Research

Dr. Schumacher's primary research interests involve understanding organized precipitation systems. In particular, those that produce extreme amounts of precipitation are of interest because of the potential they have for causing destructive flooding and flash flooding. A full list of scientific publications can be found here.

In the simplest terms, the most rain falls where it rains the hardest for the longest.* Therefore, we need to know what makes it rain hard, and what makes it rain for a long time. For example, it is uncommon for a single, ordinary thunderstorm to last long enough to produce so much rain that it causes a flood. But it is common for several storms to organize together into what is called a "mesoscale convective system" (MCS). Most MCSs move fairly quickly, producing relatively small amounts of rain over large areas. (These MCSs are very important to sustaining agriculture in places like the central United States.) Sometimes, though, they move slowly, or are arranged such that convective cells repeatedly pass over the same area, which can lead to huge rainfall amounts over small areas. These heavy-rain-producing MCSs are often difficult to predict, as it is often not apparent exactly where they will develop or how fast they will move.

Because of this, we want to know the answers to questions like:

• What are the synoptic, mesoscale, and storm-scale conditions that are most conducive to extreme local rainfall?
• What processes determine whether a particular storm system will produce small amounts of rain spread out over a large area, or a huge amount of rain in a local area?
• How good are numerical weather prediction models at forecasting these heavy rain events?
• Are there methods that we can use to make those forecasts better?

We use a variety of tools to explore these questions, including observations (including both routine observations and data collected in field campaigns) and numerical models of varying complexity.

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Our research on convective precipitation is currently (as of fall 2021) supported by the National Science Foundation and NOAA for the following projects:

• Improving probabilistic forecasts of high-impact weather with the CSU-Machine Learning Probabilities system (sponsored by multiple NOAA projects)
• Multi-disciplinary investigation of concurrent tornadoes and flash floods in the Southeastern US (sponsored by NOAA)
• Impact of Convectively-Generated Gravity Waves on Mesoscale Convective Systems (sponsored by NSF)
• Using RELAMPAGO observations to understand the thermodynamic, kinematic, and dynamic processes leading to heavy precipitation (sponsored by NSF)

In addition to these specific projects, Dr. Schumacher has broad research interests that include many other aspects of mesoscale meteorology, climatology, and the societal impacts of weather and weather forecasts.

Click one of the links below to continue reading about previous and current research:

• Organization and motion of heavy-rain-producing convective systems
• Mesoscale convective vortices
• Moisture transport by tropical cyclones into midlatitudes
• Widespread, multiple-day rainfall and its predictability
• Communication and interpretation of weather forecasts and warnings
• Banded convection
• Identifying and understanding displacement biases in numerical forecasts of elevated convective systems
• Using machine learning to improve heavy rainfall forecasts
• Understanding Colorado's complex weather and climate

Description of past grants and projects:

• Multiscale examination of warm-season precipitation extremes (sponsored by NSF)
• Explicit forecasts of recurrence intervals for rainfall: Evaluation and implementation using convection-allowing models (sponsored by NOAA)
• Global investigation of atmospheric processes associated with extreme rainfall (sponsored by NASA)
• Big Weather Web: A Common and Sustainable Big Data Infrastructure in Support of Weather Prediction Research and Education in Universities (sponsored by NSF)
• Measurement and analysis of nocturnal mesoscale convective systems and their stable boundary layer environment during the Plains Elevated Convection at Night (PECAN) field experiment (sponsored by NSF)
• Applying weather analysis and forecasting techniques to understand the transport and deposition of atmospheric nitrogen from eastern Colorado into Rocky Mountain National Park

A full list of publications can be found here.

*This is sometimes called the "First Law of Quantitative Precipitation Forecasting." It is attributed to C. F. Chappell, and examined in depth by Doswell et al. (1996).

This material is based upon work supported by the National Science Foundation under Grant Nos. AGS-1157425, AGS-1359727, ACI-1450089, AGS-1661862, and AGS-1636663. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.