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North American Impacts of El Nino

North American Impacts of El Nino. Jon M Schrage. r (-SOI 3mrm ,OLR ’ ), r (-SOI 3mrm ,  ’ @200), r (-SOI 3mrm , winds @ 200). Rossby Wave Source. Conservation of Absolute Vorticity The twin anticyclones aloft are what initially displaces the air parcels.

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North American Impacts of El Nino

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  1. North American Impacts of El Nino Jon M Schrage

  2. r(-SOI3mrm,OLR’), r(-SOI3mrm,’@200), r(-SOI3mrm,winds@ 200)

  3. Rossby Wave Source • Conservation of Absolute Vorticity • The twin anticyclones aloft are what initially displaces the air parcels. • Results in a pattern of troughs and ridges far downstream.

  4. PNA PATTERN

  5. PNA PATTERN

  6. The following slides are composites from January 1998. http://www.cdc.noaa.gov/cgi-bin/Composites/printpage.pl

  7. 500mb heights

  8. 1000mb T

  9. 1000mb T

  10. OLR

  11. OLR

  12. Precip

  13. Precip

  14. Sea Level Pressure

  15. Sea Level Pressure

  16. Changnon • What counted as an impact of El Nino? • The general monthly and seasonal temperature and precipitation conditions • The lack of Atlantic hurricanes • Snowstorms? • An event attributed to El Nino by a NOAA employee speaking in an official capacity

  17. Changnon • Losses during El Nino: • Rain in the southeast (including Florida) • Unusual tornadoes • Crop damage by rain • Reduced tourism • Direct damage from storms

  18. Changnon • Losses during El Nino: • Storms: • October, 1997 in Midwest • January, 1998 in New England • April, 1998 in Ohio Valley

  19. Changnon • Losses during El Nino: • Drought in Hawaii • Ski resorts in Midwest • Producers of salt, natural gas, snowmobiles, etc. • Fires in Florida

  20. Changnon • Benefits during El Nino: • Mild Winter in Midwest: • Few lives lost (13 vs. 757!) • Lower fuel costs (10% nationally!) • Fewer airline and shipping delays • Longer construction season • Snow removal costs

  21. Changnon • Benefits of El Nino: • No landfalling hurricanes • 13 lives, $5 billion, saved

  22. Changnon • Benefits of El Nino: • Difficult to quantify: • Improvement in lifestyle • Recharging reservoirs

  23. Changnon • Losses: • Human lives lost: 189 • Economic costs: $4.2 billion • Benefits: • Human lives saved: 850 • Economic gains: $19.6 billion

  24. Changnon • Lessons: • “…the need to focus on both the good and bad impacts of predicted weather conditions. The media tends to focus only on the negative outcomes.”

  25. Changnon • Lessons: • “News… writers tend to approach “local” experts for interpretations of the events… [resulting] in widely different interpretations…”

  26. Changnon • Lessons: • “…all weather conditions produce winners and losers”

  27. Changnon • Lessons: • “…predicting future impacts on lives and the economy due to expected weather is likely as difficult as making accurate long range weather predictions.”

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