2017 Hurricane Season and Beyond

Transcription

1 2017 Hurricane Season and Beyond Ken Graham National Hurricane Center Building a Weather-Ready Nation

2 Much of U.S. Coast Saw Tropical Wind Watches or Warnings

3 2017 Hurricane Season Facts and Figures 7th most active season on record (by ACE) Most major hurricanes since 2005 Record three category 4 landfalls in the U.S. Harvey set U.S. tropical cyclone rainfall record with inches of rain!

4 Records and Other Highlights Five category 5 landfalls 4 by Irma in the Caribbean 1 by Maria in the Caribbean Costliest year on record for the US with $265 Billion in damage 2 nd (Harvey), 3 rd (Maria) and 5 th (Irma) costliest U.S. individual storms Several hundred direct and indirect deaths in the US, but NONE known from storm surge

5 Hurricane Harvey $125 billion in damage 68 fatalities Deadliest hurricane in Texas since 1919 Storm surge maximum of 8-10 feet near Rockport Meandering track after landfall led to historic rainfall Over 60 inches! Maximum Storm Surge Inundation Estimate 57 total tornadoes from Texas to Tennessee

6 Hurricane Irma Category 4 landfall in the Florida Keys Category 3 landfall in SW Florida Significant surge damage in Florida Keys, and wind impacts across much of the state

7 Hurricane Irma Over Eighty Indirect Deaths in Florida Most frequent factors: cardiovascular, loss of electricity, vehicle accident, and evacuation

8 Hurricane Maria Category 4 landfall in Puerto Rico, but category 5 winds likely occurred at some elevated locations Significant storm surge and devastating rain-induced flooding occurred Death toll remains highly uncertain

9 2017 Season in Review: Storm Surge Unit Successes First-ever storm surge watch & warning in the U.S. No known fatalities from storm surge despite four U.S. landfalling hurricanes New surge products assist in hurricane evacuation execution and part of the national conversation

10 2017 Season in Review: Hurricane Program Successes Potential Tropical Cyclone Advisories Allows issuance of watches & warnings Resulted in additional lead time on systems developing near land Time of Arrival Graphics Earliest Reasonable Most Likely

11 2017 Season in Review: Forecast Accuracy Success Record low average NHC Atlantic track errors at all forecast lead times Track errors for Harvey, Irma, & Maria much lower than the 5- year mean About 36 hours prior to Harvey s landfall the forecast successfully called for Harvey to intensify from a tropical storm to major hurricane

12 2017 Season in Review: Consistent Forecasts Every NHC forecast predicted landfall in Puerto Rico. All but the first predicted major hurricane intensity at landfall.

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15 Shrinking Forecast Cone Not an Impact Graphic! No reduction in storm size = More impacts occurring outside the cone! Graphic courtesy of B. McNoldy UM/RSMAS

16 Forecast Improvements Over the Past 25 Years Andrew 1992 Katrina 2005 Irma 2017 Brian Norcross Policy: Global models not used for official forecast GFS did capture an L with one or two closed isobars - considered a success Policy changed after Andrew Accelerated use of models for 5-day forecasts Model runs captured intensification/track - broad cone of uncertainty Intensity changes advertised 1-2 days in advance still a challenge 10-day model runs used to track Irma: development of storm as a wave off Africa right turn in the track Still have issues nailing down the details Track changes Rapid intensity changes still a challenge

17 Impact Based Decision Support Services Improvements Andrew 1992 Katrina 2005 Harvey/Irma/Maria 2017 NHC connected with National/State Ems Very product centric NHC connection with National/State EMs vastly expanded Variable connectivity with local, state/parish EM community Entire NWS connected to National, State, Local EMs and Water Resource Managers CONSISTENT messaging of forecasts and impacts Ready-Set-Go with EM community 7 days in advance Strong connection (embedding) at every government level, especially at the local level All hands on deck to support field structure before, during, and after events NWS surges resources 17 where needed

18 Communicating Risk This is just a CAT 1 hurricane It has never flooded here before I ve been through a CAT 3, nothing happened here I saw the new forecast, that GFS thing says it won t come here, phew! This is the same surge forecast as the last one and I didn t flood then We are going to evacuate for all CAT1 hurricanes from now on Ah great, I have a GIS map. Finally something accurate But, I m outside the cone We just had our 100 year storm last year

19 Rainfall Risk Considerations 1% annual flood risk (1% chance every year) 1 in 100 chance 26% chance of flooding in a typical 30 year mortgage 27% greater chance of flooding than having a house fire Over 100 years, there is a 63% chance of your house flooding This is the best guess flood area and changes with time

20 Communication Challenges WPC Excessive Rainfall High Risk SPC Severe Weather Moderate Risk How are these threats interpreted by the public?

21 2017 Tropical Storm Cindy

22 Hurricane Irma Storm Surge Sensitivity to Track Observed Track and Simulated Storm Surge Forecast Track and Simulated Storm Surge Ft. Myers Beach Sanibel Is. ~30 nm ~50,000 people with 3+ foot surge ~200,000 people with 3+ foot surge

23 1992: Inactive Season

24 2005

25 2010

26 2017

27 Key Message Graphic and Initial Wind Field on Cone Graphic NHC Key Message Graphic Combines Key Messages from the NHC Discussion and pertinent advisory graphics Available via NHC social media accounts and on NHC website Storm size information (initial wind field) was added to the cone graphic in 2017 Helped to illustrate hazardous wind conditions that occur outside the cone

28 Beyond 2018: Research Plan Hurricane Forecast Improvement Project Goals: Reduce forecast (model) guidance errors, including during rapid intensification, by 50% from 2017 Produce 7-day forecast guidance as good as the day forecast guidance Improve guidance of pre-formation disturbances, including timing, track, and intensity forecasts, by 20% from 2017 Improve hazard guidance and risk communication based on social and behavioral science to modernize the tropical cyclone product suite for actionable lead-times for storm surge and all other threats

29 Beyond 2018: Developing a 3-10 Year Vision The conversation: Graphic showing inland AND coastal tropical cyclone watches and warnings Improve inland flood threat communication through new WPC products and education Extend real-time storm surge guidance to 72 hours before landfall Official forecast points out to 7 days Improve understanding and communication of indirect hazards

30 Thank You We can t do it without you, before, during and after the next storm