# Presentation: 192703

## PLANS FOR PROBABILISTIC GUIDANCE PRODUCTS FOR HIGH IMPACT EVENTS & CORRESPONDING PERFORMANCE MEASURES

- 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

## 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

## 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**

## PROGRAM DESCRIPTION (PNGHIE)

- Scope / participants:
- Applied research - External community: THORPEX AOs, OAR Labs
- Transition to operations - NCEP/EMP
- Operations - NCEP/NCO, NCDC

## 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)

## 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

## 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

## PERFORMANCE MEASURES FOR NEWPROBABILISTIC 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?

## 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

## 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)