1. 1 Requirements for hurricane track and intensity guidance Presented By: Vijay Tallapragada and Sam Trahan (NWS/NCEP) Contributors: HWRF Team at EMC, NHC & HFIP

2. 2 Operational System Attribute(s) System NameAcronymAreal CoverageHorz Res Cycle Freq Fcst Length (hr) Hurricane Weather Research and Forecast Modeling System HWRFAll global tropical cyclone basins, max. 7 storms, on demand by NHC/CPHC/JTWC 18/6/ 2 km 4126 Message Passing Interface Princeton Ocean Model for Tropical Cyclones MPIPOM- TC North Atlantic & North Eastern Pacific 6 km4126 SystemAttributes HWRF One-way Hybrid Global EnKF – Regional 3DVAR for North Atlantic basin. For Tail Doppler Radar data assimilation, global ensembles are replaced by 40-member high-resolution HWRF ensembles MPIPOM-TC Feature based initialization of loop current, cold/warm core eddies and TC induced cold wake in the North Atlantic; GDEM Climatology based initialization for North Eastern Pacific System Data Assimilation or Initialization Technique

3. 3 Why System(s) are Operational  Primary stakeholders and requirement drivers NHC, CPHC, JTWC and NWS PR Various WFOs, WMO RSMCs and various international TC forecast agencies  What products are the models contributing to? Tropical Cyclone Track, Intensity, Structure, Size, Swaths of Maximum Wind and Storm Total Rainfall, Synthetic Satellite Imagery and Simulated Radar Reflectivity, hourly high-res winds  What product aspects are you trying to improve with your development plans? Tropical Cyclone Track, Intensity, Rapid Intensity Changes, Structure, Size, QPF, landfall impacts (storm surge, significant wave heights, rainfall, flooding and inundation)  Top 3 System Performance Strengths The only high-resolution cloud-resolving non-hydrostatic ocean-coupled model operating at 2km resolution, specifically designed for tropical cyclone forecast guidance The only operational model capable of ingesting aircraft reconnaissance data (inner-core Tail Doppler Radar and dropsondes) in real-time Top performer for track and intensity forecast guidance for all global tropical cyclones through their life cycle (including areas of investigation) to NHC, CPHC and JTWC  Top 3 System Performance Challenges Forecast performance for Rapid intensity changes (RI/RW) Representation of multi-scale interactions and scale-aware physics Assimilation of all-sky radiance data and all manned/unmanned aircraft reconnaissance data Coupling to Waves and Hydrology

4. 4 System Evolution Over the Next 5 Years  Major forcing factors NHC Track and Intensity GPRA goals: Saving lives & property through reduced errors and increased accuracy of tropical cyclone forecasts Continuous forecast improvement goals targeted by HFIP and NGGPS Reliable and accurate high-resolution forecast guidance for significant weather events associated with tropical cyclones Comprehensive forecast solutions for all aspects of tropical cyclones from genesis through dissipation, including downstream applications  Science and development priorities Continuous improvements to model resolution, dynamics and physics, modeling storm-storm and multi-scale interactions; Assimilation of all-sky radiance and all available data; Improved air-sea-wave-land-hydrology coupling and High-resolution ensembles  What are you top challenges to evolving the system(s) to meet stakeholder requirements? Rapid transition of scientific research and developments supported by HFIP and NGGPS; Computational resources; Data collection, quality control and real-time transmission, Technological and engineering aspects of, appropriate representation of scale-aware and stochastic physics, ensemble strategies  Potential opportunities for simplification going forward Transition to NMMB/NEMS  Unified mesoscale models for convective scale forecasts unified non-hydrostatic global model with high-resolution nests coupled to ocean, waves, land and hydrology

5. 5 Top 3 Things You Need From the UMAC 1.Strategies for unified regional (meso-scale) models in the NEMS framework Be able to meet the performance of current operational HWRF Be able to provide TC-related products for all global tropical cyclones Accommodate future development strategies including coupling to ocean, waves, land, surge and hydrology Retain and expand community interactions fostered by HFIP Flexible options for inner-core data assimilation Enable future ensemble strategies and potential genesis and 7-day intensity forecasts 2.Strategies for unified global model with multiple moveable nests Be able to meet the performance of current operational HWRF Be able to provide TC-related products for all global tropical cyclones Accommodate future development strategies including coupling to ocean, waves, land, surge and hydrology Retain and expand community interactions fostered by HFIP and NGGPS 3.Strategies for serving the next-generation needs of operational tropical cyclone forecasters Expand the products to include deterministic and probabilistic forecast guidance on genesis, rapid intensity changes, size, structure, storm surge, rainfall, flooding and inundation and warn on forecasts