Precipitation is an essential aspect of climate, and also drives many climate impacts. The primary tool for projecting future precipitation is climate models. Climate models are already being used, both directly and indirectly, to quantify anticipated impacts of climate for the purpose of making decisions. Improving precipitation in models requires (1) quantifying characteristics of precipitation in relevant observational datasets, (2) comprehensive comparison of climate model precipitation against observations, and (3) sustained model development efforts focus on improving precipitation in models. It also requires addressing the many characteristics of precipitation, ranging from its mean spatial pattern through its variability across timescales from hourly and diurnal extending through extreme events (whether dry or wet).

We invite presentations in this session that address:
- metrics to quantify the characteristics of precipitation in observations,
- evaluation of climate model simulations against observations, and
- development efforts aimed at improving precipitation in models (including seamless modeling systems).