BOLDER, Co. – Computer simulations show how summer thunderstorms will become more frequent, grow larger and stronger, unleashing far more rain this century in a changing climate.
The threat of flooding is a growing risk with a warmer atmosphere.
A large part of why storms will become more intense, is that the atmosphere can hold more water as it gets warmer, thereby generating heavier rain.
A study, by scientists at the National Center for Atmospheric Research (NCAR), shows storms are becoming more intense as the atmosphere is warming. In addition to higher rainfall rates, the new research finds that the volume of rainfall from damaging storms known as mesoscale convective systems (MCSs) will increase by as much as 80 percent across the continent by the end of this century.
MCS storm clusters are more destructive than the typical summer t-storms we experience around Jacksonville. These are miles wide and last for hours, producing flash floods, high winds, and/or hail.
The persistent storms over Houston in the wake of Hurricane Harvey were an example of an unusually powerful and long-lived MCS.
"The combination of more intense rainfall and the spreading of heavy rainfall over larger areas means that we will face a higher flood risk than previously predicted," said NCAR scientist Andreas Prein, the study's lead author. "If a whole catchment area gets hammered by high rain rates, that creates a much more serious situation than a thunderstorm dropping intense rain over parts of the catchment."
The research team drew on extensive computer modeling that realistically simulates MCSs and thunderstorms across North America to examine what will happen if emissions of greenhouse gases continue unabated.