1 / 29

Performance of the Experimental 4.5 km WRF-NMM Model During Recent Severe Weather Outbreaks

Performance of the Experimental 4.5 km WRF-NMM Model During Recent Severe Weather Outbreaks. Steven Weiss, John Kain, David Bright, Matthew Pyle, Zavisa Janjic and Brad Ferrier. Why Examine High Res. WRF Models?.

kyran
Télécharger la présentation

Performance of the Experimental 4.5 km WRF-NMM Model During Recent Severe Weather Outbreaks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Performance of the Experimental 4.5 km WRF-NMM Model During Recent Severe Weather Outbreaks Steven Weiss, John Kain, David Bright, Matthew Pyle, Zavisa Janjic and Brad Ferrier

  2. Why Examine High Res. WRF Models? • Severe weather types (tornadoes, hail, wind damage) can be closely related to convective mode • Tornadoes (discrete supercells) • Damaging wind (bow echoes and QLCSs) • SPC working to increase lead time of watches and provide probabilistic information about tornado, hail, and wind threats in Day 1 Severe Weather Outlooks • Accurate forecasts require knowledge about “where” and “when” storms will develop and how they will evolve • There is a need to better predict convective mode and character of storms(stormscale details) • Environmental clues (CAPE/shear, etc.) may not be sufficient • Operational mesoscale models often lack smaller scale details

  3. NOAA Hazardous Weather TestbedSPC/NSSL Spring Programs • Spring Programs in 2004 and 2005 examined various configurations of convection-allowing WRF models • Partnerships with EMC, OU-CAPS, and NCAR • Can high resolution WRF provide useful guidance for severe forecasting? • Since April 2004, EMC has been running an experimental 4.5 km version of the WRF-NMM once daily • 36 hour forecasts from 00 UTC start • Very large domain (eastern three-fourths of CONUS)

  4. High Res. WRF-NMM Configuration (No Parameterized Convection) ( see http://wwwt.emc.ncep.noaa.gov/mmb/mmbpll/cent4km/v2/)

  5. Simulated Reflectivity in WRF Output • Simulated Reflectivity • Computed from model predicted grid-resolved hydrometeor fields • Highly dependent on model physics (especially microphysics) • Appealing to forecasters because it closely resembles radar images of precipitation systems • Allows identification of mesoscale and stormscale structures • Easier to subjectively verify model forecasts by comparing directly with observed radar images

  6. Simulated Reflectivity in WRF Output • High res WRF reflectivity can provide mesoscale and near stormscale details not seen in traditional output 21 hour forecasts valid 21 UTC 15 Nov 2005 NAM-WRF 3h Pcpn 4.5 km WRF-NMM Reflectivity

  7. Simulated Reflectivity in WRF Output • Model resolution impacts structural detail, intensity, and realism of simulated reflectivity forecasts 21 hour forecasts 1 km AGL reflectivity valid 21 UTC 20 May 2006 12 km NAM-WRF 4.5 km WRF-NMM

  8. Recent Significant Tornado Days

  9. 4.5 km WRF-NMM and Radar31 hr WRF forecast valid 07z 6 Nov 2005 F3 tornado 0759z 25 fatalities WRF-NMM 1 km AGL Reflectivity Radar

  10. 4.5 km WRF-NMM and Radar21 hr WRF forecast valid 21z 15 Nov 2005 F3 tornado 2030z 1 fatality WRF-NMM 1km AGL Reflectivity Radar

  11. 4.5 km WRF-NMM and Radar24hr WRF forecast valid 00z 28 Nov 2005 F3 Tornado 0015z 1 Fatality WRF-NMM 1km AGL Reflectivity Radar

  12. 4.5 km WRF-NMM and Radar27hr WRF forecast valid 03z 12 Mar 2006 F3 Tornado 0310z 4 Fatalities WRF-NMM 1km AGL Reflectivity Radar

  13. 4.5 km WRF-NMM and Radar27hr WRF forecast valid 03z 12 Mar 2006 F3 Tornado 0310z 4 Fatalities WRF-NMM 1km AGL Reflectivity Radar

  14. 4.5 km WRF-NMM and Radar25hr WRF forecast valid 01z 3 Apr 2006 2 F3 Tornadoes 0056 and 0143z 22 Fatalities WRF-NMM 1km AGL Reflectivity Radar

  15. 4.5 km WRF-NMM and Radar18hr WRF forecast valid 18z 7 Apr 2006 WRF-NMM 1km AGL Reflectivity Radar

  16. 4.5 km WRF-NMM and Radar19hr WRF forecast valid 19z 7 Apr 2006 F3 Tornado 1927z 8 Fatalities WRF-NMM 1km AGL Reflectivity Radar

  17. 4.5 km WRF-NMM and Radar20hr WRF forecast valid 20z 7 Apr 2006 WRF-NMM 1km AGL Reflectivity Radar

  18. 4.5 km WRF-NMM and Radar21hr WRF forecast valid 21z 7 Apr 2006 WRF-NMM 1km AGL Reflectivity Radar

  19. 4.5 km WRF-NMM and Radar22hr WRF forecast valid 22z 7 Apr 2006 WRF-NMM 1km AGL Reflectivity Radar

  20. 4.5 km WRF-NMM and Radar23hr WRF forecast valid 23z 7 Apr 2006 WRF-NMM 1km AGL Reflectivity Radar

  21. 4.5 km WRF-NMM and Radar24hr WRF forecast valid 00z 8 Apr 2006 WRF-NMM 1km AGL Reflectivity Radar

  22. 4.5 km WRF-NMM Summary • On many days the 4.5 km WRF-NMM exhibits credible mesoscale prediction skill of convective systems • Especially during strongly forced situations • Current 4.5 km grid length permits “approximation” of stormscale structures • Convective mode details often very helpful • Discrete cells, quasi-linear and multicell systems • But resolution is too coarse to simulate realistic updrafts • “Large” model updrafts are slower to develop • Not uncommon for model storms to develop 1-2 hours late • Key forecaster challenge • Hi Res WRF-NMM forecasts often appear plausible • How do we know when to believe the stormscale details and when to discount them? • Suggests role for high resolution ensembles

More Related