Dynamic Ensemble Model Evaluation of Elevated Thunderstorms sampled by PRECIP

Transcription

1 Dynamic Ensemble Model Evaluation of Elevated Thunderstorms sampled by PRECIP Joshua S. Kastman, Patrick S. Market, and Neil Fox, University of Missouri, Columbia, MO Session 8B - Numerical Weather Prediction NWA 2016 Annual Conference Norfolk, VA

2 Acknowledgments National Science Foundation Special Thanks to Mike Bodner from WPC for his collaboration Special Thanks to Dr. Scott Rochette of SUNY Brockport Special Thanks to my wife Anna for putting up with some strange hours and sudden departures

3 PRECIP This project is part of the PRECIP study at the University of Missouri What is PRECIP?

4 Problem to be Solved Operational models consistently advance lower tropospheric boundaries too rapidly poleward Boundaries are often observed to stall As a result QPF and QPE do not match up Typically models under-forecast the local maximums as they disperse the available moisture and lift over a larger area as the front progresses What causes the boundaries to stall?

5 Problem to be Solved Elevated convection north of boundaries Models under-develop cold pools Thus under-develop gust fronts Boundary collision seems key Disrupts low-level flow & locks boundary in place Enhances frontogenesis

6 How to Address the Problem? Reanalysis Ensemble Model Dynamic not perturbation nor time lagged Ensemble mean not expected to perform well Is there individual members that do perform well forecasting heavy rain (> 50.8 mm?) Is there a microphysics family that performs best across the board while mixing other variables? What About Planetary Boundary Layer (PBL) parameterizations What explicit convection vs. high resolutions parameterizations Grell 3D

7 Background Ensemble work using mixed dynamics have been done recently Though not explicitly looking at elevated convection Schumacher and Clark, 2014 Ensemble prediction of heavy-rain-producing mesoscale convective systems 36 member ensemble Schumacher et al., 2013 Spread in initial conditions shows up after a about a day (perturbation ensembles) Tapiador and Coauthors, members Mixed single physic perturbation members with dynamic (multiple physics) ensemble Clark et al., members 10 explicit convection; 30 cumulus parameterization

8 Ensemble Model Weather Research and Forecasting High Resolution Heavy Precipitation Ensemble forecasting System (WRF-HRHPEFS) Advanced Research WRF (ARW) core 48 individual members Varied microphysics, cumulus parametrization, boundary layer physics and moisture advection RAP initial fields for lateral boundary & initial conditions 9 km grid spacing (outer) & 3 km (nest) Centered on the area of heaviest observed precipitation

9 WRF-HRHPEFS details 6 Microphysics: Lin, Ferrier, WSM 6, Thompson, Morrison, WDM 6 Explicit Convection & Parameterized (Grell-3d scheme) Boundary layer physics Yonsei University Scheme(YUS), Mellor-Yamada-Janic (MYJ), Mellor-Yamada Kanishi Niino (MYNN3) Local vertical mixing (MYJ & MYNN3) and non-local vertical mixings scheme (YUS) Moisture advection Positive definite, WENO WENO only for double moment schemes Member Name IC Micropyhsics PBL Scheme Cumulus Physics LYE RAP Lin YUS Explicit PD LYG RAP Lin YUS Grell 3D PD LME RAP Lin MYJ Explicit PD LMG RAP Lin MYJ Grell PD LNE RAP Lin MYN Explicit PD LNG RAP Lin MYN Grell PD Advection Scheme

10 WRF-HRHPEFS details Member Name IC Micropyhsics PBL Scheme Cumulus Physics Advection Scheme LYE RAP Lin YUS Explicit PD LYG RAP Lin YUS Grell 3D PD LME RAP Lin MYJ Explicit PD LMG RAP Lin MYJ Grell 3D PD LNE RAP Lin MYNN3 Explicit PD LNG RAP Lin MYNN3 Grell 3D PD

11 WPC Mesoscale Forecast and Observed Rainfall: 5 June 2016 WPC QPF Observed QPE

12 Case Study 24 hr GFS forecast valid: 0000 UTC 950-mb Temperature ( C) RAP Initial Field Valid: 0000 UTC 950-mb Temperature ( C) Notice the difference location and strength of the cold pools

13 Case Study 0000 UTC Equivalent Potential Temperature GFS (24 hr frcst) BLUE RAP (initial field) - Magenta 0600 UTC Equivalent Potential Temperature GFS (30 hr frcst) BLUE RAP (initial field) - Magenta

14 MET & MODE Analysis Verification Via: Model Evaluation Tools (MET) verification package MET Grid Stats and Neighborhood Stats calculated Method for Object-Based Diagnostic Evaluation(MODE)

15 Model Findings Best Microphysics Family: WSM6 8 Families each with 6 members WENO Scheme (Morrison WDM6) families performed near the bottom in all categories Best PBL Family: MYJ 3 Options (YSU, MYJ, MYNN3) each with 16 members Best Cumulus Option: Grell 3D Grell 3D or Explicit each with 24 members Best Individual Member: WSMG WSM6 Microphysics Mellor-Yamada-Janjic PLB Parameterization Parameterized (Grell 3-D Scheme) Convection

16 MODE: WSMG Forecast WSMG 50.8 mm Forecast QPF WSMG 50.8 mm (2 in) Area (shaded)

17 MODE: NCEP Stage IV QPE NCEP Stage IV 50.8 mm (2 in) QPE NCEP Stage IV 50.8 mm (2 in) Area (shaded)

18 MODE: WSMG Forecast (Shaded) & NCEP Stage IV QPE (Outlined)

19 MODE: Cluster Object Information

20 MET & MODE Best, Median, Worst Results: Forecast (Shaded) & NCEP Stage IV QPE (Outlined) Best: WSMG Median: MNG Worst. MNEW

21 Thoughts & Conclusions Operational models consistently advance lower tropospheric boundaries too rapidly poleward during instances of elevated convection Poor handling of convective generated cold pools 48 Member Ensemble Initial Results: WSM6 with Grell 3D cumulus and MYJ PBL parameterizations performed best WENO runs performed very poorly.

22 References Clark, A. J., W. A. Gallus, M. Xue, and F. Kong, 2010: Convection-Allowing and Convection-Parameterizing Ensemble Forecasts of a Mesoscale Convective Vortex and Associated Severe Weather Environment. Weather and Forecasting, 25, Schumacher, R. S., and A. J. Clark, 2014: Evaluation of Ensemble Configurations for the Analysis and Prediction of Heavy-Rain-Producing Mesoscale Convective Systems*. Monthly Weather Review, 142, Schumacher, R. S., A. J. Clark, M. Xue, and F. Kong, 2013: Factors Influencing the Development and Maintenance of Nocturnal Heavy- Rain-Producing Convective Systems in a Storm-Scale Ensemble. Monthly Weather Review, 141, Tapiador, F. J., and Coauthors, 2012: A Comparison of Perturbed Initial Conditions and Multiphysics Ensembles in a Severe Weather Episode in Spain. Journal of Applied Meteorology and Climatology, 51,

23 Thank You! Questions