1 Extratropical Storm Surge Modeling Presented By: Jesse Feyen (NOS/OCS, Storm Surge Roadmap) Contributors:

2 Operational System Attribute(s) System NameAcronymAreal CoverageHorz Res Cycle Freq Fcst Length (hr) Extratropical Storm Surge Operational Forecast System ESTOFSAtlantic, Pacific 1-3 km 4x/dy172 SystemAttributes ESTOFS Hot start from previous simulation cycle using global tidal database (no D/A) System Data Assimilation or Initialization Technique

3 Why System(s) are Operational  Primary stakeholders and requirement drivers NWS/Weather Forecast Offices, NWS/Ocean Prediction Center, emergency managers, coastal managers, media Need for surge+tide predictions for forecasting, coupling to NCEP/EMC nearshore wave predictions  What products are the models contributing to? NWS inundation forecasts in AWIPS, NWS surge prediction websites  What product aspects are you trying to improve with your development plans? Cover Pacific Islands and Alaska, increase ensemble members, improve resolution, couple to river hydraulic models for total water prediction  Top 3 System Performance Strengths Advanced hydrodynamic model ADCIRC supports fully nonlinear physics, wave and river coupling, unstructured grids to resolve complex coastline Leverages extensive federal investments in model (USACE, FEMA) Well validated for accurate water level predictions  Top 3 System Performance Challenges Computational cost limits resolution, coverage of coastlines Limited ensemble members cannot address met uncertainties/scenarios Not currently coupled to waves, rivers

4 System Evolution Over the Next 5 Years  Major forcing factors Part of Storm Surge Roadmap strategy to develop ensemble of coupled total water prediction system to inform forecasters via coupling with wave, river hydraulic models Need to provide inundation guidance over all vulnerable coastlines (e.g., outlying Pacific Islands, Alaska)  Science and development priorities Add additional forcing to increase ensemble members (now only GFS) Develop, test, and transition coupling to wave and river hydraulic models to provide total water predictions Increase resolution to accurately predict local flooding (new Hurricane Storm Surge Operational Forecast Sys. in dev. - down to 250 m)  What are you top challenges to evolving the system(s) to meet stakeholder requirements? Insufficient computing resources for coupled ensemble high-res models Insufficient model developers to sustain total water prediction R&D, O&M  Potential opportunities for simplification going forward Coupled total water prediction connections between ADCIRIC and hydraulic models Continue coordination of inundation model dev. via Surge Roadmap

5 Top 3 Things You Need From the UMAC 1.Clarity on importance, significance of total water prediction within NOAA modeling suite so that coupling and coverage can meet requirements 2.Support for computing resources for total water prediction (ensemble surge+tide+wave+river) 3.Recommendations on ensemble total water prediction coupled modeling strategy