Cold might just be an understatement for most of the viewing area on Thursday.School will still in be session in Green Bay but the district and medical experts say people should still take precaution in the subzero temps. Across the area Thursday will see -20 degrees temps resulting in a cold weather advisory. Schools in Green Bay will still be in session, but parents should still make sure their children are dressed appropriately for the extreme cold, the school district said. Medical experts said frostbite during an advisory can occur on exposed skin in 30 minutes The public is advised to store an extra pair of gloves, a winter hat and a blanket in case of emergency.(The following is a transcription of the full broadcast story)"This is cold, you need to do something," Kurt Kotenberg, National Weather Service warning coordination meteorologist, said.With temperatures reaching the -20 degree threshold, a cold weather advisory has been issued for our areaIn what used to be called a "wind chill advisory", Kotenburg said the name change brings more clarity to the public.A wind chill warning is now changing to extreme cold warning as well."It says it right in the title, extreme cold, so we know what's coming," Kotenberg said. "And cold, we know that this is colder than usual."With school still in session, Lori Blakeslee, Director of Communication at the Green Bay Area Public School District said safety guidelines are in place from the bus stop to the classroom such as no outdoor recess and supplying warm clothing to families in need."The first priority for the school district is to always ensure safety of our students and our faculty," Blakeslee said.Health experts say bundle up and limit outdoor exposure to avoid serious cold-related health risks."When it gets cold you got to take those extra precautions," Kyle McCarty, HSHS St. Vincent Hospital Emergency Medicine Director, said.He said children can be more susceptible to frostbite."Relative to their body size, (children) have a large head, so they're going to lose a lot of heat through their head, so making sure that kids have hats on is extremely important," McCarty said.The National Weather Service says frostbites on exposed skin can occur in 30 minutes."Just wearing a jacket like you would on a normal day, might not be enough," Kotenberg said. "You need the hat, the gloves, the layers."He also recommends drivers to store an extra pair of gloves, a hat and a blanket for yourself or someone else in case of an emergency.The school district said parents can still choose to keep their children home if they feel its unsafe. For those who do so, the district says they should make sure to call the school their child attends so they can be excused from classes.