The National Weather Service is forecasting temperatures below zero and in the single digits this week, starting tonight.Expected temperatures will cause frostbite on exposed skin in as little as 10 minutes, the National Weather Service warns. Hypothermia is another concern.People are encouraged to check on neighbors who are vulnerable to the cold, to ensure their safety.The temperature is expected to drop to about 7 degrees this evening. Tuesday night the area will have a low of minus 7 degrees and wind chill values as low as minus 25, with wind gusts up to 24 mph.Come Wednesday, forecasters are expecting a high temperature of 4 degrees and a low evening temperature of minus 3 degrees.People who must go outside need to dress in layers, cover exposed skin and limit their time outside. Pets should be brought indoors. Motorists should be prepared to cope with the cold in case of a roadside emergency.The arctic cold ends Thursday, with temperatures in the 20s and a 40 percent chance of snow Thursday night. The rest of the week returns to more the familiar temperatures of 30s, 40s and 50s.The cold snap in Missouri is part of winter vortex pushing through about a dozen states. Some parts of the country will feel temperatures not felt for 20 years.Winter weather