1. School of Marine and Atmospheric Sciences Stony Brook University
Synoptic and Mesoscale Overview of Three Severe Convective Events Over Long Island in 2007
Kelly Lombardo
John Murray
Brian A. Colle
School of Marine and Atmospheric Sciences
Stony Brook University
from Jeff Tongue (NWS)

2. Role of mesoscale features
Severe weather NYC/LI?
Synoptic evolution
Instability & CAPE
Role of mesoscale features
Three cases from 2007:
8 August 1035 UTC (Brooklyn tornado)
18 July 1315 UTC (Islip Terrace tornado)
11 October 1900 UTC (Nassau County mesocyclone)
Terrain elevation (m)

3. August 2007
UTC
through
UTC

4. 7 August UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

5. 7 August UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

6. 8 August UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

7. 8 August UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

8. X 500 Z, 800:600 lpse 500 Z, 800:600 lpse 6 August 1200 UTC
400 hPa
600 hPa
800 hPa
500 Z, 800:600 lpse
Pittsburgh, PA 7 August 1200 UTC
8 August 1200 UTC

9. 8 August 2007 Soundings 0000 UTC KOKX 600 hPa ACARS 0827 UTC EWR, NY
CAPE ~
1500 J/kg
600 hPa
800 hPa
(kts)
1000 hPa
0827 UTC EWR Hodograph

10. Surface Analysis (0900 UTC 8 Aug 2007)

11. 8 August 2007
0902 UTC
1030 UTC L

12. July 2007
UTC
through
UTC

13. 17 July UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

14. 17 July UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

15. 18 July UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

16. 18 July UTC X
300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed),
700 hPa hght (m/s, blue solid)

17. 18 July 2007
0000 UTC
1200 UTC
900 hPa hghts (m, green solid), 900 hPa thte (K, brown dashed)
900 hPa wnds (kts), CAPE (J/kg-K, shaded)

18. 18 July 2007 Soundings 1200 UTC KOKX 600 hPa 800 hPa
ACARS 1026 UTC JFK, NY
1000 hPa
CAPE ~
400 J/kg
600 hPa
800 hPa
(kts)
1000 hPa
JFK 1026 UTC Hodograph

19. Surface Analysis (1200 UTC 18 Jul 2007)

20. 18 July 2007
0958 UTC
1258 UTC
KOKX
KOKX
KOKX
KOKX

21. 11 October 2007 1800 UTC 300 hPa wnd, 700 hPa hght, 700 hPa omeg
900 hPa hghts, 900 hPa thte,
900 hPa wnds, CAPE

22. 11 October UTC

23. 11 October 2007 Soundings 1200 UTC KOKX 400 hPa 600 hPa
ACARS 1959 UTC JFK, NY
800 hPa
400 hPa
1000 hPa
600 hPa
800 hPa
1000 hPa
(kts)
1959 UTC JFK Hodograph

24. 11 October UTC

25. Summary
Upstream disturbance, low-level trough (warm season tornadic events)
Elevated instability with marginal CAPE
Mesolow interaction with baroclinic zone (synoptic low cool season), enhancement of low-level shear
Outstanding questions…
Development of mesolow: terrain, convection (MCV)
Origin of instability
Role of the marine layer, proximity to Appalachians

26. Extra Goodies

27. 8 August 2007
0000 UTC
1200 UTC
900 hPa hghts (m, green solid), 900 hPa thte (K, brown dashed)
900 hPa wnds (kts), CAPE (J/kg-K, shaded)

31. 12 October UTC X
300 hPa wnd (m/s, shaded), 700 hPa hght(10*-3m/s, blue solid),
700 hPa omeg (m/s, green dashed)

32. 11 October UTC X
300 hPa wnd (m/s, shaded), 700 hPa hght (10*-3m/s, blue solid),
700 hPa omeg (m/s, green dashed)

33. 11 October UTC X X
300 hPa wnd (m/s, shaded), 700 hPa hght (10*-3m/s, blue solid),
700 hPa omeg (m/s, green dashed)

34. 12 October 2007 0000 UTC 300 hPa wnd, 700 hPa hght,
700 hPa omeg
900 hPa hghts, 900 hPa thte,
900 hPa wnds, CAPE

35. L
Surface Obs
11 October UTC