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NCEP Regional Ensemble Status and Plans

NCEP Regional Ensemble Status and Plans. Geoff DiMego and Jun Du NOAA/NWS/NCEP Environmental Modeling Center. Presentation Outline. Status Plans Challenges. Regional Ensemble Prediction Systems (EPSs) at NCEP. * See poster. Current SREF Methodology. IC aspect:

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NCEP Regional Ensemble Status and Plans

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  1. NCEP Regional Ensemble Status and Plans Geoff DiMego and Jun Du NOAA/NWS/NCEP Environmental Modeling Center

  2. Presentation Outline • Status • Plans • Challenges

  3. Regional Ensemble Prediction Systems (EPSs) at NCEP * See poster

  4. Current SREF Methodology IC aspect: • Multi-analysis (NDAS, RR, GDAS) • Perturb ctl anl (bred vector, global ETR, regional ETR) • Perturbed LBCs (from global EPS) • Land surface initial states such as soil moisture and temperature (tested) Model aspect: • Multi-model (NEMS-NMMB,WRF-ARW, WRF-NMM) • Multi-physics (various convection and cloud schemes) • Stochastic parameterization (tested) Residual Part: • Post processing including: bias correction downscaling (HREF)

  5. Convergence of NAM & RUC into hourly NARRE & HRRRE Based on a new common modeling infrastructure called NEMS (NOAA Environmental Modeling System) 84 hour guidance from NAM & SREF will continue as extensions to longer range of the 00z, 06z, 12z and 18z cycle runs

  6. NAM WRF-NMM (Egrid) GSI analysis 4/Day = 6 hr update Forecasts to 84 hours 12 km horizontal 60 layers with 2 mb top 12 hr pre-forecast assimilation period with 3hr updates (catch-up) RUC Non-WRF RUC model RUC 3DVAR analysis 24/Day = hourly update Forecasts to 18 hours 13 km horizontal 50 layers with 50 mb top Continuous forward cycle with no pre-forecast assimilation period (no catch-up) CURRENT2009-2010 RUC-13 CONUS domain

  7. NAM NEMS based NMMB Bgrid replaces Egrid Parent remains at 12 km Multiple Nests Run to 60hr 4 km CONUS nest 6 km Alaska nest 3 km HI & PR nests Reinstate Fire Weather/IMET Support/DHS run to 36hr Locate single 1.20-1.33 km run In either CONUS or Alaska Rapid Refresh WRF-based ARW NCEP’s GSI analysis Expanded 13 km Domain to include Alaska Experimental 3 km HRRR WRF-Rapid Refresh domain – 2010 RUC-13 CONUS domain Original CONUS domain Experimental 3 km HRRR 2011

  8. North American Rapid Refresh ENSEMBLE (NARRE) NMMB (from NCEP) & ARW (from ESRL) dynamic cores Common use of NEMS infrastructure and GSI analysis Common NAM parent domain at 10-12 km Initially ~6 member ensemble made up of equal numbers of NMMB- & ARW-based configurations Hourly updated with forecasts to 24 hours NMMB & ARW control data assimilation cycles with 3 hour pre-forecast period (catch-up) with hourly updating NAM & SREF 84 hr forecasts are extensions of the 00z, 06z, 12z, & 18z runs – for continuity sake. SREF will be at same 10-12 km resolution as NARRE by then SREF will have 21 members plus 6 from NARRE for total of 27 NARRE requires an increase in current HPCC funding 2012-2013

  9. High Resolution Rapid Refresh ENSEMBLE (HRRRE) Each member of NARRE contains 3 km CONUS, 4 km Alaskan, 2.5km Hawaii & Puerto Rico nests The two control runs initialized with radar data & other hi res obs This capability puts NWS/NCEP[+OAR/ESRL] in a position to Provide NextGen Enroute AND Terminal guidance Provide PROBABILITY guidance with full Probability Density Function specified Provide a vehicle to improve assimilation capabilities using hybrid (EnsKF+4DVar) technique with current & future radar & satellite Address Warn-on-Forecast as resolutions evolve towards ~1 km NAM nests are extensions of the 00z, 06z, 12z & 18Z runs. HRRRE requires an increase in current HPCC funding over and above that required for the NARRE 2012-2013

  10. A Catch-Up Cycle for NARRE & HRRRE could constitute the Analysis of Record Catch-up concept: reach back in time to include late arriving observations Assimilate ALL in situ and remote data sources Use state-of-the-art 4-dimensional data assimilation technique Likely NCEP’s hybrid Ensemble Kalman-Filter and 3D-/4D-Variational Able to take quick advantage of its evolution Use state-of-the-art nonhydrostatic numerical models Advanced Research WRF (ARW) core from NCAR & ESRL/GSD Non-hydrostatic Multiscale Model on B-Grid (NMMB) from NCEP Interoperable physics from WRF community & NCEP operations Able to take quick advantage of their evolution Extend to include NextGen required parameters This AoR requires an increase in current HPCC funding 2012-2015

  11. SREF Future Plans 2010 2011 2012 2013 2014 2015 SREFSREF SREF SREF SREF SREF* (21mem, 32km, 4-model) (21mem,22km, 3modelsWRF&NEMS) (12km, NEMS-only + CMC) (NARRE extension) NARRE NARRE NARRE (6mem, 12km, hourly update, 24hr, 2-model) HRRRE HRRRE HRRRE (CONUS, AK, 3km, nests in each NARRE member, hourly update to 24hr) VSREF(RUC/NAM) VSREF(=NARRE) after (time-lagged ensemble based probabilistic products for aviation NextGen) HREF(SREF/HiResWinRuns) HREF(=HRRRE) after (dynamically downscaled from SREF using HiResWindow runs for high impact weather) *NEMS = NOAA Environmental Modeling System (a unified modeling framework) *SREF (3222km12km, 6-hrly update to 84h for general weather forecasts) *NARRE = North America Rapid Refresh Ens (10-12km, hrly update to 24h for aviation) *HRRRE = Hi-Res Rapid Refresh Ens. (3km, nested in NARRE, hrly update to 24h for high-impact events for targeted CONUS, AK domains) *VSREF = Very Short-Range Ens Forecast for aviation NextGen prob products *HREF = High-Resolution Ensemble Forecast

  12. SREF Future Plans (Cont.) • IC perturbation • Regional ETR (with DET), comparing to downscaled GEFS ETR • any other better methodologies (with DET) • Model perturbation • Stochastic parameterization • GEFS stochastic physics • Any other better ones (with DET) • Post processing • CDF-adjusting for precipitation bias correction • NAFES post-processing package (Bayesian processor) • Any other better ones (with DET) • Products • Any thing good from community

  13. Challenges • Day-1 ensembling techniques • How can stochastic physics reproduce the effectiveness of multi-model approach? • Lack of enough computer resource • Lack of enough human resource

  14. Probabilistic Forecast Performance (Ranked Prob Skill Score): little or no skill comparing to 12km NAM at day 1

  15. Effectiveness of multi-model approach: can itbe reproduced by stochastic physics?

  16. Computer Resource Reality • Stochastic -> Single executable limits flexibility • Projected is Problemmatic • Acquisition for 2012 is postponed/delayed • Funding for the bridge and transition in doubt • Could be left with no net increase next 4 years • Nothing close to what is needed for a truly MESOSCALE ensemble

  17. Key to the success of R2O and O2R • Community needs to understand • operational needs • restrictions of an operational environment • Establish SREF baseline at DET • R2O tests new methods in context of this baseline for potential implementation • Agreement on standard verification measures

  18. Questions?

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