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

Introduction Introduction Methodology Methodology Results Results Other Research Possibilities Other Research Possibilities Conclusion Conclusion Outline

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

Methodology Analyze NAO and ENSO 3.4 monthly values Analyze NAO and ENSO 3.4 monthly values Time Period: Nov - Apr (1950-present) Time Period: Nov - Apr (1950-present) Data Data NAO ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/tele_index.nh NAO ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/tele_index.nh ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/tele_index.nh ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/tele_index.nh ENSO ftp://ftp.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/sstoi.indices ENSO ftp://ftp.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/sstoi.indices ftp://ftp.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/sstoi.indices ftp://ftp.ncep.noaa.gov/pub/cpc/wd52dg/data/indices/sstoi.indices

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

Methodology Plot composites of the next month’s temperature and precipitation ( Plot composites of the next month’s temperature and precipitation (

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

Largest NAO 2-month Negative (–) Changes Month and Year ValueDifference December March March March April March March

NAO 2-month – Changes Temperature Warmer in eastern two-thirds of U.S. Warmer in eastern two-thirds of U.S. Cooler in Northwest Cooler in Northwest

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

Largest NAO 2-month Positive (+) Changes Month and Year ValueDifference April April April December March April April April

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

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

Largest NAO 3-month Negative (–) Changes Month and Year ValueDifference March April March January March March March

NAO 3-month – Changes Temperature Warmer in Northeast, Northwest, Great Lakes, and Rockies Warmer in Northeast, Northwest, Great Lakes, and Rockies Cooler in Midwest and Gulf of Mexico coast Cooler in Midwest and Gulf of Mexico coast

NAO 3-month – Changes Precipitation Dry in Northwest, Southeast, upper Midwest, and New England Dry in Northwest, Southeast, upper Midwest, and New England Wet in Southwest, parts of Midwest, and PA region Wet in Southwest, parts of Midwest, and PA region

Largest NAO 3-month Positive (+) Changes Month and Year ValueDifference April January January February February February February February February

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

NAO 3-month + Changes Precipitation Dry in Southwest and Northeast Dry in Southwest and Northeast Wet in Ohio River Valley and upper Midwest Wet in Ohio River Valley and upper Midwest

Largest ENSO 2-month Negative (–) Changes Month and Year ValueDifference April January April April April April

ENSO 2-month – Changes Temperature Warmer in Northwest, upper/lower Midwest, CA coast, and southern FL Warmer in Northwest, upper/lower Midwest, CA coast, and southern FL Cooler in Midatlantic, Ohio Valley, and Southeast Cooler in Midatlantic, Ohio Valley, and Southeast

ENSO 2-month – Changes Precipitation Dry in TX, FL, and upper Midwest Dry in TX, FL, and upper Midwest Wet in Northeast and Ohio River Valley Wet in Northeast and Ohio River Valley

Largest ENSO 2-month Positive (+) Changes Month and Year ValueDifference March January February February February February February

ENSO 2-month + Changes Temperature Warmer in Southeast, NM, OK, and northern TX Warmer in Southeast, NM, OK, and northern TX Cooler in Northwest, upper Midwest, ME Cooler in Northwest, upper Midwest, ME

ENSO 2-month + Changes Precipitation Dry in Southwest, Rockies, and FL Dry in Southwest, Rockies, and FL Wet in Great Lakes, Ohio River Valley, OR, WA, MS, and AL Wet in Great Lakes, Ohio River Valley, OR, WA, MS, and AL

Largest ENSO 3-month Negative (–) Changes Month and Year ValueDifference April April April March April April

ENSO 3-month – Changes Temperature Warmer in Northwest, Midwest, and Northeast Warmer in Northwest, Midwest, and Northeast Cooler in Southeast, Midatlantic, and CA Cooler in Southeast, Midatlantic, and CA

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

Largest ENSO 3-month Positive (+) Changes Month and Year ValueDifference March January February February February February February

ENSO 3-month + Changes Temperature Warmer in Southwest and FL Warmer in Southwest and FL Cooler in Northwest and upper Midwest Cooler in Northwest and upper Midwest

ENSO 3-month + Changes Precipitation Dry in Southwest, Rockies, and FL Dry in Southwest, Rockies, and FL Wet in MN, Great Lakes, and Midatlantic Wet in MN, Great Lakes, and Midatlantic

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

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