/8 WSI 16 9 5 4/15 NCSU 15 8.5 4.5 1981 - 2010 Avg. 12.1 6.4 2.7 Latest Warm AMO Avg. 15.2 8.0 3.7
  • High Activity Does Not Necessarily Translate Into More US Landfalls NAMED ATLANTIC STORMS VS U.S. HURRICANES Correlation: US Hurricanes with Named Storms = 0.51 with Hurricane Count = 0.54
  • Past NOAA Hurricane Season May Forecasts Letter grades summarize HURR / MAJ forecast quality Season Probability (%) Storm Counts ABOVE NORMAL BELOW NAMED HURR MAJOR 2006 75 20 5 12-15 7-9 3-4 10 5 2 2007 85 10 5 13-16 7-9 3-5 15 6 2 2008 85 10 5 14-18 7-10 3-6 16 8 5 2009 25 50 25 9-14 4-7 1-3 9 3 2 2010 85 10 5 14-23 8-14 3-7 19 12 5 2011 65 25 10 12-18 6-10 3-6 19 7 3 2012 25 50 25 9-15 4-8 1-3 19 10 2 2013 13-20 7-11 3-6 3+ ? ?
  • Key Drivers Impacting Hurricane Activity • AMO - Atlantic Multidecadal Oscillation – Still in Warm Phase of Cycle (since 1995) • El Niño / La Niña – ENSO – A cool neutral ENSO is expected persist throughout the season. • Atlantic Sea Surface Temperatures (SST) – Currently above average SSTs throughout most of the basin. • Wind Shear – Tropical Atlantic – Currently high wind shear in Lesser Antilles and Cape Verde and low wind shear elsewhere. • Saharan Air Layer Outbreaks – Dry air is currently present off Cape Verde. – The wild card that negatively impacts forecast skill.
  • Near-Term Model Frequency – Based on Warm AMO
  • 500 mb Heights in 1950s and Recent Years Source: NCEP-NCAR Reanalysis 1950s 2006-2012 7 Hurricane Landfalls (NC-ME) 2 Hurricane Landfalls (NC-ME)
  • Western North Pacific Typhoons – Season forecast and prior years’ seasonal forecast – Factors influencing this season’s activity
  • 2013 Typhoon Season Forecasts Forecaster/Date Named Typhoon Major Typhoons Tropical Storm Risk- 7 May 2013 25.6 (±4.2) 16.0 (±3.4) 8.9 (±2.6) Normal 27 17 9 City University, Hong Kong – City University of Hong will not issue pre-season forecast in 2013 in order to incorporate latest research into forecasting scheme.
  • Past TSR Typhoon Season May Forecasts Letter grades summarize HURR / MAJ forecast quality Season Probability (%) Storm Counts ABOVE NORMAL BELOW Named Typhoons Major 2006 15 50 35 25-33 16-22 7-12 22 14 10 2007 36 46 18 23-31 14-20 5-11 25 16 9 2008 35 48 17 25-32 15-21 5-10 28 13 9 2009 16 46 38 24-31 15-21 7-12 23 15 7 2010 15 43 42 20-28 12-18 7-12 14 8 4 2011 20 43 37 24-32 15-21 5-10 21 10 7 2012 23 43 34 21-30 12-19 6-11 25 16 10 2013 38 42 20 21-30 13-19 6-12 6+ 2+ 1+
  • warm phase cool phase PDO – Pacific Decadal Oscillation • WARM Phase – Above average SST in the tropical Pacific – More frequent El Niño Events – Below average SST in the N. Pacific – More favorable environment for development of typhoons • COOL Phase – Below average SST in the tropical Pacific – More frequent La Niña Events – Above average SST in the N. Pacific – Less favorable environment for development of typhoons • Roughly 20-30 years in each phase with inter-annual variation – 1945-1975: COOL phase: 31 years – 1976-1997: WARM phase: 33 years – 1998-present: Recent COOL phase
  • Cool Phase Cool PhaseWarm Phase PDO – Pacific Decadal Oscillation
  • PDO: Affect on Tropical Cyclones Annual Count PDO shift to cool phase
  • Key Drivers Impacting Typhoon Activity • Pacific Decadal Oscillation (PDO) – 40-60 year cycle of warmer/cooler than normal sea surface over the North Pacific • Multi-decadal cycle – 16-32 year cycle associated with El Niño / La Niña and PDO • El Niño/Southern Oscillation (ENSO) – 2-7 year cycle of warmer/cooler than normal sea surface over tropical eastern Pacific • Western Pacific Subtropical High (WPSH) – Strength and extent of WPSH pressure system
  • CatWatch™
  • Pre-Season • Hurricane and Typhoon Season Primer During the Season • CatWatch Alerts • Post disaster Survey • Post-event Reports • EQECAT Briefings Post-Season • Season Recap Webinar Information & Communication Subscribe to CatWatch Email Alerts: www.eqecat.com/catwatch/subscribe/
  • CatWatch • EQECAT's catastrophe event notifications compiled before, during, and after natural catastrophes. • Providing critical event information about spatial distribution of damage, potential post-event effects, and its impact on the in/reinsurance industry. Basins Named Storms Hurricanes / Typhoons Landfalls Atlantic 3 0 2 E Pacific 5 4 1 W Pacific 6 2 3
  • CatWatch Team • The CatWatch team monitors natural catastrophe activity around the world, and issues notifications about significant events before and after they occur. • Emphasis is on events that impact insurance industry in regions covered by EQECAT’s peril models. • Offers early insights and determines the impact of the event on your finances. • This helps you plan accordingly for capital outlays, and gauge possible market-wide effects.
  • www.eqecat.com/ For more information, Contact EQECAT, Inc: In the Americas: (201) 287-8320 In Bermuda: (201) 287-8320 In UK/Europe/Asia: +44 207 265 2030 Email : information@eqecat.com Thank You