The Breakdown: Why the Mid-South is facing frost and freezing temperatures this weekend

MEMPHIS, Tenn. (WMC) -Sunshine will be back for the weekend, but don’t let the bright skies fool you. The Mid-South is heading into a much colder stretch, with widespread frost and freezing temperatures possible on both weekend mornings.

Temperatures will fall into the 20s and 30s Friday night into Saturday morning. After a chilly Saturday afternoon, another round of widespread frost and freezing temperatures is possible Saturday night into Sunday morning.

So what’s behind the chilly setup? It starts with a fresh supply of cold air—and gets a boost from clear skies overnight.

First, a cold air mass moves in

Northerly winds are bringing colder Canadian air into the Mid-South Friday. Even with plenty of sunshine, afternoon temperatures are forecast to reach only the lower 50s.

That gives us a colder starting point as the sun goes down. Once daylight fades, the ground loses heat, and temperatures near the surface begin to fall.

Clear skies help temperatures drop

Think of clouds as a nighttime blanket. They can absorb and send some of the outgoing heat back toward the ground, helping slow the cooling process. With clear skies, more heat can escape, allowing the ground and the air near it to cool more efficiently.

Skies are expected to stay clear Friday night and Saturday night. When clear skies are paired with lighter winds, cooling can be especially effective because there’s less mixing between colder air near the ground and the air above it. Wind conditions and cloud cover can still affect exactly how cold individual locations get.

Frost and freeze: What’s the difference?

A freeze occurs when the air temperature reaches 32 degrees or lower. That can damage or kill cold-sensitive plants, depending on how low temperatures fall and how long they stay there.

Frost forms when surfaces cool enough for water vapor to deposit as ice crystals. You can sometimes see frost even when the official air temperature is a few degrees above freezing: Grass, car roofs and other exposed surfaces can cool faster than the air measured by a thermometer several feet above the ground. Low-lying and sheltered spots can also turn colder than surrounding areas.

That means your neighborhood—and even different spots in your yard—may not all look the same in the morning.

How to prepare

Before temperatures drop Friday evening:

• Bring tender potted plants indoors and protect sensitive outdoor vegetation. If covering plants, secure the cover to the ground and remove it after temperatures rise.
• Check exposed outdoor pipes and disconnect garden hoses where appropriate.
• Bring pets inside and check on neighbors who may need help staying warm.
• Allow extra time in the morning to clear frost from your car windows.

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