Zoltan Toth Environmental Modeling Center NOAA/NWS/NCEP Acknowledgements:

1. Zoltan Toth Environmental Modeling Center NOAA/NWS/NCEP Acknowledgements: Aimee Devaris, Sreela Nandi, Fred Toepfer, Marty Ralph, John Gaynor, Paul Hirschberg, Yuejian Zhu http://wwwt.emc.ncep.noaa.gov/gmb/ens/index.html PLANS FOR PROBABILISTIC GUIDANCE PRODUCTS FOR HIGH IMPACT EVENTS & CORRESPONDING PERFORMANCE MEASURES

2. NOAA PLANNING, PROGRAMMING, BUDGETING AND EXECUTION SYSTEM (PPBES FY2010-14) PROBABILISTIC NUMERICAL GUIDANCE FOR HIGH IMPACT EVENTS • Goal: Provide highest quality, coordinated, and seamless probabilistic automated guidance products, including information on forecast uncertainty • Deliverable: Comprehensive suite of ensemble forecast systems (“forecast engine”) that facilitate the generation of automated forecast guidance as a basis for high impact event forecasting for NOAA operations regarding high impact events • Range of use: All high impact weather, water, and climate forecast applications • Motivation: Need unified approach for ease of implementation, maintenance, and use, where scientifically possible / justified; THORPEX concepts generalized in NFUSE process; linked with NUOPC • Supporting programs: STI & EMP

3. PROGRAM DESCRIPTION (PNGHIE) • Time/spatial scales: All spatial and time scales, including • Now-casting (6-12 hrs, local scale modeling) • Short range (up to 3 days, regional modeling) • Medium- and extended range (up to 15 days, global modeling) • Sub-seasonal (10-60 days, coupled global ocean / land surface / atmosphere modeling) • Seasonal (2-12 months, coupled global OLA modeling) • New aspects of forecast process • Integrated from observations to user applications • Focused on high impact events • Probabilistic to capture forecast uncertainty • Seamless guidance from minutes to seasons • Adaptive to provide best case dependent info • User controllable to cater to users’ needs

4. PROGRAM DESCRIPTION (PNGHIE) • Scope / participants: • Applied research - External community: THORPEX AOs, OAR Labs • Transition to operations - NCEP/EMP • Operations - NCEP/NCO, NCDC

5. PROGRAM ACTIVITIES (PNGHIE) • Design of observing system for high impact events • Development of observing instruments/platforms to fill gaps in current system • Optimal design of satellite & in-situ observing network • Adaptive collection and processing of observations • Advanced data assimilation techniques • Ensemble-based forecast error covariance • Initial ensemble perturbations • Numerical modeling for high impact events • Ensemble techniques for high impact applications • Air quality/dispersion, tropical cyclones, extra-tropical storms, fire weather, etc • Model-related uncertainties in ensemble forecasting • Variable-resolution modeling for high impact events • Socio-economic applications • Statistical bias correction (lead time dependent errors) • Downscaling (fine resolution information) • Combination of all forecast information • Product generation • User applications (Decision Support Systems)

6. DRIVERS • External • National Research Council (NRC) Report • Completing the Forecast: Characterizing and Communicating Uncertainty for Better Decisions Using Weather and Climate Forecasts • Recommendation for NOAA/NWS to become leader in the development and use of probabilistic and ensemble forecast methods within weather/water/climate enterprise • National Unified Operational Prediction Capability (NUOPC) • Tri-agency (NOAA, US Navy, US Air Force) effort at unified probabilistic global prediction capability • Multi-center ensemble forecasts at its core (extension of NAEFS, linked with TIGGE / GIFS) • Internal • NOAA AGM FY2010-14 PRIORITIES • Twelve references to improved and extended ensemble, probabilistic numerical guidance for high impact events • NWS Forecast Uncertainty Service Evolution (NFUSE) Team • Probabilistic Numerical Guidance is one of three major areas coordinated under NFUSE: • “Human factor” – How numerical forecasts are improved and communicated by human forecasters • Outreach – What products the external user community needs, and how they use them

7. COORDINATION WITH OTHER PROGRAMS • NWS Forecast Uncertainty Service Evolution (NFUSE) Steering Team • Probabilistic Guidance for high impact events will be communicated to, and modified by human forecasters; final, official numerical ensemble guidance will be made available for use by general public and special users • W&W – LFW • Distribution, manipulation, display, depository, verification of ensemble forecast data, training of forecasters • W&W – STI • Provides: Observing instruments and platforms, decision support tools, outreach to external users • Receives: Probabilistic/ensemble guidance for HMT demo projects • Water resources - Hydrology • Climate Goal – Predictions and Projections Program • Weather-Climate connections, Sub-seasonal and seasonal forecasting • Climate Goal - Climate Observations and Analysis (COA) Program • Archive and distributed web services access to ensemble forecasts though the NOAA National Operational Model Archive and Distribution System (NOMADS) • Building Community Resilience in the Face of Coastal Hazards • Provides: Critical application area for probabilistic forecast activities • Receives: Early numerical warning for high impact events

8. PERFORMANCE MEASURES FOR NEWPROBABILISTIC GUIDANCE • No official NWS requirement exists for probabilistic products • In practice, isolated examples within NWS • NFUSE will coordinate proposed change in official requirements to include forecast uncertainty / probabilistic information? • Consider NRC recommendations, along with examples within & outside NWS • Draft in half year, full proposal in a year? • Technical question of what measures to use for assessing skill associated with new requirements • Consider broad literature, existing practice within/outside NWS • Draw on technical expertise within NWS & NOAA • Half year effort, can be done after or along development of requirements • Plan for systematic introduction of “Probabilistic numerical guidance for high impact events” • POP under EMP, to be coordinated within NFUSE • How to define performance measures? • Use more general language now, refer to plan for developing detailed requirements and associated measures?

9. PERFORMANCE METRICS DISCUSSION • Start discussion for planning period FY2010-14 • Performance measures for numerical guidance must be also relevant for LFW • Bridge / connecting point between EMP & LFW • What needs to be done? • Design new products, define corresponding measures • Identify “legacy” scores with long record • Procedure • Select type of products to be highlighted in performance measures • Discuss probabilistic measures • Need metric that measures both • Statistical reliability • Related to systematic errors • Statistical resolution • Related to random errors • Define details later for both products & metrics • Application • Evaluation of bias corrected ensemble-based numerical guidance on model grid • Evaluation of downscaled probabilistic numerical guidance on NDFD grid

10. PROPOSED NEW / LEGACY PRODUCTS TO BE MONITORED • Possible new probabilistic guidance products for high impact events • Hydrometeorology • Extreme hydro-meteorological events, incl. dry and wet spells (CONUS) • Quantitative extreme river flow forecasting (OCONUS) • Tropical / winter storm prediction • Extreme surface wind speed • Extreme precipitation (related to wet spells) • Storm surges • Aviation forecasting • Flight restriction • Icing, visibility, fog, clear air turbulence • Health and public safety • Hot and cold spells • “Legacy” internal probabilistic scores to assess long-term progress • With years of existing archive and/or • Can be easily recomputed • General circulation • Probabilistic 1000 & 500 hPa height forecasts • Tropical storm • Strike probability for track • Probability of intensity (central pressure or wind-based)