Friday’s beautiful weather with temperatures in the 50s and the sun shining brightly may seem like a faint memory next week.

Forecasters say bone-chilling cold with a slight chance of snow will rush in Sunday night, and it’s going to stick around for the rest of the week.

“There’s been this large area of high pressure building in the Arctic for some time now, and it’s finally moving down our way,” said Shawn O’Neill, meteorologist with the National Weather Service in Morristown, Tenn.

The National Weather Service predicts the cold weather will be confined to the evening hours this weekend and through the middle of next week.

Though the snow forecast is shaky, there’s little doubt that it’s going to be a cold week, Mr. O’Neill said.

“The first cold front seems to be coming in late Tuesday, and another reinforcing cold front is coming Wednesday,” he said. “There isn’t a really good source of moisture — either from the Gulf or from the Pacific — to really drive a lot of precipitation.”

A 20 percent chance of rain comes Wednesday, with daytime temperatures in the upper 30s to lower 40s. That night, however, it will be cloudy with a 20 percent chance of snow and temperatures dipping into the high teens or low 20s.

Just the thought of snow and a possible day off from school had Amanda Miller and Summer Cagle, both 14, excited. Hamilton County and many other students missed a day of classes earlier in the week when floods turned roads into temporary ponds.

But old-timers who’ve seen many a snow prediction over the years said the girls might be getting excited for nothing.

“I’ve lived here all my life, and I’ve seen enough weather forecasting to know that whatever they say it’s going to do — in the winter, especially — that most likely it’s not going to do that,” said Jim Ashley of Soddy-Daisy, who was walking downtown Friday.

A chance for snow hangs around for Thursday, although it remains just a 20 percent chance. Highs will be in the low 30s and the overnight low will be around 19. On Friday, temperatures will climb closer to the normal high of 30 to 40 degrees.

“I’d be glad to see cold weather, and I like a little bit of snow. I don’t like wimpy winters where it feels more like a cool fall,” Mr. Ashley said.

Even those who have experience with the white stuff say 20 is too cold for the Tennessee Valley.

“I’m used to it, but 20 is still cold,” said Jamie Starr, 20, of Chattanooga, who hails from Michigan. “It’s been so flip-floppy this winter. This has been the weirdest winter season I have ever seen. How can it be 60 degrees one day and then 20 the next week?”

Chappell Craw, 18, of Chattanooga said the constantly changing temperature “is how people get sick. They don’t know what to put on in the morning.”

“That sounds like northern weather, and I don’t do North weather,” he said.

The coming temperatures, while cold, are not record-breakers. For the dates of next week, the record low was set on Jan. 11, 1886, when temperatures dipped to minus 7 degrees, according to the weather service. The record high for that day was set in 1949 when it was a balmy 78 degrees, the service shows.

The average temperature for this week in January is 39 degrees.