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 M.S. Thesis Seminar Presentation Department of Earth and Atmospheric Sciences, University at Albany, Albany, NY 1 July 2008

2. Background and Motivation  Sea breezes studied well before 20th century and accurately described thermodynamically: Wales (1914) and Clowes (1917) Images from http://weather.cod.edu/sirvatka/seabreeze.html (top)  Complexity of sea-breeze front due to its lobe-and-cleft structure not realized until recently: Galvin (2006) and Fig. 1 from Galvin (2006) (bottom)

3. Background and Motivation (continued)  Significant impact of prevailing synoptic-scale flow pattern on sea breeze evolution and intensity: Estoque (1962) Fig. 5 (left) and Fig. 9 (right) from Estoque (1962) 5 m s −1 offshore prevailing geostrophic wind5 m s −1 onshore prevailing geostrophic wind

4. Background and Motivation (continued)  Many examples of sea-breeze convection cases found in literature: Kingsmill (1995) in FL, Medlin and Croft (1998) in AL, Bennett et al. (2006) in Great Britain, etc.  Fewer cases in literature for Northeast exist: Moroz and Hewson (1966) from MI, Clodman and Chisholm (1994) and King et al. (2003) from Ontario, and Wolf (2004) in IL  Lots of research for Great Lakes during winter (lake-effect snow), but much less research during summer (lake-/sea- breeze severe convection)

5. Research Goals  Investigate influence of thermodynamic and dynamical processes, along with physiographic effects from complex Northeast topography, on lake-/sea-breeze severe weather  Increase awareness and understanding of lake- /sea-breeze severe convection

6. Methodology  Warm season: April–October  Domain area shown by map  Selected cases from search of SPC archived storm data, along with input from NWS meteorologists, for 2000–2006  Verified from NCDC archived radar data OH PA NY VTME MD DE NJ CT RI MA NH

7. Methodology (continued)  Obtained 32 km-resolution NCEP/NARR gridded datasets for all cases to perform synoptic-scale analyses  Acquired 20 km-resolution RUC gridded datasets for three cases to perform mesoscale analyses  Collected soundings, radar data, satellite images, water temperature data, and surface observations  Classified cases into separate categories and conducted case study analyses

8. Case Classifications  Pure Case: mesoscale forcing primary; synoptic-scale forcing secondary  Mixed Case: mesoscale forcing and synoptic- scale forcing of similar importance  Null Case: convection suppressed by lake-/sea-breeze processes

9. Case List Cases chosen for RUC analysis highlighted  Pure Cases 9 August 2001 (Ontario) 6 July 2003 (Erie) 7 August 2005 (Chesapeake) 2 August 2006 (Ontario)  Mixed Cases 19 April 2002 (Erie) 19 June 2002 (Atlantic) 24 July 2003 (Erie and Ontario) 1 August 2005 (Huron and Ontario) 30 June 2006 (Erie and Ontario) 23 July 2006 (Erie and Ontario)  Null Case 11 July 2006 (Atlantic)

10. Storm Formation Areas and Tracks: All Cases Legend Red: Storm Formation Areas Pink: Tornado Risk Area Green: Null Case Area Arrows: Storm Tracks

11. SPC Verification of Cases using Convective Outlook Reports for 2003–2006  Pure Cases (3) Slight Risk: 2, General Thunderstorms: 1  Mixed Cases (4) Slight Risk: 1, General Thunderstorms: 3  Null Case (1) Missed Null Area (Slight Risk)

12. Case Example  2 August 2006 (Ontario) Pure 1200 UTC 2 August 2006: 200 hPa NARR Analysis 2 4 6 8 10

13. 1200 UTC 2 August 2006: 500 hPa NARR Analysis 4 8 12 16 20 24 28 Pure

14. 1200 UTC 2 August 2006: Surface NARR Analysis Pure BUF

15. 1200 UTC 2 August 2006: Sounding http://weather.uwyo.edu/upperair/sounding.html Parcel taken from lowest 500 m to determine CAPE Pure

16. 1600 UTC 2 August 2006: 925 hPa RUC Analysis 340 345 350 355 360 Pure

17. 1600 UTC 2 August 2006: CAPE and 1000–700 hPa Wind Shear RUC Analysis 500 1000 1500 2000 2500 3000 3500 4000 Pure

18. 1700 UTC 2 August 2006: Surface Observations Pure

19. 1800 UTC 2 August 2006: NARR Cross-Section Analysis Pure −3.5 −3.0 −2.5 −2.0 −1.5 −1.0 −0.5 0.0

20. 1700 UTC 2 August 2006: Radar 70 60 50 40 30 20 10 Pure

21. 1800 UTC 2 August 2006: Radar 70 60 50 40 30 20 10 Pure

22. 1900 UTC 2 August 2006: Radar 70 60 50 40 30 20 10 Pure

23. 2000 UTC 2 August 2006: Radar 70 60 50 40 30 20 10 Pure

24. 2100 UTC 2 August 2006: Radar 70 60 50 40 30 20 10 Pure

25. 2200 UTC 2 August 2006: Radar 70 60 50 40 30 20 10 Pure

26. 2300 UTC 2 August 2006: Radar 70 60 50 40 30 20 10 Pure

27. 1702 UTC 2 August 2006: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Pure

28. 1825 UTC 2 August 2006: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Pure

29. 1902 UTC 2 August 2006: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Pure

30. 2002 UTC 2 August 2006: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Pure

31. 2125 UTC 2 August 2006: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Pure

32. 2202 UTC 2 August 2006: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Pure

33. 2302 UTC 2 August 2006: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Pure

34. 2 August 2006: SPC Storm Reports http://www.spc.ncep.noaa.gov/climo Pure 40 wind and 5 hail reports

35. Case Example  19 June 2002 (Atlantic) Mixed 1200 UTC 19 June 2002: 200 hPa NARR Analysis 2 4 6 8 10

36. 1200 UTC 19 June 2002: 500 hPa NARR Analysis Mixed 4 8 12 16 20 24 28

37. 1200 UTC 19 June 2002: Surface NARR Analysis Mixed WAL

38. 1200 UTC 19 June 2002: Sounding http://weather.uwyo.edu/upperair/sounding.html Parcel taken from lowest 500 m to determine CAPE Mixed

39. 1800 UTC 19 June 2002: 500 hPa Vorticity NARR Analysis Mixed −10 −8 −6 −4 −2 2 4 6 8 10

40. 1800 UTC 19 June 2002: 925 hPa RUC Analysis Mixed 320 325 330 335 340 345 350

41. 1800 UTC 19 June 2002: CAPE and 1000–700 hPa Wind Shear RUC Analysis Mixed 500 1000 1500 2000 2500 3000 3500 4000

42. 1800 UTC 19 June 2002: Surface Observations Mixed

43. 1800 UTC 19 June 2002: Radar 70 60 50 40 30 20 10 Mixed

44. 1900 UTC 19 June 2002: Radar 70 60 50 40 30 20 10 Mixed

45. 2000 UTC 19 June 2002: Radar 70 60 50 40 30 20 10 Mixed

46. 2100 UTC 19 June 2002: Radar 70 60 50 40 30 20 10 Mixed

47. 1732 UTC 19 June 2002: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Mixed

48. 1902 UTC 19 June 2002: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Mixed

49. 2002 UTC 19 June 2002: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Mixed

50. 2132 UTC 19 June 2002: Visible Satellite http://dcdbs.ssec.wisc.edu/inventory Mixed

51. 19 June 2002: SPC Storm Reports http://www.spc.ncep.noaa.gov/climo/ Mixed 3 wind and 27 hail reports

52. Case Example  11 July 2006 (Atlantic) Null 1200 UTC 11 July 2006: 200 hPa NARR Analysis 2 4 6 8 10

53. 1200 UTC 11 July 2006: 500 hPa NARR Analysis Null 4 8 12 16 20 24 28

54. 1200 UTC 11 July 2006: Surface NARR Analysis Null OKX CHH

55. 1200 UTC 11 July 2006: Sounding http://weather.uwyo.edu/upperair/sounding.html Parcel taken from lowest 500 m to determine CAPE Null

56. 1200 UTC 11 July 2006: Sounding http://weather.uwyo.edu/upperair/sounding.html Parcel taken from lowest 500 m to determine CAPE Null

57. 1800 UTC 11 July 2006: 925 hPa RUC Analysis Null 320 325 330 335 340 345 350

58. 1800 UTC 11 July 2006: CAPE and 1000–700 hPa Wind Shear RUC Analysis Null 500 1000 1500 2000 2500 3000 3500 4000

59. 1800 UTC 11 July 2006: Surface Observations Null

60. 1800 UTC 11 July 2006: NARR Cross-Section Analysis Null −3.5 −3.0 −2.5 −2.0 −1.5 −1.0 −0.5 0.0

61. 1600 UTC 11 July 2006: Radar Null 70 60 50 40 30 20 10

62. 1700 UTC 11 July 2006: Radar Null 70 60 50 40 30 20 10

63. 1800 UTC 11 July 2006: Radar Null 70 60 50 40 30 20 10

64. 1900 UTC 11 July 2006: Radar Null 70 60 50 40 30 20 10

65. 2000 UTC 11 July 2006: Radar Null 70 60 50 40 30 20 10

66. 2100 UTC 11 July 2006: Radar Null 70 60 50 40 30 20 10

67. 11 July 2006: SPC Storm Reports http://www.spc.ncep.noaa.gov/climo Null 21 wind and 32 hail reports

68. 24-hour Quantitative Precipitation Estimates ending at 1200 UTC 12 July 2006 http://www.hpc.ncep.noaa.gov/npvu/archive/rfc.shtml Null

69. Pure Case Conclusions  No synoptic-scale disturbance present, 1000–500 hPa thickness ≥570 dam, land/water temperature difference ≥5°C in afternoon  T ≥30°C and T d ≥20°C in afternoon, CAPE ≥1500 J kg −1 and CIN ≥−125 J kg −1 from 1200 UTC soundings  Placement and timing signal given by 925 hPa θ e -ridge axis with θ e ≥335 K, and tendency to sometimes become squall lines  1000–700 hPa onshore wind shear ≥15 kt for organized storms, and boundary intersections can further enhance convection  Occur most often during hottest months of summer with a moist atmosphere (PW ≥40mm)

70. Mixed Case Conclusions  Synoptic-scale disturbance present, 1000–500 hPa thickness ≥555 dam, land/water temperature difference ≥5°C in afternoon  T ≥20°C and T d ≥10°C in afternoon, CIN ≥−100 J kg −1 from 1200 UTC soundings  Placement and timing signal given by 925 hPa θ e -ridge axis (320 K ≤ θ e ≤ 350 K) and presence of cyclonic vorticity advection  1000–700 hPa onshore wind shear ≥20 kt for organized storms, and boundary intersections can further enhance convection  Occur most often during late spring, early autumn, and cooler portions of summer (PW ≥25mm)

71. Null Case Conclusions  Preexisting convection interacts with a lake or sea breeze and crosses over into the marine air  Convection suppressed with the boundary layer too stable to maintain updrafts (less CAPE, more CIN)  Significant θ e -difference (≥10°C) between the contrasting air masses  Conditions for severe convection can be highly favorable aloft in the null region due to synoptic-scale patterns  Key to these cases is boundary layer characteristics

72. Summary Flowchart Is PW ≥25mm at 1200 UTC, and will CAPE be ≥500 J kg −1 by 1500 UTC? Severe weather highly unlikely NoYes Will the water be ≥5°C cooler than the air over land after 1500 UTC? Will there be onshore surface flow ≥5 kt by 1500 UTC to persist the rest of the day? Is there a synoptic-scale disturbance present? Lake-/sea-breeze-induced severe weather unlikely Yes No Yes No Pure case likelyMixed case likely

73. Null Case Questions  Is there a persistent lake or sea breeze present (synoptically and/or mesoscale driven)?  Is large CIN (≤−125 J kg −1 ) present to promote a deep and possibly impenetrable cap?  Is there a significant departure in temperature and θ e between air masses (lake-/sea-breeze air vs. non- lake-/sea-breeze air)?

74. Eating Establishment in Park City, UT on 26 June 2007 during 22nd WAF conference Thank you to all of my family and friends and the faculty, staff, and graduate students of the department for all your help, education, and moral support!

75. Questions or comments? pwilson@atmos.albany.edu All research material available online at: http://www.atmos.albany.edu/student/pwilson/