El Nino in the Winter of 2014? David W. Pierce Div. Climate, Atmospheric Sciences, and Physical Oceanography Scripps Institution of Oceanography

Why does El Nino affect other places?

Global atmospheric pressure pattern “steers” weather Horel and Wallace, 1981

Typical winter weather response Precipitation

Typical winter weather response Precipitation Temperature

Satellite-measured Cholorphyll Concentrations

Conditions in tropical Pacific as of Aug 5 9

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14 El Nino

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16 El Nino: Benefit or burden?

El Nino 97/98 damage in U.S.  189 deaths from storms/flooding  Property losses: $2.8B  Federal relief costs: $400M  State assistance costs: $125M  Agricultural losses: $600-$700M  Lost sales in snow removal eqpt: $60-80M  Losses in tourist industry: $180-$200M (Changnon, BAMS, 1999)

El Nino 97/98 benefits to U.S.  ~850 lives saved from warm N. winter  Reduced heating costs: $6.7B  More retail activity in winter: $5.6B  Less snow removal needed: $ M  No Atlantic hurricanes: $6.9B  More winter construction: $ M  Reduced transportation costs: $160M (Changnon, BAMS, 1999)

El Nino 97/98 balance sheet  Losses Lives: 189 Economic losses and costs: $ B  Benefits Lives: ~850 Economic savings and generation: $ B (Changnon, BAMS, 1999)

Summary  El Nino is when equatorial Pacific ocean temperatures are warmer than usual  Changes where water vapor gets into atmosphere and typical path of winter storms  Warms waters and elevates sea level all along the west coast of the Americas  Best forecast right now: ~75% chance of modest El Nino this winter  Really big anomalies from this spring have dwindled 20