Changes in NAO and ENSO 3.4 and Their Effects on U.S. Climate

1. Changes in NAO and ENSO 3.4 and Their Effects on U.S. Climate by Elise Lancaster METEO 497A April 22, 2003

2. Outline • Introduction • Methodology • Results • Other Research Possibilities • Conclusion

3. Introduction“The Idea” • Find the largest 2-3 month differences in NAO and ENSO 3.4 • Note temperature and precipitation patterns of the month after the change

4. Methodology • Analyze NAO and ENSO 3.4 monthly values • Time Period: Nov - Apr (1950-present) • Data • NAO ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/tele_index.nhhttp://www.cpc.ncep.noaa.gov/data/teledoc/nao.html • ENSO ftp://ftp.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/sstoi.indiceshttp://www.cpc.ncep.noaa.gov/data/indices/index.html

5. Methodology • Calculate 2 and 3-month changes in values • Examples • 2-month: Dec – Nov, Apr – Mar • 3-month: Jan – Nov, Apr – Feb • Determine largest changes/differences – use the most common month

6. Methodology • Plot composites of the next month’s temperature and precipitation (http://www.cdc.noaa.gov/USclimate/USclimdivs.html)

7. Results • Graphs of values • Composite U.S. temperature and precipitation maps • Observations of the composites

9. Largest NAO 2-month Negative (–) Changes

10. NAO 2-month – ChangesTemperature • Warmer in eastern two-thirds of U.S. • Cooler in Northwest

11. NAO 2-month – ChangesPrecipitation • Dry in Southeast, lower Midwest, Rockies, and CA/OR • Wet in Great Lakes (especially MN/WI) and Ohio Valley

12. Largest NAO 2-month Positive (+) Changes

13. NAO 2-month + ChangesTemperature • Warmer over majority of U.S. • Warmest in western states • Cooler in Northeast and on Gulf of Mexico coast

14. NAO 2-month + ChangesPrecipitation • Dry in Northwest, CA, TX, OK, MO, AR, Great Lakes, Southeast, and Northeast • Wet in central Midwest, Southwest, and Ohio Valley

16. Largest NAO 3-month Negative (–) Changes

17. NAO 3-month – ChangesTemperature • Warmer in Northeast, Northwest, Great Lakes, and Rockies • Cooler in Midwest and Gulf of Mexico coast

18. NAO 3-month – ChangesPrecipitation • Dry in Northwest, Southeast, upper Midwest, and New England • Wet in Southwest, parts of Midwest, and PA region

19. Largest NAO 3-month Positive (+) Changes

20. NAO 3-month + Changes Temperature • Warmer on east coast and western U.S. • Cooler in Midwest

21. NAO 3-month + ChangesPrecipitation • Dry in Southwest and Northeast • Wet in Ohio River Valley and upper Midwest

23. Largest ENSO 2-month Negative (–) Changes

24. ENSO 2-month – ChangesTemperature • Warmer in Northwest, upper/lower Midwest, CA coast, and southern FL • Cooler in Midatlantic, Ohio Valley, and Southeast

25. ENSO 2-month – ChangesPrecipitation • Dry in TX, FL, and upper Midwest • Wet in Northeast and Ohio River Valley

26. Largest ENSO 2-month Positive (+) Changes

27. ENSO 2-month + ChangesTemperature • Warmer in Southeast, NM, OK, and northern TX • Cooler in Northwest, upper Midwest, ME

28. ENSO 2-month + ChangesPrecipitation • Dry in Southwest, Rockies, and FL • Wet in Great Lakes, Ohio River Valley, OR, WA, MS, and AL

30. Largest ENSO 3-month Negative (–) Changes

31. ENSO 3-month – ChangesTemperature • Warmer in Northwest, Midwest, and Northeast • Cooler in Southeast, Midatlantic, and CA

32. ENSO 3-month – ChangesPrecipitation • Dry in TX and surroundings, upper Midwest, and FL • Wet in Ohio River Valley, Northeast, Great Lakes, and CA/OR

33. Largest ENSO 3-month Positive (+) Changes

34. ENSO 3-month + ChangesTemperature • Warmer in Southwest and FL • Cooler in Northwest and upper Midwest

35. ENSO 3-month + ChangesPrecipitation • Dry in Southwest, Rockies, and FL • Wet in MN, Great Lakes, and Midatlantic

36. Other Research Possibilities • Same process, but by month • See monthly trends, not just most extreme trends • Note similar trends between NAO and ENSO

37. Conclusion • Trends are evident in NAO and ENSO monthly “jumps” • Trends can be used in long range forecasting