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AFWA Ensemble Prediction System. Mr. Evan Kuchera HQ AFWA 2 WXG/WEA Template: 28 Feb 06. Approved for Public Release - Distribution Unlimited. Overview. Purpose: To discuss progress towards an AFWA ensemble prediction system
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AFWA Ensemble Prediction System Mr. Evan Kuchera HQ AFWA 2 WXG/WEA Template: 28 Feb 06 Approved for Public Release - Distribution Unlimited
Overview • Purpose: To discuss progress towards an AFWA ensemble prediction system • AFWA is exploring how ensembles can best be exploited to improve DoD forecast processes and warfighter decision making • Diverse global and mesoscale models • Probabilistic algorithms for “high impact” variables • Concise, warfighter-focused products • Emphasis on training and outreach
Webpage https://weather.afwa.af.mil/host_home/DNXM/JEFS/jefs.html Available products for global (JGE) and mesoscale (JME): Precipitation Amount Precipitation Type Snow Amount Cloud Cover Lightning Dust Lofting Severe Weather Blizzard Surface Wind Gust Visibility Wind Chill Heat Index Realtime verification also available on webpage
Mesoscale Ensemble • Pre-processing • GFS ensemble from six hours earlier is used for initial/lateral boundary conditions • Model configuration • 10 independent model configurations with varying physics and lower boundary conditions (land surface, SSTs) run twice a day • Also producing 31-member merged JME-SREF over CONUS • The table lists different physics packages used by each member
Current Mesoscale Domains 30km 30 km 10 km East Asia SWA 10 km 3 km 3 km resolution reserved for complex terrain areas 30/10 resolutions best for available resources Hourly output on the 10 km domains to 48 hours CONUS
Calibration Algorithms • As opposed to “traditional” calibration… • Observations/gridded analysis for real-time calibration are not always available • Real-time calibration can reduce skill in forecasting rare events and pattern changes • Use regression with past model-obs data sets and physics-based algorithms to produce a climatologically calibrated forecast • Accounts for diagnosis uncertainty for unresolved variables • Does not necessarily account for model biases • Lightning, visibility, and precipitation type created so far
30 hour ice storm forecast SNOW PROBABILITY “MIX” PROBABILITY FRZR PROBABILITY
Precipitation Meteogram Observations in circles
Way Ahead • Global (2009) • Begin work to operationalize products that are ready • Mesoscale (2009-2011) • Further work needed to generate more representative mesoscale initial condition/model perturbations—crucial to success • Continue making products in development environment • Statistical post-processing work also important • Forecast variables of interest with algorithms; mitigate biases • Large effort required—reserved for highest impact variables • Training and outreach • Outreach to decision makers; work hand-in-hand with forecasters for maximum exploitation capability • Formalize training on certainty forecasting principles