WCD-15. Subseasonal Precipitation Forecasts of Opportunity over Southwest Asia

Abstract
Southwest Asia is a semi-arid region that includes several food-insecure countries including Afghanistan, Pakistan, and Tajikistan, where precipitation determines the water available for agriculture and consumption. Consequently, subseasonal precipitation forecasts are provided for southwest Asia to the Famine Early Warning Systems Network during the rainy season from November to April. Forecasts are generated using a linear stochastic model – namely a linear inverse model – which can assess the confidence of its own forecasts based on the forecast signal-to-noise ratio. We find that forecasts with high confidence are indeed more skillful than the remaining forecasts, and that the likelihood of a high confidence forecast increases during La Niña, El Niño, and Madden-Julian Oscillation (MJO) phases 2-3 and 6-7, particularly during high-amplitude events that impart the strongest ‘signal’ to the system. Consistent with past research, La Niña and MJO phases 2-3 precede anomalously dry forecasts, and El Niño and MJO phases 6-7 precede anomalously wet forecasts, by generating upper-level anticyclonic and cyclonic anomalies over southwest Asia, respectively.