How long would it take to remove all of an extratropical cyclone's initial moisture via precipitation?

Oral Presentation

Quantifying how quickly cyclone's dry out due to precipitation, and to what extent the moisture in a cyclone is replenished, can help us to understand and predict the precipitating phase of a cyclone better. Precipitation efficiency is a measure of how much water in the atmosphere falls as rain compared to how much is available to fall. High precipitation efficiencies indicate that moisture is rapidly lost from cyclones resulting in a short precipitation phase. In this study, we estimate how efficient precipitation is for 400 cyclones in the Southern Ocean. 

We find that when the cyclones are strongest, about 60% of the available water vapour turns into rain every 6 hr near the warm front of the cyclone where air is rising rapidly. Normally, within a day or two of a cyclone forming, all of the available water vapour in the cyclone gets turned into rain. However, the rain can persist for longer because cyclones pick up more moisture as they move, which gets turned into more rain. This can make the rain from a cyclone last on average for 60 hr, even after the initial moisture is all gone.