The National Weather Service issued an updated cold weather advisory at 3:18 a.m. on Tuesday valid from 6 p.m. until Wednesday 9 a.m. for Limestone, Madison, Morgan, Marshall, Jackson, DeKalb and Cullman counties.

The weather service comments, “Very cold wind chills of 2 below to 5 above expected.”

“Frostbite and hypothermia will occur if unprotected skin is exposed to these temperatures,” explains the weather service. “Keep pets indoors as much as possible. Make sure outdoor animals have a warm, dry shelter, food, and unfrozen water. Make frequent checks on older family, friends, and neighbors. Ensure portable heaters are used correctly. Do not use generators or grills inside.”

Understanding cold weather alerts

Cold weather advisory: Be Aware. A cold weather advisory is issued when seasonably cold air temperatures or wind chill values, but not extremely cold values, are expected or occurring. Be sure you and your loved ones dress appropriately and cover exposed skin when venturing outdoors.

Extreme cold warning: Take Action! An extreme cold warning is issued when dangerously cold air temperatures or wind chill values are expected or occurring. If you are in an area with an extreme cold warning, avoid going outside. If you have to go outside, dress in layers, cover exposed skin, and make sure at least one other person knows your whereabouts. Update them when you arrive safely at your destination.

Extreme cold watch: Be Prepared. An extreme cold watch is issued when dangerously cold air temperatures or wind chill values are possible. As with a warning, adjust your plans to avoid being outside during the coldest parts of the day. Make sure your car has at least half a tank of gas, and update your winter survival kit.

Advance Local Weather Alerts is a service provided by United Robots, which uses machine learning to compile the latest data from the National Weather Service.