Dan Cayan Scripps Institution of

Oceanography, UC San Diego USGS Water Resources Discipline

much support from David Pierce, Mary Tyree, and other colleagues

Sponsors: California Energy Commission NOAA RISA program Southwest Climate Science Center U.S. Army Corps of Engineers

El Nino 2015

will it alleviate the 2012-2015 drought?

CEC Workshop Sacramento 8/28/2015

Highest sea levels occur during big storms, high waves Highest sea levels occur during big storms, high waves

During high sea levels, the sea is often not quiescent January 1983 Monterey Bay, California

1983

1998

Extreme sea level occurrences San Francisco observed at or above 99.99% historical hourly threshold 1.41m above mean

Highest Californiasea levels have

mainly occurred ina few stormy years,

especially during large El Niños (e.g.,

1983 and 1998)

from hourly sea level record at Ft Point,

mouth of San Francisco Bay

1983 El Niño1983 El Niño

1998 El Niño1998 El Niño

Global SST Departures (Global SST Departures (ooC) During the Last Four C) During the Last Four WeeksWeeks

During the last four weeks, equatorial SSTs were above average across the central and eastern Pacific and the Indian Ocean, and below average in the Atlantic Ocean.

NOAA

Niño Region SST Niño Region SST Departures (Departures (ooC) Recent C) Recent

EvolutionEvolution

The latest weekly SST departures are:

Niño 4 1.1ºCNiño 3.4 2.1ºCNiño 3 2.2ºCNiño 1+2 1.7ºC

NOAA

Sub-Surface Temperature Departures in the Sub-Surface Temperature Departures in the Equatorial PacificEquatorial Pacific

Most recent pentad analysis

Recently, negative anomalies were evident in the far eastern Pacific and western Pacific, while positive anomalies have persisted across the central and eastern Pacific.

During the last two months, positive subsurface temperature anomalies were observed across most of the equatorial Pacific

NOAA

Central and Eastern Pacific Upper-Ocean (0-300 m)Central and Eastern Pacific Upper-Ocean (0-300 m)Weekly Average Temperature AnomaliesWeekly Average Temperature Anomalies

During January – March, a significant sub-surface warming occurred across the eastern Pacific. Since March, sub-surface temperature anomalies have remained large, but with some minor fluctuations in strength. Following a drop in June, the anomalies increased in July. Since early August, positive anomalies have persisted.

NOAA

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SUMMARY

Rather strong El Niño conditions have developed in the tropical Pacific. El Niño will likely remain in place through winter 2015-16.

If winter El Niño is strong, we could see above normal storminess in Southern California and maybe Northern California.

Historical El Niño’s have resulted in a wide range of California precipitation during the water year. Strongest odds of wet winter in SoCal.

Historical El Niño’s have produced large Pacific storms along with high waves and high sea levels along the Calfiornia coast. Periods with highest tides would producestrongest impacts if large storms were present

SUMMARY

Rather strong El Niño conditions have developed in the tropical Pacific. El Niño will likely remain in place through winter 2015-16.

If winter El Niño is strong, we could see above normal storminess in Southern California and maybe Northern California.

Historical El Niño’s have resulted in a wide range of California precipitation during the water year. Strongest odds of wet winter in SoCal.

Historical El Niño’s have produced large Pacific storms along with high waves and high sea levels along the Calfiornia coast. Periods with highest tides would producestrongest impacts if large storms were present

Frank Gehrke, California Cooperative Snow Surveys, DWR 10

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