PNNL

Abstract

Wildfires are extreme events associated with weather, climate, and environment, and have been increasing globally in frequency, burning season, and burned area. It is of great interest to understand the impacts of wildfires on severe convective storms through releasing heat and aerosols into the atmosphere. In this study, we have developed and evaluated a new model capability by considering the impact of sensible heat fluxes from wildfires on thermodynamics. The pyrocumulonimbus clouds associated with the Texas Mallard Fire on 11-12 May 2018 are well simulated by accounting for both heat and aerosols emitted from the wildfire. Both heat and aerosol effects increase low-level temperatures and mid-level buoyancy, and enhance convective intensity. Intensified convection along with more supercooled liquid condensate at high altitudes due to stronger transport, result in larger hailstones and enhanced lightning. The effects of heat flux on the convective extremes are more significant than those of aerosol emissions.