1. August 6, 2001Presented to MIT/LL The LAPS “hot start” Initializing mesoscale forecast models with active cloud and precipitation processes Paul Schultz NOAA Forecast Systems Laboratory Local Analysis and Prediction Branch

2. August 6, 2001Presented to MIT/LL The LAPS team John McGinley, branch chief, variational methods Paul Schultz, project manager, modeler Brent Shaw, modeler Steve Albers, cloud analysis, temp/wind analysis Dan Birkenheuer, humidity analysis John Smart, everything

3. August 6, 2001Presented to MIT/LL Goals Address NWP “spin up” problem –Explicit short-range (0-6 h) QPFs and cloud forecasts Focus on a “local” modeling capability –Must be computationally inexpensive –Exploit all locally-available meteorological data –High-resolution grids –Robust data ingest, QC, and fusion Develop a flexible solution for easy technology transfer –Hardware/OS independence –Choice of mesoscale model

4. LAPS II Three-Dimensional Cloud Analysis METAR

5. August 6, 2001Presented to MIT/LL Cloud typing Cumulus vertical motions

6. August 6, 2001Presented to MIT/LL LAPS II Dynamic Balance Adjustment ( ) b are background quantities; (^) are solution increments from background; ( )’ are observation differences from background

7. August 6, 2001Presented to MIT/LL LAPS II Dynamic Balance Adjustment FHFLFHFL

8. August 6, 2001Presented to MIT/LL Results 3D Simulated Clouds 00Hr Fcst, Valid 28 Mar 01/00Z01Hr Fcst, Valid 28 Mar 01/00Z

9. August 6, 2001Presented to MIT/LL Example: first forecast hour, 5-min frames

10. August 6, 2001Presented to MIT/LL First real-time implementation Real-time diabatically initialized MM5 runs since Fall 2000 –MM5v3-4 with minor modifications 125 x 105 x 34 domain, 10-km grid spacing K-F cumulus parameterization Schultz explicit microphysics –Four 24-h forecasts per day with hourly output –Displayed on AWIPS (FSL and BOU NWS) and WWW http://laps.fsl.noaa.gov/cgi/laps_fcst_products.cgi –Typically available 1.5 h after cycle time

11. August 6, 2001Presented to MIT/LL Quantitative Assessment Comparison of parallel model runs using three kinds of initialization (hot, warm, cold); otherwise identical Objective verification of model performance using hot start vs. other initialization methods –Approximately 40 forecast cycles during Jan 2001 –Gridded comparisons using LAPS analysis as truth –Computed various threat scores, RMSE, etc.

12. Model Initialization Comparisons Time-n Time MM5 Forecast LAPS Analyses MM5 NudgingMM5 Forecast Eta Eta LBC for all runs Dynamically balanced, Cloud-consistent LAPS LAPS II Cold start Warm start Hot start no LAPS analysis; interpolate from larger-scale model pre-forecast nudging to a series of LAPS analyses; sometimes called dynamic initialization diabatic initialization using the balanced LAPS analysis

13. Results of Initialization Comparisons

14. Results of Initialization Comparison

15. August 6, 2001Presented to MIT/LL Summary of first results Software is very reliable Hot start works well for winter precipitation systems –Several forecast-hours of added value What about summertime? –Verification not complete –Encouraging cases –Some known problems…

16. August 6, 2001Presented to MIT/LL Example – 21 June 2001/0600 UTC Run GOES IR+NOWRAD, Valid 21/0600 UTC MM5 00 hr Forecast, Valid 21/0600 UTC

17. August 6, 2001Presented to MIT/LL Example – 21 June 2001/0600 UTC Run GOES IR+NOWRAD, Valid 21/0700 UTC MM5 01 hr Forecast, Valid 21/0700 UTC

18. August 6, 2001Presented to MIT/LL Example – 21 June 2001/0600 UTC Run GOES IR+NOWRAD, Valid 21/0800 UTC MM5 02 hr Forecast, Valid 21/0800 UTC

19. August 6, 2001Presented to MIT/LL Example – 21 June 2001/0600 UTC Run GOES IR+NOWRAD, Valid 21/0900 UTC MM5 03 hr Forecast, Valid 21/0900 UTC

20. August 6, 2001Presented to MIT/LL Example – 21 June 2001/0600 UTC Run GOES IR+NOWRAD, Valid 21/1000 UTC MM5 04 hr Forecast, Valid 21/1000 UTC

21. August 6, 2001Presented to MIT/LL Example – 21 June 2001/0600 UTC Run GOES IR+NOWRAD, Valid 21/1100 UTC MM5 05 hr Forecast, Valid 21/1100 UTC

22. August 6, 2001Presented to MIT/LL Convection -- the next problem 10-km grid is too coarse except for biggest storms –too fine for conventional convective parameterizations –storms start late, produce excessive precip subgrid-size cumuli alias to resolvable scale 4 km? 3 km? –Improvements will come, QPF bias will persist Parameterization for subgrid cumuli probably required down to 250 m –Real life: get a computer, configure the model, solve problems as they arise

23. August 6, 2001Presented to MIT/LL Issues for Current and Future Work Consistency of LAPS vs. forecast model microphysics –Fractional cloudiness –Number, types, and definitions of species Thermodynamic constraint for balance equations Improvements to cloud analysis –Improved use of satellite (brightness temperatures) –Enhance use of WSR-88D data –Improve diagnostic of cloud vertical velocities Testing of new variational moisture analysis –incorporate GPS data Test with other models, including WRF

24. August 6, 2001Presented to MIT/LL Related Presentations at NWP conference Dynamic Balance –WAF/NWP P1.11, McGinley and Smart Cloud Analysis –WAF/NWP JP2.5A, Schultz and Albers Operational Evaluation/Case Studies –WAF/NWP 3.9, Shaw et al. –WAF/NWP P2.3, Birkenheuer et al. –MP P4.21, Szoke and Shaw Available in pdf format from laps.fsl.noaa.gov