1. Warm-Season Lake-/Sea-Breeze Severe Weather in the Northeast Patrick H. Wilson, Lance F. Bosart, and Daniel Keyser Department of Earth and Atmospheric Sciences, University at Albany, Albany, NY Thomas A. Wasula NOAA / National Weather Service, Albany, NY CSTAR II Grant NA04NWS4680005 Northeast Regional Operational Workshop VIII Presentation 2 November 2006

2. Research Goals  Investigate thermodynamical and dynamical processes along with physiographic effects  Increase understanding of this phenomenon

3. Methodology – Part I  Warm-Season: April – October  Domain: OH, PA, MD, DE, NJ, NY, VT, NH, MA, CT, RI, ME  Selected cases from Storm Prediction Center archived storm data 2000-present  Verified from National Climatic Diagnostic Center archived radar data

4. Methodology – Part II  Obtained NCEP/NARR gridded datasets for each case and plot important weather variables  Collected soundings, radar data, and surface observations  Classified cases into separate categories and conducted case study analyses

5. Case Classifications  Pure Case: mesoscale forcing primary; synoptic-scale forcing secondary  Mixed Case: mesoscale forcing and synoptic- scale forcing working together  Null Case: convection suppressed by lake-/sea-breeze processes

6. Case List  Pure Cases 9 August 2001 (Ontario) 6 July 2003 (Erie) 7 August 2005 (Chesapeake) 2 August 2006 (Ontario)  Mixed Cases 9 April 2001 (Erie) 19 June 2002 (Atlantic) 24 July 2003 (Erie and Ontario) 1 August 2005 (Huron and Ontario) 24 April 2006 (Chesapeake)  Null Case 11 July 2006 (Atlantic)

7. 1200 UTC 9 August 2001 (Pure Case) 30 35 40 45 50 55 60 65 70

8. 1200 UTC 9 August 2001 14 18 22 26 30 34 38 42 46

9. 1200 UTC 9 August 2001

10. 1200 UTC 9 August 2001 http://weather.uwyo.edu/upperair/sounding.html Note: Parcel taken from lowest 500 m to determine CAPE

11. 1500 UTC 9 August 2001 -14 -12 -10 -8 -6 -4 -2 0

12. 1800 UTC 9 August 2001 340 345 350 355 360 365 370 375 380

13. 1800 UTC 9 August 2001 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0

14. 1700 UTC 9 August 2001

15. 1700 UTC 9 August 2001 Radar Composite 70 60 50 40 30 20 10

16. 1800 UTC 9 August 2001 Radar Composite 70 60 50 40 30 20 10

17. 1900 UTC 9 August 2001 Radar Composite 70 60 50 40 30 20 10

18. 2000 UTC 9 August 2001 Radar Composite 70 60 50 40 30 20 10

19. 2100 UTC 9 August 2001 Radar Composite 70 60 50 40 30 20 10

20. 2200 UTC 9 August 2001 Radar Composite 70 60 50 40 30 20 10

21. 2300 UTC 9 August 2001 Radar Composite 70 60 50 40 30 20 10

22. 0000 UTC 10 August 2001 Radar Composite 70 60 50 40 30 20 10

23. 0100 UTC 10 August 2001 Radar Composite 70 60 50 40 30 20 10

24. 0200 UTC 10 August 2001 Radar Composite 70 60 50 40 30 20 10

25. 9 August 2001 Storm Reports

26. Pure Cases: Preliminary Conclusions  Ridge axis in place at the surface or aloft  Low unidirectional wind shear in low-levels (< 10 m s -1 for 925-700 hPa layer)  T > 30 ° C, T d > 20 ° C, CAPE > 1500 J kg -1  Placement and timing signal by θ e -ridge axis (θ e > 335 K)  Intersections of boundaries enhance convection  Tendency to become squall lines and prefer valleys  Occur most often during hottest months of summer

27. 1200 UTC 19 June 2002 (Mixed Case) 30 35 40 45 50 55 60 65 70

28. 1200 UTC 19 June 2002 14 18 22 26 30 34 38 42 46

29. 1200 UTC 19 June 2002

30. 1200 UTC 19 June 2002 http://weather.uwyo.edu/upperair/sounding.html Note: Parcel taken from lowest 500 m to determine CAPE

31. 1500 UTC 19 June 2002 -14 -12 -10 -8 -6 -4 -2 0

32. 1800 UTC 19 June 2002 320 325 330 335 340 345 350 355 360

33. 1800 UTC 19 June 2002

34. 1800 UTC 19 June 2002 Radar Composite 70 60 50 40 30 20 10

35. 1900 UTC 19 June 2002 Radar Composite 70 60 50 40 30 20 10

36. 2000 UTC 19 June 2002 Radar Composite 70 60 50 40 30 20 10

37. 19 June 2002 Storm Reports

38. Mixed Cases: Preliminary Conclusions  Troughs generally in place at the surface or aloft  Typically more wind shear (speed shear and veering winds) in low levels  20 ° C 320 K  Cyclonic vorticity and cyclonic vorticity advection important  Intersection of boundaries enhance convection  Occur most often during late spring and early autumn

39. 1800 UTC 11 July 2006 (Null Case) 330 335 340 345 350 355 360 365 370

40. 1800 UTC 11 July 2006

41. 1800 UTC 11 July 2006 Radar Composite 70 60 50 40 30 20 10

42. 11 July 2006 Storm Reports Lake and sea breezes can suppress convection.

43. 1800 UTC 6 July 2003 MODIS Satellite http://rapidfire.sci.gsfc.nasa.gov/realtime/ Questions?