First fall frost expected for some overnight

As you step out the door Friday morning, some of you might have to clean frost off your car for the first time this fall. How does it form and what should you do to prepare?

Every year around October, temperatures continue to drop as we head deeper into fall. Overnight lows start to get closer to freezing and this results in the formation of frost when conditions are right. It forms when temperatures near the surface cool to their dew point temperature, forcing water vapor to condense. The water vapor either skips the liquid phase and turns into a solid, a process we call deposition, or goes from a liquid to solid by slowly freezing with time.

Sometimes the air temperature can be above freezing and frost formation can still take place. This is because the air a few feet above the ground is warmer than right at the surface due to radiational cooling. The overnight low may be in upper 30s, but frost can still form as radiation lowers surface temperatures to freezing. Cars, plants, grass and anything close to the ground all experience this cooling and are common spots for frost formation. But clouds and high winds can prevent the production of frost, which could be the case tonight for parts of the region.

Frost damages and kills outdoor plants, so it’s a good idea to protect them before you head to bed tonight. Bring in any outdoor plants that are in pots to keep them warm inside. But if you can’t do that, there are other options like covering plants with bed sheets, blankets and plastic tarps to trap in heat. Wet soil also helps prevent heat loss, so water your plants before bed.

The first frost is also a great reminder to get your furnace inspections done soon. If your furnace is over 10 years old it is recommended that you get it serviced every year to prevent issues during the winter.

Some spots in the panhandle and central Nebraska have already seen their first frost and might experience a freeze tonight. But most of the eastern Nebraska will see their first frost tomorrow morning, right on time for when the average fall frost takes place. Our first freeze for the eastern half of the state isn’t too far behind and typically is around early to mid-October.

A Freeze Warning is in effect for most of central and western Nebraska, while a Frost Advisory is in effect for eastern parts of the state until early tomorrow morning. For more updates watch Channel 8 tonight at 5, 6 and 10 pm.

Meteorologist Brittany Foster

@BrittFosterKLKN

bfoster@klkntv.com