1 DET Mesoscale Ensemble Workshop August 2010 NCEP Regional Ensemble Status and Plans Geoff DiMego and Jun Du NOAA/NWS/NCEP Environmental Modeling Center

2 DET Mesoscale Ensemble Workshop August 2010 Presentation Outline Status Plans Challenges

3 DET Mesoscale Ensemble Workshop August 2010 Regional Ensemble Prediction Systems (EPSs) at NCEP EPSModel (s)Domain (s)MemberResolutionForecast length Update frequency Intended purposes SREF (2011) NEMS(nmm), WRF(nmm, arw) North America (NA) km3.5 days6hrlyShort-range weather HREF* (dyn dwn) (2011) WRF(nmm, arw) East CONUS West CONUS Alaska 444-5km2 days12hrly 24hrly high impact weather VSREF* (t- lag) (2011) RR(arw), NAM(nmm) CONUS km0.5 dayhourlyaviation NARRE ( ) NEMS(nmm, arw) NA610km1 dayhourlyaviation HRRRE ( ) NEMS(nmm, arw) CONUS, AK63km1 dayhourlyConvective storms NAEFS_LA M (2013) NCEP SREF + CMC REPS NA41~30km2 days12hrlyShort-range weather HWRF ens (2015?) HWRFAtlantic & E. Pacific km5 days6hrlyhurricane * See poster

4 DET Mesoscale Ensemble Workshop August 2010 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) Current SREF Methodology

5 DET Mesoscale Ensemble Workshop August 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 DET Mesoscale Ensemble Workshop August CURRENT 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) RUC-13 CONUS domain

7 DET Mesoscale Ensemble Workshop August 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 km –Locate single 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 RUC-13 CONUS domain WRF-Rapid Refresh domain – 2010 Original CONUS domain Experimental 3 km HRRR

8 DET Mesoscale Ensemble Workshop August 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 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 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

9 DET Mesoscale Ensemble Workshop August 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

10 DET Mesoscale Ensemble Workshop August 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

11 DET Mesoscale Ensemble Workshop August 2010 SREF Future Plans SREF SREF 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 DET Mesoscale Ensemble Workshop August 2010 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 DET Mesoscale Ensemble Workshop August 2010 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 DET Mesoscale Ensemble Workshop August 2010 Probabilistic Forecast Performance (Ranked Prob Skill Score): little or no skill comparing to 12km NAM at day 1

15 DET Mesoscale Ensemble Workshop August 2010 Effectiveness of multi-model approach: can it be reproduced by stochastic physics?

16 DET Mesoscale Ensemble Workshop August 2010 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 DET Mesoscale Ensemble Workshop August 2010 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 DET Mesoscale Ensemble Workshop August 2010 Questions?