1. Severe Weather? What Happened… Jim Connolly NWS New York, NY April 2009

2. Data Used NCEP/NCAR Reanalysis Upper Air Data U.S. Daily Weather Maps from the NOAA Central Library Archived Sounding Data Archived Surface Observations from NCDC NCEP/NCAR Reanalysis Upper Air Data U.S. Daily Weather Maps from the NOAA Central Library Archived Sounding Data Archived Surface Observations from NCDC

3. The Setup The following 4 slides show the Jet Stream Level analyzed 200 mb Time period 12Z the day prior until 12Z the day after The following 4 slides show the Jet Stream Level analyzed 200 mb Time period 12Z the day prior until 12Z the day after

9. The Setup The following 4 slides show 500 mb Geopotential Heights and Wind Vectors Time period 12Z the day prior until 12Z the day after The following 4 slides show 500 mb Geopotential Heights and Wind Vectors Time period 12Z the day prior until 12Z the day after

15. The Setup The following 3 slides show Precipitable Water (in inches) First slide is Normal Precipitable Water for the month Second slide is 12Z the day of the event Third slide is 00Z that evening The following 3 slides show Precipitable Water (in inches) First slide is Normal Precipitable Water for the month Second slide is 12Z the day of the event Third slide is 00Z that evening

19. The Setup The following 2 slides show 850 mb isotachs and wind vectors Time period is 12Z the day of the event through 00Z that evening The following 2 slides show 850 mb isotachs and wind vectors Time period is 12Z the day of the event through 00Z that evening

22. The Setup The following 3 slides are surface charts Time period is 12Z the day prior through 12Z the day after The following 3 slides are surface charts Time period is 12Z the day prior through 12Z the day after

26. The Setup The following 4 slides are Skew-Ts from KALB Time period is 12Z and 20Z the day of (low levels modified based on surface obs for 20Z sounding) The following 4 slides are Skew-Ts from KALB Time period is 12Z and 20Z the day of (low levels modified based on surface obs for 20Z sounding)

31. So What Happened…

32. July 10, 1989

33. F4 Tornado In Hamden, CT Strongest Recorded Tornado in the Tri- State Region (OKX Forecast Area) $250 Million in Damage 90 Injuries No Fatalities F4 Tornado In Hamden, CT Strongest Recorded Tornado in the Tri- State Region (OKX Forecast Area) $250 Million in Damage 90 Injuries No Fatalities

34. Across the Tri-State Area 6 Tornadoes Total 1 F4 3 F2 2 F0 $330 Million in Damage 96 Injuries 6 Tornadoes Total 1 F4 3 F2 2 F0 $330 Million in Damage 96 Injuries

35. Breakdown by Location

36. Questions?