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)

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)

August 2007 07 0600 UTC through 08 1800 UTC

7 August 2007 0000UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

7 August 2007 1200UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

8 August 2007 0000UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

8 August 2007 1200UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

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

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

Surface Analysis (0900 UTC 8 Aug 2007)

8 August 2007 0902 UTC 1030 UTC L

July 2007 17 1700 UTC through 18 2100 UTC

17 July 2007 0000UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

17 July 2007 1200UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

18 July 2007 0000UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

18 July 2007 1200UTC X 300 hPa wnd (m/s, shaded), 700 hPa omeg (10*-3m/s, green dashed), 700 hPa hght (m/s, blue solid)

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 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

Surface Analysis (1200 UTC 18 Jul 2007)

18 July 2007 0958 UTC 1258 UTC KOKX KOKX KOKX KOKX

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

11 October 2007 1800 UTC

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

11 October 2007 1952 UTC

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

Extra Goodies

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)

12 October 2007 0000UTC X 300 hPa wnd (m/s, shaded), 700 hPa hght(10*-3m/s, blue solid), 700 hPa omeg (m/s, green dashed)

11 October 2007 1200UTC X 300 hPa wnd (m/s, shaded), 700 hPa hght (10*-3m/s, blue solid), 700 hPa omeg (m/s, green dashed)

11 October 2007 0000UTC X X 300 hPa wnd (m/s, shaded), 700 hPa hght (10*-3m/s, blue solid), 700 hPa omeg (m/s, green dashed)

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

L Surface Obs 11 October 2007 1900 UTC