Assessing Planetary Boundary Layer Parameterizations During the 17 July 2023 Cherokee, Oklahoma, Heat Burst Event

On 17 July 2023, a heat burst was observed in Cherokee, OK, through surface observations. This event increased the air temperature by seven degrees Celsius, decreased the dew point by 15 degrees Celsius, and increased the windspeed by 15 meters per second within a 45-minute period. A heat burst is when warm, dry air aloft is cooled from evaporation over an inversion. The air parcel then sinks towards the surface and warms up considerably in a short period of time. Additionally, the relative humidity drops, and the event is typically associated with high winds. The sudden dry and warming of the air can create an unexpected risk for wildfires. Furthermore, the high winds caused by the heat burst can cause damage to properties and further increase wildfire risk. The unexpected increase in wildfire risk and wind damage in a short time frame can be predicted by modeling how well mixed the air is at the lower levels. The planetary boundary layer (PBL) is a combination of small- and large-scale eddies that mix the air near the surface which affects the magnitude and depth of an inversion. This research employed the Weather Research and Forecasting (WRF) Advanced Research WRF (ARW) model to simulate the Cherokee, OK, heat burst with various PBL schemes. This was done to identify the effect on the inversion which affects the strength of the heat burst. The PBL scheme simplifies the simulation of eddies close to the surface that mixes the air. This mixing limits how pronounced the inversion is and has an influence on the heat burst.