CSU Convective CLoud Outflows and UpDrafts Experiment (C3LOUD-Ex)

Accurately simulating updraft and cold pool characteristics within cloud-resolving models has proven challenging. The magnitudes of updrafts are often overestimated when compared with Doppler velocity measurements, which is frequently attributed to shortfalls in microphysical parameterizations. Cold pools on the other hand may be well captured by these models providing their vertical and horizontal resolutions are sufficient, however, observational datasets of cold pool intensities and depths necessary for model evaluation are rather limited. The goal of the Colorado State University Convective CLoud Outflows and UpDrafts Experiment (C³LOUD-Ex) is to obtain measurements of deep convective updrafts and cold pools in order to enhance our understanding of these critical elements of storms and to improve their representation in numerical models. Radiosonde measurements combined with radar observations from the CSU CHILL facility are being utilized to analyze the updraft characteristics of supercells and other deep convective storms, while unmanned aerial vehicles (UAVs) and surface stations are being used to observe cold pools and their associated outflow boundaries. The first phase of this field campaign was conducted over northern Colorado and southern Wyoming during the last two weeks of July 2016, while the second phase is being held from 1 May to 9 June 2017 in the same region. Initial results from the first phase of this field experiment show a lower limit of the maximum observed supercell updraft strengths of 38 m/s, while cold pools may be as shallow as 200m thus highlighting the need for high vertical grid resolution if we are to accurately simulate these aspects of convection in our numerical models. Initial model simulations demonstrate the importance of initializing storm simulations using the near-storm environmental conditions in order to accurately represent updraft strengths. Case studies from both phases of the field campaign, as well some of the initial observational and modeling analysis will be presented. The utility of UAVs in investigating storm features will also be discussed.