Kelvin Waves Influence on Seasonal and Extreme Rainfall in Northern South America

Kelvin waves (KWs) play a key role in the synoptic variability of the tropics, accounting for up to 37% of the total variance in intraseasonal variability. Previous studies have shown KWs as precursors of extreme hydrometeorological events in the maritime continent. This study characterizes the seasonality of the waves, analyzes the influence of KWs over mean seasonal precipitation and extreme precipitation events over northern South America. Results show that MAM is the season with the highest cumulative events of KWs during the period 1981-2022 with more than 120 events. During MAM, positive (negative) precipitation anomalies predominate over northern South America (Amazon) coinciding with the Wet (dry) phase of the KW. The influence of KWs over Extreme precipitation Events (EPEs) show similar spatial patterns in the different seasons but one remarkable feature show that during Wet KWs: EPEs tend to enhance inland while decreasing offshore. Finally, we selected a flood event in Turbo, Colombia reported on May 9 2007 that was influenced by the passage of a convectively active KW that contribute with enhance low-level westerly flow convergence the previous days of the event. Knowing the influence of these intraseasonal oscillation on precipitation and extreme precipitation events is key for aiding the development of early warining systems and the improvement of weather forecast in the region.