ALASKA REGION CLIMATE OUTLOOK BRIEFING November 17, 2017 Rick Thoman National Weather Service Alaska Region
Today Feature of the month: More climate models! Climate Forecast Basics Climate System Review CPC Forecasts and observations for most recent month and season Current Atmosphere and Ice Climate Drivers: SSTs, PDO, ENSO Climate Forecast Guidance ENSO Statistical Dynamic--NMME CPC Outlooks December and December-February 2017-18 Spring 2017-18
European Centers Seasonal Climate Models Long been produced but only recently made public through the Copernicus Climate Change Service (C3S) UK MET MeteoFrance EMCWF Multi-Model composite Similar forecast elements to North American Multi-Model Ensemble Mean Temp (but more ways to dice) Total Precip Sea Level Pressure
Example products
Climate Forecast Basics Climate Prediction Center: primary NOAA/NWS forecast responsibility Climate Outlooks Relation to some long term normal (e.g. 1981-2010) Categorical (often three) Probabilistic Traditional Elements Temperature: centered around average Precipitation: centered around median (can significantly differ from the normal, which by convention is the mean) Chances of this box? Chances of this box? Chances of this box?
October 2017 Temperature Anomalies Non-EC Skill Score: +100 Mid-Month Outlook Best possible: +100 No skill: 0 Worst possible: -50 Above Normal Near Normal Below Normal Preliminary data subject to revision
October 2017 Precipitation Anomalies Non-EC Skill Score: +10 Mid-Month Outlook Best possible: +100 No skill: 0 Worst possible: -50 Above Normal Near Normal Below Normal Preliminary data subject to revision
Aug-Sep-Oct 2017 Temperature Anomalies Non-EC Skill Score: +82 Best possible: +100 No skill: 0 Worst possible: -50 Above Normal Near Normal Below Normal Preliminary data subject to revision
Aug-Sep-Oct 2017 Precipitation Anomalies Non-EC Skill Score: +45 Best possible: +100 No skill: 0 Worst possible: -50 Above Normal Near Normal Below Normal Preliminary data subject to revision
Mid-November Sea Ice Comparison Nov 15, 2017 Nov 15, 2016
Arctic Wide Sea Ice Updated November 15, 2017 Blue line: 2017 Red line: 2016 Green dash: 2012
Arctic Sea Ice Volume & Thickness End of October Arctic sea ice volume in satellite era (since 1979): above the lowest few No ice with above average thickness remains PIOMAS/U. Wa
Alaska Near-Shore SSTs
Global SST Anomalies Not much of a PDO Pattern Cool equatorial Pacific
Pacific Decadal Oscillation
Upper Ocean Heat Content Anomaly Heat Content Anomaly ( C) in the upper 300m Source: CPC
Tropical Pacific
Tropical Pacific SSTs and Winds OISSTv2 Weekly 1981-2010 climo Low-level winds are close to normal in Niño 3.4 but enhanced trades west of dateline
Time Equatorial Upper Ocean Heat Anomaly
Guidance ENSO Models Expert Evaluation Statistical Trends in the Past 15 Years Correlations SST Anomalies Oceanic Correlation (PDO) Dynamic SST Anomalies Global Temp and Pcpn Anomalies
CPC Niño 3.4 Forecasts November C3S Forecasts La Niña looks likely, but how long will it last?
CPC Niño 3.4 Experts Forecast ENSO Alert System Status: La Niña Watch La Niña strongly favored: but barely reaches five seasons threshold
2002-2016 Trends December Dec-Feb Temps Precip
Constructed Analogs based on Global SSTs
PDO Correlation: DJF observed vs. SON PDO 1989-2017 Temperature 1989-2017 Precipitation
Dynamic Forecasts Extratropical SSTs Arctic Sea Ice Temp and Pcpn Anomalies
NMME Forecast Dec-Feb SST Anomalies Not a PDO pattern
NMME Skill for SST Skill of DJF forecasts made in November
CPC Experimental Sea Ice: Freeze-Up Dates Change in date since last month s forecast
December 2017 Temp Anomaly Outlooks Avg Dep ( C) 3-Category Probabilities Calibrated 3-Category Probs Member Averages
December 2017 Pcpn Anomaly Outlooks Avg Dep (mm/day) 3-Category Probabilities Calibrated 3-Category Probs Member Averages
Recent CFS Outlooks For December Important: anomalies from 1999-2010
Calibrated Probability Forecasts for December 2017 Forecast made in: September October November
Dec-Jan-Feb 2017-18 Temp Anomaly Forecasts Avg Dep ( C) Category Probs Calibrated Category Probs Member Averages
Dec-Jan-Feb 2017 Pcpn Anomaly Forecasts Avg Dep (mm/day) Category Probs Calibrated Category Probs Member Averages
C3S Multi-Model Ensemble for DJF
Recent La Niña Composites for DJF 1984, 1985, 1996, 1999, 2001, 2008, 2011, 2012 Dynamically downscaled reanalysis composites courtesy of: Peter Bieniek, UAF
Calibrated Probability Forecasts for Dec-Jan-Feb 2017-18 Forecast made in: September October November
NMME Skill for Dec & Dec-Jan-Feb Temp Pcpn
Dec-Jan-Feb 2017-18 Outlook from October
And the Answer Is
CPC December 2017 Outlook 45% 37% 55% 12% 37% 22% 30% 30% Above% Normal% Below% 22% 30% 37% 30% 37% 45%
CPC Dec-Jan-Feb 2017-18 Outlook 45% 22% 37% 30% 55% 12% 45% 22% 37% 30% 22% 45% 30% 37% 22% 45% Above% Normal% Below%
First Look: Spring 2018 45% 22% 37% 30% 45% 22% 22% 45% 37% 30% 30% 37%
Climate Forecast Links CPC Monthly http://www.cpc.ncep.noaa.gov/products/predictions/30day/ CPC Seasonal http://www.cpc.ncep.noaa.gov/products/predictions/90day/ NMME http://www.cpc.ncep.noaa.gov/products/nmme/ ENSO at CPC (including weekly briefing) http://www.cpc.ncep.noaa.gov/products/precip/cwlink/mjo/ enso.shtml ENSO at IRI http://iri.columbia.edu/our-expertise/climate/forecasts/enso/