1. A CASE STUDY OF THE GREAT PLAINS BLIZZARD OF 27-28 NOVEMBER 2005 P. S. Market, C. J. Melick, B. P. Pettegrew, A. E. Becker, and L. L. Smith Department of Soil, Environmental and Atmospheric Sciences University of Missouri-Columbia Presented at the Winter Weather Workshop National Weather Service Office, Pleasant Hill, MO 29 October 2007

2. With the aid of… John Stoppkotte, SOO North Platte, Nebraska, NWS UMC students enrolled in ATMS-4720, Synoptic Meteorology II The National Science Foundation

3. Introduction Analysis of occluded cyclone –Well-developed trowal structure Multiple bands of precipitation Blizzard conditions for an extended period in LBF CWA Lightning activity present but limited gusts (mph) snow (in.) Courtesy, NOAA/NWS LBF

4. Purpose Assess the nature of the unique trowal structure –Influence on banded precip? Assess lightning observations –Are they valid? Assess the production of extreme winds gusts (mph) snow (in.) Courtesy, NOAA/NWS LBF

5. - Synopsis -

6. 12Z 2005 Nov 28

8. 12Z 2005 Nov 28 – 925 mb

9. 12Z 2005 Nov 28 – 850 mb

10. 12Z 2005 Nov 28 – 700 mb

11. 12Z 2005 Nov 28 – 500 mb

12. 12Z 2005 Nov 28 – 300 mb

13. 12Z 2005 Nov 28 – RADAR

14. Storm total snow (in.), 27-30 Nov 2005

15. - Event Specifics -

16. 2005 Nov 28 – Surface Obs KAUH 1310Z +SN LTG DSNT SW –With NLDN flash near this time KVTN 1622Z, 1652Z, 2008Z, 2032Z, 2052Z, 2109Z TSSN –KAUH – Aurora, NE –KVTN – Valentine, NE

17. 2005 Nov 28 – NE Sfc Stations

18. 2005 Nov 28 – 1300Z Initial development of lightning and thunder Reported in Aurora, NE, METAR Corroborated by NLDN

19. 2005 Nov 28 – 13Z RUC20 – AUH Sounding

20. 2005 Nov 28 – 2100Z Redevelopment of lightning and thunder Emergence of trowal feature –And a unique double trowal signature Evolution of meso-  circulations Significant banded precipitation underway

21. 2005 Nov 28 – 19Z RUC20 –VTN Sounding

22. 2005 Nov 28 – 21Z VIS Sat

23. 2005 Nov 28 – 21Z IR Sat

24. 2005 Nov 28 – 21Z WV Sat

25. 2005 Nov 28 – 21Z Sounder CTP

26. 2005 Nov 28 – 21Z RADAR

27. 2005 Nov 28 – IR Loop 13Z-23Z

28. 2005 Nov 28 – RADAR Loop 18Z-23Z

29. - Trowal Structure -

30. Various Model Solutions for trowal 21Z Nov 28 2005 – 308 K  e

31. Cross Section through Double trowal 2100V009 Nov 28 2005 – NAM 212 Trowal Surface

32. Cross Section through Double trowal 21Z Nov 28 2005 – NAM 212 Grid Cross Section

33. WRF 12-km Solutions Valid 21Z Nov 28 2005 – 21 hr Solutions Reflectivity (Shaded & contoured)

34. WRF 12-km Solutions Valid 21Z Nov 28 2005 – 21 hr Solutions Reflectivity (shaded) with θ e

35. WRF 12-km Solutions Valid 21Z Nov 28 2005 – 21 hr Solutions θ e - Full Physics (green) / No microphysics (brown)

36. WRF 12-km Solutions Valid 21Z Nov 28 2005 – 21 hr Solutions θ e (white contours)

37. WRF 12-km Solutions Valid 21Z Nov 28 2005 – 21 hr Solutions Reflectivity with ω

38. Conclusions AUH - 13Z - One NLDN CG flash establishes a history of electrical activity VTN - 16Z, 20Z, 21Z – METARS report TSSN based upon surface sensor –Valid, to the best of our knowledge Also, soundings support existence of lightning

39. Conclusions Existence of double trowal appears valid –Reason(s) for creation of the structure are unclear –Structure seems to have some bearing on banded precipitation development and/or evolution The trowal aspect of this cyclone warrants further study

40. Thank you! Questions? Comments? marketp@missouri.edu ROCS Homepage : http://weather.missouri.edu/ROCS/http://weather.missouri.edu/ROCS/