Frost For Friday?

Looking at the weather report for Friday morning shows a possibility of frost in the morning.  The major factors contributing to frost appear to be lining up for it.  We have only seen spots of frost this year, and expect this may be the first wide-spread frost that results in a delay.

Here is a piece from a paper written by D. R. Cook, "Predicting Frost At Your House", Journal of Meteorology, Vol. 15, no. 153, November 1990.

Frost formation is a complex process, and conditions have to be "right" for it to occur. Frost forms on surfaces directly from the vapor state, without condensing as dew. If dew forms, frost formation is unlikely, even if the temperature drops below freezing.

Frost is more likely to form on surfaces above the ground first, such as house roofs, or automobiles, because the air immediately above the ground is usually a few degrees warmer than air a few feet higher. There is some heat transfer from the ground to the air a few centimeters above it. If there is much wind, frost will not form either. (Neither will dew, as both these occurrences require little or no wind, so the atmosphere will not stay mixed.) If the skies are cloudy, usually dew or frost will not form either, as the clouds reflect the radiated heat from the ground, which helps in keeping the lower layers mixed.

So the ideal conditions for frost formation is a night with clear skies, light winds, and a temperature forecast to be near or a little below freezing. Standard temperature measurements are taken from about 2 meters above ground. On a calm night the ground temperature can be as much as 5-7 degrees cooler than the standard temperature reading. If there is some wind, the air stays mixed, and the temperature difference disappears.

Here is the hourly forecast for tomorrow morning.  It is showing that we will have "a night with clear skies, light winds, and a temperature forecast to be near or a little below freezing."  Tee times tomorrow morning should plan on a delay.


Here are our other posts about frost:


Frost


Frost Delays Start Again