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Highlights

The Great Waterspout Outbreak of 2011 (Lake Michigan, Sept. 24, 2011) Wade Szilagyi, Meteorologist Meteorological Service of Canada Director, International Centre For Waterspout Research. Highlights. Major waterspout outbreak 20+ waterspouts! Major media event

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Highlights

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  1. The Great Waterspout Outbreak of 2011(Lake Michigan, Sept. 24, 2011) Wade Szilagyi, MeteorologistMeteorological Service of CanadaDirector, International Centre For Waterspout Research

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

  3. Atmospheric Conditions • Major upper low (4 closed contours at 500 mb) over southern Lake Michigan • Cool air mass (T850 = 4 C) • Unseasonably warm water (Tlake =19 C) • Moderate thermal contrast (T = 15 C) • Convectiontotropopause (Z = 23,900 ft) • Light winds (850wind = 170° / 6 kts)

  4. Event Predictability(Synoptic Pattern Recognition / 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.)

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

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

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

  8. Confirmed Sightings

  9. Milwaukee

  10. Milwaukee

  11. Chicago

  12. Kenosha

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

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

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