1. The Great Waterspout Outbreak of 2011 (Lake Michigan, Sept. 24, 2011) Wade Szilagyi, Meteorologist Meteorological Service of Canada Director, International Centre For Waterspout Research

2. Highlights Major waterspout outbreak Major waterspout outbreak 20+ waterspouts! 20+ waterspouts! Major media event Major media event Highlight of a larger event over lower Great Lakes (Sept. 23-30) Highlight of a larger event over lower Great Lakes (Sept. 23-30) 3 rd largest outbreak since studies began in 1994 3 rd largest outbreak since studies began in 1994 Last major outbreak 2003 (21+ waterspouts) Last major outbreak 2003 (21+ waterspouts) 58 photos / videos 58 photos / videos

3. Atmospheric Conditions Major upper low (4 closed contours at 500 mb) over southern Lake Michigan Major upper low (4 closed contours at 500 mb) over southern Lake Michigan Cool air mass (T 850 = 4 C) Cool air mass (T 850 = 4 C) Unseasonably warm water (T lake =19 C) Unseasonably warm water (T lake =19 C) Moderate thermal contrast (  T = 15 C) Moderate thermal contrast (  T = 15 C) Convection to tropopause (  Z = 23,900 ft) Convection to tropopause (  Z = 23,900 ft) Light winds (850 wind = 170° / 6 kts) Light winds (850 wind = 170° / 6 kts)

7. Event Predictability (Synoptic Pattern Recognition / Climatology) Alerted to waterspout potential days in advance through synoptic pattern recognition and waterspout climatology Alerted to waterspout potential days in advance through synoptic pattern recognition and waterspout climatology Major upper low, above ave. water temps., peak of waterspout season (Sept.) Major upper low, above ave. water temps., peak of waterspout season (Sept.)

8. Event Predictability (Waterspout Nomogram) Confirmation of waterspout potential using the Waterspout Nomogram Confirmation of waterspout potential using the Waterspout Nomogram  T = 15 C  T = 15 C  Z = 23,900 ft  Z = 23,900 ft 850 wind = 6 kts 850 wind = 6 kts

9. Event Predictability (Szilagyi Waterspout Index (SWI)) Quantifies waterspout potential Quantifies waterspout potential Based on the Waterspout Nomogram Based on the Waterspout Nomogram -10 ≤ SWI ≤ +10 -10 ≤ SWI ≤ +10 Waterspouts are likely when SWI ≥ 0 Waterspouts are likely when SWI ≥ 0 SWI ranged from 2 to 6 SWI ranged from 2 to 6

10. Event Predictability (New Experimental Waterspout Prognostic System) Geographical display of SWI Geographical display of SWI Dramatically reduces diagnosis time Dramatically reduces diagnosis time Dramatic increase in temporal and spatial resolution (3hr time steps for 2143 points out to 48 hours) Dramatic increase in temporal and spatial resolution (3hr time steps for 2143 points out to 48 hours) More efficient coordination More efficient coordination Upstream events identified Upstream events identified Much of Lake Michigan showed waterspout potential Much of Lake Michigan showed waterspout potential

11. Confirmed Sightings

12. Milwaukee

13. Milwaukee

14. Chicago

15. Kenosha

16. Conclusions Outbreak occurred because: Outbreak occurred because: 1. Cool air mass 2. Unseasonably warm water 3. Major upper low 4. Improved reporting technology (Twitter, Facebook, media web sites, cell phone cameras, etc.)

17. Questions ? Contact Wade at: Contact Wade at: –wade.szilagyi@ec.gc.ca wade.szilagyi@ec.gc.ca –www.icwr.ca (International Centre For Waterspout Research) www.icwr.ca