Decisionmaking using information from weather to seasonal timescales

Decision-making using information from weather to seasonal timescales Simon Mason simon@iri. columbia. edu The Caribbean Climate Outlook Forum (Cari. COF) 2019 Wet/Hurricane Season Phillipsburg, Sint Maarten, 23 – 24 June 2019

Planning Should you host an out-doors function early next week? Forecast for Wed and Thu next week (30 and 31 May) You can still make some plans, even with imperfect forecasts. 2 Cari. COF 2019 Wet/Hurricane Season

Decadal predictions Climate Change Projections (end of 21 st century) 3 Cari. COF 2019 Wet/Hurricane Season Observations (last 15 years)

1 day to 1 – 2 weeks 2 – 3 months 5 – 10 years 10 – 30 years 30 – 50 years 4 Cari. COF 2019 Wet/Hurricane Season

Example: agricultural decision making Short- to medium-range weather forecasts • Pesticide application • Pest management • Irrigation scheduling • Harvest timing • Fertilizer application Long-range weather to seasonal forecasts • Fertilizer planning • Land allocation • Selection of crop cultivars 5 Cari. COF 2019 Wet/Hurricane Season

How good are the forecasts? 6 Cari. COF 2019 Wet/Hurricane Season

Weather prediction skill temperature 3 -day forecasts 7 Cari. COF 2019 Wet/Hurricane Season

Sub-seasonal prediction skill temperature (week-5) 8 Cari. COF 2019 Wet/Hurricane Season

Seasonal prediction skill temperature 9 Cari. COF 2019 Wet/Hurricane Season

Seasonal prediction skill rainfall 10 Cari. COF 2019 Wet/Hurricane Season

11 Cari. COF 2019 Wet/Hurricane Season

Example: Red Cross / Red Crescent West Africa Preparedness Appeal Forecast for Jun-Aug 2008 issued May 2008 12 Observed rainfall for Jun-Aug 2008 Cari. COF 2019 Wet/Hurricane Season

Example: Red Cross / Red Crescent West Africa Preparedness Appeal • Faster response: 1 -2 days rather than 40 in 2007 • Fewer victims (30 instead of hundreds) • Lower cost per beneficiary (30%) Example: Red Cross volunteers in Ghana saving lives by alerting Volta fishermen that the Bagre dam would be spilled. 13 Cari. COF 2019 Wet/Hurricane Season

Summary Seasonal forecasts: - Generic warning of possible hazards (or opportunities) Sub-seasonal forecasts: - Early warning of a specific possible hazard Weather forecasts: - Early warning of a specific likely hazard 14 Cari. COF 2019 Wet/Hurricane Season

web: iri. columbia. edu @climatesociety …/climatesociety Simon J. Mason simon@iri. columbia. edu