Breaking down how frost forms
Temperatures are finally starting to fall as Mid-Missouri heads deeper into fall. Multiple cold fronts heading into the second half of this week will lead to winds returning back out of the north cooling overnight lows back towards the mid to lower 30s. This will lead to many parts of Central Missouri seeing the first frost event of Fall 2022.
According to data collected from 1971-2000, average trends typically point towards the first fall frost occurring anywhere from to late October. With Saturday morning only being the eighth day of October, Mid-Missouri will be just a tad earlier than average this year.
What frost is and how it forms?
Frost is ice crystals which form on solid structures once the air temperature or dew-point decrease to the point of freezing or below. There are two main process of frost formation.
Both processes begin the same way. The sun's energy during the day time heats up the surface of the earth.
After the sun sets, overnight temperatures begin to cool while the earths surface continue to emit heat. Eventually, the dew-point and the air temperature cool to the same temperature and condense on solid surfaces. This condensation is known as dew.
As the air temperature continues to fall at or below the freezing mark of 32 degrees, the dew begins to freeze into ice crystals forming a thin layer of frost on surfaces. The second process in the formation of frost is similar with the exception of the formation of dew. As the dew-point falls below 32 degrees, the condensation process is bypassed and the gaseous water vapor changes straight to a solid to form ice crystals in a process known as deposition.
