The forecasted weather is a big shift from the last race’s conditions in Thailand. Cloudy and wet, the Twin Ring Motegi is expected to maintain lower air temperatures with possible showers on Saturday. An increase in humidity from Friday to Saturday may push the cooler air temperatures to their saturation limit quicker than many had previously thought.
Cooler air has a smaller moisture holding capacity. This means that it takes less moisture in the air to result in precipitation when cooler conditions are present. So, possible rain on Saturday depending on the fluctuation in air temp and moisture levels. What else?
Probably one of the most significant influencers, circuit temperature. With clouds present throughout the weekend, limited incoming solar radiation will be able to reach earth’s surface meaning less energy will be absorbed. It is the balance of incoming short wave radiation and outgoing longwave radiation that impacts circuit temperature. So even if the air feels moderate, the lack of radiation reaching the surface due to cloud coverage will result in significantly cooler circuit temperatures. The moisture levels are directly related to convective activity (cloud formation) so we can expect the presence of clouds to vary day to day.
Tire choice will be as crucial as ever. The awareness of one’s riding style to acknowledge the starting grip, the potential grip partway through a race and ability to recognize the most demanding points of contact given the outlying factors will ultimately separate the leaders from the followers.