ALASKA REGION CLIMATE OUTLOOK BRIEFING. June 22, 2018 Rick Thoman National Weather Service Alaska Region

Transcription

1 ALASKA REGION CLIMATE OUTLOOK BRIEFING June 22, 2018 Rick Thoman National Weather Service Alaska Region

2 Today s Outline Feature of the month: Ocean Warmth Headed into Summer 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 & C3S CPC Outlooks July and July-September 2018 Look at Autumn 2018

3 Alaska regional oceans mostly warm

4 SST Changes through Time Trend lines are best linear fit

5 Climate Forecast Basics Climate Prediction Center: primary NOAA/NWS forecast responsibility Climate Outlooks Relation to some long term normal (e.g ) 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?

6 May 2018 Temperature Anomalies Non-EC Skill Score: -18 Mid-Month Outlook Above normal Near Normal Below Normal Preliminary data subject to revision

7 May 2018 Precipitation Anomalies Non-EC Skill Score: +33 Mid-Month Outlook Above normal Near Normal Below Normal Preliminary data subject to revision

8 Mar-Apr-May 2018 Temperature Anomalies Non-EC Skill Score: +59 Above normal Near Normal Below Normal Preliminary data subject to revision

9 Mar-Apr-May 2018 Precipitation Anomalies Non-EC Skill Score: +12 Above normal Near Normal Below Normal Preliminary data subject to revision

10 Arctic Wide Sea Ice Through June 20, 2018 Red Line: 2016 Blue line: 2017 Orange line: 2018

11 Arctic Sea Ice Volume & Thickness End of May Arctic sea ice volume: fourth lowest in satellite era (since 1979) End of May thickness above normal Laptev Sea, below elsewhere PIOMAS/U. a Sources: Data from U. Wa./PIOMAS data Graphics by Z. Labe, UC Irvine

12 Mid-June Sea Ice Comparison June 20, 2018 June 20, 2017

13 Sea Ice Near Alaska

14 Alaska Near-Shore SSTs

15 Global SST Anomalies Not a PDO Pattern Near to above normal equatorial Pacific except near South America

16 Upper Ocean Heat Content Anomaly Heat Content Anomaly ( C) in the upper 300m Source: CPC

17 Tropical Pacific

18 Tropical Pacific SSTs & Atmosphere More convection Less convection OISSTv2 Weekly climo Trade winds near normal

19 Time Equatorial Upper Ocean Heat Anomaly

20 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

21 CPC Niño 3.4 Forecasts: Models Neutral through summer, increasing consensus for El Niño autumn/winter

22 CPC Niño 3.4 Forecasts: Experts ENSO Alert System Status: El Niño Watch ENSO neutral favored through summer El Niño more likely than not for autumn/winter

23 Trends July Compared to =Below normal 34-66=Near normal =Above normal Temps Jul-Sep Precip

24 Constructed Analogs based on Global SSTs

25 PDO Correlations: Jul-Aug-Sep observed vs. Apr-May-Jun PDO Temperature Precipitation

26 Dynamic Model Forecasts Extratropical SSTs Alaska regional Sea Ice Temp and Pcpn Anomalies

27 NMME Jul-Sep 2018 SST Departures from Normal Forecast Skill Not much of a PDO pattern

28 Sea Ice Spring Meltout Outlook CPC Experimental Forecast

29 Change in Forecast Melt-out from April Outlook

30 July 2018 Temp Anomaly Outlooks Avg Dep ( C) 3-Category Probabilities Calibrated 3-Category Probs Member Averages

31 July 2018 Pcpn Anomaly Outlooks Avg Dep (mm/day) Member Averages 3-Category Probabilities Calibrated 3-Category Probs

32 Calibrated Probability Forecasts for July 2018 Forecast from: April May June

33 Jul-Aug-Sep 2018 Temp Anomaly Forecasts Avg Dep ( C) Category Probs Calibrated Category Probs Member Averages

34 Jul-Aug-Sep 2018 Pcpn Anomaly Forecasts Avg Dep (mm/day) Member Averages Category Probs Calibrated Category Probs

35 Calibrated Probability Forecasts for Jul-Aug-Sep 2018 Forecast from: April May June

36 NMME Skill for July & Jul-Aug-Sep Temp Pcpn

37 C3S Multi-Model Ensemble for JAS 2018 Average Temperature Category Probabilities Total Precipitation

38 Jul-Aug-Sep 2018 Outlook from May

39 And the Answer Is

40 CPC July 2018 Outlook 55% 12% 45% 22% 45% 22% 37% 30% 37% Above% Normal% Below% 45% 22% 30%

41 CPC Jul-Aug-Sep 2018 Outlook 55% 12% 45% 22% 45% 65% 30% 05% 22% 37% 30% Above% Normal% Below%

42 Look Ahead: Fall % 12% 65% 30% 05% 45% 22% 45% 22% 37% 30% Above% Normal% Below%

43 Climate Forecast Links CPC Monthly CPC Seasonal NMME ENSO at CPC (including weekly briefing) enso.shtml ENSO at IRI