Many Factors Involved When It Comes To Frost

Ed. Note: Congratulations to Charlie Fineran who will be inducted into the Warren County Hall of Fame on Nov. 5. Charlie has been recognized by many groups over the years, most recently as the Warren County Senior of the Year. We are truly lucky to have Charlie here in Warren County!

It is this past Saturday morning about 7:25 a.m. and I am looking at my indoor outside thermometer which is reading 37 F.

I am now looking out the window, to see if there is any frost on my car. I see some dew on the car, but no obvious frost. Going to have to give it the old “touch test”. I have to go out to the car anyway as I left my cell phone in the car last night. Arriving at my car, most of the moisture is just wet, HOWEVER, reaching up on the car roof, FROST!! Get my cell phone and now notice the roof of my house has that classic, white frost look. Get the camera from the car, snap a photo of the house roof. Our first frost! Now I’m thinking, I will have to check my insidewarren.com files. I don’t believe I have any articles on frost or first frosts!

Before we begin, WHAT IS FROST? Encyclopedic entry: Frost is water vapor, or water in gas form, that becomes solid. Frost usually forms on objects like cars, windows and plants that are outside in air that is saturated, or filled, with moisture.

Did a little checking around on the web. I have always found it interesting just how, we sometimes have frost, yet the temperature seems to be above 32 F. Let me check out all the factors involving the formation of frost. This just might be an interesting article! AND at the same time, unfortunately, looks like, I am the bearer of unpleasant news! IT IS GETTING COLDER!

GAME PLAN: I will post the photo of the First Frost of 2022 and I will check my files for some frost photos and also check for mist, dew etc. photos to add a little color. NOTE: All the photos were taken near this time and date!

***Meteorological conditions that can lead to frost conditions: This is pretty interesting, there are a bunch of factors in play when it comes to frost.

CLEAR SKIES lead to radiational cooling, allowing the greatest amount of heat to exit into the atmosphere.

CALM TO LIGHT WINDS prevent stirring of the atmosphere, which allows a thin layer of super-cooled temperatures to develop at the surface. These super-cooled temperatures can be up to 10 degrees cooler than 4-5 feet above the surface, where observations are typically taken. For example, if conditions are favorable, air temperatures could be 36 F, but the air in contact with the surface could be 30 degrees or colder.

COOL TEMPERATURES, with some moisture, that promote ice crystal development. If the super-cooled, freezing temperatures can cool to the dew point (the temperature at which, when cooled to at constant pressure, condensation occurs, moisture will have to come out of the atmosphere as fog, frost, etc.) frost could develop on exposed surfaces.

A study done on frost formation relating temperature to dew point has these guidelines for frost: temperatures from 38 to 42 F can lead to patchy frost, 33 to 37 areas of frost, and 32 and below widespread frost/freeze. NOTE that the study did not factor in other conditions to frost, such as sky cover and wind speeds.

LOCAL TOPOGRAPHY has a large role in determining if and where frost develops. Cold air will settle in valleys since it is heavier than warm air, therefore frost conditions are more prone in these regions. Valleys also shelter the area from stronger winds, enhancing the potential for frost.

Other local effects, such as soil moisture/temperature and stage of vegetation “greenness” are factors that can affect the possibility of frost forming.

Now you’ve got the rest of the frosty story!