1. Cold Season 500 hPa Cutoff Cyclone Precipitation Distribution and a Case Study Tony Fracasso Department of Earth and Atmospheric Sciences University at Albany, State University of New York Advisors: Lance Bosart and Dan Keyser NWS Focal Point: Mike Evans (Binghamton, NY)

2. Project Objectives a)Stratify precip. distribution relative to cutoff cyclone tracks as identified in composites developed by B. Smith (2003) b)Map/understand cutoff cyclone precipitation characteristics in composites c)Document mesoscale precipitation signatures in case studies representative of each of the composites

3. Project Objectives, cont. d)Document contribution of upright and slantwise ascent to precipitation in case studies representative of each of the composites e)Revisit D. Novak (2002) findings on bands/frontogenesis through selected case studies

4. Cool season composite mean cutoff cyclone tracks B. Smith (2003)

5. Progress to date Monthly composites of precipitation where a 500 hPa low was present Graphical and textual record of cool season (October – May) 500 hPa cutoff low tracks (1980-1998) –Both sets of tracks are in agreement

6. Outer Domain

7. in./day mm/day NOV MAYMAR JAN

8. 1980-1998

10. Progress to Date: Case Studies Detailed first pass on 23-30 May 2003 cutoff Preliminary information on other case studies –Christmas snowstorm (25-26 Dec. 2002) –3-4 January 2003 snowstorm –7 February 2003 snowband near Boston –Presidents’ Day snowstorm (16-17 Feb. 2003) –10-14 May 2003 cutoff

11. Current Work Categorizing cutoffs by individual track –Ex: 11 “Mid-Atlantic Track” cutoffs during Octobers 1980-1998 (total of 25 days) Use simple composite and storm-relative compositing methods Build a user-friendly database of cutoffs (1980-1998)

12. in./day mm/day

13. in./day mm/day

14. All tracks Octobers 1948-1998 Mid-Atlantic tracks Octobers 1980-1998

15. Maximum surface report: 13.19 in. (335.0 mm) at Greenland, NH (Rockingham County) 19 23 22 21 20

16. Accumulated Precipitation (cm) (24 – 29 May 2003) Dates are 12Z locations

17. 00Z 24 May 2003 – 500 hPa Heights (dam) and Abs. Vorticity (x10 -5 s -1 )

18. 12Z 24 May 2003

19. 00Z 25 May 2003

20. 12Z 25 May 2003

21. 00Z 26 May 2003

22. 12Z 26 May 2003

23. 00Z 27 May 2003

24. 12Z 27 May 2003

25. 12Z 26 12Z 27

27. 00Z 28 May 2003

28. 12Z 28 May 2003

29. 12Z 27 12Z 28

30. 00Z 29 May 2003

31. 12Z 29 May 2003

32. 12Z 28 12Z 29

33. U.S. Radar loop 00Z 23– 23Z 29 May 2003

34. Future Work Analyze precip. patterns between cutoffs of the same track Examine the other cases more closely (synoptic scale and mesoscale) Attempt to find a forecasting “heads-up” for cutoff precip.

35. Banding to beat the snow…