Chris Funk, USGS/UCSB Climate Hazards Group El Nino versus the Blob – is Spouthern California Facing more drought? Chris Funk, Research Director, Climate Hazards Center Chris Funk, USGS/UCSB Climate Hazards Group

Warming shifts the mean of distributions, causing more extreme events Temperature Probability Probability=area under the curve Threshold – crops, pregnant mothers, coral reef, snowpack, human body, …

Warming shifts the mean of distributions, causing more extreme events – example SoCal --Past 5 years by FAR the warmest on record --Every year since 2013 has been exceptionally warm --2000-2017 annual T average (61.2F) is way warmer than the 1896-1950 average (58.2F) --New mean is higher than the old maximum

The old maximum is now the new normal Mean=58.2F Mean=61.2F 66% old max 60.8F Warming shifts the mean of distributions, causing more extreme events

Warming contributes to higher sub-tropical highs – and associated droughts Time series of global average Upper-troposphere heights Upper Height ∝ 0 𝑧 𝑇 i.e. proportional to the temperature of the air below it

Warming contributes to higher sub-tropical highs – and associated droughts Map of changes in Upper-troposphere heights 2011-2018 versus 1979-1993 Upper level ridging disrupts Sub-tropical Westerly Jets Perhaps also tilting us Towards a La Nina like future

Global Land Temperatures Anomalies – Five Year Averages -- Model predictions extremely accurate (R2=0.97) -- +2F = +1.1C ~ +8% water vapor via Clausius-Claperyon -- Intensification of precipitation extremes likely due to both thermodynamic and dynamic causes

Increasing air temperatures can dry soils, plants and increases the magnitude of fires Saturation Vapor Pressure is a non-linear function of T Increasing Vapor Pressure Deficits (VPD) dry plants and soils Vapor Pressure Deficit = Saturation Vapor Pressure minus vapor pressure Low frequency VPD/Temperature impacts can accumulate over time

June-July five-year average temperatures for Southern California --Past 5 years by FAR the warmest on record --Every year since 2013 has been exceptionally warm -- Past 5 year average (62.7F) is way warmer than the 1895-1950 average (58.2F)

US Wildfires getting bigger A wildfire destroys homes in Goleta, California, on July 7, 2018. MARCUS YAM / LOS ANGELES TIMES VIA GETTY IMAGES https://fivethirtyeight.com/features/wildfires-in-the-u-s-are-getting-bigger/

El Nino versus the Blob? -- The ‘Blob’ is a region in the North Pacific linked to CA drought (~150-130W, 40-55N) -- Often warm since 2013 -- Linked to Cod/Salmon disruptions, and other marine impacts The Blob was first detected in the autumn of 2013 and the early months of 2014 by Nicholas Bond of the Joint Institute for the Study of the Atmosphere and Ocean of the University of Washington Very warm ocean temperatures can support droughts and floods

El Nino versus the Blob? Analog blog years ? 1986/87, 1993/94, 2002/03, 2014/15, 2015/16 Very warm ocean temperatures can support droughts and floods

October-March Precipitation and Palmer Drought Severity Index blob analogs (1989,2014, 2015, 2016) Standardized Precipitation Anomalies Standardized Palmer Drought Severity Index Water Supply Water Supply -Demand

Upper level height composites ~8 meters per second

Annual November-October NE Pacific height anomalies

10-year average rainfall, air temperatures and Palmer Drought Severity Index values

CPC/IRI Probabilistic ENSO Outlook Updated: 11 October 2018 El Niño is favored to form in the next couple of months and continue through the Northern Hemisphere winter 2018-19 (70-75% chance).

SST Outlook: NCEP CFS.v2 Forecast (PDF corrected) Issued: 4 November 2018 The CFS.v2 ensemble mean (black dashed line) predicts El Niño to form soon and to then continue through at least the Northern Hemisphere spring 2019.

U.S. Temperature and Precipitation Departures During the Last 30 Days End Date: 4 November 2018 Percent of Average Precipitation Temperature Departures (degree C) 1 of 2

U. S. Seasonal Outlooks November-January 2018 The seasonal outlooks combine the effects of long-term trends, soil moisture, and, when appropriate, ENSO. Precipitation Temperature

US Drought Outlook