Some unusually warm December temperatures are on tap for Philadelphia over the next few days.

But by the weekend, that warmth is likely to turn to rain, sleet, snow and colder-than-average temperatures forecasters say.

The National Weather Service says to expect a high temperature of 54 degrees in Philadelphia today, 5 degrees above normal.

And on Thursday, the mercury is predicted to surge to 64 degrees -- 16 degrees above the average high for the date.

Friday, too, is expected to be warmer than usual, with a forecasted high of 57 degrees.

That end-of-the-week warmth is likely to come with rain. And that precipitation is expected to turn to a mix of rain, sleet and snow Friday night and over the weekend.

The weather service says there's a 30-percent chance of rain Thursday during the day, with a 70-percent chance of rain in the evening and into Friday.

Then, Friday is expected to be rainy, with the potential for a thunderstorm. Overnight into Saturday, the precipitation is likely to become a mix of rain and sleet, the weather service says.

Saturday should by partly sunny but cooler, with an expected high of 45 degrees.

The precipitation may return Sunday, when forecasters are calling for a cold day with a chance of a wintry mix of rain, snow, freezing rain and sleet. The forecast for Sunday shows a high of 40 degrees, 8 degrees below normal.