Chilly nights across the Tennessee Valley

The Weather Authority

We have experienced chilly temperatures across the Tennessee Valley, especially in some of the sheltered valley areas! Low temperatures the past couple of nights have ranged from the upper 30s to the low 40s, this is expected to occur once again Monday night!

The temperatures we have seen are actually below average for this time of year. Typically during this time period, temperatures are in the low 50s; in Huntsville, it is 51°. The low temperatures we have seen are a good 10-15 degrees cooler than average!

As our winds begin to shift, thanks to an eastward progression of the area of high pressure, we will see warmer air being ushered into the region. Temperatures, both high & low, are forecasted to warm through midweek. After one more chilly morning Tuesday, overnight lows are expected to be back to near average for this time of year.

What is Radiational Cooling?

During the daytime, the surface of the earth is heated, based on the amount of sunlight we see. As the sunsets, the heated air rises which cause temperatures at the surface to cool. This is a process known as radiational cooling.

Nights when skies are clear and winds are calm are when radiational cooling is more pronounced. With clear skies and calm winds, the heat the earth absorbs is able to rise into the atmosphere. During cloudy nights the heat is trapped at the surface and with a light breeze the air is able to mix helping to keep the surface warm.

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