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Recent Storm Interrogation Developments at the National Weather Service

Recent Storm Interrogation Developments at the National Weather Service. Charlie Woodrum Meteorologist Weather Forecast Office Pittsburgh, PA. Florida State University- September 23, 2010. My Background. 2009-. 2008-2009. 1985-2004. 2004-2008. Overview. Recent Operational Advances

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Recent Storm Interrogation Developments at the National Weather Service

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  1. Recent Storm Interrogation Developments at the National Weather Service Charlie Woodrum Meteorologist Weather Forecast Office Pittsburgh, PA Florida State University- September 23, 2010

  2. My Background 2009- 2008-2009 1985-2004 2004-2008

  3. Overview • Recent Operational Advances • Super Resolution • Terminal Doppler Weather Radar (TDWR) • Four-dimensional Stormcell Investigator (FSI) • GR Level2 Analyst • Pop-Up Skew T • Google Earth • Total Lightning Mapping • Environmental Data • Temperature Planes and Convective Hail Research • Future Radar Interrogation Methods • Dual-Polarimetric Radar (Dual-Pol) • Multi-Function Phased Array Radar (MPAR)

  4. Radar Storm Interrogation • Increased situational awareness • 3 computer screens • 5 panes • 4 panels • Leads to short-fused warning decisions June 2, 2009- 0.5 base reflectivity animation of the Amanda tornado in Fairfield County, OH

  5. Convective Radar Scanning Strategies VCP- Volume Coverage Pattern

  6. Convective Radar Scanning Strategies VCP- Volume Coverage Pattern

  7. Why dBZ heights? • Reflectivity above freezing level • Heights above freezing level (-10°C, -20°C, -30°C, etc.) • Correlation 50+ dBZ level with -20°C • Increasing reflectivity aloft can increase confidence in severity FSI display window

  8. All-Tilts Analysis • Volumetric Analysis • Interrogate the storm vertically • User controlled • Higher DBZs aloft • Convergence • Divergence

  9. Four-Panel Analysis 0.9 degree storm relative (SRM) velocity and reflectivity (top); 3.1 degree storm relative (SRM) velocity and reflectivity (bottom)

  10. Super Resolution • Finer detail in base products • Azimuth/range resolution • Increased resolution in lowest 2-3 angles in each Volume Coverage Pattern • Higher data values revealed Legacy reflectivity (top); Super resolution reflectivity (bottom)

  11. Biggest Differences Legacy Super Res • 0.25 km refl. range • 0.5 degree azimuth • 248 nm display range (reflectivity) • 162 nm display range (velocity/spec width) • Not available online • 1 km refl. range • 1 degree azimuth • 248 nm display range (reflectivity) • 124 nm display range (velocity/spec width) • Data Online

  12. Hook Echo

  13. Terminal Doppler Weather Radar (TDWR) • Designed by FAA • NWS Deployment April-September 2008 • 1 minute base product updates at the lowest elevation • High resolution for nearby features

  14. Biggest Differences TDWR WSR-88D • C band • 1 minute data • Lowest Elevation Angle- 0.1/0.3 • Resolution 0.15km range by 0.55 degree azimuth out to 48nm • S band • 4.5 minute data • Lowest Elevation Angle- 0.5 • Super-Resolution 0.25km range by 0.5 degree azimuth

  15. TDWR in Action TCVG Z/SRM at 2122Z (top);KILN Z/SRM at 2122Z (bottom)

  16. Four-Dimensional Stormcell Investigator (FSI) • Different perspective for looking at radar data • New Dimension • Longer period for analysis (2 hours) • Very resource intensive • Three dimensional pan and zoom functions

  17. Constant Altitude Plan Position Indicator (CAPPI) Plan Position Indicator (PPI) Vertical Dynamic Cross-Section (VDX) Three Dimension Flyer (3DF)

  18. GRLevel2 Analyst • Advanced NEXRAD Level II analysis application. • High quality volumetric display • High resolution reflectivity • Derived graphical products

  19. Volume Explorer

  20. Custom Volume Alpha Preset - 1 40 dBz (yellow) and 50 dBz (red) • Good for evaluating storm structure • Height of 50 dBz • But…no view of inner core

  21. Custom Volume Alpha Preset - 2 50 dBz (red) and 60 dBz (white) • Can view storm structure…and the inner core • Height of 50 dBz… and hail core (60 dBz) • Volume and height of hail core

  22. Custom Volume Alpha Preset – 3 60 dBz (white) • Volume and height of the hail core

  23. Pop-Up Skew T • Real-time with all-tilts • Utilized model data • Helps forecasters projects areas of development • Serves as a reference for a given reflectivity’s position on a sounding

  24. Initial Sampling Point

  25. Final Sampling Point

  26. Google Earth NSSL Products • Verification • Post-storm analysis • Storm survey application http://ondemand.nssl.noaa.gov/

  27. Maximum Estimate Size of Hail (MESH) June 2, 2009

  28. Rotational Tracks March 27, 2009

  29. Did You Know? • In just over 3 years, 20 Florida State University graduates have been hired into the National Weather Service.

  30. Credit: Geoffrey Stano

  31. Credit: Geoffrey Stano

  32. Credit: Geoffrey Stano

  33. Environmental Data

  34. Severe Hail Criteria Change • NWS HQ changed the severe hail criteria from 0.75” (penny) to 1.00” (quarter) on January 4, 2010 • Most studies over past decade for the region are based on 0.75” • Latest research indicates that significant damage (aside from crops) does not occur until hail size reaches 1 inch • False Alarm Rate (FAR) may be impacted (at least initially) • New criteria will reduce severe thunderstorm warnings • New thresholds and techniques are needed to accurately warn for the new 1” hail criteria

  35. From Salem et al.

  36. It’s not always about the height (AGL) of the reflectivity! • Environments Vary • Winter Event vs. Summer Event • Late Spring/Summer events often dictate • BUT, every day is different! • Z-R Relationships can Vary • Tropical vs. Non-Tropical (Summer Deep Convection) • Reflectivity depends on Drop Size Distribution • Big impacts on radar reflectivity and strength thresholds • How can we solve this problem?

  37. It’s not always about the height (AGL) of the reflectivity! • Environments Vary • Winter Event vs. Summer Event • Late Spring/Summer events often dictate • BUT, every day is different! • Z-R Relationships can Vary • Tropical vs. Non-Tropical (Summer Deep Convection) • Reflectivity depends on Drop Size Distribution • Big impacts on radar reflectivity and strength thresholds • How can we solve this problem? • TEMPERATURE PLANES!

  38. Temperature Planes • Interrogate radar on a constant temperature surface • Freezing Level • Hail Growth Zone (-10C to -30C) • Eliminates need for 0C and -20C heights • New height and intensity thresholds?

  39. My Research Temperature Plane Interrogation RUC236 Data 0C, -5C, -10C, -12C, -14C, -16C, -18C, -20C, -25C, -30C 23 ILN storms analyzed thus far… 12 producing 1.00” hail with initial LSR 11 producing 0.75”-1.00” hail with initial LSR Analysis Technique Begins 3-4 frames prior to initial warning/LSR Continues through largest hail LSR Ends 3 frames after largest hail LSR

  40. >3/4” Hail Producing Storms

  41. >3/4” Hail Initial Findings Temperature Plane Interrogation -10C to -30C layers generally decrease or remain steady 10 minutes prior to warnings being issued 0C and -5C layers increase or remain steady Possible Loose Threshold Guidance? 63-64 dBZ core (0C to -12C layer) 61-63 dBZ core (-12C to -20C layer) 64-65 dBZ core (0C to -12C layer) 60-63 dBZ core (-12C to -20C layer) 64-65 dBZ core (0C to -5C layer) 61-62 dBZ core (-5C to -14C layer) Potentially 10 minutes more lead-time Potentially 5 minutes more lead-time Warning issued OR missed event LSR

  42. 0.75”-1” Hail Producing Storms

  43. 0.75-1.00” Hail Initial Findings Temperature Plane Interrogation -10C to -30C layers generally decreased 10 minutes prior to warnings being issued 0C and -5C layers increased or remained steady Possible Loose Threshold Guidance? 64-65 dBZ core (0C to -14C layer) 62-63 dBZ core (-14C to -20C layer) 64-65 dBZ core (0C to -10C layer) 61-63 dBZ core (-10C to -16C layer) 64-66 dBZ core (0C to -5C layer) 61-63 dBZ core (-5C to -16C layer) Potentially 10 minutes more lead-time Potentially 5 minutes more lead-time Warning issued OR missed event LSR

  44. >1” Hail Producing Storms

  45. >1” Hail Initial Findings Temperature Plane Interrogation -16C to -30C layers generally decreased 10 minutes prior to warnings being issued 0C and -14C layers increased up to 5 minutes prior to warnings being issued before Higher reflectivity in -20C to -30C layer Possible Loose Threshold Guidance? 62-64 dBZ core (0C to -16C layer) 59-62 dBZ core (-16C to -25C layer) 63-66 dBZ core (0C to -14C layer) 58-63 dBZ core (-14C to -25C layer) 64-65 dBZ core (0C to -5C layer) 60-62 dBZ core (-5C to -14C layer) Potentially 10 minutes more lead-time Potentially 5 minutes more lead-time Warning issued OR missed event LSR

  46. Moving Forward Continued Data Collection More ILN/PBZ storms needed (March 22, 2010 event) Student volunteer help collecting data Further Analysis Varying environments (instability, shear) Rotating vs. Non-rotating storms Long-tracked super cell analysis (June 2, 2009)

  47. The not too distant future…. …Dual-Pol

  48. Dual-Polarization Medium term Dual-pol to provide significant benefits in regards to 1” hail criteria change Polarimetric radars transmit and receive both horizontal and vertical polarization radio wave pulses. Improved radar estimation of precipitation type and rate Able to detect hailstones rather than infer their presence based on current WSR-88D limitations

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