Tonight will be the coolest night during the next seven days thanks, to a weak cold front and something called radiational cooling.

What exactly is radiational cooling?

Think of it this way: You know those mornings where you are all toasty in your bed and the air underneath the blankets is warm? Your body heat coming off of your skin (radiating) is trapped by the blanket and stays closer to the bed. Now, imagine not having that blanket.  The heat coming off of your body has no place to go but back out into the room.

OK, so that is a generic way to talk about radiational cooling.

Here is the official definition from Dictionary.com.

Radiational Cooling is: The cooling of the Earth's surface and the air near the surface, occurring chiefly at night. It is caused by the emission of infrared radiation from the Earth's surface and from the tops of clouds and the atmosphere. Because infrared radiation is absorbed by water vapor, cloudless nights usually allow for greater radiational cooling than overcast nights. Radiational cooling occurs in all regions of the Earth and is important in maintaining the Earth's energy balance.

On Thursday night, our temps will drop into the low 60s to the upper 50s inland thanks to no cloud cover and a dry air mass.

So, from our blanket analogy we learn that South Florida won’t have a blanket (covers) of cloud cover tonight to keep the warm air (body heat) close to the surface.  That allows any warm air that we see this afternoon to quickly go back into space and in turn we cool down.