NASHVILLE (AP) - Temperatures will gradually warm up over up over the weekend, but meteorologists are warning motorists to be careful of black ice caused as a result of snow melting and then refreezing when the thermometer plunges in the evening.

The latest winter storm dumped up to 14 inches of sleet and snow on parts of Tennessee, with the far northwest corner of the state getting hit the worst. Four people have died as a result of the weather, all from motor-vehicle accidents, the Tennessee Emergency Management Agency said Friday.

"A lot of snow melting could create spots of black ice," said Shawn O'Neill, meteorologist for the National Weather Service in Memphis. "We just urge folks to be cautious." A high-pressure system has caused temperatures to get unseasonably cool, but that will move out in the coming days, he said.

Forecasters say temperatures across the state could get up into the mid-50s by Sunday and warmer weather is ex pected next week - a relief after winter storms have killed dozens and raged through parts of the state within the past three weeks.

Emergency management officials said 30 people died after the first storm hit Feb. 16. Several died in traffic accidents, one was killed by a house fire and 11 died from hypothermia. Gov. Bill Haslam has asked the state Health Department to determine why so many people froze to death. Some of the victims were homeless and died on the streets, but not all. Some people died in their homes after their power went out. At least two of them were elderly people who were found dead outside their homes after falling. Police said they froze to death because the older victims could not get up after falling on the ice and had no one to help them.